CON] First Aid Radii of ( Tangents Conversic >ATA CfiEffilGHT DEPOSm 460 346 349 297 Volumes 51g Volume of Excavauon oiae xxiii jLrocauous 286-296 Required Depth of Maeadam on Different Soils Table of Macadam Quantities Square Yards of Pavement per 100' Weights of Cast Iron Pipe Weights of Corrugated Iron Pipe Weights of Vitrified Pipe Steel Bar Reinforcement Metal Mesh Reinforcement Thickness of Concrete Bridge Slabs Material Required per Cti. Td. Concrete 152 543 543 558 559 560 556 555 565 623 General Tables and Formulae 825-956 »/ HANDBOOK FOR HIGHWAY ENGINEERS 4 Vlk QrawOlillBock & 7m PUDLISWERS OF BOOKS F O R^ Coal Age ^ Electric Railway Journal Electrical World ^ Engineering. News-Record American Machinist ^ The Contractor Engineering 8 Mining Journal ^ Power Metallurgical 6 Chemical Engineering Electrical Merchandising lIBj gMPMrM^^^ HANDBOOK FOR HIGHWAY ENGINEERS CONTAINING INFORMATION ORDINARILY USED IN THE DESIGN AND CONSTRUCTION OF RURAL HIGHWAYS Part I. Principles of Design. Part II. Practice of Design and Construction. Part III. Specifications. Part IV. General Tables. Appendix. Traffic Rules and Regulations. BY WILSON G. HARGER, C. E. AND EDMUND A. BONNEY SUPERVISING ENGINEER, N. Y. ^TATE DEPARTMENT OF HIGHWAYS Third Edition Entirely Revised, Enlarged and Reset McGRAW-HILL BOOK COMPANY, Inc. 239 WEST 39TH STREET. NEW YORK LONDON: HILL PUBLISHING CO., Ltd. 6 & 8 BOUVERIE ST., E. C. 1919 '^'^% ^(\\ \ Copyright, 1919, by the McGraw-Hill Book Company, Inc. Copyright, 1912, 1916, by the McGraw-Hill Book Company, Inc. (via- iq lOiq %:' ■a: ©CI.A515659 THB MAPIiBJ PRSSS Y O K K I» A i\ PREFACE TO THIRD EDITION The present revision was undertaken in response to the sugges- tions and requests of many users of the earlier editions. The practical value of the Handbook is increased by the addition of approximately 350 pages of new material covering mountain road location and design, camp equipment, medical notes, notes on pho- tography, the selected soil and gravel treatment of moderate traffic roads, and the more recent developments of hard surfaced types. There is no change in the general scheme of the publication, which is primarily a compact collection of reference data and time saving tables. For the benefit of men not entirely familiar with the road problem, the discussion of principles has been retained, and in some cases where it has been shown that certain arguments in the previ- ous editions have failed to make the impression warranted by their importance, the discussion has been amplified and illustrated by examples of construction and design. We wish particularly to emphatize gradeline design, which is not at present receiving the attention to which it is entitled, and also point out the practically universal lack of adequate maintenance. The costs given in the body of the text are for comparative pur- poses only and are based on labor at from $0,175 to $0.20 per hour and material costs of the period 1912 to 1915. For the improvement of future editions we request your cooper- ation in the correction of typographical errors, and the addition of any omitted data generally useful in road work. Very few highway engineers are satisfied with the road legislation or technical practice of today or believe that it can be applied as it stands to solve the highway problem in this country in the next fifty years, but the data that has been collected from experience serves as a basis for future improvement. There is every reason to be optimistic in regard to road development provided the prob- lem is approached with constructive imagination and encourage- ment is given to departure from methods whose main defense lies in precedent or habit. The work of revision for this edition is entirely that of W. G. Harger. W. G. H. E. A. B. Rochester, N. Y., January, 1919. PREFACE TO SECOND EDITION Since the pubKcation of the first edition of this book four years ago, considerable progress has been made in the practice of road design and construction. To meet this advance, this handbook has been revised by bringing the material on top courses up-to-date, and by adding considerable data on tests, designs, costs, mainte- nance and specifications. Not only has much of the old material been revised, but new material, totahng approximately loo pages, has been added. The criticisms and suggestions of many who have used the book in the field and office have aided the authors in this revision. A more complete and systematic index has been prepared by Mr. Percy Waller. The general arrangement of the book remains untouched. W. G. H. E. A. B. Rochester, N.Y., May, 19 16. PREFACE TO PIRST EDITION The purpose of this book is to collect, in a compact and conven- ient form, information ordinarily required in the field and office practice of road design and construction. The book is designed to meet the requirements of both experienced and inexperienced road men. The material on the relative impor- tance of the different parts of the design, and the possibihties of economy, without impairing the efficiency of the road, are primarily for the inexperienced engineer. The collection of cost data and the tables will be useful to any one engaged in road work. As it is difficult to avoid clerical errors and mistakes in proof- reading in first editions, we shall appreciate the cooperation of read- ers in caUing our attention to any errors. W. G. H. E. A. B. Rochester, N.Y., April, 19 12. TABLE OF CONTENTS Page Preface v Introduction and General Analysis 1-9 General i Engineering design 2-5 Pioneer roads . 3 High type roads 4 Maintenance and renewals 5 Road bonds . 6 General summary 6 Value of engineering advice 8 PART I. PRINCIPLES OF DESIGN Chapter I. Grades and Alignment 10-35 Maximum Grades 10-26 Effect of horse and automobile traffic on design ... 10 Effect of grade on load 11 Effect of length of grade on load 16 Theoretical advantages of different grades 22 Practical selection of maximum grades . 22 Effect of ruling grade on cost 24 Intermediate Grades 26-28 Controlling points 26 Flexibility 26 ^'Rolling Profile^^ 26 Effect of careful design on cost 26 Effect of arbitrary limitations on cost 28 Minimum Grades 28-29 On hard surfaced roads 28 On earth roads 29 Level Grades 28 Adverse Grades 29 Proper and improper use 29 Summary of Grades . .' 29 Alignment 33~35 In well settled districts (ordinary topography) .... 7,^ Sight distance and minimum radius 33 Mountain road conditions . 33 Minimum radius 34 Effect of alignment on grade 34 Effect of alignment on cost 34 Railroad grade crossing eliminations 35 ix X TABLE OF CONTENTS Page Chapter II. Sections 36-73 High Type Roads (Inordinary Topography) 36-62 Conditions that sections must fulfil 36 Premises of design 36-41 Safe slopes for driving 36 Comfortable slope for driving 36 Required slope for surface drainage . 36 Crowns 36 Stable cut and fill slopes 36 and 40 Widths of pavement 36 and 42 Widths of roading between ditches 38 Effect of grading width on cost 39 Effect of pavement width on cost 42 Examples of typical sections •. . . . 43-62 Banked curves 45 Widening at curves 45 and 62 Mountain Road Sections 63-73 Requirements 63 One way crown on unprotected roads 63 Effect of width on cost 6^ Minimum allowable widths 64 Turnouts 65 Typical Sections 66 Side hill balanced section 66 Through cut section 66 Through fill section . 66 Turnpike 66 Wall sections 66 Intercepting ditches 66 Examples of typical sections . 68-73 Chapter III. Drainage 74-127 General Discussion Location of structures 74 Spacing of relief culverts 74 Design 74-77 Size of opening 75 Live and dead loads 76 Width of roadway 77 Type of structures 77 Rates of rainfall 78 Tables of runoff 79-^2 Examples of railroad practice in sizes of opening for small drainage areas 80, 83 Discharge capacity of small culverts 84 Culverts Types. . .^ 83 Size of opening 85 I TABLE OF CONTENTS Xl Page Plugging of culverts by ice and snow 85 Plugging of culverts by silt 85 Side culverts 86 Village culverts 86 Private drive pipes 87 Relative cost 87 Examples of current practice in culvert design . . . 89-97 Small Span Bridges 89 Safe load on foundation soils . 89 and 98 Safe pile loads 98 Scour 98 Rip rap 98 Fords 99 Examples of current practice 100-124 Underdrains Porous tile 125 Open throat 125 Location and outlets 126 Summary of the chapter 127 Chapter IV. Eauth, Sand-clay, and Gravel Roads Limitation of practical satisfactory use 128 Earth Roads 130-131 Rut roads 130 Ordinary turnpike roads 130 Approx. cost 131 Examples of current practice in sections 131 Sand-clay Roads Principle of construction 131 Mixtures 131 Examples of current practice 134 Approx. cost 137 Gravel Roads Requirements of construction 137 Suitable gravels 138 Sizing 138 Loam content 138 Manipulation of gravel 139 Typical specification 139 Typical example of gravel sections 140-142 Approx. cost 143 Miscellaneous Special Cases Alaskan conditions 144 Arid regions 146 xii TABLE OF CONTENTS Page Chapter V. Gravel and Stone Foundation Courses. 147-162 Bearing Power of Surface Soils .......... 147 Concentrated Wheel Loads 148-150 Regulation of loads 148 Reasonable limits of load 148 Ordinary present day loads 149-150 Military ordinance 149 Commercial trucks 150 Farm wagons 150 Thickness of Road Metal Required on Different Soils. 150-152 Diferent Types of Foundation Courses 153-158 Broken stone bottom course 153 Screened gravel bottom course 154 Pit run gravel bottom course 156 Field stone sub-base 154 Gravel sub- base 155 Field stone sub- base bottom course 155 Gravel sub-base bottom course 156 Telford foundation course 157 Distribution of Stone in Foundations 158 Single track roads (8-12' wide) 158 Double track roads (16-22' wide) 158 Special Foundation Designs. ^ 158 Enconomical Foundation Design 161 Conclusion 161 Chapter VI. Macadam Top Courses and Rigid Pavements 163-191 Relative merits of macadam and rigid pavements. . 163 Classification of traffic 164 Traffic census, value of in design 164 Types of Pavement 165-186 Waterbound macadam 165 Treated with calcium chloride , . . . 166 Oil or tar 167 Glutrin 167 Bituminous macadams 169 Penetration method 169 Mixing method 171 Topeka mix 171 Natural rock asphalt . . . . . . ..... . . . 172 Amiesite .- 172 Sheet asphalt 1 73 Brick pavement i73 Stone block pavement 175 Asphalt block pavement 176 Concrete pavements i77 TABLE OF CONTENTS xm Page Small cube surfaces Kleinpflaster • i8i McClintock cube pavement 182 Rocmac 184 Conclusion of Chapter Classification of pavements as safe for high speed traffic 186 Classification of pavements as safe on steep hills . . 186 Recommendation of pavements for different locations 186 Common causes of failure *. 187 Capitalized cost of different pavements under dif- ferent traffic 190 Chapter VII. Maintenance 192-214 Earth roads 192 Sandy clay roads 197 Gravel roads 197 Macadam roads 199 Rigid pavements 203 General organization methods 205 General costs 205 Detail typical costs 212 Chapter VIII. Minor Points 215-228 Right-of-way width 215 Clearing widths . . . 215 Guard-rail 216 Wooden 216 Concrete 216 Steel cable 218 Snow fences 218 Bridge rail 219 Retaining walls 220 Toe walls 222 Curbs 223 Guide and danger signs 224 Rip rap 225 Dykes 225 Cobble gutters 226 Refacing old walls . 226 Storm sewers on hills ; 227 Special drainage ditches . 228 Cattle guards .- 228 Chapter IX. Materials . . ... 229-265 Top course. Macadam stone (tests and properties). . 229-239 Screenings 239 xiv TABLE OF CONTENTS Page Bottom course. Macadam stone 240 Fillers 240 Brick 240 Bituminous Binders 241-253 Concrete Materials 253-265 Cement 252 Sand 253 Stone 254 Gravel 254 Slag 254 .Water 262 PART II Chapter X. Preliminary Investigations 266-322 General Costs 266 High Type Roads in Populous Districts 266-282 Scope of investigation 266 Field methods 267 Sampling materials 269 Estimates of cost . 273 Sample report 274-282 Pioneer Roads in Unsettled Districts. 282-320 Scope of investigation 282 Equipment 282 Field methods 282 Estimates of cost 283 Tabular Compilation of Useful Information in Con- nection with Investigations of this Character . . 285-308 Excavation amounts 285-296 Grades expressed in degrees 297 Right-of-way acreages 297 Unit prices. , 297 Masonry quantities . . . . 299 Rule for computing ft. B.M. in logs 300 Steel in bridges 301 Magnetic declination 300-308 Sample preliminary report 309-320 Reconnaissance Surveys 321-322 Methods 321 Cost 321 Chapter XL The Survey . 323-422 High Type Roads (Improvement of Existing Roads) . . 323-384 Center line ^ 323 Levels and cross sections 325 Drainage 327 Topography ._ 328 Traffic reports 329 Foundation soils . . . 330 TABLE OF CONTENTS XV Page Location and character of materials 331 Right of way 333 Stadia reduction tables 335 Diversion lines 343 Adjustment of instruments 343 Curve tables and formulae 345 Examples of curve problems 376 Pioneer Roads (Nqw LocBitions) 384-422 Cost and organization 384 Equipment 385 Base line 387 7 Levels and cross sections 388 Drainage 392 Topography ^ 392 Materials 394 Survey report 394 Meridian Determination] By polaris 394 By direct solar 402 Stadia work 416 Chapter XII. Photography, Camp Equipment and Notes on Camp Medicine. Photography 423-435 Equipment 424 Time and aperture 425-430 Effect of use of tripod 426 Motion of object 426 Altitude . 427 Latitude .• 427 Season of the year 427 Light and phase 428 Time chart 429 Exposure record 430 Developing 431 Printing 433 Camp Equipment 436-444 List of articles Tableware 436 Cooking utensils 436 Hardware 437 Tents and miscellaneous 438 Sketches of handy equipment 439 Camp Medicine and First Aid for Accidents . . . . . . 455-501 Personal hygiene 445 Clothing 445 Bedding 445 Diet 445 xvi TABLE OF CONTENTS Page Baths 445 Care of mouth and teeth 445 Care of feet 446 Fly and mosquito dopes 447 Insect bites and stings 447 Cures for vermin pests 447 Medical and surgical supplies 449 List of remedies and their use ]452 Common Sickness (Symptoms and Treatment) , . . . 455 Stomach and Bowels Constipation 455 Colic 455 Diarrhea 455 Dysentery . 455 Fevers Typhoid fever 456 Malarial fever 456 Throat and Lungs Sore throat 457 Influenza . -. . 457 Pneumonia 458 Miscellaneous Headache 458 Sunstroke 458 Poison ivy 458 Rheumatism 459 Gonorrhea 460 Nephritis 460 Piles 460 Accidents Minor Accidents Bruises 461 Sprains 461 Foreign matter in eyes, ears, nose or throat . . . 462 Serious Accidents Snake bites 464 Bad cuts 464 Burns and frost bite 471 Wounds. . 472 Drowning and electric shock 476 Poisons 481 Fractures and dislocations 483 Chapter XIIL Office Practice .......... 502-584 For the Improvement of Existing Roads {High Types) . . 503-567 Mapping the Preliminary Survey Scales. 503 TABLE OF CONTENTS xvii Mapping {continued) Page Plotting center line 504 Table of sight distances 504 Plotting topography 505 Bench level computations 505 Cross-section level computations 505 Plotting cross-sections 506 Plotting profile 506 The Design Maximum grades different pavements 507 Shrinkage of earthwork 507 Templets ^ 509 Economical grade line design 509 Vertical curves Formulae 511 Sight distance . 513 Radii for plotting 513 Planimeter work 514 Methods 514 Accuracy . 514 Substitute method 514 Computation of earthwork (tables) SiS'SS? Overhaul 539 Mass diagram 539 Sample final design report 544 Grade crossing elimination data 547 Grade crossing alignment restrictions 549 Right of way computations 549 Summary of economical design 552 Tables of quantities (stone, macadam, oil, sq. yards of pavement, etc.) . ^ . 540-554 Tables of dimensions and sizes (pipe, mesh, steel, etc.) 555-560 Tables of strength of materials (I-beams, concrete slabs, wooden beams and long columns) .... 561-567 {h) Office Practice for Pioneer Road Design General methods (graphic or analytic) 567 Drafting room instructions 568 Drafting room supplies 568 Detail design instructions 569-584 Reasonable speed of design 569 Reasonable cost of design 570 Detail manipulation (organization and methods) . 570 Progress report 578 Sample estimate forms 581 Chapter XIV. Cost Data and Estimates 585-661 Macadam Roads 585-603 Earth excavation 585 Rock excavation 586 \ xviii TABLE OF CONTENTS Page Unloading broken stone 586 Hauling. 588 Loading fence stone 590 Spreading crushed stone 590 Placing boulder stone 591 Ratio of loose to consolidated depths . 591 Amounts of filler and binder 591 Loading filler sand and spreading . 591 Spreading filler and binder. 592 Rolling 592 Crushing 593-599 Cost of ......... 593-599 Proportions of different sizes in output 594-599 Sledging boulders for crusher 597 Dustless screenings 599 Stone fill, bottom course 599 Sub-base, bottom course 600 Applying bituminous binder 600 Kentucky rock asphalt 602 Puddling waterbound roads 602 Pavements (Miscellaneous) McClintock cube surfacing 603 Amiesite 604 Topeka mix 607 Hassam concrete pavement 607 Mixed concrete pavement . 608-621 Asphalt block pavement 610 Concrete Culvert Work 621-625 , Miscellaneous, Guard rail Wooden ; 625 Concrete 626 Cobble gutter 626 Vitrified pipe 626 Organization \ Speed of work 627 Plant and payroll 627-631 Forms for Estimate^ Sample estimate macadam construction ...... 632-640 Unit Prices Minor Items 640 Sample average haul forms of estimate 641 Brick Pavements on Country Roads 647-653 Excavation 647 Concrete base 648 Preparing cushion 649 Laying brick 649 Grouting brick 649 TABLE OF CONTENTS xix Page Expansion joints 649 Edging 648 Unloading brick 650 Hauling brick 650 Form of estimate 651 Sample estimate 651 Maintenance and Repair 653-661 Cold oiling 653 Hot oiling 655 Calcium chloride 655 Recapping 655 Scarifying and reshaping 658 Patrol maintenance 660 Automobile maintenance truck 660 Distribution of maintenance charges (actual cost one year) 661 Chapter XV. Notes on Construction (Inspection) 662-697 Staking out 662 Rough grading 664 Fine grading 666 Sub-base 667 Bottom stone 669 Top courses (macadams) 670 Hassam concrete pavement 672 Mixed concrete pavement 673 Sheet asphalt pavement 677 Brick roads 679 Pipe culverts 683 Concrete culverts ^ 685 PART III ■ Specifications 698-824 Discussion of requirements 698 General Outline of Clauses (U. S. Office of Public Roads) 699-709 Examples of Current Practice (Roads and Pavements) General clauses (U. S. Forest Road Specifications) . 710-717 Materials Portland cement (New York State Specifications). 717 Water for concrete (New York State Specifications) 718 . Concrete sand (New York State Specifications).. . 718 Grout sand (New York State Specifications) ... 719 Cushion sand (New York State Specifications)*".. . 719 Coarse aggregate for concrete (New York State Specifications) 719 Stone and gravel for pavements (New York State Specifications) . 720 XX TABLE OF CONTENTS Page Bituminous materials (New York State Specifi- cations) 721 Brick (New York State Specifications) 730 Stone block (New York State Specifications) . . . 735 Asphalt block (New York State Specifications) . . 787 Wood block (New York State Specifications) . . . 790 Cast iron pipe (New York State Specifications) . 736 Reinforcement (New York State Specifications) . 736 Cast iron (New York State Specifications) .... 736 Wrought iron (New York State Specifications) . . 736 Steel (New York State Specifications) 73 7 Vitrified pipe (New York State Specifications) . . 737 Concrete pipe (U. S. Forest Road Specifications) . . 738 Corrugated pipe (U. S. Forest Road Specifications) 739 Porous tile (N.^ Y. State) . , . . 740 Timber (Washington State Specifications) .... 740 Piles 740 and 804 Construction Methods Pipe culverts (U. S. Forest Road Specifications) . . 737 Log culverts and Bridges (U. S. Forest Road Specifications) 740 Clearing and grubbing (State of Washington Specifications) 742 Excavation (New York State Specifications) . . . 743 Overhaul (New York State Specifications) .... 745 Tiles and underdrains (New York State Specifi- cations) 745 Leaching basins (New York State Specifications) . 746 Catch basins (New York State Specifications) . . 747 Cast-iron pipe culverts (New York State Specifi- cations) 747 Stone fill (New York State Specifications) .... 748 Piles (New York State Specifications) 748 Timber and lumber (New York State Specifications) 748 Riprap (New York State Specifications) 749 Concrete masonry (New York State Specifications) 749 Stone masonry (New York State Specifications) . 752 Stone curbing (New York State Specifications) . . 753 Concrete curbing (New York State Specifications) 754 Concrete edging (New York State Specifications) . 754 Cobble gutters (New York State Specifications) . 754 Concrete gutters (New York State Specifications). 755 Brick gutters (New York State Specifications) . . ,755 Concrete reinforcement (New York State Speci- fications) 755 Guard rail (New York State Specifications) ... 75^ Guide signs (New York State Specifications) ... 757 Sign posts (New York State Specifications) .... 75^ Loose stone (New York State Specifications) ... 75^ TABLE OF CONTENTS xxi Page Sub- base courses (New York State Specifications) . 759 Telford (New York State Specifications) 759 Bottom course (Gravel and macadam) (New York State Specifications) 760 Bottom courses (concrete base) (New York State Specifications) 761 Earth road construction (Iowa Specifications) . . 763 Gravel road construction (Iowa Specifications) . . 766 Chert roads (Alabama Specifications) 771 Gravel roads (Alabama Specifications) 772 Sand clay roads (Alabama Specifications) .... 773 Waterbound Macadam pavement (New York State Specifications) 774 Scarifying and reshaping (New York State Speci- fications) .... 776 Bituminous surface treatments (New York State Specifications) .777 Bituminous macadams (New York State Speci- fications) ... 778 Bitulithic pavement (New York State Specifications) 782 Amiesite pavement (New York State Specifications) 783 Hassam concrete pavement (New York State Specifications) 784 Mixed concrete pavement (New York State Specifications) 785 Glutrin 786 Wood block pavement (New York State Speci- fications) 787 Asphalt block pavement (New York State Speci- fications) 790 Brick pavement (sand cushion) (New York State Specifications) 791 Brick pavement (cement sand cushion) (Dunn Wire Cut Lug Specifications) 794 Stone block pavement (City of Rochester Specifi- cations) 799 Highway Bridge Specifications (State of Iowa) Giving materials and manipulation 800-824 Widths of bridges 807 Standard loadings 805-806 Standard stresses 807-808 Floorings, etc 805, 821 PART IV General Tables and Formulce. Table No. 68. Conversion of units of measure 825 69. Conversion inches to decimals of a foot .... 826 xxii TABLE OF CONTENTS Page 70. Areas and volumes 828 71. Squares, cubes, square roots, cube roots circum- ferences and circular areas i to 520 830 72. Trigonometric functions and formulae 843 73. Table of natural tangents and cotangents . . . 845 Table of natural sines and cosines 857 Table of natural secants and cosecants 868 74. Table of logarithms of numbers 880 75. Table of logarithmic sines, cosines, tangents and cotangents 905 76. Weights of materials 950 77. Strength of materials . 951 78. Flexure formulae of beams 952 79. Centers of gravity 954 80. Moments of inertia 955 Appendix A Traffic Rules and Regulations J Stale of Ohio 957 Traffic Rules and Regulations, State of New York . . . 968 Index 971 HANDBOOK FOR HIGHWAY ENGINEERS INTRODUCTION AND GENERAL ANALYSIS The highway question can not be treated as a local issue, as with limited funds it is often impossible to make improvements that are necessary to pioneer development, or that are suitable for modern long distance traffic. The national importance of the problem is recognized by the steady growth of State and Federal aid, which has already done much to improve engineering control and to increase financial resources. In many localities, however, it is still impossible to obtain enough money for proper design, and for these cases any solution is more or less ,unsatisf actory from an engineering standpoint. Road design ranges from the low type earth roads of sparsely settled districts to the hard surfaced pavements of densely popu- lated sections. For these extreme conditions the issues are clear cut; the first requires the greatest possible mileage with limited funds, and the last the most suitable design regardless of first cost. Intermediate cases are handled by merging the requirements pre- sented by the extremes. A reasonable design for any case depends on the needs and resources of the local community, considered in connection with the importance of the improvement to the general transportation scheme of the country and the aid that will be granted on account of its general importance. High type pavements should never be designed unless the community is able to provide its share of the construction cost by either direct appropriation, or short term, or serial bonds based on the probable life of the pavement, and in addition, to raise by some form of vehicle tax or direct appropriation its part of an annual maintenance and renewal fund of from $500 to $1000 per mile. States similar to New York, with an assessed valuation averaging $240,000 per square mile and a population averaging 210^ per square mile have demonstrated their willingness and ability to raise any amount required for the construction of the most suitable types of road, considering traffic conditions and economy of maintenance, but even these states have not yet made adequate provision for maintenance and renewal . States similar 2 INTRODUCTION AND GENERAL ANALYSIS to Wyoming, with an assessed valuation of $2000 per square mile, and a population of 2 per square mile, can not handle road con- struction in a conclusive way. They must adopt the method of progressive improvement. This represents the pioneer condition where the road question is most vital. Highways are a necessity to their development, and are considered primarily as a means of communication, not as pleasure routes, nor their improvement as a refinement to reduce the cost of transportation to a minimum. The people are willing to provide all the money they can afford, but expect some form of construction which will complete a line of communication to the point desired; a pack trail will do, a wagon trail is better, and an ordinary earth road will generally be accepted without question. The same engineering principles apply to both conditions but the emphasis is different. Where the funds are practically un- limited, the problem is comparatively easy and is strictly technical. Where the funds are limited to inadequate amounts, the solution is more difficult; the engineer must decide where technical require- ments should be retained and where ignored; he must plan the work so that whatever is done will become, if possible, a useful part of any future improvement, but above all a line of communica- tion must be opened. In the design of high type roads the engineer- ing emphasis is placed on safety, ease and economy of travel and maintenance. On pioneer roads the emphasis is placed on the selection of the best natural economic and engineering location and the greatest mileage for the funds. We have therefore arranged the discussion of design practice from standpoints required for each case, and have indicated in the chapters on Grade, Alignment, Sections, etc., the road value of different limiting engineering requirements with their effect on construction cost. ENGINEERING DESIGN Functions of Grades, Alignments, etc. — A well-proportioned design considers the relative value and the object of the different engineering elements of the problem. In this connection we may say that grades, alignment and section are the most permanent and fundamental features of construction. The ruling grade largely controls the loads that can be hauled; section, grade and alignment combined determine the convenience of the road and the economy of earthwork, while alignment and section affect the safety and are also important factors in the appearance of the highway. For these reasons these three points must be ranked as equal and first in importance. The next elements to be considered are drainage, foundation and top course, which keep the section firm and intact under traffic and weather action. Washouts are prevented and the bearing power of the soil is increased by surface and sub-surface drainage; the heavy concentrated wheel loads of vehicles are spread over a safe area of the sub-grade by the foundation course; the top course provides a surface that will withstand the abrasive action of ENGINEERING DESIGN 3 wheels and horses' shoes, that gives a good footing and offers slight rolling resistance. At the present time the problem of the top course is troublesome, on account of the conflicting demands of horse and automobile traffic. There is so much discussion of this one fea- ture that it is easy to give it too much weight and there is a tendency to economize on the more permanent elements of construction in order to get a higher grade top. In the writer's opinion this is a mistake. The different top courses will be discussed in detail, but no definite conclusions can be drawn, as this part of the design is subject to constant change and improvement. The Application of the Order of Importance of the Elements of Design to General Cases Pioneer Roads. — Considering the policy of progressive improve- ment, limited funds should be expended as far as possible for essentials which will eventually become integral parts of the complete and finished design. The engineering requirements are listed below in their order of importance. First. — Selection of the best general route, (a) Best location for the development of the territory. (&) Longest open season, (c) Least rise and fall. {d) Length and cost. Second. — Selection of the most natural engineering location follow- ing the desired general route. (a) Reasonable grades. (b) Exposure. Avoid north exposure and areas of deep snow. (c) Character of excavation. Avoid rock, slides, etc. (d) Drainage problems. Avoid flood areas, stream cross- ings, etc. (e) Avoid artificial restrictions such as section line locations, etc. Third. — Detail requirements of design. (a) Reasonable maximum grade. (b) Economical intermediate grades. (c) Safe and economical alignment. (d) Width of roadway safe for trafiic. {e) Width of roadway convenient for traffic. if) Sufficient culverts and bridges to protect the roadway. ig) Permanent construction of these culverts and bridges. (h) Sufficient width of clearing for sun to reach road. (i) Safety provisions. Protection for traffic at dangerous places. ij) Provision of liberal width of right-of-way considering future widenings and development. 4 INTRODUCTION AND GENERAL ANALYSIS Fourth. — Improvement of the road surface. (a) By selective soil treatment. {h) By gravel, chert, caliche, etc. (c) By hard surfaced pavements. The following typical cases illustrate the usual problems that occur, and indicate their general solutions. Where no road exists and the funds are entirely too small for good construction, a sufficiently cheap design is used to complete the entire length. Under these conditions the only requirement that must be met is the proper selection of general route, although it is probable that for the greater part of the distance the final engineering location can be followed. Considerable work of this kind has been done in New Mexico under the direction of State Engineer James A. French, and the solutions are ingenious. Satis- factory wagon and automobile trails have been constructed under favorable conditions for as low as $5.00 per mile (see page 130), while in difficult locations advantage has been taken of all possible expedients to keep the cost down. Where a poor but usable road exists between the terminal points, or for a portion of the distance, either the uncompleted or worst sections of the route are first considered. Under such circum- stances the funds are generally sufficient to permit a moderately good engineering design, which must provide for the proper final grade and drainage scheme on the improved sections, although the drainage structures may be cheap and temporary and the road- way narrow. Where a fair road has been previously built over the entire route, no improvement should be attempted unless it provides for the best engineering design of grades, alignment, section and permanent drainage structures. Where a first-class natural soil road is in use, the next step in progressive improvement requires either selected soil, gravel or hard surfaced construction of the traveled way. Order of Work Pioneer Road Design. — The methods employed for the field and office work are described in Chapters X, XI and XIII. Engineering of this nature forms the most interesting class of highway work, and is handled in three stages. A preliminary investigation is made to determine the general route, the best engineering location and the approximate cost of construction. It forms the basis for the general scheme of financing and design. It is the most important feature of new road location, and if well done insures the completion of a reasonable program of construction with the funds at hand. It also prevents wasteful expenditure on ill considered or unsuitable location surveys and plans. The detail location survey based on the preliminary conclusions is next made to secure the data for the final ofiice design, which carries out in detail the recommendations of the first report and completes the work preliminary to construction. Relative Order of Importance of Design Detail for Hard Surfaced Roads. — High type pavements in populous districts are necessary MAINTENANCE AND RENEWAL 5 to meet heavy traffic requirements. They reduce the cost of hauling and increase the ease and safety of light and heavy traffic. The parts of the design are more or less important in proportion to their necessity for the fulfillment of these purposes, and may be ranked as follows: 1. OC< Mrfcscj rfvO OO CO -^ vo CS rt lOvO '^ rf lO rj- 0^ o o ro <1) •"• C3 o o d ■s 4-) l« ;3 o 73 o > il ^ o ^^^ a^^ >, b S^ o ^- :^'^«*. C ^^ cfl en O S ^ o ^ o o J ^ CO T^ B ^■2. bc u o b'^J bQ'^ b' ^ 1» Jis M TJ T3 tn aa^'S B w'S S w c3 o - ^ 4-> O o u 4-) a- T3 ^ O ^ :: (u Sq rO w ^^ c^:: - 2 to o FJ M ■^-•S fig's o = 'a . . i o M pqO bO o (In 4-» C/2 o P-. -^ o M (0 M u 01 Q O 3 Q> aj ■N ^ ^ < ^ » +• O O 2 < tC 5iS S tn «s c 1 8 CD X 0) H '£ X 21 o •5 5i m UJ h- E o o z o I <0 < 5 ^U8QJ9J ui :>u©ipBJO TRUCK LOADS 21 OPTIONAL GEARING ON FIVE TON MODEL The first option is our standard gearing and will be supplied on all orders unless otherwise specified. This gearing should be used where the truck is to traverse good hard roads at all times, and where the grades do not ex- ceed 10%. The second option gives great pulling power on the low speeds, and the standard speed of 14 miles per hour on high gear. This gearing should be used only where the truck has to pull through a very short portion of poor road and the great majority of the running is done on direct drive. This option is popular with contractors, etc. The .third option is especially suited for districts where by nature of roads or traffic conditions a high speed is undesirable, or in hilly country where the road surfaces are good. This gearing is standard equipment on the long wheel base model. The fourth option should only be used where the road surfaces are ex- ceedingly^ poor, and the country very hilly. We do not advise using this gearing except in extreme cases. 2 2 GRADES AND ALIGNMENT 4. The Theoretical Advantage of Certain Grades.— From Tables 7, 7A, 7B and the previous discussion we can pick out the grades that theoretically fulfill certain trafiic requirements. I. On hard surfaced roads the same load that can be drawn up a 2/^% grade by reasonable extra exertion of a team, can be hauled on a level with ease. This makes a perfectly balanced design from the standpoint of team hauling. The theoretical load*is six tons. For earth roads 5 % fulfills this same condition with a theoretical team load of 2.4 tons. II. 5% is the maximum grade that fulfills the requirement of safe descent at a trot without brakes. This is of little importance under modern traffic conditions. III. The same load that can be hauled up a 7 % hard surfaced grade can be drawn on a level dirt road in fair condition; a 7 % grade therefore does not reduce the load of a team which must travel over an earth road for part of the distance. The theoretical load is 2.4 tons. IV. The use of short maximum grades of greater rate than the long ruling grades does not reduce the maximum load provided they are proportioned as follows for hard pavements and do not exceed 250 feet to 300 feet in length. Long 5% Short 7% " 6% " 9% 7% " 10% ">% " 12% V. 12% is the practical limit of grade for even unimportant roads on account of safe team descent with heavy loads. As a matter of fact the selection of grade depends more on the requirements of the traffic and the topography of the country than on these theoretical advantages. 5. Ruling Grades in Ordinary use and the Practical Considera- tions Governing their Selection. — Various grades on country roads have been under observation for so many years that it is safer to be guided by present practice which is the result of such observation than to trust too much to a theoretical discussion. The adoption of the ruling grades shown in Table 8 has depended partly on the ease of maintenance as well as trafiic considerations. The maxi- mum grade on which different kinds of top courses can be safely used either on account of foothold for horses or the maintenance of the surface properly comes under a discussion of such courses and will be fully covered in Chapter VI. In regard to the matter of safe team footing, it is possible to select some type of pavement which will satisfy this condition for any grade used but a change in surfacing to meet this require- ment is often omitted on account of expense and more often omitted by careless design. Most of the rigid pavement types give satisfac- tory footing up to 5 % which is the practical limit without special design. Bituminous macadams can, by variations in manipulation, be made suitable for grades up to 8%. Plain macadams give good RULING GRADES 23 footing for any grade but are expensive to maintain over 5%. From the standpoint of footing 5% has a distinct advantage on main roads where rigid types are desirable, and 7% or 8% is a reasonable limit on side roads where some form of macadam or gravel will probably be used. Table 8. — Ruling Grades in Foreign Countries Location Mountainous Districts Hilly Districts Level Districts Prussia Hanover Baden Brunswick Holyrod Road in England . s % 4 % 8 % 6 % 4 % 3H% 6 % 4 % 3%% 2M% s % 3 % Military Highway over the Alps Italian side ... 4}^i% Swiss side 6 % Location National Roads Departmental Roads Subordinate Roads France 3% 4% 6% Ruling Grades in the United States State Main Roads Side Roads Unusual Cases New York Massachusetts Connecticut New Jersey Michigan : . . Missouri Washington Illinois 5% s% 5% 5% 6% S&6% 5% 6% 7&8% 7% 6&7% S% 11% 9% 9% United States National Forest ^oads (Mountainous districts) First Class Roads Long Grades 5 % Short Grades 7 % Second " " " " 7% " " 10% Third " " '' '' 10% '' '' 12% State of Colorado (Main Mountain Roads) 6 % From the standpoint of accommodating ordinary farm team loads 7 % is the logical ruling rate. This is based on a load of 5000 pounds for farm hauling which includes wagon weight. The records of 24 GRADES AND ALIGNMENT produce dealers in the Eastern States show that the ordinary wagon weighs about 1350 pounds and that 3500 pounds is a large net load. This load of 2.4 tons corresponds with the maximum theoretical load for 7% hard surfaced grade. Team loads of six tons would be very unusual which means that the ideal teaming grade of 2 3^ % need not be considered except in level country where it can be obtained without much extra cost. From the standpoint of maintenance the cost of upkeep of ditches, shoulders and earth or gravel- surfacing increases rapidly on grades above 5%. From the standpoint of construction cost 5% to 7% can gen- erally be built without excessive expenditure even in hilly country. Practical considerations therefore indicate that for level country a 2j^% maximum is desirable but does not justify large expendi- tures and that any grade up to 5% will probably be satisfactory; that in hilly or mountainous regions on the main roads, a long ruling 5% grade is the most satisfactory rate and warrants con- siderable expenditure but that 6% or 7% are reasonable if the funds are limited; that short stretches of steep maximum grades are allow- able to reduce cost provided the element of safe footing is provided and the rate is properly proportioned and that on side roads 7% is generally satisfactory. Grades as high as 1 1 % have been constructed on State improved roads in New York and as high as 9% in New Jersey and Illinois but the general opinion of the Departments under which these grades were built is that they would not again use such a high rate except in villages where any material charge in street elevation would damage valuable properties. Outside of corporations it is bad practice to use long grades of greater rate than 7% for if any road is of sufficient importance to warrant engineering plans for the future it is certainly of sufficient importance to warrant a reduction in grade to a reasonable rate. In any case the design should be consistent. Take for example a road between two shipping points. It is first necessary to deter- mine the portion tributary to each terminal and then the practical grades on all the hills on each portion in order to decide what consistent ruling grade can be adopted without excessive cost (see example, page 329). There is no object in reducing a hill from 7% to 5% with a large expenditure if nearer the terminal there is a grade that cannot be reduced below 7%. It should be borne in mind, however, that the nearer you approach the shipping or market point, the more traffic the road will have, and if the hills are naturally flatter the ruling grade should be reduced. The direction of heavy traffic on each hill should be determined and considered. Effect of Ruling Grade on Cost. — Money spent on the reduction of ruling grade is never wasted although it is not good policy to spend large sums to reduce below 5% in hilly country or 2)'^% in level country. The effect on cost of the selection of a 5% in place of a 6% or a 6% in place of a 7% depends largely on the method af construction that must be used. Where locations are COST OF GRADES 25 fixed by well established right-of-ways and permanent structures and the cost of new right-of-way is very high grades are generally reduced by cut and fill. Under these conditions the effect of the selection of rate is very marked and no general relation can be established as each case is a law unto itself. To show the fluc- tuating amounts of excavation per mile for different improvements based on different rates of ruling grade where cut and fill was used, Table 9, page 30, has been compiled. Unfortunately many of the roads in the older states were not laid out on natural engineering locations and grade improvements Pig. I. — Balanced sidehill section. are expensive either on account of excessive cut and fill or the high cost of new right-of-way on a better location. In mountain road or ordinary locations in newly settled districts the question of right-of-way rarely handicaps the design and easy grades are obtained at moderate cost by natural locations which avoid steep adverse grades by going around a hill or develop moderate grades on a long cHmb by a longer distance. In climbing on a sidehill location the road section is generally what is known as a balanced section, that is, the cut just makes the fill by side displacement. The amount of excavation per mile is not affected by the rate of grade but usually the length of road is affected. ^ Elevation 6OOO' A \Elevafion 5000' \< ^Miies.- ^x 'P — Both Lines 6.0 Miles Fig. 2. Generalizing we can say that the effect of grade reduction on cost is not as marked as for cut and fill methods and that roughly the relation of cost to grade depends on the length which is often inversely proportional to the rate; that is, where cut and fill is used a 5% grade might easily cost three or four times as much as a 6% grade but where sidehill location is possible a 5% would rarely cost more than ^ as much as a 6 % . This is of course affected by all sorts of local conditions and may not apply at all but is true by and large and serves to illustrate the relation of rate to 26 GRADES AND ALIGNMENT cost. To illustrate: If the difference in elevation between A and B is looo feet a 6% grade would require approximately ^}i miles of length and a 5% grade 4 miles to make the ascent. If the direct distance between A and B is less than 3 J'^ miles the lengths of the two lines will be approximately as given. If the distance from ^ to ^ is more than 4 miles there would be little difference in the length as it would merely mean that the 5 % started to climb sooner than the 6%. Under most conditions the cost would be more affected by the character of the excavation on the different locations and by the number of switchbacks required for the smaller rate. The difference in cost due to the difference in rate of ruling grade in mountain location does not often warrant the adoption of excessive grades. No criticism of wasteful expenditure on ruling grade can be made in regard to most of the plans as now designed but in many instances the profile feature of intermediate grades is not intelligently handled. Intermediate Grades. — Intermediate grades include all rates between the ruling and minimum grades for the particular job in question. They afford the greatest chance for reasonable economy of earthwork of any part of the grading design and usually receive the least attention. From the standpoint of traffic they have no road value; their proper use however controls the convenience and suitability of the road to abutting property and controlling conditions. In laying a profile grade the controlling points must first be considered; these are high water levels of flood areas, eleva- tions of existing bridges, railroad crossings, all points where deep cuts or high fills would damage the approaches to valuable property; connections with other highways, portions of the road previously improved and in villages the elevation that will permit future widen- ing and curbing that will fit the case. Current practice handles most of these controlling features intelligently with the exception of grades through villages which are-almost without exception too high for future widening and curb finish. Designers are cautioned to use city street methods and to make the elevation the same as if a full width curbed pavement was being designed. Effect of Intermediate Grades on Cost. — All of these controlling points must be satisfied but they usually affect only a small per- centage of the length of any improvement and on the greater portion of the road the most economical elevation and any intermediate rate of grade can be used. A grade so established that the cut in every cross-section would just make the fill at that point would result in the least possible excavation and the cheapest kind of grading methods. This condition can never be realized but the nearer it is approximated the nearer we get to the most economical grading design. Where intermediate grades are applicable there is no restriction on any combination of rates as they have no effect on traffic loads and by an intelligent selection the ideal solution can be closely approximated. The cheapest and most satisfactory profile can be obtained by the use of the ^'rolling grade;'' by this is meant a profile made up of a combination of simple, compound, ROLLING GRADES 27 or reverse vertical curves, connected by tangent grades only when the tangent grade is the most economical or is necessary to prevent a series of short humps and hollows. Long straight grades are not required a mistake easil}^ made by engineers trained in railroad work. Short grades are not objectionable and reverse vertical curves ride easily if well built. The rolling grade is also more pleasing in appearance than a straight profile if not carried to extremes. It appears that there is too much tendency to cut the top of each knoll and fill each hollow for it is certainly a waste of money to reduce a natural 4% grade to a 3.5% or a 3.5% natural grade to a 3 % if the ruling grade is 5 % . We can not overestimate the importance of this principle as the plans of about 2000 miles of road constructed in the last ten years which the writer has looked over in this connection show a needless expenditure of at least a million dollars for grading which had no ^'Undulating Grade f Proper Use Saves Excavaf/on and is *^ at tiie Same Time an easy Riding Profile. E3 ^. hump of this Kind must be Disregarded 5t "aig hr C '^rade Pi vper Us\ 25 *€0 26 +55 27 2& 29 30 Illustrating Proper Use of Straight and Undulating Grades. FiG. 3. practical value whatever. This element of poor design in current practice is probably due to the fact that the savings are not spec- tacular at any one place but if the principle is consistently used the total result is spectacular. It is also undoubtedly true that the previous railroad training of most road engineers and college instructors has had a detrimental effect on intermediate profile design. The author has personally applied the "rolling grade" principle on construction work for the last seven years and found that the saving averaged about $500 per mile. An intelligent grade line design will also often change the method of grading as well as reduce the yardage. To illustrate we will cite the Heber Fruitland Road in Utah. The original design used long straight railroad grades which required wagon haul; the redesign used a rolling grade which not only reduced the amount of excavation by about 30% but also practically eliminated wagon haul for most of the work and made it possible to handle 28 GRADES AND ALIGNMENT the dirt with slip scrapers and road machine blade scrapers. This reduced the cost per cubic yard about 25%. The quantity re- duction plus the unit cost reductions amounted to approximately 50%. The Effect of Arbitrary Profile Limitations on Cost. — A common grade line limitation calls for tangent grades drawn to intersection with simple vertical curves easing off the apex and insists on 100' of tangent grade between the ends of these vertical curves. This sounds scientific but has no practical value and is cited to illustrate the danger of ill considered limitations. A specification of this kind often increases the grading by from 500 to 1000 cu. yd. per mile an example of which is given below. PITTSFORD— N. HENRIETTA ROAD IN NEW YORK STATE Length 2.67 Miles Original Design Revised Design Maximum Grade 5 %. Maximum Grade 5 %. Profile. — Straight grades with Profile. — Rolling grade. 100' of tangent between vertical curves. Original amount excavation Revised amount 9300 cu. yd 11,450 cu. yd. (A saving of 800 yd. per mile.) I In conclusion we may say that the matter of intermediate grades needs more care than it is at present receiving. MINIMUM GRADES Hard Surfaced Pavements. — Most road books claim that level grades should not be used because of the liability of water standing in ruts and that a certain minimum grade should be adopted that will insure their longitudinal drainage. Baker states in his '' Roads and Pavements'' that for macadam roads English engineers use a minimum grade of 1.5%, French engineers 0.8% and that Ameri- can practice favors 0.5%, Let us see what this means. For a 1.5% grade the fall would be }i inch per foot For a 0.8% grade the fall would be J^f inch per foot For a 0.5% grade the fall would be He inch per foot The flattest crown that is ordinarily used even on bituminous macadam is %'' per foot or twice as much as the greatest longitudi- nal fall in the above list. For long ruts the longitudinal grade is of course effective but the patrol system of maintenance is supposed to prevent their formation and for short small depressions the crown slope must furnish the drainage. There seems to be no reason ADVERSE GRADES 29 why level grades should not be used on hard surfaced roads; on such stretches the crown can be increased slightly to insure trans- verse drainage and the ditches given a minimum longitudinal fall of 0.2' to 0.5' per 100 ft. depending on the soil to insure the longitudinal drainage of the surface water. Earth Roads. — On earth or gravel roads attention should be given to minimum grades as for these types they have some value but not enough to warrant much expenditure. It is advisable to use a 0.4% to 0.5% grade where much snow or rain occurs but in the arid regions no minimum restriction should be specified. ADVERSE GRADES Adverse grades are defined as grades contrary to the general rise and fall of the road betw^een terminals or controlling points. It is important to avoid them on mountain road locations where the prime object is to gain elevation. They are not a drawback in ordinary rolling topography. This is so self-evident that it hardly seems necessary to state it. There is no serious objection to short adverse grades even on a long climb if by their use the alignment can be bettered and excavation saved in crossing a small gully; the main objection is to long adverse grades introducing consider- able additional rise and fall which could be avoided by a better engineering location. This point is generally considered in the selection of the general route and is covered by the comparison of routes in the preliminary investigation. Grades, Summary. — The discussion of grades may be summa- rized as follows: The road value of ruling grades can not be overestimated. Any expenditure on this feature is justified so long as it is consistent. The use of properly proportioned short maximum grades in con- nection with long ruling grades is the greatest source of justifiable economy. Minimum center line grades have no road value on hard surfaced roads and only a slight value on earth .roads. Minimum ditch grades are important. The traffic value of intermediate grades is negligible but their importance in economical design is large. The greatest faults of present practice are the needless reduction of light natural grades and the use of long straight railroad rates. Steep grades must be modified for sharp alignment which is discussed in the following text. so GRADES AND ALIGNMENT Table 9 Part i. — Compiled from the 1908 and 1909 Reports of the New Jersey Highway Commission. Name of Road May's Landing Rivervale Westwood Franklin Turnpike. . . Summit Lamberton Westfield . .r Blue Anchor Malaga Whitehouse , English Creek Paterson Plank Road Yesler Way , Camden Evesham , Schellenger's Landing Goshen , Tuckahoe Hopewell Length Maximum Max. in Original Improved Miles Grade Grade 14.0 7-o% 8.5% 3.2% 5.0 5.0% 1.2 4.5% 1.6 8.0% 2.8% 1.9 13-0% 6.5% 3-9 2.8% 2.8% 3-1 4-5% 2.9% 2.3 ^•5% 2.0% S-7 4.2% 2.0% 6.5 12.5% 5.0% 6.7 6.0% 3.9% 2.3 Level Level 2.7 12.0% 6.5% 2.4 6.7% 4.0% 2.4 6.4% 3.7% 2.1 3.4% 1-1% 2.6 3-4% 1.4% 4.3 4.1% 1.6% 2.0 7.6% S.0% Excavation in cu. yds. per Mile 2,220 4,680 2,500 8,200 S,2oo 540 6,500 3,200 1,700 4,100 2,000 (Emb.) 50,000 5,700 5,200 3,500 5,000 4,500 8,100 3,800 Table 9 Part 2. — Compiled from the Records of the New York State Highway Commission. Plans for 1911 Name of Road Character of Country Maximum Improved Grade Width of Section between Ditches Exc. in cu. yds. per mi. Pittsford — North Henrietta' Indian Falls — Corfu Rolling Flat Hilly Hilly Hilly Hilly Hilly Rolling Hilly Rolling 50% F'at 50% Hilly Rolling Hilly Flat 5.0% 2.6% l-ol lol 8.0% til 1.5% 5.0% 10.0% 6.0% 24; 24' 32' 11' 26' 28' 32 & 2^8132' 22-30' 32' 2500 2800 3600 5500 4500 6600 3400 5700 3400 3350 2800 2950 2320 Pembroke — East Pembroke Livonia — Ontario County Line Livonia — Lakeville Avon — Lima Sea Breeze — Nine Mile Point Bliss — Smith's Comers Wales Center — Wales Scottsville — Mumford Ridge — Rochester — Sea Breeze . . Medina — Alabama Pavilion — Batavia Parma Corners — Spencerport — North Chili EXCAVATION 31 Table 9. Continued Compiled from the Records~of the New York State Highway Commission. Plans for 19 10 Name of Road Character of Country Maximum Improved Grade Width of Section between Ditches Exc. in Cu.Yds. per mi. Lake Part 2 & Sweden 4th Sect. Warsaw — Pavilion . . Flat Rolling Flat Rolling 60% Flat ) 40% Hilly j Rolling Flat Rolling Hilly a Flat (( Hilly Rolling 3.8% 2.6% 5.0% 2.2% ) 7.0% ) 3.1% One hifl [ 5.0% J 4-4% 5.0% 4.1% 3.6% 0.7% 7.0% 3.7% 5.0% 32' 28'-32' 32' 28'-32' 32-40' 28'-32' 32' 32' 3o'-32' 28'-32' 24' 30 28'-32' 28'-32' 32' 32 2560 3900 2300 4000 1950 3150 3230 2800 2300 4000 6200 2820 2120 6100 3440 3800 East Henrietta — Rochester Olean — Hinsdale Leroy — Caledonia^ (i.S miles) . . Shawnee — Cambria . . . Roberts Road Sanborn — Pekin Oak Orchard, Part 2 Levant — Poland Center Dansville — Mt. Morris, II Castile Center — Perry Center . . Lake Shore — Lackawanna City Eiehteen Mile Creek Albion Street — Holley Pembroke — East Pembroke . . . Table 9. Continued Compiled from the Records of the New York State Highway Commission. Plans for 1908 and 19Q9 (Selected Roads) Name of Road Hamburg — Springville Sect. I u II Collins — Mortons Corners . . . Clarence Center . , .^ Orchard Park — Griffin's Mills County Line Geneseo — Avon Geneseo — Mt. Morris Alden — Town Line Pittsford — Mendon Pittsford — Despatch Clover Street Section I " II Rich's Dugway Left Fork — German Church . Goodrich Road Hamburg — North Collins . . . Lawton — Gowanda Chili Brooks Avenue Lyell Avenue Barnard's Crossing Character of Country Rolling Hilly (( Flat HiUy Flat Hilly Flat Hilly Rolling Hilly Rolling \ 60% Flat 1 40% Rolling HiUy (( Rolling Flat Max. Improved Grade 6.0% 7.0% 7.0% 2.5% 8.0% 5.0% 5.3% 6.0% 6.0% 6.0% S.o% 8.0% 4.5% 7.2% 6.2% S.o% ) 6.0% } 9.0% 7.5% 5.0% 4.6% 2.2% 4.4% Width of Section between Ditches 30' 30' 32' 28' 28' 28'-32' ^K 32' 22'-28' 32; 24 28' 32' 20'-28' 28' 26'-32' 22'-32' 32' 28' 24-30' 2 6 '-30' Exc. in cu. yds. per mi. ig20 3100 2250 2200 2000 2100 2200 3460 i960 3000 3600 2550 3000 5000 2000 3100 4200 5300 2800 2240 2400 2174 32 GRADES AND ALIGNMENT ^1 Table 9. Continued Compiled from the Records of the New York State Highway Commission. Plans from 1898 to 1907. (Selected Roads) Name of Road East Avenue Pittsford Fairport Ridge Road Buffalo Road White's Corners Plank Road Orchard Park Transit, Sections I & II . . . . Hudson Avenue Road West Henrietta , Scottsville, Section I .'....., " II Monroe Avenue Character of Country Max. Improved Grade Rolling 5.0% 5.0% " 5.5% " 3.3% Flat 2.0% " 3.5% " 3.9% " 4.6% Rolling 3-1% Flat 5.5% " 4.0% Rolling 5.0% Flat 4.5% Width of Section between Ditches 22 22' 2o'-22' 26' 22-25' 22' 20' 22' 2 2 '-24' Exc. in cu. yds, per mi. 8160 5840 6580 2150 1700 4600 4200 2100 7100 3400 2000 2100 1850 Table 9 Part 3. — Compiled from the Reports of the Massachusetts State Highway Commission. 1896 Name of Road Length in Miles Maximum Improved Grade Width of Section between Ditches Exc. in cu. yds. per mi. Andover 0.6 I.O \i 0.63 1.0 1.49 0.93 1.2 0.56 1.0 1-93 1.62 1.61 1.05 1.45 0.97 1.91 1.48 1. 16 1.5 2.0 3.36% 6.0 % 5.0 % 2.7 % 2.6 % 4.0 % 2.95% 5-S % 1.25% 4.25% 4.40% 1.7 % 4.0 % 6.0 % 3.8 % 4.0 % 6.0 % 5-0 % ^•° ^^ 4-25% 5.16% S-o % 24 21' 30' 2l' 21' 2l'-24' 21 21' 21' 26' 21' 21' 24' 21' 21' 21' 21' 21' 21' 21' 21' 6000 2607 1920 3200 5300 2300 8930 3000 3350 4300 4700 7S40 1500 3700 5600 3800 1200 4500 9700 1500 1810 3SOO 3800 Brewster . Dalton Gloucester . Granby Great Barrington Hadley Munson Norfolk North Hampton Pittsfield Tisbury Westport Wrentham Walpole Duxbury Fairhaven Fitchburg Gosheni Marion . . Mattapoisett Lee Leicester SIGHT DISTANCE 3$ ALIGNMENT High Type Pavements. — Alignment on this class of improvement is generally pretty well determined by existing rights-of-way. Changes are made for extremely unsafe conditions but otherwise this feature received comparatively little attention and has small affect on cost. Sharp curves on steep grades or at the foot of such grades are not safe; good practice calls for a minimum radius of 300 to 400 feet for these cases. Right angle turns even on level stretches are inconvenient and often dangerous. New York State has adopted a radius of 200 feet as a minimum, wherever possible, acquiring new right-of-way when necessary, and it is very evident that the increased comfort has pleased the traveling public. On comparatively straight stretches the position of the center line should be shifted to keep on the old roadbed as much as possible and yet give a pleasing appearance; this is done to utilize the hard foundation of the present traveled way for the sub-grade of the pro- posed metaling. Sight Distances. — In designing a sidehill road, in rough country, the ahgnment and width of shoulder often depends upon what we may call '*a safe sight distance," this means that the driver of a machine, traveling at ordinary touring speed of 20 to 30 miles per hour, must be able to see far enough ahead to turn out and pass an approaching car without the application of brakes. In attempt- ing to reach a conclusion as to what is a ''safe sight distance '^ we have written to automobile clubs throughout the country and find that, in the main, they agree on from 200 to 300 feet for speeds of 20 to 25 miles per hour. Mr. George C. Diehl, Chairnian of the Good Roads Board, A. A. A. and County Engineer of Erie County, N. Y., gave us the following information for emergency stops and passing without slowing up: ' ' The tests that we have conducted show that a car going at the rate of 20 miles per hour can be stopped at 40 feet and one going at 40 miles per hour can be stopped at 140 feet with the emergency brake. For passing a rig going in an opposite direction this distance would not be necessary." Mr. Diehl's figures are considerably less than the distances given in the other answers. A minimum sight distance of 250 to 300 feet in the practice of Division No. 5, New York State Depart- ment of Highways. In the chapter on "Office Practice,'^ tables are given showing the "sight distance" for different curves in "cuts.'' Mountain Roads. — On mountain roads, alignment is given careful consideration as it has a marked effect on cost and safety. From eastern road standpoints very few of the mountain roads of the west can be considered safe for traffic. Extreme safety is prohibitive in cost and it is out of the question to attempt to fulfil the sight distance requirement cited above. Much can be done by widening sections at sharp curves and the so-called dayhghting of curves shown in Figure No. 4 but a great deal must 34 GRADES AND ALIGNMENT be left to the care of the driver. The main advantage of the method shown in Figure 4 is that even if the driver hugs the wrong side of the road he can see ahead. In alignment design the radii are made as large as possible to fit the mountain side without excessive grading. On steep slopes the grade contour must be followed closely. There is no hesita- tion in using radii as sharp as 80' at the head of gulleys where the driver can see across the curve or a radius of 100' on outside curves where the sight distance depends on the radius. Even these limits are impractical in very rough country where radii of 40' are considered reasonable. All outside curves with a sight distance of less than 100' should be posted with danger signs. .Bench cuf- out orfSidpe .1 k i-Q inc rease S'lqhf D/'s-hafrce. J^^^^^^^^^^^^ One )^ay Crown^, Fig. 4. — **Daylighting" a curve. Effect of Alignment on Grade. — On sharp curves it is desirable for the driver to have first-class control on the score of safety. An extremely sharp curve with a large central angle also reduces the hauling capacity of a six horse team by from 20 to 40%. Con- sidering both safety and team hauling it is therefore desirable to reduce ruling grades on sharp curves. These considerations have no practical value on mountain roads for curves having radii greater than 100' but on sharper curves good practice recog- nizes this principle. Ordinary design uses radii of from 40' to 80' on difficult . switchback turns. For a 40' radius the grade should^^not^^exceed 3% and_for_an_8q' radius 4% is a reasonable maximumr« ^^ Effect of Alignment on Cost.— The arbitrary limitation of mini- mum radius has a large effect on cost. The following example will illustrate this point. These revisions were made by C. H. Chilvers on the Rabbitt Ears Pass Road in Colorado to show the effect of alignment on excavation. ^The office method of plotting a good cheap alignment are de- scribed in detail in Chapter XIII. Conclusion. — Alignment is important and worth careful study on new locations but becomes a minor feature where existing rights-of-way must be utilized. GRADE CROSSINGS 35 Rabbit Ears Road, State of Colorado, Side Hill Section Original Design First Revision Second Revision Length 8.79 miles Width of roadway 16' Maximum grade 8 % Grades flattened on switchback turns Minimum radius 100' First-class alignment throughout Total amount of exc. 91,000 cu. yd. First-class design but needlessly expensive Length 8.81 miles Width 16' Maximum grade 8 % No grade compensation on curves Minimum radius 100' First-class alignment but more curving eliminat- ing many expensive tangents Amount of exc. 65,000 cu. yd. First-class design shows effect of careful intelli- gent alignment engi- neering Length 8.94 miles Width 16' Maximum grade 8.5 % No compensation on curves. Minimum radius 40' Poor crooked alignment carried to extremes Amount of exc. 38,000 cu. yd. Illustrates extreme effect of alignment on cost From an engineering point of view there was no justification for this design for the to- pography in question Note. — On one switchback turn on this road a 100' radius required 5000 cu. yd. exc. and a 40' radius 500 cu. yd. or one-tenth as much. Short radii are justified in isolated cases but their continuous use to save small amounts is poor practice. RAILWAY GRADE CROSSING ELIMINATIONS Grade crossings are being eliminated as rapidly as possible as they are a source of danger. The overhead clearance and width of roadway in subways are given in Chapter XIII. Where a grade crossing is necessary the alignment should be straight and if it is necessary to approach the track on a grade this grade should not exceed 5 % and the portion of the road for at least 50' and prefer- ably 100' on both sides of the tracks should be practically level to permit the perfect control of a rig as it approaches the crossing. Anyone owning an automobile is familiar with the dangerous element of driving where precautions of this kind are not observed. The best examples of current restrictions in regard to grade and alignment at railway crossings are given in Chapter XIII. CHAPTER II SECTIONS The date will be presented by discussion and examples of current practice for both High type roads in ordinary topography and for mountain conditions. High Type Road Sections. (Ordinary conditions) Discussion. — (Development of Standard Section.) Sections may be considered from the standpoints of safety, convenience and economy. For safety a rig should be able to travel on any part of the road from ditch to ditch without overturning; for convenience the width ordinarily used by traffic must have sufficient pitch to drain the surface to the ditches but not enough to give an uncomfortable tilt to a vehicle; for economy the section must be flexible in order to conform to local conditions. Th» first questions are naturally: What is a safe driving slope? What is a comfortable driving slope? What pitch is required to drain different surfaces? What are stable slopes for cut and fill back of the ditch line? What is the commonly used width, and what the maximum width of the traveled way? All of these points except the last two have been pretty well determined, and, while some engineers disagree with current practice the writer believes from his experience and a study of various State sections that the following premises can be safely adopted : That z" to i' or 4 to I isthe maximum safe driving slope. That i" to i' is the maximum agreeable driving slope. That \" to i' is the minimum slope at which an earth shoulder will shed water without too much maintenance. That y^" to i' or y^" to \' is a satisfactory crown for a single track water- bound macadam and that Yi" is a satisfactory crown for a double track waterbound macadam. That W or V^" to i' is a satisfactory crown for waterbound macadam having tar or asphalt flush coats or for bituminous macadams or mineral bitumen, double track roads. That H" or^^i'' to \' is a satisfactory crown for brick, asphalt, concrete or any other rigid type of pavement used on country roads. That stable cut and fill back slopes depend on the material and climate and range from H : i to 4 : i as will be discussed later. The width of roadway carrying the greater portion of the travel and the maximum width when rigs turn out to pass are not so well established; these two points determine the most economical width of hard pavement and the minimum convenient driving width no part of which should have a transverse slope of more than \" to i'. ROAD WIDTHS 37 Probably the most systematic record of these widths can be found in the reports of the Massachusetts Highway Commission during the years 1896 to 1900 and while the data does not exactly apply to present traffic conditions it indicates the general relation between widths of heavy and light use. Table 10 gives the results on a few roads showing the form used and the variation from year to year; the footnote for Table 10 gives a summary of the observa- tions on 160 roads for the years 1896 to 1899 inclusive; this brief was prepared by J. Y. McClintock, County Engineer, Monroe County, New York, and gives a better idea of the conditions than would be conveyed by printing the original table in full. Table 10. Showing Widths OF Traveled Way Maximum Width of Width of Commonly Town or City County Traveled Way Traveled Way :s u H 1896 1897 1898 1899 1896 1 M M 1899 Athol Worcester . 17' 16' 16' 20' 18' io'-i2' 12' 14' 14' Barre Worcester . 15' — 13' 14' 14' — g' 7' 8' Bedford Middlesex . 15' — 12' is' is' — 8' 10' 9' Chicopee Hampden . 20' — 20' 20' 20' — 12' 12' 13' Dalton Berkshire . 15' 20' 20' 21' 16-21' 20' 16' 18' I2'-l8' Fitchburg (W.) Worcester . is' is' 14' 18' 18' 10' 10' 15' 14' Huntington . . Hampshire . ^5! Q, II 11' 12' 7' 8' 9. 8' Lincoln Middlesex . 15 IS' is' is' IS' 10' 9' 10 10' Marshfield ... Plymouth. . 15' 14 12' 11' 12' 8' 9' 7' 7' North Adams Berkshire . is' 10-12' 13' 14' 1 5 '-20' 8'-io' 9' 10' 12' Orange Franklin . . 17' 16' 16' 20' 20' io'-i2' 12' 15' is' Taunton Bristol is' 20' 20' is' 18' lo'-is' 10' 8' 7'-i2' Width of traveled way on 160 roads in Massachusetts, measured during the years 1896, 1897* 1898, and 1899, and printed in the report of the Massachusetts Highway Commission for 1900. The width of stone on these roads is given as 15' wide on 130, 12' wide on 3, and 10' wide on 2. It should be remembered that the stone is put on very much thicker in the middle than at the edges. The maximum width of traveled way as measured was as follows: 9 ft. wide on 2 roads 18 ft. wide on 23 roads 10 " " " 6 " 19 " " " I II " '• " 2 " 20 " " " 10 12 '■ '■ " 28 " 21 " " " 10 13 '■ ■' " 8 " 22 " " " I 14 " •' " 23 •' 24 " " " 2 15 •* " " 30 " 25 " " " 4 16 •• " " 8 " 26 " " " I 17/' " " I " 33 " " " I " The width of commonly traveled way as measured was as follows: 7 ft. wide on 12 roads 14 ft. wide on 8 roads 8 " '♦ " 17 " 15 " " " 13 " 9 " " " 25 " 16 " " " 2 10 " " " 32 " 18 " " " 4 II " '• " 10 " 20 " " " 2 12 " •' " 30 " 22 " " " I 13 " " " 3 " 25 " " " I " Crown has a marked effect on width of heavy travel. A heavy crown such as % to i' or i" to i' tends to concentrate the travel in 38 SECTIONS the center and is a detriment on a heavy travel road. With crowns of y^" or less per foot there is no tendency to concentrate. For single track pavements where the traffic naturally stays in the middle a heavier crown is desirable as being easier to maintain; on double track roads J^" or less should be used for both the convenience of traffic and the distribution of wear. The author has measured a number of the New York State im- proved roads and found that the width of heavy travel checked the Massachusetts results but that the maximum widths were more averaging from i8 to 21 ft.; this probably can be explained by the increase in automobile traffic since 1900 which because of its higher speed requires more room in passing. Briefly stated the widths subjected to hard wear on unimportant roads ranged from 8' to 10'; on well traveled roads 10' to 14' and in unusual cases 14' to 16'. The maximum widths varied from 12' to 14' on side roads to 17' to 18' on the main thoroughfares and as mentioned above have increased to 18' to 21' in the last few years. From this data it seems that the best practice at present requires 11 I k- 10'- 20'--—^ Fig. s. a driving width of about 22' with a variable width of strong metal- ling determined by the traffic requirements and ranging from 10' to 20'. We have now practically developed a standard for the 22' of driving width; the metalling that is to carry the heavy traffic has a specified crown for each variety and from the edge of the metalling to the limits of the 22' the earth shoulder must have a slope of i" to i' or possibly %" to i'. The flexibility of the section depends on the portion outside of this 22'. The function of the extra width is to keep the longitudinal drainage of surface water beyond the portion used for driving. To do this we are limited to a minimum slope of \" to i' to insure transverse drainage and a maximum of 3" to I ' on the score of safety. It is by the good judgment of the designer in using various slopes between these limits and various widths and depths of ditches, combined with the possibilities of different grades that the economies in earthwork are effected and at the same time the design is made appropriate to the local conditions. The author's experience has indicated that an open ditch does not have much effect on ground water; that its part in the design is to drain the surface water, thus preventing seepage into the roadbed with a resulting softening of the surface; and consequently whenever ground water is encountered under drains should be used. Deep ditches are not only useless but dangerous and the best practice calls for the least depth that will handle the surface water. Frequent GRADING WIDTHS 39 culverts are desirable to rid the ditches of excess water. It should be remembered that road ditches are to protect the road and not to furnish farm drainage and that deep farm ditches should be kept away from the road section. The following section is therefore suitable where there is no probability of much surface water; it is the writer's idea of the minimum width section which will be satisfactory, and where it can be adopted will give the most eco- nomical grading design for light cuts and fills. ^f ;::i..J :/. 0^74, Fig. 6. Effect of Grading Width on Cost. — The width of grading from ditch to ditch has a distinct effect on cost but no general relation can be established for the ordinary road improvement where an old road forms the basis for the new grading. Two examples are given to show the value of reasonable reduction in sectional widths. I. INDIAN FALLS— CORFU ROAD IN NEW YORK STATE Original Design Revised Design Length 1.85 miles NO CHANGE IN PROFILE No Change in Ratio of Cut to Fill Width of Macadam 14' Width of Macadam 14' " Section 30' " " Section 24' Depth of Ditch 18" Depth of Ditch 14" Original estimated Revised estimated excavation 7500 cu. yd. excavation 5200 cu. yd. This change is section alone resulted in a saving of 2300 cu. yd. excavation or at the rate of 1240 cu. yd. per mile, or in. money about $600.00 per mile. . 2. PITTSFORD— NORTH HENRIETTA ROAD IN NEW YORK STATE Length 2.67 miles Original Design Revised Design Width of Section 30' Width of Section 24' Depth of Ditch 18" Depth of Ditch i2"-i4" Ratio of cut to fill 1.35% Ratio of cut to fill 1.25% Maximum Grade 5.0% Maximum Grade 5.0% Profile — Designed with straight Profile — Rolling grades and instead of rolling grades and reverse vertical curves used, tangents of 100' between vertical curves. Original estimated excavation Revised estimated excavation 11,450 cu. yd. 6620 cu. yd. 40 SECTIONS A saving of 4820 cu. yd; 1800 cu. yd. per mile, or, in money, approximately $9oo.cx5 per mile. The revised design on this road is a good example of what can be saved by the use of a section that fits the conditions, a rolling grade, and a ratio of cut to fill that we have found from experience to be sufficient. Stable Cut and Fill Slopes Back of Ditch Line. — Economy of design and maintenance is affected by the selection of reasonably stable slopes. For the class of grading usually encountered on roads discussed in this portion of the chapter their ejffect on con- struction cost is not great and they do not generally receive much attention but for Mountain Roads cut and fill slopes are an impor- tant consideration in the design and their effect on cost are worth considering. Table 25, page 285, shows the effect in detail of various cut and fill slopes on yardage of the ordinary sidehill mountain road sections. To illustrate the point we will quote one typical case for say an ordinary double track section (S-14) Table 25. Natural Ground Surface Cross Slope Approximate Yardage per Mile Cut slope i^^ :i Fill iH:i Cut iM:i Fill i>^:i Cut 1:1 Fill i}4:i 5° 10° 15° 20° < 30 1,100 CU. yd. 2,200 " '' 4,000 " '^ 7,900 '' '[ 950 CU. yd. 2.000 " '' 3.600 '' - 7,000 " " 12,100 " '' 900 CU. yd. 1,900 '' " 3.300 " " 6,100 '^ " 10,200 '' '' 19,600 '' '\ Occasional slides can not be avoided, but continual slipping shows poor design and makes both the maintenance costly and travel dangerous. Stable slopes vary for different materials and for the same mate- rial under different climatic conditions. A combination of mois- ture and frost requires the flattest slopes for ordinary soils. On account of the great variety of circumstances affecting the design no hard and fast rules can be laid down but the following table, based on Railroad and Highway practice, indicates the slopes that are generally used. In this table and throughout the text slopes are referred to as iK- ij etc., meaning i}4 horizontal to i vertical. In some of the State Standard illustrations however slopes are shown as i on i}i meaning i vertical on iK horizontal. It is unfortunate that an engineering requirement is expressed by two different methods in such a conflicting order and care must be taken to understand which expression is used. GRADING SLOPES 41 M M M 1. S :i: ::f:' ::s \(M \(N \^ (N Tf M M M M M w a *-• ofe '^-^ (U ^ ^ -ds 4J Ti r. M M M M M M M 1^ M < 5 C0\ rH\ :i^ (N Tt MM M M V5 Si „. M M M M ^ „ M H § :^'" :^ S^ :^"' :^ i^ i^ " Q M n M M M CO M M M ^ S: 4^ 5 ^1 u ■^fe H ^ M M M M M M M M M "^ 1 1 c 3 \» 1 ^_ 1 a «j i i r-(\ :i^ i^ ::^" :^' HI M M CS M M M M c .-H M rf ^ bc d '-3 'oj c c 0) s: j^ ^ c t ot: £ 1 ^ ^ 1! > % (1) « £?5 1 3 J^ e ^ c C PC ^^ • M 1 44 SECTIONS of water is expected. If for any reason it is not practicable to cut into the hill beyond a certain depth and more dirt is needed for fill than is given by the 26' section at this depth the shoulders can be widened, provided the tops of the slopes keep within the right- of-way. It is always best to use as shallow a ditch as possible as it simplifies the construction and maintenance of entrances to the abutting properties. ^1 \^f/ Theoretical Om cle ^ I Cr own ? 'fof ' /%/» , , k- /5'. --H 1 r k - - 22'- -^->l Bituminous macadam. Fig. 8. ^ El. Theoretical Oracle \sCrownf:/!K':l. . I ■ L-lt::::::::::--/^:::::::^vl I _ l<— -- -26'- 28' - ----oJ , ^ Any Width which keeps the Top ofSlopeinjidetheff.ofW,—"-'*^ Fig. 9. Concrete GuardRaif 15 Wooden {<- lo'-ZO Ouard Rail-' |on^/V) " K ZZ'- - H Fig. II. Figure 10 gives a section showing the variations in fill. A slope of i" to i' beyond the 22' width is used on shallow fills. An embankment slope of 4 to i is used for ordinary fills up to 7' depth; beyond a 7' depth it is cheaper to erect and maintain guard rail using a I K to I embankment slope. The cost of guard rail is taken up under Minor Points. The section shown in Figure 1 1 is used for unusually heavy cuts j to keep the excavation as low as possible. If used on a sharp i TYPICAL SECTIONS 45 curve it should be widened, "banked" and "Daylighted" as in- dicated in Figures 12 and 4 to increase safety of traffic. Figure 12 shows a section well suited for sharp curves. The slope of %" to i' is not objectionable for slow traffic on macadam and makes easier riding for rapidly moving vehicles; it also decreases maintenance cost on macadam construction on sharp curves. The macadam should be widened on the inside of the curve as shown in Fig. 12. — Banked section in excavation. Figure 12 A. The superelevation on the curve is obtained by gradually raising the outside edge; the center line elevation and inner edge remain normal. The full superelevation is carried around the entire length of the curve from PC to PT and reduced to the normal crown at about 150 feet away from the curve ends. Variation in superelevation for curves of different radii is a useless refinement and good practice rarely adopts superelevation for C rown z\fo/ * k- I5'20'^^"--^ I Fig. 13. ™-~>j radii greater than 800'. The maximum superelevation is generally used for all curves of 500' radii or less and is considered to be limited to i" per i' for macadams and %" per foot for rigid pavements. The author prefers %!' to i' and J-^" to 1' for these types. Figure 13 is a satisfactory village section and by the use of a variable width will fit conditions on most streets. ~^ The preceding discussion attempts to cover only the main points for every road presents local conditions peculiar to itself that re- 46 SECTIONS quire special solutions. However, if the Engineer keeps these points in mind he will make an economical and appropriate design. ^ ^evafjonjheoretical Oracle ^' ^ .-•'■.x^ onr J^ ^ ., -8.0'- .,, 1*^- -16.0'- --4: 1 Fig. 14. — Bituminous macadam tracks on side. «:. Expansion Joint \ ' '^"''''"3 '-^J""^ '^J '.Ifol-Cro^nA'Brick I J'^ USand Cushon^ Concref^^ ff 5-Z"-^CIaiiCont.Baie .SXomreteunderSramundTie Pjt-Bdp. "^''\, I9-0-- t ,9'0'- ^^^^ Village street, brick pavement. Tracks in center, "T"-rail special grooved brick. ^WfchlngPost ^^^^^^^ \ Sidewalk .-Plain Curb ( ,, - 1^ ji/ j'v ' s :^' ^^ ^-^--io'o"- r^'"%% \h Fig. 15. — Village section. Combined brick and macadam section in front of stores, where horses will be hitched close to the curb. Prevents pawing up the macadam. PLATES The following plates show current practice in standard hard surfaced road sections and serve to strengthen the points brought out in the discussion although they may not comply with all the desirable requirements. Plate i. — New York. Plate 2. — California. Plate 3. — Massachusetts. Plate 4. — Maine. Plate 5. — Wyoming. Plate 6. — Washington. Plate 7. — New Jersey. Plate 8. — W. Virginia. Plate 9. — Iowa. Plate 10. — Pennsylvania. TYPICAL SECTIONS 47 Plate i. — New York State 19 15 Standards. Cement Concrete ->V^k- -«^ —ZA'-O" io 32'-6^-^"^" -^^ ^Btv^^^' - \5ub-boftom Course if Required I ^#^ K- -I4''0" 0rl6'-0"- -H ^ Trans verse e xpansionjoinfj, fo b€pro\/fcfecf e very 30 ft, ^hoiN be composed of a creosofedj yeJ/ow p/ne or tar paper strip ^' fhickf conforming to the cross section of roac/wciy' Each strip may be composed of tv^o piecesof equa/len^th, butt Jointed and fastened together with approved sp/ice piece of Na 26 iron. A • Waterbound Macadam * •->1/^- 7» -- 24-0" to 32 '0--- - ->i/i*K- / J I SCS^jil ^IL^l u. — : >*'^/g ^ of Theoreti caf Grade | | ^\^ K^ I 5 ub-bottom Course if Required \ ^j/^j< — ^^ 1 ' ^2y^jiE^£L^Lj^ ^Elevation of TheoreficaCradex \V\» o*J l« I >r>l I ^^^ 'bottom Course if Required \ k ia'-oWis-o" >• c Contracted Section \ks''6"-''^ l<-^r^^ e' •f /e V. of Theoi?et/ca/ Cn^ade ^ ^ -Not less than 14-0 ' ..-H. Bituminous Macadonn •>/^}<-- —7 24'-0'' fo d2''0"' r->j/f{«- .;^.x j I J^^'inJP^ SfL^i^ K-^/gK of_rheoretica l_6£qde_ \_ \ »W '-'j^'^ \Jub -bottom Course if Required \ ^^^ 48 SECTIONS Plate i,— (Continued) . \\ Crown Sp^f'ff^^^ urElev. of Theoretical Grade \ \ \^^' 'Elev. of Theoreti cal Gra o/e V77777777777A 0?> Brick _.-,,., ., '6ra\/el Shoulder) "^^-f Expansion joints, ifof poured type shall be l" thick. For premou/ded type theyshall beYforl6'width,i"foriO'to24'yviclth and 4 for 32'-mdth. Half Section Half Section p. I F-2 Top Course same asA.B orEas Specified--^ 5ub -base as Bottom Course 6 ^77777777? Top Course same as A. B or E as Specific "^^'^'^^^^^m ^^ ^ 'wwm '^'When Xelford replaces Sub -base, it is made 6" thick (bottom course to have the same thickness at tenter and edges yvhere Jub -base or Telford is used) Sub- base or Telford H i' ■Asphalt Brick Sand -.'-Macadam Class Concrete l2">\ HS-8"'>i Asp halt '-^^ M ^2" ' ^;-..-/^-''-...>l ^.^ ^"^c/dss Concrete TYPICAL SECTIONS 49 •; J J9d ,,f XIMOIJ 1 f^ ja ^ ^b "0 M ^S H ^, M ji % »!«) '^i- no jappoqs 10 VO 00 i •;j jad ^J UAV0J3 i H w 's H 5: VO H lo J3 to ^ •4J P4 H ^S %. *1« M to ^ t^ ja % "* 10 »o jappoqs 10 VO -M 00 1 1 •^ J Jdd ,,| UMOJ3 2 M % M % H ^s ja VO 5. lo M ^S H % M 0. j3 ^ % ^ i9ppoqs 10 VO t^ 00 < 1 1 •; J jad ^,f nMoi3 1 ^ ^a M M H lo H J=! *X0 10 ^ ^s H CO 10 M ja ^ ^ ^ ■ ^ »o 10 jappoiis 10 VO t^ 00 la jH .2 ^z 1 2^ c3 •t. c "^ Xi o< rt-r ei ^. . C -« u C CO -^ .£- > ^o22 § W) (3 o «*H ■T3- ^ 73 (1> II II .S ^ y^ p2^^ H J§ H ^ Q ;z; 50 SECTIONS Plate 2. — California Standards. CuflUSfope. I2 ^heefAsphali- or AsphalHc Concrete J M" 3\ I ^''Concrete Base fHI'^-l Type A I2 AsphalHc Concrete. ^%^ ill Pw ! ^. 5" Macadam Ba se. /r/// ^7 K- - ?b- - ->l ' TypeB. ^si" 3^" .'• 6"0il Macadam ^••^■•*;;;:::!:?::;;s::::::r.':::.r"'''""T^^////fv • ^ 1 Slope. TypeC. CutlffShpe-^ 4X0 n Crete Base /-f'BituminixedCu&hion ■]■ ^^i_^. ■.■.... Ail.. /'//^•■/ Slope r "^•^' 1 ternate S< Type D. "^ A „ >.'• \ Surfaced with Local Mater Cutr/SlopeSi^^ -ioL I ^ C^^y-ISIopel%'^^ ^ h -^' ^ X. Type E. '^'vnrnrnmff\jf,\iu u,u Slope ]<...^^.>j^......7.^'^.^.>l<-|. —'' -I' ..." .y^ I. note: I I T/7€ Thickness of Pavement- shown i&the Minimum jitso ordered bijthe y - ///^A wm/ Enginee r it is increased. * JJ P^ ' TYPICAL SECTIONS Plate 3. — Massachusetts Standards. 51 is'o''., ....:, 2i'p ."—■>■ 25'0 — -' Trap : 46 tons per 100 ^^ 91" Local- 41 f » - — - 2j'o: 25' Trap : 38 tons per /OO ft. local- "34- » » u u '2i" -:;/" • /5 0"- " 2/'q": ■ "25'0 -• Trap: 5Stor?s per/00 ft. Local- 50 i 25'0" Trap : 4? ton s per 100 ft. Local: 39 » n „ ' ., {New5toneNo.2) [^ ci'n". -sJ I (New Stone No. T) I 1<- - I5'0"' - ^ (Original Width of Macadam) l^tS'/ Section for Resurfacing Trap ■• 55fonsperlOO ft. \ L.J.—--- .- Local'- 50 *» »» » »* For Village Streets. 52 SECTIONS Plate 3. — {Continued) Note: TheBadsof Guard-Rail Posts Ivbeset one foot from Edge of Embankment for all Widths, 'V- Underdrain Cobble Riled- Large Stone atBottom,5mall otoneandOravelat Top. i^-Halve together over Posts 8'0" ^^r:-8'0"----^ |] ii ii J! Condition No. i. — See note below. .^^^^^'^'''''^—^^^^^^ouTse, No. I stone, 24 tons; screenings for binder 4 tons. Upper course. No. 2 stone, 16 tons. * ^ Local Stone— Lower course. No. i stone, 22 tons; screenings for binder 4 tons. Upper course, No. 2 stone. 14 tons. uci , 4 Condition No. 2. — See note below. Trap Rock— Lower course. No. i stone. 24 tons Upper course No 2 stone, 16 tons; screenings for binder. 7 tons. ^uurse, ino 2 Local Stone— Lower course. No. i stone, 22 tons. Upper course No 2 stone. 14 tons; screenings for binder. 7 tons. course, imo. 2 Total tonnage per 100': Trap, 47; Local, 43. rr..^S'^A'~lu ^"l*^ penetration methods— grouting or the modified Gladwell method--there should be two applications of asphaltic oil, each H gal ner fq-/d- ^TW may be also a third appHcation of ^i gal. per sq. yd.* for surface finish. For surface treatment there should be one application of l^iSi/su'fc^f^^^^^^^^^ ^^ ^^ ^^'' -^^ ^- ^^- >^^- - the ^X i'for 21. "' U... ,.,.. I^'Q Condition No. i. Trap Rock— Lower course. No. i stone, 19 tons; screenings for binder, -x tons. Upper course, No. 2 stone, 17 tons. iJ"iuer, 3 +^H°'^Ht^*°''^~~^^^^\?°''''^^' ^"^^ ^ ^*^^®» ^7 tons; screenings for binder, 3 tons. Upper course. No. 2 stone, 15 tons. Total tonnage per 100': Trap, 39; Local, 35. Condition No. 2. Trap Rock — Lower course. No. i stone. 19 tons, stone, 17 tons; screenings for binder, 6 tons. Local Stone — Lower course, No. i stone, 17 tons, stone, IS tons; screenings for binder, 6 tons. Total tonnage per 100': Trap, 42; Local, 38. Note.— Condition No. i: Bituminous Treatment— Penetration— lower course bound with stone screenings or sand. Condition No. 2: Bituminous Treatment— Surface Spraying— screenings ot sand binder m upper course. Upper course, Upper course, No. No. TYPICAL SECTIONS Plate 4. — Maine Standard Sections. 53 Ledge Slope '^- 1 Ledge Bi+uminous Macadam.. ; ^ y ^^^ m^^^'^'^'^'^^mrr^r^^^^^ <.-k%-2'0'^>^ -^'0- d'dravel Shoulder for 6rades over 6 ^. .-.-/^-^ TTfmfjTmfnfj^^ (pvarcL.Baii' 54 SECTIONS Plate 4. — {Continued) Finished Orade -16' -■ — ><-3'6"-> W^ e"-'' I Concrete 5+andarol Section, Narro w decHon to >^ be used when Ordered | Ledge Narrow Section fo ^ be used when Ordered L^■^^^^^^ ^■'^^':;; r^ii:^^^ i^^^-^IMv^^*;.;: VQAi-^ ^-Z-d^A Rock Sec-Mon Surface:"'^ Extra Rock Cut dravif 5-t-oneV' Drain. Area i6.ae>q.F^-. Outfall Ditch 6ravel V Drain Area 17.05 SqF+. TYPICAL SECTIONS Plate 5. — Wyoming Sections. 5S CL k /2 -— ->K — /^ Section fK Station Asphaltic Gravel to station- Section B Bitulifhic Pavement. Station to Station. CL. Kr~.s fOfc 12 ->k 10 fo 12 U- 8-0"' — y<- S'O"- — -~A r 1 1 \ Rise fo Crown J-l. ' Section C 1<- -/2'0 ^>j -8-0- — -M^ a-'c?"— --— J I k /O' ---; I I RisefoCroYvn l"tL Variable Section F StotiorT Earth (Machine Work) to Station 56 SECTIONS Plate 6. — State of Washington Typical Sections. -.15 — — 12'- — -X //' -i '"iT^/z^Wmw^ Ear+h £>ec+ion k- J5'—. I Min. Prof/ /A Gra^e., ^lope on Macadam 3fol' 12' H /V/>7. ^mnmm "^fiimi^. -14- 15" ©ravel Sec+ion 6rade. (One Course.) /5- _>L z^*^ A-->| Macadam ai- ' C.L is 2"above '■'-^-3- ^1. -I <--5-j9^->t<--3 -^- 7' ->|<- 7' -4<-J-4^5?-> ' Slope 2"' I im^mi^mmmmmmm Top Course 3 "Ed^e ' a/7c/ 3"Cenfer Slope on Macadam ffot' travel Sec+ion (Two Course^ / Macadam erf- CL / is 2"above Profile I Grade. **••• Base 3" Edge and 5"Cenfer TYPICAL SECTIONS Plate 6. — (Continued) 57 Cu.F't of Concrete per I in. ft of Roadwaij 16 'Wide = 3. 3093. < /5' ^^ . jq' /' [<-2 ->|<-^f>j<- 6' >k I I Pavement „ \Jt'-yS- _ .>I 3"x6"WoocfCurb to rzmain in place. 'le Grade' ^^ ^ 1--2- 3 Concrete I /V-of/A i& Fooi- Roadway. Profile drade^ 'inside £dge on Curves witfi Superele vat ion.) 3x6" Wood Curb to remain in place. 32 Profile Grade 1-2 -3 Concrete. Cu.Ft.of Concrete per Lin. Ft of Roadway 13' Wide =d. 865. >L./d:-.£iJ<-^^J<-..., 15 . Foot- Roadway. Profile Orade (Inside Edge on Curves with Superelevation^ -f ->|<-^^->l<-- -- 10' ->1<- IP' ^ \ Pavement l'^'^-C- J '"••'2 1 , • ^ '^^ >"^ ^ i.'i'/3g .>U/^--> hi?' 3x6" Wood Curb to remain Jn place. • IS-' '32 Profile 6mde^^' ' '/^'^« % 1:2:3 Concrete ■: , 20'—- ■ ^smms^^^ Cu. Ft of Concrete per Lin. Ft. of Profile Orade Roadyvaij 20 ' Wide = 11.539. (Inside Fdge on Curves with Superelevation) 20 Foo-i* Roadway. 58 SECTIONS TYPICAL SECTIONS Plate 7. — {Continued) 59 1 All Roads shown here are 20 CfoC. ofOfiches: - ->|5 h g-'^'- >! /' k- Concrete 0''af Sides, fat Cerihr. f/e/ (7f Theoretical 6rade . Typ e I Plain. ->1 1' K- , J OnSteepOrades . ■3 Concrete 6 atSides, 7c f Center. ^ / ' U- ffein forcing Metal. Type 2. Reinfprced. f --?-6-'->l<-- Concrete dht Side^eiatCentpr. ""^ ^ ' f^" Slope I "per Foo /; jT Types Plain. "^^ ' -6' >k-.-3'-><.— ^^> Concre+e 6 qt Sides, ezot^enten ' Slope I" p( Subgrad^ Flat except at Shoulders. Type 4 Plain Slope I" per Foot'' -H/'H- Plate 8. — New Jersey Standard Section. This Sect/on is the Arc of a Circle drawn through ifte hurts a.bic Crown for Waterbound Macadam Vtof! n » dituminous tt i'tot 6o SECTIONS Plate 9. — Iowa Typical Sections. i J ^"BnckSurfbce H? \Y'-"'-io'- — >(<- -e'-'A K- - 4"Concreh Base k -2^ '■ \0^ d"eravel: Half Fill Section Half Cut Section MONOMTHIC BRICK- Type ONE 4" Brick }^"=-.zz^ Surfaced Roadway^Zl^- - ->j l''5and-cemeni Bed ^ .U^ 2' Wearing Sur-foce -'' ->1 2'U-7'-e'-^-----/0^--\->\<'----/0'-j'->k-'6-'^2'k--6-'}i d"6rvvel. 4toncreh' h"7r«">v---:f4--.- ->] tee. 4 onckburtace Half Fill Section. Half Cut Section. BITUMINU5 FILLED BRICK-TYPE TWa .-f^^T Surfaced Roadway 32'-""->\ "'■\d"6n7ye/ [^'eXoncrefeSase ^pp*^^ K Half Fill Section i ^cilf Cut Section ^9" -)\24)^X •>12»<-"-//--H<- V/'-->Jpk ^-^usedbefYfeen ^ TWO COURSE 6RAVEL-TYPE \ Sfaiions36'45 eFt-.Oravel f<- Surfaced Roadwaif 32'- y^/'Sravel ^ Shoulder shown , ^i» k- — Pavinq20— ->\ ^i" /\Sfgi» ,c,\oJ. and A TO he Laiddoyrn^ in Twoy Courses.(alsoType^) ^^^^ p.„ 3^^^,.^^ ^^,^ ^^^ 3^^^.^^ ONE COURSE CONCRETE-TYPE'W (Reinforcing same as -for Two Course) TYPICAL SECTIONS 6 1 Plate io. — State of Pennsylvania Typical Sections. Header l:?:3 Concrete. if fur face Course. HeaderCurbing ^^ /RiseioCrownr:§per/'/ ^^'"^''^'"'-'^ /'^'3 Concrete. _■■ .. - iij ^ ..^i^...: .yj, .,^,rdJ^eM:/ 6^ u 7~e'- J< '7-6" -J t<-^" \%t-y ■5'—4<- F:: _.[ .^. .__^ Header Curbing Bi+uminous Speci-Pica+ion Class ^ Header Curbing ■■■n'f'""" * '■"■I" '• -' •'v . :; . m T i 1 1 i fi I - III ■ i ini'r i ' i n I 11 ^ ^ i fli i i iii.it T i - " ^ ■• ' i ~l rTi i< i l|i>m ■■ *• -5--->|< 1— /6' ->|< — -5-— -> Bi+uminous Specif ica+Ion Class B,djb" .^ ^ f^adius}'^ jn y Radius^ ^^^ ^, ^/'V \ . /FeinforcingMefal } ffise foCrorrnr'l' / <;/n^„'. 1 ^ /■?--3toncref-e \ 5' ^ <„...^..„.>(< — 8- >K 6'—- ->(< ^'-— > Reinforced One Course Cemen+ Concre+e. Radius i' \ .Reinforcing Me fa/ '^'2' Surface Course Mi^ZJIixfure. k- 5'- < '- I'^TSConcr^^ » [Radius ^" ] Q' ^ Q> ... Reinforcing %V/5.y', . plain Two Course Por + Iand Cemenf Concreto ,5" Broken Stone ,r I ^"Macadam <^ Shpeli'l' / Rise fo Crown l"'\"peri' / .S" Telford -8'- ase. -8'--' 5 — -^^y Broken S+one Bas^. Telford Base .2e'- ^ Water Bound Macadam. p'BrokenSfone ^ I .3" Macadam 1 Rise fo Crown iHier/' / 3'.' Telford '■ J 'Pe/^1/' g/._ ^ g'. .yU _5i Broken Sfone Base. Telford Base. ' — - 26'— - >\ Bituminous Macadam" PenetncJ+ion Method . 62 SECTIONS Plate lo. — (Continued) Header Curbing zCemenf Sand 1-4 TAr""? i'ExpcnsionJoinfmfh Sand Bed only. „*T ,'^.7 ., l-?-S Concrete ■ ^f^CrmniH' mfrifiedBlvk M'"""p'"'i^"^- 6-H '<'—5-0'"~'^ — ^H zei-o'-" A ^ HeaderCurbing ^'Cemeni Sand Bed M Mixture •^^^ '•^'^^m''^^^\ j Rise fo Crown jl I \ I CemeniSandBed Mi- Mixfure orl4 "Sand Bed /wood BLocK Stone DlocK. ^i'foS^\Sione I ' ''Block. I V "'i^' Expansion Join is .Raj/mi^ Rail Channel Filler h? Mixture^ Expansion Joints f^^^ f^ Crown ^V'^ \\ , Xihified orWood Blocks. m 4 Cement Sand Bed '' 1-4 Mixture or f Sand Bed ^ 5"^ X- 5"ConcVeteh3--6 >^ '^5' Vitrified Block Gutter rifled Block Bituminous Construction for Single Car Track Roads I "fo i" Expansion Joints Expansion Joihi- f^„,f,Cromf:l /l .Railway Rail ChannerTiTler I:2l1ixturii .-Vitrified or Wood Blocks 5->| K" B'Concrete 5'^ k- I'Cement Sand Bed l'^'-^ !'4 Mixture or ^"Sand Bed Vitrified Block Bituminous Construction for Double Car Track Road& , Concrete Gutter Table Showing Distance beiowCenter , for each !^"Wid+hPointforanyCrown2iD8' Curb. ?" 3" 4" 5" 6" 7' 8" '/sW/dfh l'/3 l%- 2'/4 d'/* 3fi 3'/8 4ii' '^ « '/i ^' 1" ly* I'/i lH' 2"' % V '/e- n,- '/* '/* %- '/e- '/i" Cinfer. 0" 0' 0' 0" Q- Q- 0~ Table Showinq Additional Widths of Surfacing on Curves of Drfterent R( ?dii.Qnd Superelevation per F h Width Note' ! All Proportions for Concrete as shown on Cross-Sections are Subject to such Variations as are Stated in the Specifications. Radius of CtrLine,Ff Additional Width 30 8.0 4-0 70 60 6.0 60 50 100 4.5 180 40 140 40 160 3.5 180 35 200 30 220 30 240 25 260 25 280 25 300 ^0 Kind of Surface Vitrified Block . Rise per Ft of Width. Bifuminous Surface ^ Concrete Surface. Waferbound Macadam ''^'J-Q '/* Note: fin Widening and Superelevation I Curves, carry fhe MeqularOrade I through ontheCenferLineofihe I Roadway, arrdmalte alt Widening I on Inside of Curves MOUNTAIN ROADS 63 Mountain Road Sections. Discussion. — The desirable requirements for mountain road sections are the same as for the roads previously discussed but on steep sidehill work the width of grading used for ordinary topog- raphy would be prohibitive in cost. As most of these roads are natural soil roads the crown is the only element of the section not covered in the previous discussion. For the gravel or stony material usually encountered %" to i' is generally satisfactory. For sand or heavy soils i" to i' is better practice. The old idea that crown should be increased on steep grades has been abandoned for while that expedient undoubtedly helped the drainage it caused more inconvenience to traffic than it was worth. In many cases present practice decreases the crown on steep grades to give better vehicle control. Crowns on mountain roads are also affected by the absence of guard rail or other safety provisions. The ordi- nary symmetrical crown is used where wall or guard rail protects Symme+riCQ.l Crown with Ouard Rail. One Way Crown No Ouard- Raji. Fig. 16. the dangerous outside slope but on many roads so much rail would be needed that it is prohibitive in cost and where it can not be used the road is tipped one way in a continuous slant toward the hill so that if a machine skids it will slide in against the cut slope. This kind of a section is not as comfortable to ride as the ordinary crown but if the surface is at all greasy the element of increased safety outweighs any minor inconvenience of side tilt. The width of section has more effect on cost than any other part of the design. On a new side hill location the relation of width to cost can be roughly established. It will of course vary for different side slopes of the hill and different cut slopes of the excavation but the relation will be approximately as follows, for balanced sections (Table 25, page 285). Assumed 25° sidehill slope i : i slope in cut 1 3^ : I slope in fill (S- 8) 10' width (ditch to outside of shoulder) 4,300 cu. (S-io) 12' " ' " '' 6,100 " (S-14) 16' " ' " •* 10,200 " (S-16) 18' " •• ♦• *♦ '♦ *• 12,800 •• CS-J8) 20' ;♦ :: [[ !• :* *[ is,4oo " yd. per mile. 64 SECTIONS We may say that in general a 20' width requires about sH times as much excavation as a 10' width. The relative cost of different widths is also affected by the amount of rock excavation which is generally much greater for the wider widths. This depends on the depth of soil overlying the rock. This element affects the cost so much that in certain cases it has been found cheaper to build two separate single track roads for short dis- tances rather than one double track highway. Pig. 17. CASE NO. I. All"ln Solid*' Mountain roads are classed roughly as double track or single track, meaning the same as for railroad work, a double line of traffic or a single Hne with turnouts to allow passing. As each foot of extra width is costly it is important to determine the mini- mum width of grading that will serve the purpose for these two classifications. Minimum Width Sidehill Section. — If the roadbed is benched out of solid rock a narrower width will serve as the entire width is SIDE HILL SECTIONS 6S firm and stable. If the section is a balanced section part in cut and part in fill it must be wider as embankments on steep slopes are liable to settle, slide or washout and it is not safe to drive as closely to the edge as in the first case. The amount of the road "in solid" is therefore the prime requisite and " — ft. in solid'' is often used as the specification for contract road jobs where engineering design is not used. Present practice favors a minimum single track, total grading width of lo' in rock or where the outer embankment is sustained by a retaining wall and a total width of 1 2' for the ordinary balanced section in earth. Balanced sections are generally used up to 30° side slopes and beyond that toe walls or retaining walls are necessary for earth sections. For a 30° side slope a total grading width of 12' results in approx. 7' to 8' in solid cut. A double track Quard Rail ff- '^ "—A * 5fa.659*22 ' El. 5344.5 Double Track Road Single Track Road Fig. 18 section requires a minimum total grading width of 14' in rock or wall sections and 16' in balanced earth section which gives approx. 10' in solid. These same limiting widths apply to turnout sections on single track roads. Where guard rail is used i ft. should be added to these widths. TURNOUTS On single track roads turnouts are constructed at sufiiciently frequent intervals so that drivers can see between them and there will be no danger of meeting at impassable spots. This generally requires from 5 to 10 to the mile. The minimum satisfactory length of turnout is about 60 ft. ajid the grade should be as easy as possible at these points. 66 SECTIONS Fill Sections.— -Through fill sections must be constructed wider than sidehill sections as the sides are bound to slough off under weather action and all the elements of wear tend to decrease the width; 14' is considered the minimum width for a single track road and 20' the minimum for a double track. A symmetrical crown is advisable on fills even on curves. Where guard rail is used increase these widths 2'. These sections occur on only a small per cent, of the length of mountain roads. Through Cut Sections. — These sections are rare in occurrence; the minimum width, ditch to ditch, for single track roads can be considered as 12' and for double track 18'. The use of minimum widths for either through cut or fill sections on mountain roads has small effect on cost and for that reason more liberality in their widths is allowable. Turnpike Sections. — Where the natural ground cross slope is less than 5° turnpiking is the usual construction and the difference in cost of a single or double track is so small that it is not worth considering. For this class of section a minimum of 22' between ditches will apply to any road and a width of 24' is generally used. Selection of Section. — Plate No. 11 illustrates typical mountain road sections. The turnpike section is used up to side slopes of 5° for continuous balanced work. The sidehill sections are used above 5° for continuous balanced work. The one way crown is used on all single track sidehill sec- tions where guard rail is lacking. The one way crown is used on unprotected double track roads where the side slope is greater than 15°. The symmetrical crown is used on protected double track roads and on unprotected sections where the side slope is less than 15°. Through cut and fill sections are used where required by the profile. Superelevation is used on curves in cut but rarely on high through hills. The ditch on the upper side of a superelevated through cut section can be omitted if the cut is short. Cut and fill slopes depend on the natural material and climate and were discussed on page 40. There is too much tendency to use steep slopes to save on construction cost although excessively flat slopes are not necessary or advised it being cheaper to take care of minor slides by maintenance. (For eft'ect of cut slopes see Table 25, page 285.) Wall Sections. — These sections are used where the natural hill slope is practically as steep or steeper than the stable embankment slope. Toe or retaining walls are necessary for earth embankments where the natural slopes exceeds approx. 30° and for rock fills where the natural slope exceeds approx. 40°. Wall details are described in Chapters VIII and X. Surcharged breast walls are to be avoided if possible. Intercepting Ditches. — Where considerable water runs down the uphill slope intercepting ditches are used to protect the cut slope and relieve the road ditch of excess water. These ditches discharge INTERCEPTING DITCHES 67 to the nearest cross culvert and are an important part of the design. Infercepfin^ Di+ch Bench Sections. — Bench sections are used in rock ledge work. (See Sections S-io, Plate 11, and Table No. 25, page 294.) Summary of Sections. — The entire problem of sections may be summed up as the determination of the minimum widths of grading and hard surface that will serve traffic and drainage require- ments. As a general rule current practice handles this part of the design well with the exception of ditches which are often needlessly deep and dangerous and generally fail to regulate ground water which is the only excuse for their use. The use of road ditches for farm drainage is poor policy. Any system of special farm drainage should be separated from the road design except in the matter of culvert elevation. 68 SECTIONS Plate ii. — Mountain Roads. Typical Su per- E I evafed Sections on Curves. Never use a Supers Elevaied Sect ion where the Inside of the Curve is on a Dangerous Down ward Si ope. Use Super-ElevaHons onitj on Curves liavinqa Radius Lessfhan BOOH: Use file same Super-Elevation on dOO-Fh Radius Curves as on 100' Radius Curves. Thz Center Line Elevation and Portion of the Section on the Inside of the Curve remains Normal} the Poriion of the Section on the Outside of the Curve is changed as indicated belOY/. C.L. <-- C L. Croy/n An Lf Width > Uniform Slope i- h ' IT ^ C.L. Profile Orade - Typical Super-EI-eva+ion In Fill. <-2^< C.L. AnyYiidth -> 'Standard Depth Typical Super-Eleva+ion In Cut. TURNPIKE SECTIONS Plate ii. — {Continued) 69 %■ Typical Turnpike Section© Designated T-aection. Crown Elevafionl 16" X.4? f2'. ^— j'.->| I \C.LPro-F/)^e Orade Section T-12 Crown|-"tor -<:— 5--><- Crown BlevaHort —16' ■ ;— 5'— »| C.LPro\fileOrac/i Section T-JS Crownxtol' Section T-20 Crown^"to j' No-f-et I Where Side Slopee lie between 5 De^. and 15 Deo use a Combination of 5 and F Sections, usinq ^5 Sections in the Cut Side and ^ F Sections onthe Fill Sider- Note: Use Turnpike Sections on Stapes up to 5Dea. 70 SECTIONS Plate ii. — {Continued) Typical Through fill Seotions ' Designa+ed FSec+ion&. Nofei Fill Slopes I'l Rock Fills. I^'l OrdinarLf Earth, li'l Special Cases. Utilise Wasfe Excavafion bfj Flaften/n^ Slopes in Fills. C.L. of Crown Elevafjon , ^„ -16 » C, Pro-FileOrade- Crown ElevaHon C.L Q-f Crown £L.Profl/e Oracle Section F-24 Crown |i Vol' SIDE HILL SECTIONS Plate ii. — (Continued) 7T Typical Side HillSec+ions /iofe: Designa+ed S Se ct i on s.. IUse these Sections onl^ where Side Slope is greater than l5Deg. On Side Slopes between SDeg. and iSDeq. vse Two-Wau Crown, except in Section S-Yo. Frequent Turn out- Widenin^s must be used with this Section. Section 5-8 is the Mini mum in Rock. Section S-IO is the MinimuminEarfh. C,L. of Crown , Elevation. 'T C.LProtile ! 6rade\ n 2r- n S-IO One-way Crown |.+o-| Seo+ion S-14- One-Way Crown^to l' CLofCroy/n \ Elevation. 'oti leLOrac/e "15" CL of Crown Elevation ^ ' 7" \ One-Way Crown |-tol Section 3~1& „ One-Way Crown^tdl Wherever Short Pad/ us Curves are necessarij around a Spur anditis Impossible to see ahead well, use this Section. 72 SECTIONS Plate ii. — {Continued) Typical Throu9h Cu+ Sec+ion&. Designated C Section©. Note' 'Cu-h Slopes^: I in Rock f Jj'l all Ordinaru Earfh 2' I Dtsm+egrafed Rock. y^- ; / Special Soils ni Boulders ondEarih / . / oneSfeep Side Hills where the Use |.-/ Lar^e Sandstone Slabs ^ ,i .7 Uuldmake unreasonable andEarlh. Long Slope. \^ Elevafion-^^^^^ \\l2' C.LProHle ^ urade\ Section C-IO. Crownl'tol' I5\,4 ^ Section C-IS. Crown ^"toT ■Profile Grade '.6rade Section C-14. Crown |-"tor 4 '.CL.ofCror^s Elevaf/on Section C-I& Crown ^"tol' 4" WALL SECTIONS Plate i i . — (Co7ttinued) n Typical Wall 6ec+ion. Double Track Road. Minimum Wid+h. otion Wi2. I.5'io2.0' ^^; NOTE. ' tfallq^neralludry j rubble masonrij. c ffsubjecffo creek I wash, mor-tar rubble I or concrete. Face baiter 3 4- ro-f-DrLj Rubble '-'\o.5'hW' 'to I'. . ^ Typical Wall Sec+iori. Single Track R.oad. Minimum Wid-^h. Sec-i-iom W-6. Wall Sec+ions. Designated W. Sections. CHAPTER III DRAINAGE (i) General Discussion. (2) Culverts. (3) Small Bridges and Fords. (4) Underdrains. General Discussion. — There are three classes of drainage prob- lems in road work; cross drainage; longitudinal drainage and sub- surface drainage. Cross drainage includes culverts, bridges and in rare cases fords. Longitudinal drainage includes surface ditches, ditch protections and in unusual cases storm sewers on long hills; and sub-surface structures for collecting ground water cover blind and open throat porous drains. This chapter deals with the smaller structures only. For the theory and practice of reinforced concrete, masonry or steel long span bridges the reader is referred to the standard works on those subjects. The conditions for transverse drainage to the ditches were given in Chapter II and minimum ditch grades were referred to on page 29. Ditch protection on steep grades, storm sewers, and the flow of water in ditches will be covered in Chapter VIII. Any complete drainage scheme protects the road from wash and seepage, which requires culverts or bridges at all points where there is a natural cross drainage of accumulated water such as streams, swales, established drainage or irrigation ditches, etc.; at all sags in the road profile and on long grades at frequent intervals to re- lieve the road ditches of excess water and prevent washouts. The spacing between these ditch relief culverts on sidehill locations depends on the grade, soil, ditch lining and width of section. A narrow 10' mountain road requires more relief than a 20' road in the same location as even a small washout will put the narrow road out of commission while a moderately bad ditch scour will not stop traffic in the second case. No set rules on spacing can be given but current practice favors ditch relief culverts on 8% grades at intervals not exceeding 300 feet and on 5% grades not exceeding 500 feet unless cobble gutter or concrete ditch lining is used when the distance can be materially increased. On long cut and fill hills drop inlets into storm sewers are sometimes necessary. Design. — Culvert and Bridge design considers the size of opening required for the maximum flow, the strength necessary to carry traffic or to hold deep fills; the width of roadway and the type of structure most suitable to the requirements of topography, foundations and available funds. If the funds are limited the cheaper types may be used but all necessary structures must be built not only to protect the road but to establish a reasonable 74 WATERWAY 75 drainage scheme which as the country develops is recognized and becomes fixed by usage; it is very diflScult to change surface drain- age in well settled districts without annoying and expensive lawsuits. Size of Opening. — The size of opening is usually determined by noting the size of the old structure or, if none exists, the size of other structures over the same stream and by inquiries of neighbor- ing residents or the road commissioner as to how the existing structure has handled the water in the past. As a general rule the size of opening or span should not be reduced below that of the present structure but in the case of steel bridges that have been sold to town boards by enterprising bridge companies it is often found that the span is needlessly long. The evidence of existing structures is the most reliable basis of design but the conclusions should be checked theoretically and for small drainage areas in villages and all drainage areas affecting new locations in sparsely settled districts either the physical evidence of high water or some maximum run off formula must be used. Run off formulae are based on the rate of rainfall, area of the watershed, topography and soil. The rate of rainfall varies for different geographical locations and the length of the storm. Reliable information for any locality can be obtained from the weather bureau. Short storms develop the greatest intensity and produce the largest runoff for small watersheds. The rates reached jy these storms should be considered in designing ditch relief culverts or cross culverts with small drainage areas. A liberal basis for these cases is the 5 or 10 minute duration rate of Table 13, page 78. Table 14, page 79, illustrates the method. Most culvert design is based on a 24 hour precipitation as illustrated in Table 16, page 82, and applies to watersheds of say 0.5 sq. mi. and up. Streams requiring structures of over 10' span generally produce physical evidence of highwater which can be safely used. Table 15, page 80, gives the size of opening used by the Santa Fe Railroad; Table 17, page 83, gives the size of opening for small culverts used by the New York Central. Table 18, page 83, gives the size of culvert used by the Iowa Highway Commission. These tables serve to illustrate the application of this principle of design. Weather bureau records show maximum 24 hour precipitations of 7.66 inches at Portland, Oregon, 5.12 inches at Los Angeles, California, 2.06 inches at El Paso, Texas, 7.03 inches at Kansas City, Missouri, 9.40 inches at New York City and 8.57 inches at Savannah, Georgia. These rates are rarely used for runoff com- putations as they represent extreme cases of rare occurrence. Good practice uses a 24 hour rate of from 4 to 6 inches. Openings based on these rates where the culvert will handle the water with- out quite running full will take care of unusual cases by the forced discharge due to the formation of a shallow pond on the up stream side of the road. Table No. 19, page 84, gives the normal discharge of small culverts laid at different rates of grade. To illustrate the use of tables 13 to 19 three examples will be given. Suppose water from 2 sq. mi. of flat farming country in the North Atlantic 76 DRAINAGE States is to pass through a culvert having a natural slope of 0.5' to the hundred. Table 16 is figured for a 4'' rainfall in 24 hours which is reasonable for this section. This table shows a runoff of 334 second ft. for flat farm land. For a slope of 0.5 ft. per 100 table 19 shows that a 5' X 5' culvert will carry the water. Suppose we have steep rocky ground of say 200 acres or }i sq. mile in Oklahoma and a culvert slope of 2' per 100. The best data is the Santa Fe table No. 15 which gives an opening of 51 sq. ft. at 10 ft. per second or a run off of 510 second feet. Table 19 shows that a 5' X 4' culvert on a 2% grade will carry this but that the velocity is high and the culvert must have a solid bottom and riprap protection at both ends. Where pipes or solid bottom culverts are used high velocity is not objectionable but where the bridge type is used a sufficiently large opening to keep the velocity down to 10 ft. per second or less is advisable. Suppose a ditch relief culvert drains 2 acres in the cloudburst region and can be laid on a slope of 3 ft. in a hundred. Use last column Table 14 which gives 12 second feet which from Table 19 gives a 16'' pipe. Strength. — Dead loads are readily determined but reasonable live loads are a matter of judgment. Many of the states limit a vehicle load to 1 5 tons on improved roads without special permission but loads in excess of this occur now and then. The old culverts and bridges on our roads are practically without exception too light for modern traffic. Permanent culverts should be designed to carry the dead load plus a 20 ton vehicle load with 25% impact. Standard culverts shown in Plate No. 15, page 92, seem needlessly strong but small concrete culverts are generally backfilled and used during construction before they develop their full strength and practical considerations require the excess material. A design load of a 20 ton vehicle with 30% impact is desirable for small permanent solid floor bridges of 10' to 50' span and this loading is often used for even timber bridges in States similar to Wyoming where oil development, etc., requires the movement of heavy ma- chinery, although usually where timber is used a 10 ton live load with 50% impact is considered good practice and for mountain roads 6 tons will usually be acceptable. For long span solid floor steel or masonry structures a live load of 150 pounds per square foot plus a 20 ton vehicle with 30% impact is first class modern practice. This value is higher than generally used. These loadings are safe for military purposes as the following statement of Major General W. M. Black, Chief of Engineers 191 7 will show. "Our existing ordinance liable to accompany a field army will have its heaviest representative in a 12-inch howitzer weighing about 27,000 lb., 18,600 lb. of which are on the front wheels. The base or distance between the front and rear axles is 18 ft.; width of track 7 ft. 4 in. width of tire 8 inches; width of tire shoes 12 inches. This howitzer is drawn by a 75 H. P. caterpillar tractor weighing 25,000 lb. Comparison with the largest present : day commercial trucks shows that a road or bridge substantial enough for such will suffice for the ordinance load." TYPE OF STRUCTURES 77 Table No. 51, page 561, gives the safe load for steel I-beams. Table No. 52, page 563, gives the safe load for timber beams. Table No. 53, page 564, gives the safe load for concrete slabs. Table No. 53 A, page 565, gives the effect of depth of fill on con- crete slabs. Table No. 54, page 566, gives the safe load for concrete beams. Table No. 55, page 567, gives the safe load for timber columns. Width of Bridges. — Culverts are made long enough to accommo- date the normal road section. There is nothing more unsightly or dangerous than the narrowing of the normal section at a culvert. First-class design widens the section at culvert locations and even with minimum head room uses an out-to-out dimension of not less than 30 feet. This same rule applies to short span permanent bridges up to about 25' span which on high type road improvements should have a clear width of 22' between parapets. Above 25' spans the roadway width depends largely on the location of the structure and probable traffic but for most main roads a 20' clear roadway is satisfactory for permanent structures and a 16' roadway for temporary timber structures. Plates No. 20 to No. 30, page 100 to 124, illustrate current practice. Type of Structure. — For small drainage areas some form of pipe culvert is generally used which will be discussed in more detail under Culverts. From 2' to 5' spans the box culvert type is' popular. From 5' to 20' spans the slab or stringer form of construction is reasonable except under deep fills where the semicircular arch is better practice; from 20' to 50' spans Pony Truss or Parapet girder types are available for most conditions or arches where the founda- tion is suitable. Pony Trusses are desirable up to about 80' span and beyond that the through Truss type. The following list illustrates the practice of the Iowa Highway Commission. 1. Box culverts and slab bridges 2' to 20' span. Not economical over 20' span. 2. Reinforced concrete arches 8' to 100' span. Foundation must be excellent. 3. Pony truss steel bridges with solid concrete floor 30' to 80' spans. 4. Reinforced concrete girders 20' to 50' span. Very economical but j require careful design and construction. Not economical over 50' span. In the matter of type the author desires to emphasize the desira- ■ bility of simple design particularly for small structures. Mass I concrete for sides and bottoms is preferable to thin reinforced sections (see New York Standards, page 92). It may not be as scientific or theoretically as cheap but better results are obtained with the usual inspectors. Road commissioners often do not under- \ stand the object of the reinforcement and either leave it out alto- \ gether or get it in the wrong place. For large structures where a I competent inspector can be employed this objection does not hold but even for such structure mass concrete for abutments, retaining ! wall, etc., is to be preferred. 78 DRAINAGE Table No. 13.— Rates of Rainfall. Short Storms Short storms of the greatest intensity occur as cloud-bursts in the mountain and arid regions between the Sierras and the foothills of the Rockies. The intensities of these storms are not well recorded but partial records indicate as high a fall as 11 inches in one hour. For these regions culverts for small drainage areas should be made at least twice as large as for eastern or southern conditions. (See last column, table No. 14.) Maximum intensity of Rainfall for different periods taken from the U. S. Weather Bureau Records. Intensity at rate of inches per hour. Location 5 Minute Duration 10 Minute Duration One Hour Duration Atlanta, Georgia Boston, Mass Chicago, 111 Cleveland, Ohio Denver, Colo Detroit, Mich Duluth, Minn Galveston, Tex Jacksonville, Fla Milwaukee, Wis Memphis, Tenn New Orleans, La Norfolk, Va Omaha, Neb 5 . 5 in. 6.7 in. 6 . 6 in. 5 . 6 in. 3.6 in. 7 . 2 in. 3.6 in. 6.5 in. 7.4 in. 7 . 8 in. 6 . 6 in. 8 . 2 in. 5.8 in. 6.0 in. 5.4 in. 6.6 in. 4.8 in. 7.5 in. 5 5 5 3 3 6 2 5 7 4 4 4 5 4 4 6 3 5 5 in. in. 9 in. 7 in. 3 in. m. 4 in. 6 in. 1 in. 2 in. 8 in. 9 in. 5 in. 8 in. in. in. 8 in. 1 in. 1 . 5 in. 1.7 in. 1 . 6 in. 1.1 in. 1 . 2 in. 2.2 in. 1 .4 in. 2.6 in. 2.2 in. 1 . 3 in. 1.9 in. 2.2 in. 1 . 6 in. 1 . 6 in. 1 . 5 in. 2.2 in. 2 . 3 in. 1.8 in. Philadelphia, Penn Savanah, Geo St. Louis, Mo Washington, D. C RUNOFF 79 Table 14. — Maximum Runoff. Small Watersheds Burkle-Ziegler, Sewer Formula Cubic feet per f Av. cu. ft. rainfall 1 4 /Av. slope of ground in second per acre = C X -j per second per acre \ X A g culvert. [ during heaviest fall. J ' / feet per 1000 reachin ^ No. of acres drained C = 0.75 for paved streets and built up business blocks. C = 0.625 for ordinary city streets. C = 0.30 for villages with lawns and macadam streets. Assumed C = 0.25 for farming country. Note.— -This value is high from the standpoint of sewer design but culverts are short and might better be liberal in size. One inch of rainfall per hour equals i cu. ft. per seconc per acre. Discharge in Cubic Feet per Second Rate of Rainfall 4" per Hour * *Assumed Area Runoff Steep Stony Moun- in Fall 5' in 1000 Fall 20' in 1000 Fall 50' in 1000 tain Slopes Acres C = o.30 C = o.25 C = 0.30 C = o.25 C = o.30 C = o.25 Rainfall 8'' per Hour I 1.8 1-5 2.5 2. 1 3-1 2-7 6 2 3.0 2.5 4.2 3-5 5.4 4.5 12 3 4.1 3.4 5-7 4.8 7.2 6.0 18 4 5.0 4.2 7.2 6.0 9.0 7-5 23 5 6.0 5.0 8.5 7-1 10.7 8.9 28 6 6.8 5.7 9.7 8.1 12.2 10.2 33 7 7-7 6.4 10.9 9.1 13-7 II. 4 38 8 8.5 71 12.0 10. 15. 1 12.6 42 9 9.3 7.8 13.2 II .0 16.5 13-8 46 10 lO.I 8.4 14.3 XI . 9 18.0 15.0 50 20 16.9 14. 1 24.0 20.0 30.2 25.2 90 30 23.0 19.2 32.5 27.1 40.7 33-9 120 40 28.5 23.8 40.3 33.6 50.9 42-4 150 50 33-6 28.0 47-7 39.8 60.0 50.0 180 60 38.6 32.2 54-6 45. 5 68.7 57-3 200 70 43-3 36.1 61 .4 51-2 77-3 64.4 225 80 48.0 40.0 679 56.6 85.2 71.0 250 90 52.4 43-7 73-9 61.6 93.1 77.6 275 100 56.7 47-3 80.2 66.8 100.8 84.0 300 200 95-4 79-5 134-6 112. 2 169.7 141. 4 550 300 129-0 107.7 182.9 152.4 229.7 191. 4 750 400 160.0 133-6 227.0 189.2 285.6 238.0 880 500 190.0 158.0 268.0 223.5 336.6 280.5 980 600 216.0 180.0 307.0 256.0 387-0 322.8 1,050 640 230.0 *I92.0 323.0 269.0 406.3 338.6 1,100 * 200 second feet by Table 16. ** Based on Santa Fe Table 15. 8o DRAINACxE siouim "^• ^a 1^ ^ o ^^ "* 'yc/j •c w rJ d (A O^ w (U w C C<^ u w aj 05^ < s w V uuinpQ p % 09 9sn jo:^'B9j:^g jo ^sBg (NOOOioOOioOvoioioii^OOOOOiOOvoioii^O MMtHMMMMMMMMMMMM(NtCSoo Os 0\ O O »-< (N MMMMMMMHMMMMMMI-(HHMM(N(NN< "^O 0\0\iOMioJ>fOO moo O O cs CO lOvO C> M -^ r- 0^ CN "^-O oo O -^oo m 10 0\ fO 10 Ov c>« ■^■^TtTt'^'^ioioio 100 -O O vO t^ I> t^oo 00 00 0\0\0\0 O t-i CO -^ 1000 O ro vo r^ O C^ '^vO t^ m -"^ t- O fOvO O l> t^oo 00 CO 00 C^ 0\ S9|ip^ 9JBnbs UI paUT-BiQ B9JY (N "*vO oOOiOOiOOiOOiiOOiAOOOOOOOOOO •^Tf-^Tj-iotovCO l^t^oooo 0\0>0 M N r0'=tiO\O t^oo 0\ STOUT^I <1> . -Se ^^ ^ «4-, CT ^W ;3 d O'^ w ?^ l§§^ < S M s^lIK 3-i'Bnbs UT pgUIBIQ 'B9JY Y uuin|OQ JO % 08 9sn jo;B9j:^g jo ^S9^ Y uuinpQ JO % 09 9sn jo:;'B9j;g jo ^^s'Bg 000000000000000000000000 Mrl-t^O>-iMMi-tMCi(scscN(NfO"^"^"oo 0\ O N -"^O 00 O N '^ 10 t^oo MMMMMMMMMI-(HCSCS(N(NrOfOrOCOfOrO loO^oOMNfO'^ iO\0 t^oo 0\ O <^ •^O 00 O N rfvO oO O 00O\O\ • ■ •MMMMMMMHHMNO>CS^0000000000000000 CD W , 00 0\0»o0i00v00W50Wi0i00«o0 OOOOOOOOOMHWCiroro ■^^tiOiOOO t^ t^oo 000000000000000000000000 RUNOFF 8i Y uran^oQ p % og 9sn jo^'B9j:^g jo ;s9^ Y uuinpQ JO % 09 9sn 20:^-691:^5 jo :^s'B3 OOOioOOOOvoir>tr)iiOir> lovo c^o^oo t>io'^i^i^p^ r^M M M cs N f<5 "^ 10 lOvO l>00 00 0\ OOir:000»oO»00000 M ■^ O t^ t^ -^ -^O M O 00 cs rt- 00 M \0 0\ rCO '^ M 00 ir> O 10 M 000\CNO\OOi-iNCsro-^'^iO MMMHMMMMM 0000000000000 0000000000000 o N Tfvo oooiooioo^ooio WO»oC On O 000 M -^t^O rOO 0\c^ 1^500 -i <^^0 lOOsOOOO t^l>-t> r^oo oc 00 oooooooooooco voOtOOOOOOOOOOO 00a\O\Oi-i(Nf0-<* 100 I>0C On Y uuin^oQ JO % 08 9sti jo;b9j;s JO :^S9^\^ Y tiuin[03 JO % 09 9sn jo;E9j:^g jo :^sBg OOOOOOOi^OiOiOOO o*nO ^(NO-oc^r^-^ONf^t^o ^0 00 O c^ -^0 C\ M •^O ro '-< vf- lOOOiOirjiOOvoOOOOO M r» O fOO oO'-icsrofOC^'-iO O t^ 0\ O i-< (^vO 00 O M -^vO 00 OiOOiOOOOOOOOOO O MVOt^OiOOlOOl^OiOO ro ro ro fO -^ "^ »o io\0 O t^ t^oo Y uiun^oQ JO % 08 9sn jo:}.'B9j:i.s jo :).s9^ Y iiuinp3 JO % 09 9sn jo:;b9j:^s jo :^s'Ba; OiOOOOiOOiOiOOC^OO (N vooo ■^ ro "^O O t'-oo 10 re i-H 000\0Mf0'^*'5Ol^0v'-4rciO i/>»oooioir)OOOiovr)Oio MOOooO'^C'iOl^w^t^ON ro •^ »o voO t^oo On 0\ w c^ fO "^ 0000000000000 (N ro ■^ too t^oo On O CI -^tO 00 MMHHMMMM(NWCiCS(N O 3— < ,. G »; C ^ w^ W rt (U 5:5 w +j (UriJ Q-- u,^ ,11 a-ii aJxi O n C> > W W C rH 'rt S* M J;^ aj-M43^ cJ a «H.c c ;3 o ^ ''^JD o S .C3 b S ?^. 9 i^^-- f" C'-M 5 "^ 1^ ?1f^.5^ C'^ COG -I O vO.-t^ (U G aJOrH«k_i>ja) '^ > ^H^ .^ <^ > C'O .« 2^ G "^ C > ^-d O w^ *^ h? J^ O ^ ft o.^ cd (u.jH o^ t^v^i 3<:5^g:5^^^* ^cgi^^^^.t^^-S , P 2j- ■ r '-'^ O^ ^.S <^ ,-. '.-^^-S^^c-o o-S a^'2^'2 2 o- U >4^ cU'd ;3 CUT3 ft? < On Si •30 82 DRAINAGE Table i6. — Maximum Runoff, Dickens Formula D = C-x/M^ Runoff expressed in second feet. The following tabulation is for a 24 hour precipitation of 4" rain and for topography similar to the farming sections of the Eastern Atlantic States. For 6" in 24 hours correct the quanti- ties in proportion to C as follows. 4'' Rainfall 6" Rainfall Flat Country Flat C = 200 Country C = 300 Rolling Country C = 250 Rolling Country C = 325 Hilly Country C = 300 Hilly Country C = 350 For steep stony watersheds and a ()" rainfall use the Oklahoma Column of Table 15. Area in Square Miles Flat Country C 200 Rolling Country C 250 Hilly Country C 300 O.I =64 acres 36 45 54 0.2 60 75 90 0.3 81 lOI 121 0.4 100 125 150 o-S 119 149 180 0.6 136 170 204 0.7 -^^Z 191 229 0.8 169 211 253 0.9 i8s 231 ■ 277 I.O 200 250 300 2.0 334 417 501 3.0 456 570 684 4.0 564 705 846 5-0 668 ^2>S 1002 6.0 764 955 1 146 7.0 860 1075 1290 8.0 950 1 188 1426 9.0 1038 1297 1556 lO.O 1122 1402 1682 20.0 1890 2362 2834 , 30.0 2560 3200 3840 40.0 3180 3975 4770 50.0 3760 4700 5640 60.0 4310 5400 6480 70.0 4840 6050 7260 80.0 5360 6700 8040 90.0 5840 7300 8760 lOO.O 6320 7900 9480 For areas under o.i square mile, see Table 14. CULVERTS 83 Table 17.- -New York Central and . Hudson River R. R. CULVERTS FOR SmALL DrAINAGE ArEAS. Steep, Rocky Ground. Acres Flat Cultivation, Long Valley. Acres Size. Diameter in Inches Equivalent Capacity. Pipes 5 10 10'' 10 20 12" 20 40 16" 25 50 18" two 16" pipes 30 60 20'' two 16 ^ pipes 45 90 24" two 18" pipes 70 140 K two 24" pipes no 220 K two 30 " pipes 150 300 A2" two 30'' pipes 180 360 48" two 36" pipes 280 560 60'' Note. — To be used only in the absence of more reliable infor- mation, particularly existing culverts over the same stream. Table 18. Culvert Design. Iowa State Highway Commission 1 Size of Culvert Opening Maximum Acres . Minimum Acres 2'X 2' 4'X A' 6'X 6' 8' X 8' 10' X 10' 70 _ 376 1300 2700 5000 28 140 520 1120 2000 CULVERTS Engineers do not differ much in the design of these structures. For high type roads they should be permanent; should be large enough to take the flood flow; should if possible be self -cleaning; must admit of being cleaned easily and as previously stated must be long enough to accommodate the normal width of road section. For low typ^ roads the requirements are the same except that temporary or semi-permanent culverts may be used if the funds are limited. The different kinds are as follows: Concrete or masonry culverts Permanent Cast iron pipe culverts " Double strength vitrified clay pipe Semi-permanent Ordinary concrete pipe culverts *' " Corrugated metal pipe culverts " " Dry rubber masonry culverts " " Timber and log culverts Temporary 84 DRAINAGE § 5 1 i 1 > 0^ u g a O OVO ^ O t^ M lO cod g 1 X to .a Q 1 Q."^9 »0 H CI 8- .a u tJ o to a 1 "o ^ . ^^ II ll I.' *© s. i^ Sj .a- J" ii ll «>> !l o 2 ^1 i 1 00 O O 1 ^2^^ 5 (^ N cooq <>» O CO VO ■-" H H M M CS X .S9 ft v2R?? o« CO lO P4 d s lO 00 N to cs lo O O lood M 4mdo6 6 H H M H PI CO X ^o «5 S Ov -sM^ CO !>. lO to rf M C< CO ^ q^ to w > 0\ OOO lo M vd CO d> M M . Th O ""too M M W rt i->. q\ -^ CO CO q lo iA d CO »o r^ d» H M M M H > vq t^vo M vd CO 6> H M C< . t^ CO MO > 00 to lo d lo q q q w . M lOOO M rt o 00 M Ph' l-H u 1 en 5 O O COO 00 O CO W H M C< O) 0> CO CO CO M d > t^ r^ q v> q q d> CO d> CO r~. H M M C^ CJ CO X .52 ft t^ CO M MOO 0> OO cs r^ M Tj- r>. M M (N C^ N o o d>M > 4vc> d> H CO 4vd H H M M ^ t^ tN. O to to O d> CO 0» CO t^ w HI M M c^ tj- lo Md X .a ft 01 to to O OVi O to t>. O fO ^O QO vd d > VO lO »OVO 00 to od t^ " ^ «M VO 00 q ti dd w CO H W H \o M X ft W O V3 q q q q q q d M cJ CO "t lovd II 5 it «oq q q q q o O M CI CO tJ- lOvd OBSTRUCTIONS TO CULVERTS 85 Cast iron pipe or concrete box culverts are generally used on high class improvements. Corrugated metal, concrete or vitrified pipe and dry masonry on low class improvements and timber or log culverts in mountain road work. For moderate sized drainage areas the culvert opening is pro- portioned to the runoff but for small areas the size is determined by the convenience of cleaning rather than by the discharge capacity. Where sufficient fall can be obtained to make the culvert self- cleaning, a 12'' pipe is feasible under shallow fills but where the flow is sluggish, nothing less than a 16" or 18'' pipe will serve satisfacto- rily. Long culverts under deep fills should never be smaller than 2' wide and 3' high to permit cleaning by hand if necessary. The self-cleansing velocity of flow for sand and earth particles is about one foot per second; for coarse gravel about three feet per second (Ogden's Sewer Design, page 134). A pipe laid on a slope that gives a velocity of five feet per second when flowing one quarter full should keep clean. This requires a fall of approx. two feet per hundred for a 12'' pipe and is the minimum grade at which the 12" size should be used. It is our opinion that a culvert should have the same slope as the stream bed. If given a greater slope the outlet end tends to clog and if a lesser the inlet end will plug. It is unusual for culverts to fill badly except when placed at the foot of a steep hillside where the stream velocity is naturally reduced. At such points an extra large structure should be designed with the idea of providing suffi- cient waterway even after the contraction caused by this settlement has occurred. Such a culvert should be cleaned after each freshet. The use of paved dips in the roadway at such points in place of culverts is not advised as they are dangerous and cause accidents unless very gradual. A man not familiar with the road often loses control of his car. Ditch relief culverts on grades should be laid at an angle of about 45° with the center line in order not to retard the water at the inlet end. More trouble is experienced from culverts becoming filled with ice due to alternate freezing and thawing weather. This is par- ticularly true of small culverts draining springs. Culverts as large as 2 X 2 have frozen solid in this manner and if this condition is anticipated the size should be regu- lated accordingly or trouble will be experienced dur- ing the spring break up. The following ingenious expedient has been successfully used on roads where the culverts fill with ice and snow during the winter. A small pipe is suspended inside of the normal cul- vert. In the fall this small pipe is plugged and in the spring just as the snow begins to melt the plugs are removed and the first water flowing through the small pipe melts the ice and snow rapidly for the entire length of the culvert so that it is generally completely free to handle the main spring runoff. Where pipe culverts are laid on steep slopes special buttresses well imbedded in the hard slope should be provided to prevent 86 DRAINAGE crawl or slip. Well built headwalls should hold up to slope and beyond that extra anchors should be provided. say 12 Fig. 20. In designing culverts under side roads, the length must be great enough to provide an easy turn for traffic; many times a saving Main Road Macadam Side Cuk in Ditch Line •"-^ "1 \^ 5icle Culvert Set Back on Side Road\ Fig. 21. in length can be made by placing the culvert a short distance down the side road as shown in Figure 21. Sidewalk Fig. 22. Figure No. 22 shows a form of culvert often used in village streets where deep ditches at the culvert site would be objectionable. While vitrified pipe or concrete pipe are not recommended for cross culverts in high-class improvements they are the most suitable RELATIVE COST 87 construction for ditch drainage under driveways etc., the wooden boxes built by some departments are not economical which is shown in the following estimate of relative cost of small unimportant ' culverts given by A. R. Hirsch in Wisconsin Road Pamphlet No. 4. Kind Size of Opening Length First Cost and Maintenance for 100 Years 3" Hemlock box Concrete box 15 in. sq. 15 in. sq. 18 in. 18 in. 18 in. 18 in. 18 in. 20 20' 28' 26' $252.00 40.00 35-00 41.00 42.00 166.00 196.00 Concrete oioe Single strength V. T. P. . Double strength V. T. P. . Cast-iron Dioe Corrugated steel Relative Cost of Culverts. — The relative cost depends largely on the location, material available and length of haul. The following costs are approximately correct for the northeastern states during the years 1912-1914. Table 21 gives comparative costs for permanent culverts and shows that cast iron is generally not economical over 18" in diam- eter. Pipe is to be preferred where the headroom is small. The following list shows the approximate cost per ft. of vitrified and corrugated metal pipe culverts. 12" 15" 18'' 24" 36" 48" Vitrified pipe culverts Corrugated metal cul- verts $0.60 I 25 $0.90 I 50 $1.10 1.80 $2.00 2.75 4.00 $6.50 Corrugated metal is to be preferred to vitrified tile if the head- room is small as it is not as hkely to fail under heavy loads. Small log culverts cost approx. as follows : Size of Opening 12" X 18" 12" X 24" 14" X 36" 24" X 36" Approx. Cost per Foot $1.30 1.40 1 .60 1 . 70 The difference in cost between corrugated metal and log culverts is not enough to warrant the use of small lot structures except in unusual cases. 88 DRAINAGE o 1 u i N rj-vooo « ^vooo N Tfvooo H < t^ M VO O ID O PO >o 00 ^ H H H C O la rO H 0\ t^ O 00 O w CO »D M H M H ^ ^ « 00 "* O to t^ 60 O Tf to t^OO o •-• t^OO Ov O M CN ro tO^O 1^00 On O w ro -^ HMHCSM(NMMC< O H c^^ ro ^ tO^O t--00 O O MMHI-lM-00 O 0\ O M . fO -^ too MMMMHHMHH....... O to o X l^tort. OOOvO Tj-. OOOO tOCOH Oi O M . PO -^ '^ »OVO t^OO 00 O O H . . ^MMMMHHMHHMH.... ^ ^ o U X O t^TtHOOO POO t^-*. OVO PO O 00 OvO»0 M M . ro^-^ lOvO "O t^OO O O PO X J^TtMOOvO POOOO to. ONt^-^M OVO OOMH.POTf^t too O r^OO 0\ O O ^MMHHHHMHMHMHHM. vg' X OvO . O^toHOO •^Mt^coO'O fOO>to t^-cQ 0»0\0 MM . POPO-^to lovo VO r^ O Oh < X vOhvOmvOhvOhoOhvOhvOmvOm f>00 000>OOOHH..roPO'^'^to o to 4 s *Vo X PCOO .t^HVOHioO T^O^ Thoo ro t^ N o VO i> t^oo ooo>aoooHM..ro o PO 3« N '*vO 00 O W TtO 00 O . rhvO 00 O . c< . Ci CI rQtococOPO'^"*'^'<*-^to 4J -M ^ S-i ^ 2i «» "' SMALL SPAN BRIDGES 89 Plates 12, 13 and 14 show standard pipe culverts. Plate 15 shows first-class simple massive box culvert design. This is as satisfactory a type as there is in use. Plates 16 and 17 show good examples of semicircular and circular culvert practice. Plate 18 shows the combined masonry and concrete type which is suitable where stone is plentiful and concrete costly. Plate 19 shows log culverts used on mountain roads. The shape of opening for small concrete culverts should permit the use of collapsible forms. Plate 12. — Cast Iron "Pipe Culvert. New York State Standard. p I a K- ;; -Z4-4''ioZ6-4-- V I \„ 2f Mof Lessfhan. J , ■'•■9" '''6",NofLessfhart.' 6'; Hoi Less than'.' Longi'+udinal Section. SMALL SPAN BRIDGES The area of opening, width, live loading and economical type were discussed in the first of. the chapter. Most ordinary soils afford satisfactory foundations for small span bridges but piles must be used for muck or quicksand and are advisable if much scour is anticipated which can not be prevented by rip rap protec- tion. Pile foundations are required for all large structures where rock foundations are not available and are desirable for any con- crete structure over 30' span. The safe foundation load on various soils recommended by the "New York Building Code" and ''Baker's Foundations" are as follows : New York Building Code Soft clay I ton per square foot Ordinary sand and clay in layers, wet and springy 2 tons " " " Loam, clay or fine sand, firm and dry. . . 3 " " " " Dry firm coarse sand, stiff gravel or hard clay 4 " " {Continued on page 98.) go DRAINAGE "5 £i ± o E E s 1 |0 Eg *o VSk « c at t :? :§* )( ^ i" 1 1 d r $ ( ^ ^ ^ E o CNJ 15 5 s s Zi O O cn U l- o o fW If ;a.//yy/7^/7 /-/?:? §& ill 1-kl, . 4 ^k^ •S: as aj ^ » » ^ P> (^ (^ c^ (^ «T ««T :gVi METAL CULVERTS 91 Plate 14. — Corrugated Metal Culverts. Hampshire. ^ It State of New Longi+udinal Sec+ion End Elevcation. TABLE OF PROPERTIES. Diame+er %f.^ Capaci+LjjCu. Ff.perSec. Concrete Cu.Yd&. 10" 0.048 1.64 1.75 12" 0.033 2.36 2.0 14" 0.025 3.21 2.3 16" 0.020 4.20 2.6 IB" 0.0/6 5.31 2.9 20" a 012 6.54 3.2 24" 0.010 9.42 3.8 30" 0.007 /4.73 4.9 36" 0.005 21.21 6.1 VeJocltu:r3.0 Fi.perSec. **n*''^ 0.027 \ Quantifies Figured -from Minimum Dimensions, 92 DRAINAGE Plate New York State Small Box Culverts. Alternative Cross Section for Collapsible Forms. «■'' Longitudinal Section. Culverh to be Bui It with End Walls.) End Wall. c a «/3 ■7^-5 c 1 Pi \- < Is? Z'O" e" 12" 0.6 3'0" 6'- 12" 1.2 4'0" 6" 12" 1.2 5'0" 6" 12" I.Z Table of Dimensions. r~~""~~*'~r5r. •^ m^^^ -DoYveh 0.25°' NetArea rO"lon0}l2C.toC. l One End I.Hcu.yds. K— - 6'6" \J3iZ Si «/5i One End I39cu.yds. ^2^^^V^ n <-/^v 0.089 cu.yds* per ft-. K- g^'-X O.M4cu.yd^ perfr. r- One End K61 cu.yds. 0.123 cu.yds. per-ft-. I1 One End 1.91 cu. yds. K- 56 "H 0.18 cu. yds, per ft-. 94 DRAINAGE o CO fir- to ^ ^ g ^ I ^ I ^ -5 J. s ^ .^ ^ •§ t -5 ' ^c^^^ ,s^^; 1^ i n ■<7J/r> >| j9]^''-"-lj2- '^^'"'•Y^joJ^'^^ctBjOd gjg CULVERTS 95 OQ ^ -^ ti: o . O 4- ^ H- O y I .....f.f,.;.>L...f.^^..,>| ^ "^J — A\^ h o si L'S« XT) c c o + D > UJ Si IS k 96 DRAINAGE Plate i8. — Typical Masonry Culvert. State of New Hampshire. Plan 3— [<-3-'-->)<- 9'-3"- -^^^1^1 Part Longi+udinal Sec+ion m m \c:^\P^ c^l.:^^ Half Section B-B Half End Elevation. Depth Fill Length Bar&A'/2"Sq. Masonry Cu.Yd& Concrete CaYds Paving Spacing Number Length / 21-0' 7 " 40 5''9" 24.3 3.0 10.2 2 2/'-6' 6'/2" 43 99 24.6 3.0 10.4 3 24-6" 1V2" 43 99 26.6 3.4 If.d 4 27^6" 7 " 51 99 2d. 6 3.8 13.1 5 30^6" 1 " 56 99 30.6 4.2 14.4 6 33'''6" QVz'^ 66 ♦ » 32.6 4.6 I5.S d 39-6" 6 " 33 «« 36.6 5.4 10.4 TABLE OF.QUANTITiES 4x4-'CULVERT LOG CULVERTS 97 O CL -J iO 98 DRAINAGE Baker's Foundations Rock (poor) 5 tons per square foot " (solid & first quality) 25 " " Dry clay 4 '' " Medium dry clay 2 ] " " Soft clay I ton " Cemented gravel 8 tons " Compact sand 4 " '' Clean dry sand 2 " " Quick sand and alluvial soil }4 ton " Where piles are used for types of construction where slight settlement is not objectionable a loading of from 10 to 15 tons for a sound well driven pile is conservative practice. The safe load for a timber pile driven with a gravity hammer can be figured from the following simple formula. (Iowa Bridge Specifications.) Safe load in lb. = — ; — s + I W = weight of hammer in lb. H = fall in feet S = average penetration in inches per blow for the last three blows. Scour. — Scour is produced in different soils at approximately the following stream velocities. Sand 2 to 3 ft. per second Loam 2 tosK " " " Firm gravel 5 to 6 " '' " Riprap protection reduces scour. According to Trautwine a velocity of 8 miles per hour or 12' per second will not derange quarry rubber stones exceeding J^ cu. ft. deposited around piers or abutments. If the natural stream velocity is not over 10 ft. per second the span is usually regulated so that the velocity under the bridge during freshets will not exceed 10' per second. If the natural stream velocity of flow at the bridge site is not known it can be approximated roughly for small streams by the formula. V = cVrs Where V — Velocity of flow in feet per second C = Constant assumed value 60 _, ^-. , ,. ,. Cross sectional area of flow K — Hydraulic radms :prr~r. — \ = :: Wetted perimeter S = Slope of stream Example,— To approximate the freshet velocity of the stream shown having a fall of i.o' per 100' or 53 feet per mile. FORDS 99 ^ Water Arlcn 100 °Lrl ^'' hefted P^/7We^'"'2S ft. V = c Vrs C = 60 100 4 R s = 25 I F = 60 V4 X o.oi = 60 -\/o.o4 = 60 X 0.2 = 12 ft. per second. Where much ice occurs piers in small streams should be avoided. They can be used to advantage to reduce cost however if there is no danger of ice or debris jams particularly if the flow is sluggish and in the latter case for wide shallow streams the trestle design is economical. Paved Fords. — For wide shallow arroyos of the arid regions of the west paved fords are in general use. These channels only carry water during sudden severe storms and it would be practically prohibitive in cost to provide large enough structures 0§^s^ Marking Posts. Fig. 23. — Paved ford. to carry the sudden large infrequent flows. The road across an arroyo is kept slightly below the natural elevation of the wash and is paved with concrete, cobblestone or timber (see sketch). The alignment is straight and the location of the pavement is shown during flood by 4 marking posts 2 at each end which also indicate the depth of water so that it can be used even if covered with water unless the depth is too great for safety which can be determined by the gauges on the range posts. As the concrete is below the bot- tom of the stream no scour occurs and generally a thin layer of sand is deposited on the concrete which can be easily cleaned off with a road machine. lOO DRAINAGE Plate 20. — Light Wooden Bridges. vState of Wyoming. ^ 4x6 Curl?. J :^ \i-Max.6-8'--^\ ^^^^^^^ ^^^^^^^ Cut Washer. §x9 Bo If, Cui Washer Pile AbiMf-ment CnbAbufment ' ^ ' fhandLo^s. Side Eleva-Mon. {men Piles are drive rr for Head or Win^ Walls, use 4 Piles in End denf. (Painf Rails and Posfs HOT£ \ wifh Two Coafs ofWhiie [Lead. + Roadway 16-—-" ,.''-?x6"Bloch,2'CfoC. '~ T'Steel Wire Spihes, 2perJoisfs. fxaydolf:. 12x12x24' _ fOriffP/nJ^ Z'Long. fxddolf , f| ilxlO'lagScrews/ctoC. y^4\6"Curb. Half Section Pile Abutment. Half Section Crib Abutment. TIMBER BRIDGES lOI wd ft: W % fc % Vf+3 nd'd^ ft: ft: ft: ^ % M '"' 00 X t^r^t^'0OO\/\/N/vy' 05 -M -M =u.=i=imiH^^^^t J J Tf rtlO »0 (NO 1 1 1 \ ^ ^ 00 2 00 ^^ vO wd ft: CO On i-i'-^'n TJ'dS: ft: ft: ft: ft: % M l-i 00 X t^ t^ t>\o vovo XXXX -M -<-> < wd 1 1 1 1 1 1 1 1 \M\po\ao\ooo\ ft: 5: °T < O M 000 M M -tJ ^ J < 1 1^ wd 1 1 1 1 1 1 1 \M\X\X\X«oN p2 5 6^ % % =*:=tfc=fc=«fc=te=fc=fe=*=in\«\W5\K5\ , H 02 6 J J On woo rl- s 1 + N M vC w 75 "^S C\lO\»0\«\ , OvO 0000 100 1 1 1 1 ^ t^ t--oo to lovo «i: 1 1 H V V «N 4i-o -^^^ M M M ^ ^ >^ >>'^ VVV^V >^>>>)>^> Pi XBiJA p^o-a Ih' Vh' v^' ;-! v^ wi 000000 CO Y (U CO qHqricacCcCtC ^ 0, T-H % % SS ft: ft: ft: ^ ^ *rt ^""t ^fO ro fO C/' ^ '^•WiVHW(WitH»-.''^COCOCOb C C3 "^^ 'M V+-4 t+M M-, *+-, t^ Q Q Q,^ " 'rid WMc/3cococo'~'nnn(i ^s:^^&^^^6^^^^ I02 r — DRAINAGE CJ J J J -^ s H D n •fc* < s o H O •J 1 Ph 1 0^ o o (N to a :^ CtJ ^ < : X X XX X X XX xxxxxx % % % % ft ft ft ft ft ft ft ft ft ft ft ft ft ft cs N cs r I- « 00 00 *b "b V 00 00 00 00 000 wd M MM Ml- M MM MM M M P< N M M M M M M > X XX XX : X XX XX X XX XX XXXXXX +j -M % ft % ftt % ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft < tJ- CS N Ci t ^ rt es 0 "^ '^vO 00 nO ^ wd M M M M Wl M M <-« M M Vh M M Vh M M V4 M 3 x°xx*=xx : x^xx^xx X^XX^XX XXXXXX Ov ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft 1 1 PO Tj-ro '*^ ro '=tro 'stc* fO "tpp rfN 't '^P^ C« .%tb b b b '0 wd g^CH NM MH- fe N W(5« NMrtMMPlMPl 0^ ►-» ^X XX xx :'dX XX XX ^X XX xx^xxxxxx rtft ft ft ft ^ft ft ft ft ft ft ■Oo TtP4 NftgO"^ "*vO 00 ;, X^XX^XX^XXXXXX "^^ u ^B 'dft ft ft ft ft rtfe % % % % . ^'^ nJvO ■^ f^ N "^ J- sO rt 04 CS ri wd M Wl M M Wl M 0jj M JH M M JH M *^ Wh4H P^X'^XX^XX u x°xx°xx 05 "0*0 ft ft ft ft ft ft Oft ft ft ft ft Oft ftft ftft>.ftftftftftft a 1 1 ro "*ro TJ■^ 1 PO ^ro rt- « 1^ wd N M Ml- N M MM P« CS P< M ;Jm| X X XX : X X XX X X XX XXXXXX rS^^ ■♦-> +J ft ft ft ft ft ft ft ft ft ft ftft ft ft ft ft ft ft P^ w^ vO W N •^ ^ cs cs -^ vO M N "^ vO Tj-rJ-vOoovO 0^ wd M M l-i M M M ti M M M J;j M at X x*^xx : X x°xx X x*^xx XXXXXX oi ^ "0 ft ft ft ft ft ft ft ft ft ft ftft ft ft ft ft ft ft J ^ fO '*^ rd- PO ^P* "* PP "jtCN ■^ tJ- P) PI PI 0» 'to III 0\ »0 lOf 1 1 II 1 1 u UtUi WD N V V V ». ft ^0 ^/i vO nO^C 10 00 00 rj 1/5 00 vO rJ- Tl- TtvO wd N M M H P« M MM N P4 P» M M M M M M H X X XX : X X XX X X XX XXXXXX X +3 4J ft ft ft ft ft ft ft ft ft ft ftft ft ft ft ft ft ft 00 N NT r 00 p« p^ Tj 00 N N -* '"t-'tOOOO wd M M V. M M M tH M M M 1-1 M H^ X x'='xx : X x^xx X x*=^xx XXXXXX Oi ft ft ft ft ft ft ft ft ft ft ftft ft ft ft ft ft ft 1 1 rt fO "^M Tl- fO Tl-M "<* PO rJ-OJ "- t^f > ii- a 1 1 1 1 MINI N N M t^ t^ tJ- potn4i-4j-«ltt- Vh b ) «3 iH bo 1 -a 1 1 1 ^ ^ 8 ^ 1 § ? ^ fL, K ^ f^ K P^ « I04 DRAINAGE ? •:t t 1 .•§ .^ fl" «i ; \ IJ^ '^i ^K. ^'^^^^ t -> ^ "^-/^^ r i 't ••■■'" / 1^ s^ j 5j' / 1^ ^ 11^ tli t !"S S" \^.«^E t ■I-'? 2^ * 1 s ^■■Mi-jh S :•- 'mm 3 '^ 't ^K t 1 •'^ ^ *- .r : 1^ Is ^ => O u-> J 'w "^ z < o w CN O H^ «d WW « 2 PQH Z < w« qH O ^g g^ < .. ^S oO WO wd wo o o +j •+-> WO wo wo wo o o \0 ir> WO o o wo o 0\ w ft: % O Q\i- -I 00^ I I I I % % 5: % \00 III \00\00\00\XW5\ III \QO\QO\QOft >0\ nii «s * % % \*4J _ _ O Q\ H r^3 ♦dTJ* % ft: M MOO X a^.^^'^xxxx^ J I \Q0\OO\00\0Oi0\iO\ . O loO 000 I I I I i 00 00 00 I 11^ O NOO '^ ^ r^\0 00 O >>>>>»>»>» CO t/3 I . M M M M M M M a fe XXXXXXX 1 o P^ o 1 ft: 5: %; %: ft: % * g '^^^ro fO ^fO H 00 M 1 M 1 1 1 1 . tt w C :3 u O oo o (It! o J < ft; fe ft: ft: fe fe %: 2 CO \0 "^O •^ c^ c< M M M M M M M 5 ^ 05 o 1 XXXXXXX ^ M >.>.>»>.>. ft; ft: % % % ft: % ^ 1 c c c c c %, rt ■'^ Tt fO ro ■^ ro o :;3<<<;<<: M 1 1 1 1 1 1 1 P^ CM N M N CS W M C 3 o -M ^* 6 vO 13 (D o H^ OvO CM M OsoOvO rt (^ ^ Hi ^ XI 6 (-4 :3 DO bfi c3 c5 ^ ^ 6 • bfl .S .5 tfl _ g' -^J^i^^ B .3 Q-a c;^J^•2 rt n:; aJ rt d *:■ rt ^ io6 DRAINAGE i + S^ o a CO a B WO o o 4J •♦-» mo ?? wo wo wo wo ?? wo wo J! \0 vi WO 6 OS X X X X I i o oo o M M M M X XXX ft ft ft % X^XXX ft ft ft ft i ill X XXX ft ft ft ft ''xxx X 00 00 X X ft ft X X ft ft I i X XXX ft ft ft ft M Wt M H x^xxx X XXX x°xxx I I : i i ^ I X X X X 1 1 X XXX x°xxx ft ft ft ft ro Tf rt N xxxxxx xxxxxx ft ft ft ft ft ft tJ- rj- N ,ft I I I ^1 MM CO M XXXXXX x^xxx xxxxxx ftftft ftftftft^- I m|| M I 1 I M M ^ H X XX ft ft ft 00 W Tt X XX ' 'I Wpq M M I xx-b ft ft M X XX r n Ci 00 O O oOvO W MM X XX 00 N Tt H M X XX n w« CS| M >, M M M M xx5xxxx ft ft ^ft ftftft X XX ft ft ft -i I I rj- 00 N O OO OJ N M X XX X XX XX ft ft 00 vO xxxxxx ft ft ft ft ft ft t}- tJ- CM N N N 1 1 1 1 1 1 M ^CS z^- 1 ->.z/4. ^^nn "ifi T-^. n ' r r^ ^^ JM ™" f+ 1 v)^ >; 4(H » -^ H i. H ^ -^ +lt «^ en 1 ' % tl't til " 1 tl 11/ li PILE TRESTLES 109 1^- ■ tlH- "S ^-^ 5 >- Q -^i-^ ^ i'^' k o t Si. 5 v.^*^ ^^6-^ '^^'^1 -^riii?#M 1^1 V:|<— - .^:r — ^ V* (W W no DRAINAGE Plate 24. — (Continued) Dimensions and Quantities for Superstructure Capacity is-Ton Truck Intermediate Panel Panel Length (L) Size of Joists Joists Floor Railing Details Total Lumber Bolts, Washers, Spikes, Nails Feet Inches Ft. B. M. Ft. B. M. Ft. B. M. Pounds ID 6X12 590 800 1390 80 4X14 460 840 1300 II 6X12 650 870 1520 90 4X14 500 920 1420 12 6X12 700 940 1640 90 4X16 620 990 1610 8X12 lOIO . 1020 3030 13 6X14 880 1020 1900 90 4X16 670 1070 1740 8X12 1080 1090 2170 14 6X14 950 1090 2040 90 4X16 720 1 140 i860 15 8X12 1150 1170 2320 100 6X14 lOIO 1170 2180 16 10X12 1530 1240 2770 6X14 1070 1240 2310 100 6X16 1230 1240 2470 17 10X12 1620 1340 2960 8X14 iSio 1340 2850 120 6X16 1300 1340 2640 18 10X12 1710 1410 3120 8X14 1600 1410 3010 130 6X16 1370 1410 2780 19 10X12 1800 1490 3290 8X14 1680 1490 3170 130 6X16 1440 1490 2930 20 8X14 1760 1560 3320 130 8X16 2020 1560 3580 21 loX 14 2310 1640 3950 140 8X16 2110 1640 3750 22 loX 14 2410 1710 4120 150 8X16 2210 1710 3920 PILE TRESTLES III Plate 24. — {Continued) Capacity io-Ton Truck Panel Size Intermediate Panel Bolts, Length (L) of Joists Joists Floor Railing Details Total Lumber Washers, Spikes, Nails Feet Inches Ft. B. M. Ft. B. M. Ft. B. M. Pounds 10 4X12 400 640 1040 70 3X14 350 680 1030 II 4X12 430 700 1130 80 3X14 380 740 II 20 12 6X12 700 760 1460 80 3X14 410 800 1210 13 6X12 760 810 1570 80 4X14 590 860 1450 14 6X12 810 870 1680 4X14 630 910 1540 90 4X16 720 910 1630 15 6X12 860 930 1790 4X14 670 970 1640 90 4X16 770 970 1740 16 6X12 920 990 1910 6X14 1070 990 2060 100 4X16 820 1030 1850 17 6X12 970 1070 2040 6X14 1130 1070 2200 no 4X 16 870 mo 1980 18 8X 12 1370 1130 2500 6X14 1200 1130 2330 120 4X 16 910 1 1 70 2080 19 8X12 1440 1 1 80 2620 6X14 1260 1 1 80 2440 120 4X16 960 1220 2180 20 8X12 15 10 1240 2750 6X14 1320 1240 2560 120 6X16 1510 1240 27 50 21 lOX 12 1980 1300 3280 6X 14 1390 1300 2690 130 6X 16 1580 1300 2880 22 loX 12 2070 1360 3430 8X 14 1930 1360 3290 130 6X16 1660 1360 3020 23 loX 12 2160 1420 3580 8X 14 2020 1420 3440 130 6X16 1730 1420 3150 24 loX 12 2250 1470 3720 8X 14 2100 1470 3570 130 6X16 1800 1470 3270 25 loX 14 2730 1560 4290 8X 14 2180 1560 3740 150 6X16 1870 1560 3430 26 loX 14 2840 1610 4450 160 8X 16 2600 1610 4210 27 loX 14 2940 1670 4610 160 8X16 2690 1670 4360 28 loX 14 3050 1730 4780 160 8X16 2780 1730 4510 29 loX 14 3150 1790 4940 160 8X16 2880 1790 4670 Washers to be ogee type cast iron ; or steel plate washers for j^^" bolts. ' and %" bolts, and cut wrought iron 112 DRAINAGE Plate 24. — {Continued) Dimensions and Quantities— Substructure Grade to Ground Feet 10-12 12-15 15-18 18-23 23-26 One cap io"X I2"X i7'-o" Sway Bracing — Intermediate Bent Sets No. Reqd. Length Feet 18 20 5 & 20 20 Lumber Ft. B. M. 90 100 no 190 200 170 Bolts Pounds 35 35 35 60 60 Grade to Ground Bulkhead— End Bent LumjDer Spikes Feet Ft. B. M. Pounds 4 6 7 8 27P 360 460 550 640 5 5 10 10 10 FRAMED TRESTLES 113 Plate 25. — Typical Framed Trestle. Illinois Central Railroad. > ^.,^»„ . e'x /4"5frmgers. ^ 2x4- Bracing. ^ ; flooring 3x12x16' Planks.; vo ^x H-Sf ringers ^ ^ 2x4''' Bracing. I 2'^/0) ! 3 xl4^f ringer. \ J Plan "3x14 Stringer ,, %/**• Slope /fof '^-^''*- Slopeljfol Sfcfe E'eva+ion. (\j CO ^ oj cvj .lt:|:?|:l*;^Sf| 2-io^'^y\'^'W2^icP fz'xizxid'J:\^-'fP-4'-^^^ e'xe'xS'Post. \ p^-'^ \%^^^''xl5'Bol-hs. \^3^'x22'Dr!H-bolf. I ^"x22"Dnff'bo/ts% \ 3^xld"Dri-ffl?o/-fs/ •» -12K.!2xl6Cap. "^ 3'J(5x20'Brace. "^ 3x8 X 16 'Co /far Brace. -'3x8x20' Brace. "^t^l2^xld'5ili --8x12x3' t2'xl2"x24'Po5h Mudsills. dxIZ'xd'Muc/Siils.V 3(S5^8-h'0' Bent© 2 ond B. Showing Road way for Single Track Crossing 3x8 Brace 2x4" Bridging ":;^ 3"x8 Collar Brace '•\j4^l8"Bol-t5. •.^ ^4x2\" Balis, ■./ 00 POO (U(U(U4) m o M M M c^ cs-+J4J-t->4->-M-fJ (U ph " ^mmuimxntn ^^^^jiiSi U5 AA>^AAA C/3 o m o O ;3 w . o n 1 1 oooooooaooo <5j c t-t-oo roo a C C C C C 4j 3 O roO MrfoOOOOO w (2 M M M M «^000000 Q (U 'd'd^'d^'d ^ 2 ' 03 >^>^>H>H>H>H < ^ ^ (U (1) V-i ^ d d d d d d a £ OJ ^•^"^Mc^OOOOUO s .s^ t^O t^OO ^^-i '5 .a ^ c C? O* C D* D* '4-1 '^ m tn tn vi w . % % % S: % G OJ do ^^^;:^^^ ^ 52 ^ ?-S 13 < rt cS d cede C M ^ '^ w c H ^H M M M M M co^-a^ J3 53 +J 4J +J 4J 4-> n la w hJ cS (3 d) O O 0) < 4J O +* rt:i:l o ^i\ bo Qi ^ d O g c« la ^•^ o o 2^a Q.a« ii6 DRAINAGE Plate 27. f k-W '\N^rt(0x2") End §)evatioh. General Dimensions Semi-Circular Arch Culverts s span Thickness at Springing Line Thickness of Ring Height of Haunch T K C R J V Concrete Masonry Concrete Masonry Concrete Masonry 6 2'-6" 2'-6" xo" 10" i'-9" 2'-o" 8 2'-6" 2'-6'' 11" 12" 2'-6" 2'-6" 10 a'-o" 3'-o" 12'' 12" a'-o" 3'-o" 12 a'-e" s'-e" 14" 15'' s'-e" 3'-9" 14 s'-Q" 3'-9" IS" 15" 4'-o'' 4'-6" 16 4'-o'' 4'-o- 16" 15" 4'-8" S'-o" 18 4'-6" 4'-6'' 18" 18" S'-o" s'-e" 20 ,'-o" Sl-o" .. 18" 18" K'-6" e'-o" SLAB BRIDGES 117 Plate 28. — New York State Slab Bridges. Note All rods to have a deformed cross-section. All rib metal to be of medium steel. 2d class concrete in all slabs and parapets. 3d class concrete in wings invert and abutments. Wing walls on the outlet end of all square culverts with concrete floors to be built parallel to the center line of the culvert. Round all exposed edges to i^ inch radius. ffocfs 0.25°"NetArea., Spaced IZ"C.toC. W^iSpansS'todS!) Plan. DowehO.iS IZ"Cfrs. Pile Foundations to be UsedinLiqhtandShiir- ^.^ ing Soils. Pave when Wc Ordered by Div. Engineer .'Pods in Slab to be Exfen- \ ded 24 Diams. beyond \ ^ Neat Lines of , \ " Abutment Elevation. BottomWidihofthe Abutments not less than ^ of Total Height from Bottom of Abutment toTop of Slab. Section on CenterLine For Typical Section "F" Where culvert covers become a part of con- crete base for brick pavement, transverse reinforcement should be extended 12" beyond back of abutment into concrete base. IS%r45''Skew\J ZdhrmrlS'A i \ \ \ Rods in Slab to be Extended 24 Diams. beyond Neat Lines 7-\ of the Abutments. ':Rod5 0.25'' NetArea; ^ Spaced IZ ^ CrtoC. Dimensions of slabs on page ii8 DRAINAGE Plate 28. — (Continued) Span Thickness of Slab* Net Area of • Rods Rod Spacing C-C Length Dowels 5 8" 0.25sq/' 4¥ 12" 6 9"^ <( 4" n 7 10" o.39sq-" Si" u 8 10" n Si" {( 9 11" it S" u 10 12" li 4-1" « II 12" o.s6sq." 6i" iC 12 13" << 6" 18" 13 13" it Si" u 14 14" U sr <( IS 14" « s" u 16 IS" (( 4f" (( 17 IS" (< 41" « 18 16" {( 4l" (( 19 17" a 4i" « 20 18" o.77sq/' si" (( 21 18" a Si" iC 22 19" u 5" 24" 23 19" (1 S" (( 24 20" « 4f" « 25 21" i.oosq." Si" « For Spans 5' to 19' W = 18'' For Clear Height 10' or less " " 5' to 19' W = 24" " " " 11' to 15' " " 20' to 25' W = 24" " " " 15' or less For Clear Height 7' or less E = 3'- o" 8' to 10' E = 4'- o" " above 10' E = s'-o'' * Note. — The thickness of slab given is for shallow fills. For the effect of deep fills see Table 53A, page 565. STRINGER BRIDGES 119 Plate 29. — New York State I-beam Bridges. fxpanded Metal Embedded in b "Concrete (Z^CIass)^ Length of Culvert '\<^/'e Exp.Metal- Steel Barj'--'^. Cross Section of Parapef Showing Reinforclncj. ^ Paintall Beams 1^2 Coats Lead and OiL \^j^i^^^{^mf^^m^mw^WMM^^'' Round all Expoied Edqe5to2^'Rad. Exp. Metal to be , J'e"ord'>tlZ"Mesh\ v/eiqhinq not less than I2lbs. persq.it Longitudinal Section. Part End Elevation. ^5teell-Beam W^' I- Beams Spaced as Shown on Table I. Expanded Metal Ernbedded In 6" 2S Class Concrete. . ()'tolZ'high,x-'Z4't(Hx2{') Spansl8to30Feet. |<--x-->i e 'tolZ'high, x= l8^(Hx2^') IZ'to.20'" ,x^l8t(Hx3") Spans 6 ton Feet. ^- Length of Culvert ^ ^Z enqth of Culvert is taken as the .,,„ ^Distance from Outs.foOutside ofPara- .^Vpetsorfrom 0,to0.of6uarclRailandMeaS' vuredonaiineatFlghtAnglestoCLofRoad. ^ Span is Taken as tfie Distance bet Abutm'ts yy. ^i^easured on a Line parallel to the C.L.ofRoad. ^at Top of I- Beams. Angle of Skew is the Angle bet the C.L. of Culvert and a Line at if. Angles to C.L.ofRoad. ti=Total Height of Abutment ^ ^ A and B = Deflection of Wings in Degrees. L and M^Lenath of Wings. , , ^ ^_. P = Length of Abutment i^leasured along Face of Top^ Skew Culv&rt. I20 DRAINAGE lI^H9djji-ynn VOOO O N tvooo O N tvooo O N rfvOOO O N rj-vo oo O n ■* Ut'J . qi3u37 ;ooj Sz uStJ *^ (U 2 q;Su3i ,;ooj J9 J torofoco-t-'l-^ioioiovovovovo <^ t- t>.00 00 (» Ov S O. Ov C 00 Ov O M Cj fo '^ >OvO t^OO Ov O M (M fo lovo f^OO Ov O c^ fO ? Mcjc^cscswc^focofoeo 0000060666666666666666666 lOqvOVO .tOM00 OvlOlOH t^TtO t^foioMOO^ tj- xo lovo t^ t>»oc5 ovovOMt CO X mSUa'J 00 Ov O H M fO •^ tovo t>.00 0» M N ro -^ tovo t^OO 0> O H N fO ;ooj Sz •3 3 azjs •3 V3 "* en ao I cs Cj c^ C0f0f0r0'«t'^'<4-'*>0t0 lovo VO VO vO *>.*'.*>. t>.00 00 M OvvO "ti- N vovo ^00 M u-> t^ 00 VO O M N Tt O t^OO Ov o> O ^, ^.^ -r^OvMroioOPJOOMTj-i^M M W cs f0f0r0r0i0»0 lov© t^OO 0> Ov 0» O ^^^-5«^,„'' * ^ * 5„5*-.**'L*.5^5^ *-.*_* * * nh«n|-«nHnhfni'4iH«t-|'« OtoooO^^^Or^lDC . _ O f0i00vi0f^0vt~«.0 rOVO OvMD OvO t MMHHNWMCO"^10»0 lovO VO Ov C O O M H W VO t^ t>.00 4£^l 00 Ov O M e^ fO ^ tr>vo f.00 0» M c« fo ■* i/^vo t^oO O O m w fo SnpBdg OvOOvOOOvOOOOOvOOOOO Ovvo b b o o "' •-' •^' ^' v' v' J v' v' v' v' v' O v' v' v' v' v' v' v' ^' ^' saqouj q:jdaa M9^g M9^S *0 f* 1^00 OOOvO O c^ « w M NV)ioiiOxoio VO tooooooooo rt- vjvovo ^^00 OvOvO^ ,,, w-,^>^ N o»vo ^9 Q r^ -^ H ovvq foq ^■^►^oq locj qvv6 "ro 6 oo io ci' Tt ^ ir>vO t^ t^oo 0*0^6 H cJ c5 co-^rj- irjvo vd lAoo 6> 0\ 6 m HHMHHHMHHHHHHHWC* O VO fj OvvO fO OvvO N OvvO W OvvO N OvtOWOO »/^N00 tOMOO oj q ov t«.vo »^ po N H 0*00 *:• »^ -^ fo H o Ov t^vo «o to n h p> lovovo i>o6 6^ 6 t O VO ^0 OvvO ^^ OvO W OvtON OviOMOOvO WOO tOHOO tOMOO »OvO t^OO 0> O H W CO -4 tovd lAoO Ov d H w fo ■^ v>vd t^oo 00 MHWHMHMHMHWCSC- q POO 00 q "^ qs cooq fo qv H \-K \-< (N cs cs rOfO'^'^^iO tovO ^ 3;3JDU03 00 Tt■c^lOT^T;^. m M H c^ CS CO '^0 t^OO W '^O 0^ M H H H H s.inqv 2 1^ t^o c^ H to Tj-vq CO tooq t^oq -^ c^o .H00 000 tood CO rj-od CO d 00 c. d w IH M CO CO too t^ O^ M cs rf t^ H M M Hi s^;nqv z (N "«tO CS 01 tOOO t^ H H CO <>< r}-O\tOH00 toC^OO too t^OO 01 cs CO '^ •^ TjoO r».00 On w CS CO to f5 « J>- Q coo ON M 01 toOO 01 tooO w -THOO tocoO t^toCN 0\i>-'rt*H On CO to i>.o6 d oi rj- to !>. d* d "N tJ-vo" t^- MHMHHM0401CS0101 A M\o oio 01 t^oioo cooo H 00 rt- 0^ rh tOOO H t^CSOO COtOTj-H tOMO 01 CO too CO O^'H. oi Tt-tot^ONd oi coto HHMMHHO1010101 CO II « o O CO 11 < O Cubic Yds. each ft. in length of Culvert more or less than 25 ft. Xjuosispi i>- H 00 to too ON O^ On Ht tJ- On t^O t^ H ^0 On oi 1000 •^OO CO *>• H M NO HMHHoioioicocOTt-Ttto toNO 3;3Jouo3 •^ t^OO COOO ^^ M ^^ to too to CO Q\ H covq 00 M -"^ q CO i>- H ^ q "^^ On d H H M w oi oi cocOco-^-^tototo Cubic Yards Third Class Masonry • S3UTA\ ^^ toON-^t^-Oi H H coioO rj- t->-vo *^ "^ vd d 0' oi d On On tJ-CO* 4 m d ci ^ »-^ M H OJ 00 CO -^O t^ ON M CO lA t^ H M ^ H OJ s,;nqv 2 tOCOtOCO»OCOtOt^01 01 iocOcoi>-io 00 ^ t^Tt-c^ d '^"'^"^Tf too i>. On 01 CO •-•}■ rl- too i>»00 On H 01 co "^ to -ggcS s3niM^ tooioq "^"^"^w ^^"^01 ONThw to tOON^ONtocOOl toOO O1O0 to-^O dN H H 'N CO "^ tovo 00 On H CO to i>. \^ ^ \-K ¥^ s,;nqv z CO CO q q "^ cooq ^^qqi-^. oot^q cooo rf d CO d oi H H M H M oi "4 01 0> CO rt" Tj- too t^OO On H 01 CO Tf 2. % t^ COO On M On 01 toOO OI toOO H 00 COO t^tooi ONt^rJ-H 0^\0 CO H cotot^ONd oi ^tot^ONH oi -"^vd 00 MMHHHH01O1OI0101 ^ 1^ COO ON 01 ON 01 tOOO OI tOOO H CO NO COO t^tOOl ONt^TfM OnO CO M C0tOl>.dN0 01 riftot^ONM CS ■^000 MMMHMMOIOJOIOIOJ :iu9m;nqy JO :^qSi3H K . t^OO ON H 01 CO "d- too i>.00 On HMMlHMMMMMMOl 122 DRAINAGE °0 II W o' II < o Cubic Yds. each ft. in length of Culvert more or less than 25 ft. XiuosEp\[ 9;ajDuo2 rt CO vo 0\0 ""^vO vO vO H t^vO OO W On fovq <^ ^. ^ q "^ ci t^ fooc Tf o t^ CO HHHcJ cicOCO'^'^lO lOsd !>. I>.06 Cubic Yards Third Class Masonry sSmjv^t' 00 « woqoq q "^q^q -^ "^oq t>. t^vo vd M l>.COIH H H l>.COC>t^t^C>'4H H H « CO Tt »OVO 00 On M t^lOOO H H H H M (^^ s,;nqv 2 lo looq lO lO -00 O cs CO "^NO 00 On H CO H M H M M M M r» M Us sSujAY ^ IOI>.IOCO(N HOOOO HVOVOOO H H to On tJ- t^ lO "s^j-OO H t^ fO H H Tt On H c^ oj co-^tot^CO O CN'^vooO H H H M M s,;nqv 2 q ^foq Tfioo^ooo t^o Ono o CO O 00 t^vO lOVOtot^O tJ-OncO 0\nO ro ""t Ti- lO-O t-*00 O w CO f to t^OO O MMMIHMMI-4M 'g 1 If )^ ThvO On M ^0 lO t^ -^ cotot^O^H CO HHHHHCSC<.0 rf" q CO tooq H rj-oq -"^-oo co t>- m t^ cooo HMHMCSC^CSrOCOTt-Tj-tO lOVO NO < Cubic Yards Third Class Masonry s2m/^Y ^ 00 CO q 00 t^ On Tf tooq lO CO M i>. Th (N VO H f^COM O »-< f^C^ ONl>.t^ONTj-H H H cs CO "^ too 00 On M CO tOOO H s,:>nqv z co.i>-co"^Ti-qN^^ h loio tood Tf O* O "^ cooo* M O* CS M M cooo* H CI CS CO '^ to t^OO O CS Tj-O OO IH M H M H s,:inqv c o oq to CO t^NO q^^qqo^^qoo t^ CS* OnO- CO w d ^O t>od ON CS rf 00 CS CO CO ''t too 1:^00 On w CS Tt loO ll 1^ TfO O^'r* CO to r^ . dv H* CO to !>. dN CS* rf HHMHHCSCJCSC) M CO CO h5 Tj-qN-^ON-^qNTtONrtONTt-qN'^qNT}- CO ri"0 !>. d» d 8 n /" /6'-0' ?4 VfffT. ?o II'- 0' >V>(iZ.S /? taf-cf Hl)H. « V 25i0> » 7V vfffr V.-l^ir'o'a.Aelw*! »V|2*ifl' " BEAM 33^£^ » ^ -7^ " v£«r. fOOTISS «Arr 9'0' 4-3' ALL BARS-Sq. WISTED-HILD STEEL 41"-//' ^•1-23-6" %"-l2'' Section- A- A Planfor 4x4 Piling if Necessary yJioadSurface. Camber Formsfo prevent Sag. deiel Strips to be Used on all Exposed Corners All Steel iobe Placed before Concrete Is Started. Concrete to be I'M Mixture. Elevation „ t'^ raceOldmilniih Concreie.l2"thick. Depth Dmaube increased if a Firm Footinq can be Found wfhin a Short Distance: if not4x^'s/Kil/- be Driven to Solid Bearing Design used by Monroe County, New York State. UNDERDRAINS I2S Underdrainage The purpose of under drains on hard surfaced roads is to intercept the ground water before it reaches and softens the sub-grade. On a sidehill road the drain is usually placed under the ditch on the uphill side (see Figure No. 24, position No. i) where the greatest Position No. I Direction of Seepage Fig. 24. depth can be obtained with the least excavation and where the water is caught as it flows out of the hill. Some engineers place the drain in position No. 2 (Figure 24) but this requires more excavation for the same depth and for side fa ? T/jroat^^ Position N0.2 I Position No. I Position No. 2 Pig. 25. seepage is not as effective. The usual depth for drains is three feet below the surface. Where the road is on a descending grade, the water will flow out of the hill directly under the stone and the drain is placed as in Y--2.0'--^^ }<-- 2.0'-^^ Baclifili^^^^;^i^^^m^^^<^f^^lf No. 4 Stone-: No. 2 Stone orOnuveii ParmTile } Joints — ^ — V^r'Open Tfiroat WrappeoHnBuriap^'O'^ ^'l-O^ Fig. 26. Figure 25, position _i, or two drains are built in position No. 2. Position I is the usual practice, being cheaper and more effective. The argument for the two side drains is, that in case the throat becomes clogged, a side drain can be taken up without disturbing 126 DRAINAGE the macadam. This rarely occurs in a center drain, as it is better protected than those in position 2 and in case the center drain does clog, side drains can be constructed at any time. There are two kinds of drain in general use: No. I is built entirely of stone with an open throat roughly laid as shown; it is satisfactory in a water-bearing strata of gravely M '>"""i>n>>\"">l{f Trrrrf — - a! Fig. 27. loam or clan, but does not work so well in quicksand, which is liable to fill it up. It is generally cheaper, however, than No. 2. No. 2 is built of porous farm tile or vitrified tile of a suitable size (usually 3" to h") with open joints, wrapped with a double or triple layer of burlap; the pipe is surrounded and covered with clean gravel or %^" crushed stone to a depth of 6", the remaining depth of the trench being filled with large stone. If this drain has a good fall and the outlet is kept free, it will rarely clog even in bad quicksand. SUMMARY 127 The author has successfully used the following method to pre- vent the outlet from clogging; after being brought out from under the macadam, the drain is continued under and across the ditch line, then keeping outside the ditch line, and using a slightly smaller gradient than that of the open ditch, the tile is continued down the hill until it reaches a point eight or nine inches above the ditch grade. Here it is turned into the open ditch through a small concrete head-wall and w^hat little material it tends to deposit is washed down the ditch by the surface water (see Figure 27). Summary of Chapter. — The present bridge situation demands attention as even in the richer states it is lagging behind the im- provement of the roads. The separation of Bridge and Highway funds and the lack of central control often results in the ridiculous situation of a modern road limited in use by antiquated bridges. Road pavements can be strengthened from year to year by additions in thickness and the construction of better surfaces on top of existing improvements but structures must be rebuilt entire to increase their strength and for this reason more foresight in re- gard to future traffic must be exercised in their design. A liberal allowance for increased loads is desirable. Liberality in size of waterway for culverts is also good policy as it adds only slightly to the cost and materially decreases the difficulties of maintenance. The design of drainage must be complete and reasonable and if the existing scheme is not feasible it should be changed regardless of law-suits as whenever an improvement is made it is always cheaper to correct mistakes at that time than it will be at a later date as every year's use fix the channels more firmly. The selection of type offers the greatest chance for reasonable economy in culvert and bridge design. CHAPTER IV LOW TYPE EARTH, SAND -CLAY AND GRAVEL ROADS These types of construction are the initial steps in final road improvement and serve to gradually pull traffic ''out of the mud.'* They are the only types that can be reasonably built in unsettled communities or scattered agricultural districts without outside aid and if properly located, graded and drained are well worth very careful engineering attention. They constitute such a large percentage of the mileage of road work that they are probably of more economic importance than the higher type macadams and rigid pavements. They however are only makeshifts under adverse weather con- ditions (5 months in the year) as compared with the more substan- tial forms and must be regarded as such. They require continuous maintenance but not the same degree of perfection in maintenance as better roads nor anything like as much money in yearly upkeep as traffic is light and no one expects or demands that roads of this kind be kept in perfect condition. The gravel road will serve in a fairly satisfactory way up to about 250 moderately light rigs per day. The following table taken from Agg's Construction of Roads AND Pavements gives an idea of the traffic capacity of gravel and macadam roads. This shows approximately the practical limit of these roads and indicates that earth, sand clay, or gravel are reasonable for a large mileage. 128 TRAFFIC LIMITS 129 Average Daily Traffic Limits in Massachusetts Table showing results of observations of traffic on different types of road surfaces in Massachusetts. ^ Standard road, 15 ft. in width; gravel or water- bound macadam, 5 or 6 in. in thickness, with adequate drainage and proper foundation, with 3 ft. gravel shoulder on each side. Type of Surface Light Teams, Carriages, Wagons Heavy Teams, One-horse Heavy Teams, two or more Horses Automobiles A good gravel road will wear reasonably well and be economical with 50-75 25-30 10-15 50 to 75 Needs to be oiled with 50-75 25-30 10-15 Over 75 Oiled gravel, fairly good, heavy cold oil, ^^ gal. to the sq. yd. applied annually with 75-100 30-50 20 500 to 700 or more Waterbound macadam will stand with 175-200 175-200 60-80 Not over 50 at high speed Cold oil or tar will prove serviceable on such macad- am with 175-200 175-200 60-80 50-500 Macadam will then stand, but the stone wears, of course, with 175-200 175-200 60-80 500 or more *Waterbound macadam with hot asphaltic oil blanket will be economical with 100-150 50-75 25-30 1500 and more with fewer teams And stand at least 50 trucks But will crumble and per- haps fail with over (On narrow tires, ice, farm and wood teams, etc.) 150 75 30 * Waterbound macadam with a good surface coating of tar (3'^ gal. to the sq. yd.) will stand with 100-150 50-75 25-30 1500 or more (But requires to be recoated annually with }i gal. of tar per sq. yd.) It Is assumed that all road surfaces are kept constantly patched, that be- fore applying bitumen the road surface is cleaned and patched, and the bitumen covered with pea stone and sand or gravel and kept covered so that it never picks up. * Author's Note. — One coat penetration bituminous macadam will stand any number of light autos and more steel tire or truck traffic than shown above, because it takes the wear more directly and has no blanket coat which crumbles under such traffic. 130 SAND-CLAY AND GRAVEL ROADS EARTH ROADS Rut Roads. — The simplest form of road is the so-called rut road used in the arid regions of New Mexico and the southwest. They are constructed, by clearing the right-of-way of brush and then cutting two shallow parallel ruts in the surface vegetation or soil crust by means of two cutting irons gaged to fit the ordinary wagon track. A wagon trail of this kind can be constructed for from $5.00 to $15.00 per mile; can be used by autos with fair com- fort at speeds up to 15 miles an hour and on the flat mesas of this mmsvjmmmmm. -^^i'— Rut road.^ district are more lasting and satisfactory than the ordinary turn- piked section as so little rain falls that an elevated fill grade does not consolidate and is worse than useless for traffic. On these rut roads any rain storms that occur wash the coarser particles of the soil into the ruts and gradually an armored track is formed below the general elevation of the mesa. No drainage structures are necessary where construction of this kind is adopted. n:-> Cutting rig for rut road. Earth Roads. — The same principles of grade, section and drainage apply to this class of road as to the higher types except that the surface ditches are generally made slightly deeper and more care is taken with the underdrainage; this is necessary as the earth road becomes more easily saturated with water than types which are sealed over on the surface. If the natural soil is good road ma- terial such as gravel, disintegrated rock, hardpan or sandy loam this type of construction carefully graded, drained and shaped by blader finish and maintained by dragging makes a satisfactory road for light traffic. Their cost depends on the amount of grading required and the methods that can be used. The cost of drainage culverts, incidentals, etc., will vary but will run about $600 per mile for good work. Simple blade machine turnpiking, where the dirt from the ditches SAND-CLAY ROADS 131 makes the center fillcost (in districts similar to Wyoming in 1914- 191 5) about $150 per mile. The same work at present (1918) is bid off for about $200 per mile. A fair relative price for first- class work of this kind including drainage and incidentals can be placed at $600 to $800 per mile. In rolling country requiring grade reductions by cut and fill and wagon haul a fair relative price including drainage and incidentals is approximately $1500 to $3000, where no rock is encountered. In mountain road work where the excavation runs anywhere from 1000 cu. yd. to 30,000 cu. yd. per mile with a large percentage of rock the cost will run anywhere from $1000 per mile to $25,000 per' mile. A fair average for such conditions is $3000 to $6000 per mile. As previously stated it is entirely a matter of required grading. The approximate cost of different classes of grading are taken up in more detail in Chapter X on "Preliminary Investigations." Current practice in earth road sections is shown in the following plates. Mountain Roads, Plate No 11, page 68 Wyoming Standards " " 5, " ^55 Iowa Standards " " 31, " 132 Pennsylvania Standards, " "32, " 132 Current practice in grading and finishing are given in typical specifications, page 139. Earth road maintenance is discussed in Chapter VII. Where the soil is not a good road material the surface is improved by artificial mixtures of selected soil or by surfacing with gravel, chert, disintegrated granite, slag, shell cinders, etc., in fact any local material that gives body to the surface and prevents softening. Sand- Clay Treatments Where the natural soil is clay the resisting power of the surface during wet weather can be increased by the addition of sand. Where the natural soil is deep sand the surface can be made firm and resilient by the addition of clay. The so-called sand-clay treatment aims to provide a surface layer of mixed sand and clay about 10" to 12" deep (see Plate No 33, Alabama Standards) in which the sand forms the body and the clay just fills the voids in the sand and acts as a binder. It can be readily seem that different materials will require different proportioning of the sand and clay; the only sure way to get the best results is by experiment on the road during construction but to give an idea of the approximate proportioning the following list of recommended mixes is taken from the Good Roads Year Book of the American Highway Association, 191 7. Sand- Clay Roads The grains of which sand is composed are usually hard and tough and able to resist abrasion if held securely in place. In an asphalt pavement they are held by the asphalt and a wearing surface of great resistance to 132 SAND-CLAY AND GRAVEL ROADS Plate 31. — Iowa Typical Section Earth Roads. X ^^V^' L- ll'tQ. ^ Jlp. .; L-_ n TQ >u Ji.w. .>J I /3' ; 13' 1 [--"■■ — H-->b^lk- — -^ Boftom of Difches' fo be Rounded. Plate 32. — Pennsylvania Standard Earth and Gravel Roads. Rise fo Crow n^: I Ordina -y Soil. 2'^ /5'_._.___.->i< IS'.. ^Risefo Crown /f V ' TTTTTTTTrmrmmTTTTTTTrmmmr^^ . ^30'- — >| Gravel not fo exceed I in Di'a Rise fo CroY/n^ -7 ' 4"eravef / or 10%0-fClaj and Free from ^ allLumpSi Oravel Roadwau. Xlean Ban kdravelfo Pass ^2 „. , ^ ,1,1 ^ Screen, retained bua^ Screen. Rise fo Crown I' I . ' ^^J jru,, • l^ i nfwimiJr}i\}nw)in)nm 77TTTmf7m^^ ^^<^c?fnfe/^/r7^ fo be Pebbles. Id' .^- I 30' Sandtj Loam . SAND-CLAY ROADS 133 abrasion results. In a sand-clay road they are bound together by clay in a less firm manner but one giving excellent results on well drained roads carry- ing light traffic. The aim of the builder of such a road is to employ just enough of the stickiest clay at his command to fill the pores of the sand and to mix these materials together so thoroughly that there are neither lumps of clay nor pockets of loose sand left in the surfacing. This gives the maxi- mum amount of hard sand to carry the traffic and the minimum amount of clay to bind it. More sand makes a less durable road and more clay makes one which becomes soft more rapidly when wet. There is a great difference in the value of different clays for such work. Some of them become dough-like when mixed with a certain amount of water and can be molded into objects which retain their shape after drying. If these molded objects are immersed in water they will retain their form for a long time. These varieties are called "plastic clays "_ and the most plastic are called "ball clays." There are other varieties which fall to pieces more or less quickly when wet, as quicklime does, and they are therefore called ''slaking clays." They are more easily mixed with sand than the plastic clays but they have much less binding power and a road built with them is less durable when dry and more easily rutted when wet. The amount of clay to be used can be determined by a simple field test described as follows by Andrew P. Anderson: From typical samples of each of the available clays, test mixtures, varying by one-half part, are made with the sand so that each clay is represented by a set of mixtures ranging by successive steps from one part sand and three parts clay to four parts sand and one part clay. These are worked up with water into a putty-like mass and from each mix two equals quantities are taken and rolled between the palms of the hands into reasonably true spheres, labeled and placed in the sun to dry. When thoroughly baked, a set of spheres representing any one clay is placed in a flat pan or dish and enough water poured gently into the pan to cover them, care being taken not to pour the water directly on the samples. Some samples will begin to disinte- grate immediately. Those breaking down most slowly contain most nearly the proper proportion of sand and clay for the particular materials. The relative binding power of the various clays may then be determined by comparing the hardness and resistance to abrasion of the various dry samples having the correct proportion of sand and clay, as determined by the water tests. In February, 1917. representatives of 21 state highway departments and of the U. S. Office of Public Roads recommended the following mixtures for hard, medium and soft classes of sand-clay roads. Hard Class. — Clay, 9 to 15 %; silt, 5 to 15 %; total sand, 65 to 80%; sand retained on a 6o-mesh sieve, 45 to 60%. Medium Class. — Clay, 15 to 25%; silt, 10 to 20%; total sand, 60 to 70%; sand retained on a 6o-mesh sieve, 30 to 45 %. Soft Class. — Clay, 10 to 25 %; silt, 10 to 20%; total sand, 55 to 80%; sand retained on a 60-mesh sieve, 15 to 30%. By clay is meant material separated by subsidence through water and possessing plastic or adhesive properties; it is generally below q.oi mm. in diameter. ^ By silt is meant the fine material other than clay which passes a 200-mesh sieve and is generally from 0.07 to o.oi mrn. in diameter. ^ By sand is meant the hard material which passes a lo-mesh sieve and is retained on a 200-mesh sieve, and is generally from 1.85 to 0.07 mm. in diameter. The larger part of the following explanation of the construction of sand-clay roads was prepared by W. S. Keller, State engineer of Alabama, where many miles of sand-clay roads have been built and are giving good satisfaction. Every farmer who lives in a section of country where both sand and clay are prevalent, is more than likely traveling over a section of natural sand- clay road but is ignorant of the fact. He can call to mind some particular spot on the road he travels though it may not be more than 100 feet in length, that is always good and rarely requires the attention of the road hands. Good drainage will be noticed at this place and if he takes the trouble .to investigate, he will find that a good mixture of sand and clay forms the wearing surface. If this 100 feet of road is always good then the entire road can be made like it provided man will take advantage of the lesson 134 SAND-CLAY AND GRAVEL ROADS SAND-CLAY ROADS 135 136 SAND-CLAY AND GRAVEL ROADS taught by nature and grade the road so that the drainage will be good and surface the balance of the road with the same material. If it is not possible to find this ready mixed surfacing material convenient to the read it may be possible to find the two ingredients in close proximity. In case the road after grading shows an excess of sand, clay should be added, or in case clay predominates, sand should be added to produce good results. There are four general ways in which sand-clay roads may be built. 1. Ready mixed sand and clay placed on clay, sand or ordinary foundation. 2. Sand and clay placed on soil foundation and mixed. 3. Clay hauled on a sand foundation and mixed with the sand. 4. Sand hauled on a clay foundation and mixed with the clay. Taking up the various methods in order. 1. A natural mixture of sand and clay can often be found where the two materials are found separate. The most important point is to know the natural mixture when seen. The very best guide to this is to find a natural piece of good road. A sample from the best of this good section will, fby comparison, indicate what is required, close to the road to be surfaced. This natural mixture of sand and clay can be noticed where red clay and sand crop out, usually well up in the hills, having ditches and cuts the appearance of red sandstone. A good stratum of well mixed sand and clay will stand perpendicular in cuts and ditches, resisting erosion almost as well as sand- stone. A test of the best natural sand-clay mixtures will show the sand forms about 70% of the whole. The test is very simple. Take an ordinary medicine glass, measures 2 ounces of the mixture into the glass and wash out the clay. Dry the remaining sand and measure again on the medicine glass. The loss will be the amount of clay originally contained in the mass. Before placing any sand-clay on the road, the road should be graded to the desired width. The surface of the graded road should be flat or slightly convex. The sand-clay should be put on from 8 to 12 inches in thickness, depending on the character of the sub-grade or foundation. With a hard clay for foundation, 8 inches of sand-clay will suffice. If the sub-grade is sand it is well to put on as much as 12 inches of the surfacing material. After a few hundred feet of surfacing material has been placed, a grading machine should be run over it to smooth and crown the road surface before the top becomes hard and resists the cutting of the blade. It is a good plan to turn the blade of the machine so as to trim the edges of the surface part, discharging the excess sand and clay onto the earth shoulders. After one round trip with the blade turned out, the remaining dress work with the machine should be with the blade turned in, with the exception of one trip down the center of road with the blade at right angles to the axis of the road for the purpose of distributing any excess of material left in the center. After the machine work, it is well to follow with a drag, which smooths any rough places left by the machine and leaves the road with a smooth, even surface. A sand-clay road, unlike other roads, can not be finished in a short space of time. It can be left in an apparently finished condition with a hard smooth surface, but it will be found on close examination that the hard surface is in reality only a crust, below which there are several inches of loose material. After the first hard rain the crust softens, the road be- comes- bad and the work appears to be a failure. This, however, is just what is needed to make it eventually good. After the surface has dried until the mass is in a plastic state, it should be dragged until the surface is once more smooth, with proper crown, and should be kept this way by drag- ging at least once a day until the sun has baked it hard and firm. The mis- take of keeping traffic off during this process of resetting should not be made. The continuous tamping of the wlieels of wagons and hoofs of horses is just what is needed to compact the sand-clay into a homogeneous mass. The ordinary roller is not very effective in this work, but corrugated rollers have given excellent results. One type which is widely used has 18 cast iron wheels weighing 300 pounds each, which compress the bottom of the mixture first. As the material becomes more and more compact the wheels ride higher and higher and finally the surface is so hard that the roller does not sink into it at all. A drag is an indispensable machine in the construction of any kind of sand-clay road. 2. Sand and clay placed on a soil foundation and mixed. This is neces- saiy where the old road has neither a sand nor clay foundation and it is impossible to find the two ingredients ready mixed, but possible to get both in separate state near at hand. The clay should first be placed on the road to a depth of 4 inches and the required width. It is not wise to place more GRAVEL ROADS 137 than a few hundred lineal feet of clay before the sand is hauled, as the clay rapidly hardens and makes the mixing process difficult. After, say, 400 feet of clay have been placed, the clay should be broken by means of a plow and harrow, if it has become hard, and sand to a depth of 6 inches placed on it. This should be plowed and harrowed in thoroughly. This is best done immediately following a rain, as the two can be more satisfactorily mixed. The traffic aids the mixing and should be encouraged on the road. After the mass appears to be well mixed, the road should be properly shaped, as previously explained. The road should be given watchful attention and should sand or mud holes appear, a second plowing and mixing should be given it. 3. Clay hauled on a sand foundation and mixed with the sand. The mixing process is similar to that described under second head. It is only necessary to add that as the foundation is sand, a little more clay will be necessary than where the foundation is of clay or soil. 4. Sand hauled on a clay foundation and mixed with clay. The clay foundation should be plowed to a depth of 4 inches and harrowed with a disk or tooth harrow until the lumps are thoroughly broken or pulverized. Sand should then be added to a depth of 6 inches and mixed as before described. Sand and clay can be mixed best when wet, but as most road construction is done in the summer months, it is necessary to do most of the mixing dry and keep the road in shape after the first two or three rains, while the pass- ing wagons and vehicles give the road a final wet mixing. A sand-clay road is the cheapest road to maintain, for the reason that it can be repaired with its own material. With a drag or grading machine ruts can be filled with material scraped from the edges, whereas on gravel or macadam roads, this is not possible. The repairing of these roads can be^ done almost exclusively with the drag, only enough hand work being required to keep the gutters open and the growth of weeds cut on the shoulders. Holes are repaired by adding more sand-clay, and when many of them appear fresh sand-clay should be spread over the surface of the road. If the road gets into really bad condition, the roadbed should be plowed up, reshaped and fresh sand- clay added. This is unnecessary where the road is maintained properly and the travel is not too heavy for the type of construction. The maintenance of sand-clay is discussed in Chapter VII. Specifications for sand-clay are covered in Part III. Sand-clay roads can not be considered as finished until traffic has used them for a year or two and all the small areas showing improper mix have been remedied by maintenance. The cost of surfacing with sand-clay varies as any form of con- struction with labor, length of haul, cost of materials, etc., but generally adds from 15c. to 35c. per square yard to the cost of an earth road. A fair comparative figure would add $1000 to $2000 per mile for a 16' width of sand-clay to the cost of an ordinary dirt road in the same location. Sand-clay construction is not advised if good road gravel or other coarse local materials are available. GRAVEL ROADS A coarse well graded gravel is the most satisfactory material for a cheap road. It giv^es body to the traveled track, binds well, rides easily and with a consolidated depth of 8" to 20" holds all ordinary loads after it is well consolidated. For wheel pressures and depths of metaling see Chapter V, page 152. At the present time 50% of the mileage of surfaced roads in the U. S. are gravel roads. They are however hard to consolidate quickly and need carefully continuous attention to prevent the formation of ruts, holes, or 138 SAND-CLAY AND GRAVEL ROADS humps. Gravel roads can not be built by merely dumping loose gravel on the road and then hoping that traffic will put it in shape. A large mileage has been built on this principle and the results are shameful. A successful gravel road requires careful select ion of the gravel, careful spreading, careful consolidation and constant maintenance. The best practice is shown in typical specifications Part III but the essential features will be summarized at this point. Size of Gravel Gravels suitable for road work are widely distributed over the country. They occur in bank deposits and in stream beds. The prime requisite of a gravel for foundation courses is that it contains a large percentage of coarse pebbles to give body and distribute the wheel loads. The prime requisite for a surfacing gravel is hard- ness of the stone and well graded coarse and fine particles which will take the wear evenly and bond well. Pit run gravel varies greatly as to size and composition even in a single pit and for this reason no definite limits can be well set for the proportion of sizing. In general it can be said that for foundation courses any coarse gravel, which when screened through a ^i^" mesh contains less material passing the screen than retained on it, can be success- fully manipulated without screening to remove the excess sand. In some localities this limit is not feasible on account of excessive fine material and the limit of fine material passing a }yi" mesh is placed at 60 % but in reality a gravel of this fineness does not produce satisfactory results and a road on which it is used becomes more nearly a sand-clay construction than a gravel type. For a top course the large stone above i J'^" in size should be screened out and if pit run is used the sand passing the J^" mesh should not exceed 40% of the volume. The most satisfactory top is a screened gravel but this adds materially to the cost. Where screened gravel is used '^'2" to 3" is satisfactory size for the bottom course and J^" to !%" for the top course. The following specification has been recommended by the com- mittee on Materials of the American Society of Civil Engineers. Two mixtures of gravel, sand and clay shall be used, hereinafter desig- nated in these specifications as No. i product (for top course) and No. 2 product (for middle and bottom courses). No. I product shall consist of a mixture of gravel, sand and clay, with the proportions of the various sizes as follows: All to pass a I'^i" screen and to have at least 60 and not more than 75 % retained on a ^^ inch screen; at least 25 and not more than 75 % of the total coarse aggregate (material over 3'i inch in size) to be retained on a ^^ inch screen; at least 65 and not more than 85 % of the total fine aggregate (material under 3^ inch in size) to be retained on a 200-mesh sieve. No. 2 product shall consist of a mixture of gravel, sand and clay, with the proportions of the various sizes as follows: All to pass a 2^ inch screen and to have at least 60 and not more than 75 % of the total coarse aggregate to be retained on a i inch screen, at least 65 and not more than 85 % of the total fine aggregate to be retained on a 200-mesh sieve. Bonding Properties. — Clean gravel will not bond well. A small percentage of clay, loam or lime dust is desirable and necessary. This GRAVEL ROADS 139 per cent, ranges from 10% to 20%. For bottom course, pit run a gravel which contains over 20% of clay or loam should not be used; from 10% to 15% gives the best results. For top course 10% is about the maximum clay or loam allowable. Many so- called cementitious gravels of lime rock contain or produce under trafl&c a first-class rock dust binder of the highest grade. Clay or loam can be added to a clean gravel by mixing at the pit or by placing a thin layer of such material over the gravel as spread on the road and mixing it with the course during consolidation. Spreading. — Gravel must be uniformly spread; there are two general methods; the trench spread (Plate No. 34) and the feather edge spread (Plates 35 and 36). The feather edge spread is probably the better method. In either case the depth should be uniform and the surface properly crowned. Gravel should not be dumped in piles; it should be spread along in windrows and the spreading finished by shoveling, raking or by road machine blade scrapers. If pit run gravel is used the course should be harrowed to distribute the sizes uniformly. The ratio of compacted to loose depth is approximately 1.2 or 1.25. That is a loose depth of 8" will compact to about 6J^". If screened gravel is used the filler should be added before the course is rolled. Consolidation. — Consolidation is the hardest feature of pit run gravel construction. Detail methods are described under gravel' foundations, Chapter V, page 156. A combination of traflSc and roller consolidation while the gravel is moist gives the best and quickest consolidation although traffic alone will put it down firmly if given time and the shape is kept intact by constant drag- ging with a hone or road machine. The following Minnesota Specification shows the methods employed where a road roller is not used. MINNESOTA SPECIFICATIONS Graveling Description. — Graveling shall be construed to mean all surfacing with pit run gravel, screened gravel or crushed rock, or crushed rock screenings built in two or more successive courses. Material. — All materials shall be of a quality approved by the engineer and shall be the best obtainable from the specified pit or quarry. Materials for the first course shall contain no stone which would be retained on a screen having 2}^^ inch openings. Materials for the second course shall contain no stone which would be retained on a screen having i inch openings. If available material contains an excess of sand, such excess shall be handled as provided by special specification for each job or project. Sub-grade. — The cross-section of the sub-grade shall be as shown on the standard cross-section # accompanying the plans. Graveling upon a wet pauddy roadbed will not be permitted. If the graveling is not done in con- junction with the grading as a part of the same contract, the sub-grade for the full length of job embraced in the graveUng contract, shall, before being graveled, be dressed by the County to the cross-section above mentioned. Thereafter, the contractor shall keep it dressed to the specified cross-section and free from ruts, waves and undulations, as part of the graveling contract. If the grading and graveling are performed under the same contract, the preparation of the sub-grade shall be performed as part of the grading item and no additional charge will be allowed therefor under the graveling. Loading and Hauling. — Loading from pits shall be performed in such a manner and by such methods that a uniform grade of materials will be delivered upon the road. Stone exceeding the sizes specified, shall not be I40 SAND-CLAY AND GRAVEL ROADS Plate 34. — Iowa Typical Gravel Roads. J 's" . '^ Shoulder Drain. /Requires 2450 Cu. Yds. oi 6rave! per Mile. \Maximum'Z'6" "half Section m Fill, Half Section m Cut. CUA5S"A" DOUBLE TRACK ©RAVEL ROAD. CLASS A SINGLE TRACK 6RAVEL ROAD. Requires I&&5 Cu.Yds. of6ravelperMife. Hal-f Section in Fill . Half Section in Cut. (Mi'nimum'l'6\ \Maximum'Z-6' It to lO'fo 4/^^-~.-J --M — e- Requires 680 Cu. Yds. of Gravel per Mile. Half Section in Fill Half Section in Cut, CLASS "b" 10 FT. SRAVEL ROAD. ITTrc f^frol Sq&few -for Maintenance Is recommended -for all gravel Roads. The Class's^ Section is approved only wifh the understanding that a suitable Patrol System for Maintenance will be adopted. Wider Cross-sections using the same Thickness ofQwvei mil be approved on application, GRAVEL ROADS 141 142 SAND-CLAY AND GRAVEL ROADS Plate 36. — Minnesota Gravel Road Section. {'Sub-grade 5hapeda& shown ^F^rsf- Course'' "^'"^ ©ravel Surf «acl n q -for Li9h+ Tra-ff i Qo |<_- /g' ^ 12' ZZLo.3' Dep+h la^Course O.OO' O.OO' Depfh2]<- 12' -^- 0,00 SOOCaYd.perMi. O.OO' 400 »» »» »f *> 0.00' 1200 »' '» •» »» -H ^ ! *5fCour&€ O.OO' i^Course O.OO ^OO' 0.10' ToialDepfhO.OO 0.17* 0.30' £.17' 0.20' t5oo' ,0.23 0.27' 0.30' 0.30* 0.30' 0.27 0.23' 0.20' 0.17' 0.20 0.20' 0.20" 0.20' 0.20' 0.17' O.IO' 0.40' 047 0.50' 0.50' 0.50' 0.4V' 0.40' 0.30" 0.17* 0.00'IOOOCaYd.perMi. 0.00* 0.00* 600 " '» »' " .0.17' 0.00'l600"»» » *' ^n Excavation U---* minr ->Kr 2 '->K— WadeLine\ j Genera 1 Grading Section InEmbankment- C.L. , -12' >t<- -12 H „^> 0,2' Finished Line Irt Excavation. 16rade fo Cross-section shown bu Heavy Line) Ciaij or of her good Bearing Material being placed in Top to Cover poorer Soil.- diaded and Planed Finishing to produce Crown indicated by Dotted Line. Grading Section in Sand InFmbankment .....yp ' ^- /2' ->, ir 0.2' tnDeep Soundings. Grading Section in Swamp In Firm Swamp, GRAVEL ROADS 143 loaded. No earth, sod or any foreign or vegetable matter, nor an excess of sand or clay, will be allowed in the gravel, and care must be taken that strippings be not mixed with the gravel. Any loads taken to the work containing such objectionable materials will be rejected. Dumping and Spreading First Course. — The first course material shall be deposited in a uniform ridge on the center line of the road and shall be spread immediately upon the sub-grade to a uniform section. This work shall be started at a point on the road nearest the pit or loading place and shall proceed therefrom until the extreme haul in that direction is reached. Shaping and Compacting. — The surfacing material shall be shaped, while being compacted under travel by the use of a blade grader, tooth harrow, planer or other suitable means. Ruts formed by the hauling or by travel shall be dragged full at least once each day and more frequently if necessary, to prevent cutting through the surfacing material into the sub-grade. Holes, waves and undulations, which develop and are not filled by dragging shall be filled by adding more material according to the direction of the engineer. The shaping of the material shall be performed according to the direction of the engineer and shall be continued until the material is well compacted, free from ruts, waves and undulations and is made to conform to the cross- section indicated on the standard above mentioned. If the material is not sufficiently compacted by the above methods within twenty days after placing, the engineer shall direct the character, amount and method of applying the binding material necessary to produce a com- pacted surface, and the contractor shall provide the necessary labor and equipment to perform such additional work at the unit prices submitted for the application of the regular surfacing material. The County shall furnish this binding material in the same manner as provided for the regular first and second course material. Second Course. — When the first course is compacted and shaped as speci- fied, to the satisfaction of the engineer, he shall authorize the application of the second course materials. It shall then be applied, shaped and com- pacted by the methods specified for the first course. _ The work of shaping and compacting shall be continued until the material is well compacted with the surface free from ruts, waves and undulations and conforming to the specified cross-section. Maintenance. — Maintenance is discussed in Chapter VII. Oiling. — Oiling with a light cold asphaltic oil or cold tar is re- sorted to under a moderately heavy automobile traffic. No gravel road should be oiled till at least a year old so that it is com- pletely consolidated and firmly bound. The surface must be well cleaned of excess fine dust and the oil applied in two or three successive light coats of approx. J^ gallon per square yard at inter- vals of two or three months. It takes more than one application to give even moderately good results as the clay and loam in the road tends to prevent the formation of a good bond between the oil and gravel but if persistent treatment is adopted this method in- creases the power of gravel roads to withstand touring car traffic but of course does not increase their structural strength or make them suitable for heavy unit freight hauling. Cost. — Pit run gravel varies in cost from 50c. to $1.50 per con- solidated cubic yard in place. Screened gravel from $1.00 to $2.00 per consolidated cubic yard. Gravel surfacing adds approximately $1000 to $3000 per mile to the cost of an earth road in the same location and a fair compara- tive price for this type including drainage and incidentals ranges from $2000 to $5000 per mile. Other Coarse Materials. — The same principles apply to the use of any available local material such as slag, chert, caliche, disintegrated granite, cinders, shell, etc., each one of which can be used to advantage in special localities. r44 SAND-CLAY AND GRAVEL ROADS Miscellaneous Special Cases. — Alaskan Climatic and soil re- quirements afford special problems; the following quotation from Engineering and Contracting of March 6, 191 8, indicates an inter- esting condition as described in the report of the Alaskan Highway Commission. "The most unusual and troublesome feature encountered in construction is the permanently frozen ground which covers a large portion of the entire interior, and which is protected from thawing during the summer by a thick layer of moss, turf, or decayed vegetable matter. The character of this frozen material varies largely in different sections of the territory, and even in the same section. It may be gravel, clay, silt, peat, or clear ice, or a com- bination of two or more of these elements. When gravel is encountered the problem presents no special difficulties; the moss or turf is stripped off, and the road graded in the usual manner. When the material is clay, experience has shown that the same procedure can usually be followed, but the grading is a slow and rather expensive process. After the protective covering of vegetable matter is removed, it is necessary to allow the soil to thaw and dry out somewhat before it can be worked, and unless a considerable period is allowed to elapse between the stripping and the grading, it will be found that the thawing has not extended to sufficient depth to permit of completing, the grading in one operation. When the necessity for the road is not pressing, an appreciable saving can be effected by stripping the road bed and digging drainage ditches during one season, completing the construction the next year. In those localities, however, where the frozen material is silt or peat, the stripping of the roadbed quickly results in the formation of a quagmire through which a man or horse, even without a load, can pass only with the greatest difficulty. Such soil has sufficient bearing value only as long as it remains frozen, which makes it desirable that the moss or turf over-lying it be kept intact. This layer of vegetable matter is not of itself able to sustain traffic, necessitating the addition of a protective covering — usually pole or brush corduroy when timber is available. Fortunately the growth of scrub spruce timber which covers a large part of interior Alaska, except the Seward Peninsula, affords excellent material for this corduroy. Where the trees are large enough pole corduroy is constructed by grubbing all stumps and roots from the roadbed, leveling it, and laying perpendicu- larly to the axis of the road a single layer of poles from which the largest and stiffest branches have been trimmed. Ditches are then dug at a dis- tance of 3 to 5 ft. from the ends of the poles, and the material therefrom, after rejecting the top layer of vegetable matter, is placed on the corduroy for the double purpose of protecting it from wear and affording a smoother roadway. If the soil in the ditches is entirely unsuitable for this covering, other material, preferably gravel, is hauled on from the nearest available source. Where the spruce timber is of very small size, or where only small willows are available, as on the Seward Peninsula, brush corduroy is used. The method of construction is similar to that described above, except that the single layer of poles is replaced by mattress of untrimmed brush containing sufficient material to give a thickness of at least 6 inches when compressed. When corduroy has been properly protected, its life in most parts of Alaska is quite long. Poles taken out of the road after 10 years of service have been found to be in excellent condition. The 3 to 5 ft. berm which -s left between the ends of the corduroy and the ditches is very necessary to protect the corduroy from undermining, as the ditches, under the action of sun and rain, slough and cut rapidly. Ordi- narily, as the frozen soil thaws and cuts away the moss of the berm gradually assumes a gentle slope to the bottom of the ditch, effectually protecting the corduroy, but where the cutting is severe, it often becomes necessary to revet the insides of the ditches with moss or turf. Frequent outlets from the ditches must be provided, and when the amount of water reaching the ditch on the upper side of the road is large it is advisable to construct an additional ditch parallel to the road and about so ft. away, with sufficient outlets to culverts of ample size. Along the Pacific coast of Alaska no frozen ground is encountered, but the mountainous character of the country, the excessive rainfall, and the difficulties of clearing, have made the work, as a rule, even more expensive ALASKAN ROADS 145 than in the interior. Unless the soil encountered in this region is gravel, it will not stand up under traffic during the heavy and continuous rains, and some protective covering is required. Fortunately gravel is usually found at no great distance; otherwise corduroy or plank roads are constructed. The numerous swift streams of glacial origin found in the Pacific coast section and throughout the Alaskan range in the interior have been the source of much trouble and expense. Flowing through gravel beds varying in width with the volume of water carried up to 2 miles or more, they rarely have any fixed channels. It is by no means uncommon for one of these streams to abandon an old channel and establish itself in a new one ^i mile away almost over night. When warm weather causes rapid melting of snow and ice in the glaciers, these streams become raging torrents of enor- mous destructive force, and roads paralleling them are in constant danger of being washed away. Numerous methods of bank protection to prevent damage from this cause have been tried, of which the following has proved to be the cheapest and most effective: A layer of loose brush of sufficient length to give the requisite protection is placed on the threatened bank, per- pendicular to the current and weighted below the center with stone enveloped in galvanized-wire netting, the whole being anchored in place by wires ex- tending to "dead-men." For emergency work when the water is too high to permit of placing the wire netting and rock, the brush is made into fas- cines inclosing sacks of earth, which are then placed against the threatened bank and wired to it and to each other. This form of protection is easily and quickly constructed and has repeatedly demonstrated its effectiveness. As now constructed, the width of wagon roads varies with the formation of the ground and the amount of traffic expected, but as a general rule roads graded by other means than the road grader are given a minimum width of 20 ft. between ditches, and those on which the road grader is used a minimum width of 24 ft. On steep sidehills and where rock work is involved, the width is reduced to 10 or 12 ft. The standard width of clearing is 30 ft. but this is increased to 60 ft. where necessary in order to secure the beneficial action of wind and sun on the roadbed. Sled roads for winter traffic only are cleared for a width of 16 ft., with all stumps, hummocks and similar obstacles removed for a width of 8 ft. _ They are constructed where the amount of traffic is not great enough to justify a wagon road, where the cost of building a wagon road would be prohibitive, or where the communities along the route are amply served by water trans- portation during the open season, as is the case with the Fairbanks-Fort Gibbon sled road. If it seems probable that future development may de- mand or justify a wagon road, the location is made as for a wagon road, in order that work done on the sled road may be of use when the improvement is made. Trails designed for travel by dog team in winter or by pack train in sum- mer are given a width of 8 ft., with all stumps and underbrush cutoff as close to the ground as possible. In the past, the work of constructing and gradually improving the roads has been so generally intermingled with maintenance operations that a sys- tematic plan for maintenance has not been put into effect, nor would such a plan have been feasible in view of the uncompleted state of the roads. At the present time, however, the condition of parts of the more important roads, notably the Valdez- Fairbanks Road, is such as to make practicable their maintenance by dragging. As Alaska has only a very small agricul- tural population, the method adopted in many states of contracting with farmers adjacent to the road for the necessary dragging can not be used, but it is intended to place on completed sections small maintenance crews consisting, as a rule, of two men each, supplied with a team, wagon, drag, and the necessary small tools. Two such crews have been employed on the Valdez-Fairbanks Road during the present summer, with very satis- factory results. On several of the gravel-surfaced roads in southeastern Alaska the patrol system of maintenance has been used in connection with more extensive repairs. The results show the method to be very effective for roads of this character. The average costs per mile, including construction and maintenance of all roads and trails constructed by the board since its organization in 190S are as follows: Wagon road, $3,419; sled road, l379;. trail, $ii3; ^A division of these amounts to show the exact cost of construction proper is impossible, but a careful analysis of the available data indicates that the following unit costs of construction, including bridges, may be accepted as approximately 146 SAND-CLAY AND GRAVEL ROADS correct: Wagon roads, $2,475 per mile; sled roads, I300 per mile; trails $65 per mile. The average costs of maintenance during the past season were as tollows: Wagon roads, $250 per mile; sled roads, S14 per mile- trails, $8 per mile." * Arid Regions. — In the arid regions fills must be avoided. Ordinary earth roads are constructed below the general elevation of the ground as follows: Na-hura! 6round Surface -•, which keeps them mqjst longer; shallow ditches are used for the same reason. In many cases a hardpan formation underlies the sand surface and in these conditions the sand surface is scraped off and the road built on the underlying strata. Where fills must be used they should be made during the rainy season and the addition of clay to a sandy soil helps consolidate the traveled way. Readers are referred to the reports of the y^Surfaceo fSand UnderlLfin^ Hardpan State Engineers of New Mexico and Arizona for further data on the special treatment of roads under these conditions. Summary of Chapter. — Roads of the type discussed in this chapter form the groundwork of future high-class pavements and represent the greater percentage of mileage of roads in this country. They are entitled to more engineering supervision than they have received in the past. CHAPTER V GRAVEL AND STONE FOUNDATION COURSES FOR HARD SURFACED PAVEMENTS Concrete foundations are considered under "Rigid Pavements'^ in Chapter VI. The real foundation of a road is the earth sub-grade; generally, however, the term foundation is used in speaking of the lower course of stone, gravel, etc., used to help distribute the concentrated wheel loads. A discussion can be developed under the following heads. 1. The bearing power of different soils. 2. The concentrated wheel loads on improved roads. 3. The distributing action of foundation courses and the depth required for different soils. 4. The different kinds of foundation courses. 5. The distribution of the stone in the foundations. 6. Special cases. I. Bearing Power of Soils The sub-grade develops its greatest bearing power when dry. In the following discussion we assume that the soils are protected by a well designed drainage system. Mr. W. E. McClintock, Mem. Amer. Soc. C. E. Chairman of the Massachusetts Highway Commission, published in the 1901 report of the Commission a valuable statement of the results of their inves- tigations on the bearing power of soils and the distribution of wheel loads by the macadam. "The Commission has estimated that non-porous soils, drained of ground water, at their worst will support a load of about 4 lb. per square inch; and having in mind these figures the thickness of broken stone has been adjusted to the traffic. "On a road built of fragments of broken stone the downward pressure takes a line at an angle of 45 degrees from the horizontal and is distributed over an area equal to the square of twice the depth of the broken stone. If the division of the load in pounds at any one point by the square of twice the depth of the stone in inches gives a quotient of four or less, then will the road foundation be safe at all seasons of the year. On sand or gravel the pressure can be safely put at twenty pounds per square inch. "Acting on this theory the thickness pi the stone varies from four inches to sixteen inches, the lesser thickness being placed over good gravel or sand, the greater over heavy clay, and varying thicknesses on other soils. In cases where the surfacing of broken stone exceeds six inches in thickness, the excess in the base may be broken stone, stony gravel or ledge stone; the material used for the excess depending entirely upon the cost, either being equally effective." 147 148 GRAVEL AND STONE FOUNDATIONS It will be noted that the values of the safe bearing power of soils are well under those used for building foundations. The depths however are not enough for modern traffic as will be discussed later. For purposes of convenient reference traffic is classified on page 164 and will be referred to as Classes I, II, III and IV. 2. Concentrated Wheel Loads There should be some limit placed by law to the maximum load per lineal inch of tire for vehicle using improved roads. The roads can then be designed for this load with no danger of failure from unreasonable pressures. Road work is handicapped in this country by the lack of wide tire statutes and the regulation of traction engines using sharp lugs on the wheels. At present it is necessary to assume a loading that will probably not be exceeded by the unregulated traffic. Many engineers favor a law limiting the load on improved roads to 700 to 800 lb., to the lineal inch of tire width, which is a reasonable limit; with a six inch thread this would mean a load of nine tons for a four wheel wagon provided the load was uniformly distributed. This is beyond the limits of team hauling. Most of the mechanical trucks in present use have tires wide enough to reduce the pressure below this limit. Near some of the large cities, however, mechanical trucking has increased to propor- tions that amount to a regular freight line and excessive loads are carried; the load and speed for such trucks must be regulated, for no road can stand abuse of this character. In special metropolitan districts where truck freighting is desirable to relieve rail congestion or where it is economical by means of its direct loading and delivery, specially designed toll roads, which are self supporting financially, could be built to handle much heavier loading, but for free public use roads, maintained by the community, a gross vehical load of 12 tons is a reasonable limit. The following regulations governing the control of motor trucks and traction-engines were prepared by the New York State High- way Commissioner to go into effect in 19 14. Regulations for State and County Highways Adopted BY THE Commissioner of Highways of the State of New York Section i. — No traction-engine, road-engine, hauling-engine, trailer, steam-roller, automobile truck, motor or other power vehicle shall be operated upon or over the state or county highways, the face of the wheels of which vehicle are fitted* with flanges, ribs, clamps, cleats, lugs or spikes. This regulation applies to all rings or flanges upon guiding or steering wheels of any such vehicle. In case of traction-engines or hauling-engines which are equipped or provided with flanges, ribs, clamps, cleats, rings or lugs, such vehicle shall be permitted to pass over said highways provided the cleats are fastened upon all the wheels of such vehicles, and are not less than 2>^ in. wide and not more than i^i in. high, and so placed that not less than two cleats on each wheel shall touch the ground at all times, and the weight shall be the same on all parts of said cleats. MILITARY LOADS 149 Section 2.-^No traction-engine, trailer, steam-roller, automobile truck, motor or other power vehicle shall be operated upon or over the state or county highways; nor shall any object be moved over or upon any such highways upon wheels, rollers or otherwise, in excess of a total weight of 14 tons, including the vehicle, object or contrivance and load, without first obtafning the permission of the State Commission of Highways as here- inafter provided. No weight in excess of 8 tons shall be carried on any one axle of any such vehicle. Section 3. — The tire of each wheel of a traction-engine, road-engine, hauling-engine, trailer, steam-roller, automobile truck, motor or other power vehicle (except traction-engines, road-engines, and hauling-engines) shall be smooth, and the weight of such vehicle, including load, shall not exceed 800 lb. upon an inch in width of the tire, wheel, roller or other object, and any weight in excess of 800 lb. upon an inch of tire is prohibited unless permission is obtained from the State Commissioner of Highways as here- inafter provided. Section 4. — No motor or other power vehicle operated upon any state or county highway shall be of a greater width than 90 in., except traction- engines which may have a width of no in. Section 5. — No traction-engine, road-engine, hauling-engine, trailer, steam-roller, automobile truck, motor or other power vehicle, carrying a weight in excess of 4 tons, including the vehicle, shall be operated upon any state or county highway at a speed greater than 15 mi. per hour; andno such vehicle carrying a weight in excess of 6 tons, including the vehicle shall be operated upon any such highway at a speed greater than 6 mi. per hour when such vehicle is equipped with iron or steel tires, nor, a speed greater than 12 mi. per hour when the vehicle is equipped with tires of hard rubber or other similar substance. Section 6. — The State Commissioner of Highways, upon proper applica- tion in writing, may grant permission for the moving of heavy vehicles, loads, objects, or structures in excess of a total weight of 14 tons over state and county highways, upon proper application in writing being made there- for, and under such restrictions as the Commissioner may prescribe. Section 7. — The owner, driver, operator or mover of any vehicle over any state or county highway shall be responsible for all damages which said highway may sustain as a result of a violation of any of the provisions oi the foregoing Rules and Regulations, and the amount thereof may be recovered in an action of tort by the State Commissioner of Highways or by any County Superintendent of Highways of any county or by any Town Superintendent of Highways of any town in which said violation occurs. I. Section 8. — These regulationstake effect October 20, 1913. "Section 24 of Chapter 25 of the Consolidated Laws entitled 'The High- way Law ' provided that any disobedience of any of the foregoing rules and regulations shall be punishable by a fine of not less than |io and not more than Si 00 to be prosecuted by the Town, County or District Superintendent, and paid to the County Treasurer to the credit of the fund for the mainte- nance of such highways in the town where such fine is collected." Under these regulations properly enforced any of the ordinary foundation courses can be successfully used provided the depth is varied to meet the soil condition. Military Loads. — Major General W. M. Black, Chief of Engineers, gives the following information on the loads military roads must be expected to carry. Our existing ordinance liable to accompany a field army wilt have its heaviest representative in a 12-in. howitzer weighing atout 27,000 lb., 18,600 lb. of which are on the front wheels. The i>ase or distance between the front and rear axles is 18 ft. ; width of track 7 ft. 4 in.; width of tire, 8 in.; width of tire shoes, 12 in. This howitzer is to be drawn by a 75 h.p. cater- pillar tractor weighing 25,000 lb. Comparison with the largest present-day commerical trucks shows that a road substantial enough for such will suffice for the ordinance load, so that in this particular, as well as in a strategic way, roads suitable for commercial purposes will meet the military requirements." Secretary of War Baker gives the following requirements for military roads: I50 ' GRAVEL AND STONE FOUNDATIONS *' The following requif^ments as to construction within the areas mentioned are recommended: (i) Road to have a smooth, hard surface of broken stone or a. pavement not less than 20 ft. in width and capable of supporting the loads hereinafter specified for bridges; (2) grades not to exceed 5 per cent., except for short distances (less than 50 yd.) where they shall not exceed 10 per cent.; (3) bridges to be of iron or masonry and of type to support loads of a 6 in. howitzer (3000 lb. on front wheels and 6500 lb. on rear wheels, distance between axles 12 ft., width of wheel track 5 ft.^ or a 3 ton truck loaded (6000 lb. on front wheels, 8000 lb. on rear wheels, distance between axles about 10 ft., width between wheels, center to center, about s ft.^i- In hilly country, where road foundations are necessarily hardpan or rock, the importance of artificial surfacing is less important than the completion of a well drained roadbed joining the roads in the adjacent valleys; and it is therefore recommended that in such cases the completion of an unsurfaced graded road be completed before the requirement as to artificial surface is enforced." Commercial Loads. — Records of produce dealers show that heavily loaded farm wagons weigh about 5000 lb. of which about 0.6 is on the rear axle. The rear wheels carry approx. 1500 lb. on 3 to 3 J^" tires and allowing for 25% impact exert a pressure of approx. 600 lb. per linear inch of tire. Large modern trucks^ loaded weigh about 10 tons and carry approximately three-fourths of the weight on the rear axle. Each rear wheel is generally equipped with two six inch rubber tires and exert a pressure of approximately 700 lb. per linear inch. The author believes that a road designed for a 5 ton load on a 1 2" tire or at the rate of 800 lb. per linear inch should be safe. Note. — The length of wheel bearing on a well constructed mac- adam road is about i". The use of this loading and the application of the rules for dis tribution of pressure given by Mr. McClintock in the preceding quotation results for ''Main Roads" (Class II and Class IIA traffic, see page 164) subjected to heavy frost action in northern climates, in a total consolidated depth, including top course, of 9" on fine gravel or coarse sand and 22'' on wet heavy clay or fine loam of which more than 30% passes a No. loO sieve. For feeder roads (Class III traffic) in northern states and for Class II traffic in chmates free from frost these depths can be safely reduced to 5" to 7" on gravel and 15" to 20" on clay. The thickness to be used in the intermediate cases must depend on the judgment of the engineer. The following examples are intended only as a guide for the more common cases for roads on which the traffic makes a macadam design reasonable. The amount for special cases often depends on trial. Coarse sand and gravel require from 5" to 9", New York State uses 7" as a minimum. Massachusetts uses the following section on good gravel (Fig. 28). Wherever the stone is less than 6" it should be laid in one course and classified as top stone. 1 Pierce Arrow 5 ton trucks have the following specifications (19 18). Maximum body width, 7' Weight of chassis, 7800 lb. Wheel base, 14' to 17' Body, 2500 lb. Gage, 69" Net load, 10,000 lb. Two 6" tires on each rear wheel. 75 % of net load on rear wheels. Total weight of truck loaded, 20,000 lb DEPTH OF MACADAM 151 For a light clay loam an average depth of 9" to 1 2" is sufficient in cut; for fills over 2' deep 9'' is enough; high fills even of clay often having onee settled rarely give trouble with 9" of stone. Heavy clay requires at least 15'' in cut; if the soil is springy or especially poor 18" to 24" is advisable. For shallow fills see Figure 29. In shallow or "pancake" fills, clay or fine sandy loam should never be used where the natural surface at this point is of a better variety, as they are almost certain to become saturated with water and will either squeeze or heave out of shape; long shallow fills are to be avoided, which is considered in laying the grade line, but where unavoidable, the best available material should be obtained and the original surface well broken up to form a bond with the new fill. Where clay is used it should be treated as in cut. For clay fills of intermediate depth (i to 2 ft.) a stone depth of 10" to 12" is satisfactory. Oici Surface ^ Oood Matenah Fig. 29. To illustrate the different stone depths that may be used in a short distance an extract follows from the construction report on foundations for "Clover Street Sec. i" a road near Rochester, New York. This was built in 1907-1908 and has held satisfactorily under farm traffic (Class III). Clover Street Road, Section i The normal depth of stone on this road was 7" — 3" top, 4'' bottom. Station to Station Character of Sub-grade *rotal Depth of Stone 180 183 + 25 183 + 25 186 + 25 186 + 25 187 187 190 190 191 191 193 193 200 Cut in sand and gravel Clay fill Light Clay cut Sand, gravel and clay Ordinary Clay cut Clay loam fill Sand and gravel 6" 8" 11" 7" 12" 7" 6" 152 GRAVEL AND STONE FOUNDATIONS G a o u S a a B o u -a a; <: Q < < o tn W H e^ Q Q W H < Q t^ O O U <; H O H » j W (U So o < So Ed ^ O «5 2H O * • ba • t/J o . o 3 g : >. ^ tfi cj o f^-s >. SE? > o J2 0^ o:: o < u-i «J < c3 ►J C O O O b « OJ OS 5^ o •*-» 00 -M ^ ^ ^ oc ^ 3 cr 'g o 03 o u O o ^ g c3 e O G ^ O t« > S2 o ^ ^ c« ^- Cj (U " one-coat top, using 1.75 gallons per square yard from $0.50 to $0.60 a square yard. The flush coat using 0.4 gallons per square yard will add about $0.06 to the above costs. For the purpose of comparison with the macadam a fair set of prices is 2" Bituminous top, one coat of bitumen $0.40 per sq. yd. 2" '' '' flush coat 0.45 " '' " 3" '' " one coat of bitumen 0.55 '' '' *' 3" " '' flush coat 0.60 '^ " '' Depth of Top Courses for Bituminous Macadams. — In 19 10 New York State adopted a depth of 2 " using 1.25 gallons as binder and 0.5 gallon as flush coat per square yard. In 191 1 a 2>" depth was used with 1.25 gallons per square yard as binder and 0.4 gallon as flush coat. In 191 5 a 3" depth was used with 1.75 gallons as binder and 0.5 gallon as flush coat. A 2" bituminous top will not fail by raveling, the defect men- tioned for a 2'' waterbound macadam course, but it has certain constructional difficulties. To construct a 2" course no stone should be over 2" in its largest dimension. Because of the tendency to The author has had better success with hand pouring for the first coat than with machine work. For flush coats, however, a pressure machine is absolutely necessary. If bitumen is poured by hand it must be poured across the road (never along the road) as this method of work largely elimi- nates humps formed by overlap. It is much easier to control the hand spread than the machine spread as to amounts and the stone spread is not disturbed or rutted up during the pouring. While the machine spread is uniform this is in itself a drawback on the first coat as the rough stone sizing is never uniform and a hand spread can be varied to conform to the non-uniformity of the stone sizing. lyo MACADAM TOP COURSES crack under concentrated wheel loads, none of the stone forming the main body of the course should be less than one inch in size. These limits of size are so narrow that difficulty has been experienced in procuring sufficient stone for top when crushing local material, and even when the stone is obtained from a commercial plant the same difficulty is often encountered. Also in spreading such a depth with stone ranging in size from i" to 2" ^ there will be places where the metaling is only one stone deep and the fragments do not fit as closely together nor have the same chance to interlock as in a deeper course. The spaces between these stones are filled with No. 2 (%'0 size, which wears more rapidly under traffic than the larger pieces and the road tends to become rougher than would occur if the iK'' stone fitted closer together. This last argument does not apply to flush coat roads. The argument is often made that a 3'' top will last one and one- half times as long as a 2'' top because it has one and one-half times as much material, but the life of a top course rarely depends on its total thickness, as it will become so badly out of shape before the general elevation has worn down an inch that it will need recapping. In attempting to meet these difi5culties, 2 J^'' and 3" courses have been built; as far as the author has been able to judge, the 2}^" depth remedies the defects, and can be used where imported com- mercial crushed stone is available, but where the stone is crushed locally a 3'' depth is better with a slightly greater range in top stone size. When pouring bitumen in the penetration method, a pocket of fine stone, dirt, etc., will sometimes hold the binder near the top in too great quantities; during hot weather the bitumen swells and, as the voids are full in these spots, it rises to the surface and forms a hump or wave. This trouble is not so frequent on either 2}/^" or 2>" courses as on the 2" depth. The writer's present opinion is that while a 2^2' depth, using about 1.4 gallons bitumen per square yard in one coat, will give satisfaction that a 3'' depth using 1.7 gallons in one pour is better practice on a macadam bottom. On a pit run gravel bottom T^yi" with 1.8 gallons of bitumen is desirable. Where bituminous macadam is used to resurface an old worn out concrete road on steep grades 3'' to -^Yi" is the best depth. Crowns. — The crowns used on bituminous macadams range from 34" to I ' to %'' to i'; Y^' to i' is generally used and is ap- parently satisfactory. Footing. — A single coat road affords good footing on any grade that will be adopted as suitable for heavy hauling; such a top course will not wash, which makes it easy to maintain on hills. Advantages and Disadvantages. — Bituminous macadam without a flush coat provides good footing for horses; it will not ravel, is easy to repair for small depressions and ruts, is comparatively dustless and keeps its longitudinal and transverse shape well, making a comfortable riding road for fast travel. On the other hand, it will probably wear more rapidly than the flush coat TOPEKA MIX 171 construction as the traffic comes directly on the stone; it is subject to the practical disadvantages of construction of all roads where bituminous materials are used; it is not waterproof when first constructed; this last defect, however, is remedied by the traffic which grinds up the surface wearing coat and forces it into the voids. As a matter of fact, the combined action of traffic and weather puddles the road, and after about six weeks' use we can say that the road has a bituminous bond and a water-puddle finish. Flush coat bituminous macadams are more dustless than the single coat, are more nearly waterproof when first built, look smoother at first, and will probably cost less to maintain. How- ever, they do not give as good a footing as the single cost and are liable to develop waves and humps disagreeable to fast traffic. If a flush coat is used there seems to be no advantages in a bitu- minous binder, as the flush coat alone prevents raveling, and, if such is the case, the binder used throughout the depth of the course is a waste of money; a waterbound bituminous flush coat course might better be used. In choosing between a flush coat construction or a single coat bituminous macadam, the author believes that a single cost bituminous macadam is the better design; although it will probably cost more to maintain, the in- creased safety and comfort to the traveling public is worth the expen- diture. Unusual care in construction is required (see Chapter XV). Gravel Bituminous Top. — A gravel bituminous bound top is rarely satisfactory as it lacks the interlocking action of broken stone which increases the stability of construction. The use of this type is not advised. Mixing Method — Open Mix. Type I. — The stone and bitumen are mixed hot in specially designed machine mixers. The mixture is then spread in the same way as sheet asphalt. A flush coat can be used if desired. The 191 5 New York State specifications call for No. 2 stone (^^'' to iJ^'O; when finished thickness is to be 2" or less and a mixture of No. 2 and No. 3 stone {j.}/^' to 2Y^')\ when finished top course is greater than 2", the stone to be proportioned as directed by the engineer. Approximately 18 gallons of bitu- minous material to each cubic yard of loose stone. %- In this "open" mix, it is unavoidable that pockets of mixed top material will be placed which have a greater percentage of voids than the average. Whether or not a seal coat is used, these pockets will wear more rapidly than the surrounding pavement. In a simi- lar manner, variations in the size of the stone will cause uneven wear. Both conditions tend to produce a humpy pavement after some use, but generally a smoother riding road is produced than is attained with carelessly built penetration roads. Mixing Method— "Tight Mix" or "Topeka." Type 11.— The stone, sand and bitumen are mixed hot in specially designed ma- chine mixers. The mixture is then spread in the same way as sheet asphalt. The thickness varies according to the foundation. It is generally a consolidated depth of 2" on a concrete foundation and 2y'2" on a firm macadam foundation. The various sizes of the 172 MACADAM TOP COURSES mineral aggregate and the percentages of each are specified within certain limits varying slightly to meet gradations peculiar to the material available (see specifications, page 781). Because of the fine aggregate used in work of this type, there is not sufficient stability to withstand a mixed traffic and the surface ultimately forms in disagreeable waves. Attempts have been made to prevent this waving by using a high penetration asphaltic cement which will permit the pavement to iron itself out. However, if a heavy slow-moving trafiic be carried on this type of road, the surface will rut. Apparently, the best results in mixed bituminous macadam have been secured when the coarse aggregate was used — stone between three-quarter inch and one and one-half inches in size, which were filled with a matrix of fine material of sand and bituminous mate- rial. Such pavements have sufiicient "body" to materially de- crease the ''creeping" under use and take a more even wear than the open mixed type. Where used to recap an old concrete or macadam road an open binder coat is desirable to even up the old surface and allow a uniform depth of surface mix. The prices for this type of top course run from Type I, $0,615 , $1,105 :- . ^ TT (n> /: to -X per square yard Type II, $0.60 $1.25 Natural Rock Asphalts. — Sandstones and limestones containing a certain percentage of bitumen are known as rock asphalts. The most common source of supply for the Eastern States is Kentucky, and the product is known as ''Kentucky Rock Asphalt." It is a sandstone containing about 7% to 10% of maltha. It is pulverized at the mine and is shipped and applied cold in the following manner : 2" to 2 J^" of stone, ranging in size from %^' to i^i'^ are^readand rolled slightly. The rock asphalt is run through a shredding ma- chine and spread over the stone, using approximately 40 lb. per square yard. The whole mass is the thoroughly rolled, preferably with a 6- or 8-ton tandem roller; 40 lb. per square yard of pure rock asphalt is then spread as a wearing coat and well rolled; the rolling is continued intermittently for a number of days after the traffic is turned on the road. The cost of such a course has been about $0.70 per square yard in Western New York. The crown ordinarily used is 3^'' to i\ Advantages and Disadvantages. — The road is pleasing in appear- ance, is not as slippery as sheet asphalt, and will not ravel under motor traffic. However, it is hard to construct in cold weather, is not uniform, and will ravel in spots. It has defects in common with sheet asphalt of showing wear by developing short humps and . hollows disagreeable to fast traffic. The steepest grade on which it can be used advantageously is about 5%, as it becomes slippery in cold weather, and in warm weather it sometimes softens enough to make hard pulling for heavy loads. Amiesite. — Amiesite, a patented material made of crushed stone coated with asphaltic cement, has been used on many miles of BRICK PAVEMENT 173 road with good results. It is shipped cold in a friable and granu- lated state, spread on either macadam or concrete base and well rolled. Amiesite screenings are then spread and rolled, forming the surface. This construction costs about $1.00 per square yard, 3'' thick. It resembles asphalt in appearance and has the advan- tages and disadvantages of all roads of this class. It is particularly adapted for small jobs where it would not pay to set up an asphalt plant or where suitable asphalt materials are not locally available. For further information, see Chapter on ^'Cost Data and Specifications. " Other Surfaces of a Bituminous Nature. — There are any number of patented pavements that can be classed under this head to which we can not give space. Sheet Asphalt and Warren Brothers' Bitulithic are used in unusual cases, but constitute such a small percentage of the mileage that for information concerning them we refer the readers to books by Richardson, Hubbard, Tillotson, etc. We include some notes on inspection of construction, page 677. BRICK PAVEMENT The ordinary brick pavement construction is probably familiar to most readers. On a concrete foundation 5" to 7'' in thickness a sand cushion varying in depth from \" to 2" is spread and the paving brick are laid on this sand bed so as to break joints; the brick are well rolled and the joints are filled with sand, cement grout or paving pitch. Longitudinal expansion joints of bituminous material are provided next to the curb or edging; transverse expansion joints spaced 30' to 50' apart are used by some designers. The latest practice tends to make the cushion as thin as possible \" to ij-^'', acting merely as an evener of the concrete surface. It is also rare to find any material but cement grout used for filler though this tendency is not necessarily an improvement. The use of transverse expansion joints is being relegated to the back- ground but this also is open to argument. Premolded asphaltic strips form the best kind of expansion joints where they are needed. In the last few years the former theory that the i J^" sand cushion prevented crushing of the brick and gave the amount of resiliency necessary to a pavement of this type has been disputed and ap- parently successfully so, by the increased use of the cement sand cushion. Upon the finished concrete base a bed of dry cement and sand uniformly mixed in the proportion of one part cement to four parts sand is spread not over i" deep. This cushion is shaped by striking with a template and finished by rolling with a hand roller weighing about 300 lb. and restruck or luted. After the brick are laid theron, culled and rolled, the pavement is thoroughly sprinkled to set up the cement sand bed. The use of this kind of bed undoubtedly overcomes the loosening of bricks near cracks or expansion joints and prevents shifting of the sand cushion which sometimes occurred with pure sand and resulted in depressed areas. It is possible that the use of this kind of a cushion in con- 174 RIGID PAVEMENTS junction with bituminous joint filler will help to overcome the serious fault of surface cracks which develop under frost action. In 191 5 several experimental brick pavements were constructed where the mortar cushion and brick were laid upon concrete which was still plastic. The concrete foundation was shaped by a tem- plate and the brick laid, inspected and rolled before the cement had taken its initial set. This is immediately followed by grouting. It is too early to say whether or not this so-called "monolithic" construction will be successful. The expense and difficulty of manipulation are increased and it is doubtful if any material advan- tages are attained. Brick pavement construction is essentially rigid, intended to withstand heavy traffic. The cost, including foundation and sur- facing, ranges from about $1.60 to $3.00 per square yard, the average price in Western New York being about $2.00. Brick pavements on heavy traffic roads have been extensively used in Ohio and New York. Macadam foundations for brick surfacing have not proved satisfactory in the Northern States, as the surface is too rigid and cracks under the heaving action of I -I yi^Pftth Expansion Joint '■^m^i-f'-' ' Note •■ Transverse Expansion Jowfs Spaced ^I0\. 30foSOft:maybs(j6ect._ Fig. 36. — Brick pavement, flush edging. the frost. Even on a concrete foundation longitudinal cracks often develop from this same action. It is more difficult to prevent this on country roads than in cities where the sewers keep the earth sub-grade comparatively dry, and the necessity for a center drain under the concrete base is being recognized by many designers. Some engineers believe that the i to i cement grout in general use is too strong, and that if a weaker grout or a sand filler were adopted in its place the heaving frost action would merely separate the bricks slightly instead of breaking them and that as the road settled they would fall back into close contact. This is an attempt to make a theoretically rigid construction flexible and seems to be striving to adapt the construction to conditions for which it is not fitted. Longitudinal Cracks. — These cracks have been carefully studied, as they seem to be the most discouraging feature of brick pave- ment construction on country roads. Mr. Wm. C. Perkins, Chief Engineer of the Dunn Wire Cut Lug Brick Company^ states from a careful examination of a large mileage of brick roads built under his supervision, that longitudinal cracks have always occurred within 2' or 3' of the center of the road; that the cracks extend down through the concrete base and .that less difficulty is experienced in preventing them as the crown of the pavement is reduced. From these observations he has been STONE BLOCK PAVEMENT 175 led to experiment with a concrete base having a perfectly flat bottom, as shown in Figure 36 A, crowning the'road by making the concrete thicker in the middle than on the edges. The claim is made that this style of construction is helping to prevent such cracks. Transverse Expansion Joints. — The use of transverse expansion joints has not been successful locally. Difficulty has been expe- rienced with the brick loosening at these joints, and whenever a temperature heave has occurred it has appeared at the joint. Their use has been abandoned for rural roads in Western New York. This does not occur with a cement sand bed but excessive wear does occur at such a joint. Br/'cH'. , SandCush/on ^^Lonqffvdinat Expansi'on Joint F1G.36A. CROWNS The crowns in use on brick pavements range from Y4!' to i to %'' to i'. For the methods of figuring ordinates for para- bolic crowns see page 551. Brick pavement does not give a good foothold for horses on grades above 5 % unless some special form of brick is used. For steep grades, on heavy traffic roads, it is better practice to use some form of stone block. Stone block pavement, including concrete foundation, costs from $2.70 to $3.30 per square yard. It is suitable for the steepest grades that are constructed and is the most durable pavement that can be used. >rfoi\ ,' Pitch Expansion Jo/nf- Note : If Pitch Filler is used between Stone Block, no Special Expansion s/ofnf is needed. Fig. 37. — Stone block pavement, flush edging. Where stone blocks are used on hills it is better practice to use second quality blocks; these blocks are identical with the first quality blocks as to material but are not dressed as carefully and cost about fifty cents per square yard less; their rougher surfaces and wider joints afford better footing. For the difference in size and joints see specifications, Medina Block, page 736. The first cost of brick pavement for country roads restricts its use to roads where it can be conclusively proved that macadam will not be suitable. It is a reasonable design for Class I traffic in villages. 176 RIGID PAVEMENTS ASPHALT BLOCK The asphalt block pavement laid in New York has been very satisfactory. The proportion of ingredients is about 70% crushed rock, usually trap, which has passed a )^'' ring, about 20% limestone dust to act as filler and approximately 10% of asphaltic cement, molded under a pressure of 2 tons per square inch of block having a 2'' depth. This produces a dense asphalt much superior to the ordinary sheet. The asphalt used is Trinidad. This is refined and fluxed so that the resulting A. C. may be varied as to adhesiveness, penetration, etc., to meet varying conditions peculiar to different localities. ySfee/ Reinforcement- A J Plan Section Pig. 38. The penetration is made high enough to give a certain amount of pliancy to the block, to avoid crumbling at the edges and to make the joints self-healing. The use of blocks containing steel anchors, laid across the road, approximately 15 ft. apart, has eliminated any movement of the block under traffic. These blocks are placed at more frequent intervals on curves. Block pavements have been laid using a longitudinal row of these anchor blocks in place of edging. The results appear satisfactory. After the base is prepared a mixture of i to 4 Portland cement mortar is spread J^ in. thick. This mortar bed is carefully screened and the block laid thereon, joints being broken at least 4 in. An interesting comparison with brick occurs in the "pinning in" at curbs. Instead of bats being broken by hand, a large mechanical shear is used. Each fractional block is measured and cut to fit exactly. CONCRETE PAVEMENTS Asphalt Block Data 177 Highway No. County Mile- age Bottom per Sq. Yd. Top per Sq. Yd. Per Mile i6'-26' 5357 Westchester 0.95 $0.61 $1.49 $26,593 5375 n 1-34 Old Mac 69 18,114 5388 Rockland 2. 16 ii ii 70 ^27,025 0.59 70 ^32,525 1153 Niagara 0.97 0.60 37 '31,800 5482 Westchester I. 16 0.66 50 29,270 1167 it 1.28 0.61 38 24,245 1053 << 1.45 Old Mac 60 21,205 5528 Warren 0. 61 0-59 60 35,990 5356 Westchester 0.53 Old Mac 63 ^26,960 5361 n 0.68 0.61 44 '23,512 5362 ii 0.25 0.67 37 25,569 5364-A it 0.31 0.47 47 23,166 5373 ii 2.85 0.58 152 Av. 0.599 Av. 1.533 1 Cost from preliminary estimate. ^ • All costs not marked with ^ from bid prices. After being laid, the pavement is given a light coat of sharp sand which is broomed into the joints. Traffic is permitted in four or five days. Advantages. — The pavement shows a smooth, uniform surface, dustless and practically noiseless. Its life has yet to be determined. Pavements that have been down ten or fifteen years are still in good shape. Within a reasonable freight radius from the point of manufacture, it can be laid for approximately the cost of brick. Disadvantages. — A mist or light rain makes the pavement very slippery. It should not be used on grades over 4%, CONCRETE PAVEMENTS Introductory Inasmuch as there is some difference of opinion as to the value of this type each author has written his interpretation of the avail- able facts. Concrete Pavements By W. G. Harger Many miles of these roads have been constructed in the last few years. The construction has varied from poor i to 6 pit run gravel concrete to first-class i : i J^ : 3 stone concrete 6" to 9" thick. 178 RIGID PAVEMENTS There is enough data to conclude that cheap concrete is a failure. An effort was made to protect the surface of such a mix with a thin bituminous surface coat of asphaltic oils or tars. These coats have not been successful as they peel off and produce an unsightly, rough riding and a high maintenance cost road. The type of concrete road now being built and which has many enthusiastic supporters is a first-class i : i J'^ : 3 stone or screened gravel concrete which takes the traffic directly on its surface. The concrete is carefully manipulated (see specifications, page 785). The ordinary section used is shown in Figure 39. Expansion joints of premolded asphalt or patented steel plates with tarred paper filler are provided at intervals of approximately 30 ft.^ The cost of this pavement has been from $1.10 to $1.80 per square yard. They have the advantages" and disadvantages of all rigid types of construction. They should not be used on grades over 5%. Pavements of this class have been built on roads having light, medium and heavy traffic and are advocated by Cement Manu- facturers as an economical road under all classes of traffic. The author believes that while this type has its place that a great mileage is being constructed which from an engineering viewpoint is not justified. The roads have not been down long enough to obtain reliable data as to their length of life before resurfacing. Con- sidering in a general way, however, what we know of the material and the action of the weather and traffic on rigid types of pave- ment, an allowance of 10 to 15 years would appear liberal. When they arrive at the point when they need resurfacing a large expense is involved. It has been demonstrated that cheap thin bituminous coats have not been successful; it is not possible to successfully resurface with a thin layer of concrete which means that probably asphaltic concrete, asphalt block, brick or some other form of block or cube pavement will be used at a cost of from $9,000 to $16,000 per mile. The fact that resurfacing when it occurs re- quires such a large expenditure eliminates this type from use on any but the more important roads which constitute a small percentage of the mileage of any large system.* With the data at hand the indications are that this type is a good design for Class I roads outside of villages and possibly for the heavier Class II roads under special conditions. Under Class I traffic an average depth of 8" of concrete is recom- mended and a minimum width of 18' on account of the difficulty of shoulder maintenance (see Plate 9, page 60) . 1 The author personally believes that better results will be obtained by- eliminating these joints altogether. The artificial joints are sources of weakness in that they tend to localize the wear. Apparently less wear occurs at a natural crack and it is certain that a smoother riding road is obtained. CONCRETE ROADS 179 If used on Class II roads a depth of 7'' will probably be sufficient but no reduction in width is allowable. The fact that more width is desiraole for all rigid pavements than for macadams on Class II traffic is an added reason for the use of macadams under these conditions (see Chapter on ''Sections," page 42). Under climatic conditions free from frost an average depth of 6" is sufficient and under ideal soil conditions 4" to 5" have been built (see ''California Standards," page 50). First-class concrete is showing up better than anticipated under Class I traffic but the desirable depths, w^idths and necessary refinements of construction to insure success are increasing the cost per square yard and eliminate it as a competition for macadam on Classes II and III roads where macadam materials are available. CONCRETE BITUMINOUS ROADS By E. a. Bonney Some four or five years ago, a tremendous wave of publicity swept concrete roads into the limelight. The construction at that time consisted of a second-class concrete base with a skin coat from M" to %" in depth, composed of screenings, mixed with hot oil or tar, and sometimes a combination of the two. The base was laid without joints and gravel or any kind of stone was used for aggregate. Under this type at least a dozen patented pavements were developed practically none of which have to any degree borne out the extravagant claims made at that time. The bituminous skin coat has not been satisfactory. It is subject to all the disadvantages of other bituminous macadams and with few exceptions has not adhered to the concrete for any length of time. There is a road known as the Bedford- Goldens Bridge State Highway in Westchester County, on which 2.67 miles of concrete base has been laid when the original contract was canceled. The unfinished portion was covered with an experimental skin-coat treatment which today (1916) is as sound and intact as when laid. Work was finished in the early summer of 191 5. The road was subjected to the enormous automobile traffic peculiar to West- chester County all season. A brief description follows: The concrete was cleaned, all dust, dirt or caked material re- moved. It was then coated with a cold application of low carbon tar, very light grade, almost a creosote. This was spread about 3^0 gallon per square yard and allowed to dry for two hours. About one- third of a gallon per square yard of Bit. Mat. " T " low carbon was then applied hot and covered with approximately 37 lb. binder of No. 2 stone per square yard. A second coat of H gallon per square yard was then applied and covered with about 32 lb. per square yard of No. i stone (screenings). This treatment so far looks extremely well and has not broken away from the concrete. It is still too early to classify as a success. lao RIGID PAVEMENTS The cost of the top course only was lyj^c per square yard. Base cost 68c. making total of 85c. CONCRETE PAVEMENTS By E. a. Bonney i:iJ'^:3Mix Concrete pavements are showing as each season passes by, that they are worthy of much more consideration than has been given them up to the present time. For roads subjected to heavily loaded and slow moving vehicular traffic or for roads so located or traveled that any type of macadam road would be subjected to costly maintenance, the concrete pavement has come to stay. The wear seems to be inappreciable and because of the flat crown, traffic is spread over the entire width of metal. Great care must be exercised in the selection of aggregates. Many sands that are considered good enough for ordinary concrete work will not give satisfactory results in concrete pavement. Stone or gravel should be limited to those . showing a high coef- ficient of wear. Considerable attention should be paid to the percentage of voids in the sand and stone. Experiments should be made to determine approximately the mixture giving the lowest percentage of voids. The authors do not believe in the blind adoption of a specified mix. It is often essential that the mix be varied to correspond to the gradation of available sand and voids in coarse aggregate. Several containers of uniform volume and a pair of scales are all the apparatus necessary to show whether or not the specified mix is the best mixture for the aggregates available. The approximate percentage of voids, may be found by water. By making up several concrete cubes or cylinders of the same volume, beginning with the specified mix and varying the others as indicated by the percentage of voids, the heaviest product will indicate the proper mixture. Any data given herewith is based upon a one-course road. The authors are not personally familiar with two-course roads. Bulletin No. 249 of the Office of Public Roads, U. S. Department of Agriculture, cites the advantages and disadvantages of concrete highways as follows: "Advantages. — i. As far as can be judged, they are durable under ordinary- suburban and rural traffic conditions. While it is true that there are no very old concrete pavements in existence, the present condition of many of those which have undergone several years' service would seem to warrant the above statement. "2. They present a smooth, even surface, which offers very little resistance to traffic. In the past the surface of concrete pavements have sometimes been roughened in order to insure a good foothold for horses. This practice has now been abandoned, except on very steep grades, because it tends greatly to accelerate deterioration of the pavement, and because the smooth surface has been found to afford a fairly satisfactory foothold under all ordinary conditions. "3. They produce practically no dust and may be easily cleaned. CONCRETE ROADS i8i *'4. They can be maintained at comparatively small cost until renewals become necessary. "5. They may be made to serve as an excellent base for some other type of surface when resurfacing becomes desirable. "6. They present a pleasing appearance." "The Disadvantages. — i. They are somewhat noisy under horse traffic. "2, There is no method of constructing necessary joints in the pavements which will entirely prevent excessive wear in their vicinity. Furthermore, joints do not altogether eliminate cracking and wherever a crack develops it must be given frequent attention in order to prevent rapid deterioration of the pavement. "3. They can not be readily and effectively repaired as many other types of pavements." This summation of concrete roads in general seems eminently fair. We believe, however, that to the disadvantages should be added the inevitable rut which appears between the edge of the concrete and the earth shoulder. These ruts are dangerous to fast-moving traffic and require constant maintenance for their elimination unless the shoulders are armored with crushed stone or gravel for 2 ft. or more from the concrete. The question of reinforcement -and joints are still the subjects of .much discussion among engineers. The item of reinforcement largely increases the cost of the roads and it is yet too early to sa3c.that the addeid expense is justified. Premolded Asphalt Joint as Laid The joint problem affords an unlimited field for a variance of opinions. Few engineers are satisfied with any of the existing armored joints, patented or otherwise. The author believes that experience to date has divided the problem of joints into two fields: i.e., on roads under continued maintenance a bituminous joint will prove satisfactory and is renewable at small cost; on roads which receive spasmodic main- tenance or none at all, some sort of steel joint should be used. On New York State work where maintenance is continuous the most satisfactory joint to date is of premolded asphalt, which is so placed that it projects from %" to 3^" above the surface of the concrete; as shown above (A). A combination of hot weather and traffic spreads the asphalt out, leaving a bituminous mat over the joint. i82 RIGID PAVEMENTS For concrete roads not under maintenance, the better joints are being made of soft steel tempered to the same relative hardness as the concrete. A hard steel joint simply transfers the point of wear from the joint-edge proper to the concrete back of the joint. The proper length of concrete slabs between joints is another subject of speculation. Many roads are now being built with varying distances between joints in an endeavor to determine how few can be used with success. The average cost of this type in New York State for 6" depth of pavement is $1,121 per square yard of pavement only. Total average cost for mile of completed highway, including excavation, drainage structures and pavement, is $15,320 (191 6). Small Stone Block Surfacing. — In Germany, Hungary, Austria, and England a surfacing made of granite blocks, ranging in size from 2^^" to 4", has been used successfully. This pavement is known as Kleinpflaster in" Germany, and as **Durax" armoring in England. The stone cubes must be cut with considerable accuracy in order to give a smooth and durable surface. The blocks are laid on a thin sand cushion of about %" depth, on either a macadam or concrete foundation; they are thoroughly rammed to give a firm bearing and the joints filled either with clean sand flushed in, or a bituminous filler. The joints do not exceed 3'^" in width. The courses of cubes are laid either diagon- ally to the direction of the traffic or in concentric rings. Where the stone is broken by hand the cost is high and it would be impossible to consider its use for rural roads in this country. A machine^ has, however, been developed in Europe for breaking these cubes which is claimed to produce a satisfactory product at a reasonable rate. It is a belt-driven friction drop-hammer having a stone chisel mounted on the anvil; the hammer head is shaped like a stone-cutter's sledge. The power needed for each machine is about i J^ h.p. About 400 of these machines are in operation, and a plant in Sweden is turning out 700,000 square yards of pavement per year with 62 machines. Provided the pavement can be laid for $1.00 to $1.25 per square yard, it seems a type that must be seriously considered. A price as low as this, however, would necessitate the use of convict labor in the manufacture of the cubes. McCLINTOCK CUBE PAVEMENTS By W. G. Harger This is a patented pavement devised by J. Y. McClintock, County Engineer of Monroe County, N. Y. It is very similar to "Kleinpflaster" except that under his patent artificial cubes as well as stone cubes are proposed. It appears to be a very promis- ing type. 1 A detailed description of this machine is given in Engineering News, March 27, 19 12. McCLINTOCK CUBES 183 The construction is essentially as shown in Figure 40 and consists of a top course of 2Y4!' cubes placed on a thin sand cushion sup- ported by either a macadam or concrete base. The cubes have been made of concrete, vitrified paving brick material and stone as in Continental practice. They are loaded, hauled and dumped like broken stone; laid in close contact by means of a pallet and rake 128 at a time on a sand cushion J^ to 3^^'' thick, no care being taken to br^ak joints. They are then rolled to bring to an even and firm bearing; the joints are filled with a sandy loam and the surface treated with a light coat of light road oil or cold tar if the foundation is macadam. The joints are grouted if the foundation is concrete. Temporary shoulders of 2" plank are put down during the laying of the cubes after which they are removed and replaced with broken stone or gravel as shown in Figure 40. The experience of the past six years has shown that this form of construction using a sand-tarred joint is flexible under frost action which makes it suitable as a surfacing on a macadam base. It keeps its shape under traffic and shows no tendency to ravel or break down at the edges and can be successfully held with a macadam or gravel shoulder without the formation of a rut OravelorSfone Shoulders-^ Fig. 40. along the edge which is a difficulty always encountered where a rigid edging is designed. It gives a satisfactory surface in both wet and dry weather and can be laid late in the season. The cubes require comparatively little inspection and can be successfully used as a patch in maintenance with simple manipulation. They reduce the tonnage and freight cost where imported materials are required. Concrete cubes have not served satisfactorily, failing in spots, but this is to be expected as it is not a reliable material for a road surfacing of this nature (that is for such small units). Vitrified shale cubes with wide sand joints laid on a macadam base have shown ability to stand medium traffic. Vitrified shale cubes with close tarred joints laid on a thick macadam base serve very satisfactorily under moderately heavy traffic, and the indica- tions are that these cubes laid on a concrete foundation and grouted will meet all but the heaviest traffic satisfactorily. Consider briefly the present tendencies in highway construction. There are two distinct types: the flexible form represented by the macadams and the rigid types, such as brick, asphalt, stone block, etc., having concrete foundations. Each has a distinct field and their relative economy depends largely on the traffic. 1 84 TOP COURSES It is sufficient for this discussion to note that macadams are suitable for light and medium traffic (Classes II and III); that they are able to withstand climatic changes better than the rigid pave- ments and that with a moderate yearly expenditure they can be kept in good condition when used under the volume of traffic stipulated. They fail either under high velocity traffic or heavy hauling; the first being a surface failure and the second a foundation failure for most of the roads in this locality but a surface failure for some which have a thick well consolidated base. That is, if some better flexible surface can be used on a first-class macadam founda- tion, this type of road will be able to handle a heavier volume of traffic than at present with a moderate maintenance charge. The indications are that the brick cubes with sand-oiled joints will serve this purpose. The rigid roads develop defects due to temperature changes; frost heave and the settlement of fills. Subsequent movement is localized along these lines and eventually expensive repair and reconstruction is necessary. Under heavy traffic, however, the cost is less than for the macadam type and the inconvenience of continual repairs is avoided. The first cost of brick and asphalt block which are generally con- sidered the best of the rigid types is so high that designers often hesitate to use them where they are actually needed. If it were possible to reduce the cost and yet obtain practically the same class of improvement a larger mileage could be used to advantage. The indications are that the brick cubes on a concrete foundation will serve this purpose at a cost of about $0.40 per square yard less than the present paving brick. Highway designers do not hesitate to use macadam for the light traffic roads or expensive rigid constructions for the extremely heavy traffic; the great mileage that lies on the verge of either form of construction offers the real difficulty. It is for this class of road that the cubes are particularly adapted by reducing the cost of brick and increasing the efficiency of macadam. This applies also to the resurfacing of concrete and macadam roads. ' The author believes that provided this type fulfils its present indications that it will meet a recognized need in highway construc- tion and for this reason has given more space than perhaps is justified to a method which has not been tested out by a large mileage of construction. A reasonable cost of the brick 2" cube surfacing is approximately $0.95 per square yard in Western New York. This form of road material is adaptable to manufacture by convict labor. Rocmac. — Rocmac is another patented pavement which deserves mention, as the roads which the author has seen built by this method compare favorably with other types of construction. The claim is made that, under favorable conditions, it will cost only fifteen cents per square yard more than plain macadam. The only available example of cost details given below is hardly a fair sample of what can be done. ROCMAC i8s We quote an extract from the 1910 report of the New York State Highway Commission: "Experimental pavement according to the Rocmac System as laid over the westerly portion of Buffalo Road, Section No. 2, County Highway No. 83, located in the Town of Gates, County of Monroe, New York. "The Rocmac system differs from ordinary macadam construction in that the aggregate of crushed stone is cemented together by a matrix com- posed of limestone dust (as rich as possible in carbonate of lime) mixed with a solution of silicate of soda and sugar, the silicate of soda combining with the carbonate of lime, an unstable compound, forming silicate of lime, which is a very stable compound. "The materials used in this experiment were Leroy limestone flour for the matrix, being the entire crusher product which would pass a screen of ^4t in. mesh, and Akron limestone No. 3 size with some No. 4 size mixed for the aggregate. The No. 3 size being retained on a screen of iK in. mesh and passing a screen of 2 in. mesh, the No. 4 size being retained on a screen of 2 in. mesh and passing a screen of s'^i in. mesh. "The delivery point for material shipped by rail being Cold water Sta- tion, a dead haul of one mile to the beginning of the work. "The supervision given this work consisted of occasional inspections by the divisions superintendent of repairs and the inspector in charge of this section, neither of whom could devote much time to this particular work without interfering with other duties. Had the work been constantly directed by a competent foreman more progress would have been made and the cost probably would have been decreased. "The method pursued during the laying of this surface was to scarify by hand the original foundation course, removing all loose material by brooming, upon this prepared foundation so spread the matrix composed of limestone dust and solution, to an average depth of about 2 inches, upon this spread the crushed limestone aggregate to such a depth as would give finished rolled thickness averaging about 3^i inches when properly crowned, then roll- ing same until thoroughly consolidated and continuing rolling and sprinkling with water by hand until the matrix which flushed to the surface in the form of grout has nearly disappeared, when the pavement is covered with a light coat of screenings and considered complete. "The total length of this resurfacing extending from Station 237 to Station 275-76 is 3876 lineal feet, aggregating an area of 6890 square yards surface upon which was used 1004 tons of No. 3 and No. 4 crushed lime- stone, 520 tons of limestone flour and 4050 gallons of silicate of soda solution. "Deducting from total expenditure materials not used and expense of labor trimming shoulders and ditching would leave total cost of this re- surfacing, including all material and labor necessary to form pavement complete in place $6400.82 or $0.9288 per square yard. "This expense is itemized as follows: Item Total Per Square Yard Cost of stone f.o.b. cars delivery point $2026.59 617.28 1408.79 408.61 547-28 1341.64 50.63 $0.2941 0.0896 0.2044 0.0593 0.0794 0.1947 0.0074 Cost of Rocmac solution Cost of teams hauling stone, solution, water and coal Freight and duty on solution Roller and coal Labor Tools, tanks, blacksmith, oil and wood Total $ 6400.82 $0.9288 ' * The averstge price paid per ton for all stone f.o.b. cars at delivery point is $1,253'^; price paid per hour for labor $0.22; for teams $o.56H per hour; roller rent $10 per day. "During the progress of this resurfacing traffic was not intefered with at all, all traffic being permitted to go over the work in whatever stage of progress. This is an advantage worthy of consideration. 1 86 TOP COURSES **The finished surface after five months' traffic has the appearance o£ a well-constructed macadam road, being hard, smooth, well bound, and clean, no discoloration being apparent except immediately after a rain, when it shows light brown in spots, due to the solution, which being soluble in water comes to the surface. "No ravel developed during continued dry weather when freshly laid and under traffic; road is relatively dustless; this, however, depends upon the percentage of silica in the stone used. The theory being that whenever the pavernent becomes wet the solution is brought to the surface, resulting in absorbing and hardening down any fine material which had been pro- duced by the abrasion of tires. "It can be laid in all excepting freezing weather, and while smooth yet it is sufficiently rough to afford good footing for horses and rubber tires. There is nothing entering into the construction to soften under high tem- perature and nothing to form mud in wet weather. It is claimed to be s»lf-healing, due to continual chemical reactions taking place whenever the road becomes wet." Conclusion. — In this chapter the authors have attempted to show the approximate cost of the different styles of construction in general use or such experimental tops which they have seen which promise well. The costs given are relative only, to be used in the comparison of the various constructions and are based on roads in New York during the period of 191 2 to 1915. The data may be summarized as follows, showing the desirable requirements, location and approximate first cost of the different constructions. The comparative yearly costs including main- tenance and renewal are shown in Table 22 compiled from maintenance data. The type selection shown in Table 21 C does not consider the requirements of steep grades. On steep grades stone block is the best solution, hillside brick second, penetration one coat pour bituminous macadam third, and waterbound macadam fourth. The last two become slippery if maintained by surface oiling and it has been necessary in some cases to build a specially wide shoulder treated with gravel or stone for horse traffic. Classification for Safety of Traffic The sheet asphalts, topeka mix and similar constructions are dangerous for high speed traffic even on fairly level grades during sleet storms or light rains and are not recommended for roads outside of villages. Bituminous macadams, concrete, brick, stone block, waterbound macadams and small stone or brick cubes can be ranked as safe surfaces for high speed traffic. Recommended Types. — Bituminous macadams are recom- mended for Class II and IV traffic and resident village streets. Waterbound macadam for Class III traffic. Concrete for Class I outside of villages. Brick for Village business streets. Stone block for hills on Class I traffic. Asphalt block for extremely heavy Class I traffic. Sheet Asphalt, Topeka, etc., are to be avoided where traffic travels at high speed. Its most suitable location is a resident village or city street. FAILURE OF PAVEMENTS 187 FAILURES The common causes of failure of different pavements due to structural defects are as follows. The details of inspection are taken up in Chapter XV. Stone Block. — Failures rare; will stand lots of abuse in construction. Asphalt Block. — Failures rare. When they occur due to poor block. Waterbound Macadam. — Failures rare. When they occur are generally due to poor rock, small sized stone in top courses, and insufficient rolling or puddling. Penetration Bituminous Macadam. — Failures not uncommon due to the use of too much soft binder; unequal application and overheating of Binder. The asphalt companies advocate the use of too much bitumen. Concrete. — Failures not uncommon due to inferior materials particularly dirty sand and to poor manipulation, weak mix, and too much water content. Brick. — Failures not uncommon due to poor brick and careless grouting. Sheet Asphalt and Topeka Mix. — Failures not uncommon due to overheating and poor mix. 1 88 TOP COURSES Best Location if Used Anywhere except resi- dent sections of villages. Anywhere. Outside of villages. Village streets. Outside of villages. Anywhere. < Approx. Cost per Mile In- cluding all Grading, Draining, Incidentals, Etc. $36,000 28,000 20,000 26,000 22,000 $18,000 17,000 14,000 12,000 88 0^ 0^ c>oo" Approx. Cost per sq. yd. Includ- ing Base 0000 CN vO t^ crj (S H — 1 1— 1 U • OC 15' plus stone shoulder 1— t (-H (— i cn U H 10' plus gravel shoulder ■M c g > 0) (J 2 C/5 i 1 a < 0. a B 8 en J?. V 4-> . <^ E 8 'C PQ 4-) > t-i O to fe en +j O (h o o o o o o o o o o o rt-g uo ^H S o o o o »o O lO lO M o >o o O ^•'^ ^ S fO M Tt ro q_ O rt"^ M^ q CM pT pT (N cT pT M flS .'d 1 « ost of R( lurfacing istribute ver orob ble life o Road on Yearly Basus o o o o o o o o o o o o o o o o o »oo o >r5 lO H H M 00 lOiO ':t ^5 to O ^''d o rt nd 0^^ O »0 IT) lO ITi o w M ro M H M ro 'v^ ro ro pi «»% >> Th OJ -M o o o o o O O O O O o rt to to , Tf-CNOO Tt o N vOOO \0 CN 00 " ^-^ w "^Moo q 00 t>.io -^ fO fO ^ >HfefeO MM M ^^sg^ *% T^ CO First Cost per mile including Grading, Pavement, Drainage and all Incidental o o o o o o o o o o o o o o o o o o o o o o 9. 9. ^. 9. o d o^ q q^ q_ 00 rf ci C^ q^ 00* q pT PO N cs (N cs M M M M > to^ ^l > 1 < 1 t-l HHt-HI-t l-H h-l t-HI— It— ll-H 1— 1 (— IhHhH t— 1 *"* HH Ji , V ^ V ^ ;[ V V V o bfl r^ CO •jS.S O CO roOvoo O 00 l^ N N 0\ o O M M M M _ 3 (U g§ X! ^ to 'S 00 00 00 00 CO 00 lOlO rf o o ^3 (U M M M M M M g" ^ •s ^88 :^ Jl; rj jrt »-fl +3 o c o o o 'd 52 o a o ^ CO CO «-(.S o fe^m^^°"^ ^fo o YEARLY COSTS 191 To afford a comparison of high and low type roads the following data is inserted at this point for Earth, Gravel, and Sand Clay roads. Approx. Approx. 4% Yearly Total Type Cost per Interest on Mainte- Yearly Cost mile First Cost nance and Renewal Per mile Earth . $2000 $ 80 $ 50 $130 Sand Clay. . . . 3000 120 75 200 Gravel 4000 160 240 400 CHAPTER Vn MAINTENANCE Maintenance will be divided into two classes: the care of low type (earth, sand-clay and gravel) roads and the more costly attention required to keep the higher type macadams and rigid pavements in good condition. Maintenance is a relative term and the costs given in reports mean very little unless each man person- ally understands the conditions under which the work was done and the degree of perfection in maintenance attained. The authors have had no personal experience in earth or sand- clay maintenance work; the data pertaining to these types is compiled data and while the explanation of methods are clear and definite the general costs must be accepted merely as approximate. The data on maintenance of high type roads is based on our personal experience and while this may limit its general application some- I ill. Iron Brace A.. -7>1^'^- \ ''-J Jron/^oct. ' Iron Sfr'ip, :;fx3xd\ Fig. 41. what it is more definite in the matter of costs and more valuable than the ordinary State Reports which often are difficult to in- terpret correctly, due to indefinite bookkeeping and to the transferral of charges between various funds. Low Type Roads. — The maintenance of these roads consists in keeping the grass and weeds cut, the ditches clean, culverts clear, overhanging trees trimmed and the surface of the traveled way scrapped and dragged. One shaping with a blade road machine in the spring generally is all the heavy work required the rest of the work being done with road drags, hones, planers, etc., at frequent intervals during the balance of the year. On sand-clay and gravel roads surfacing material is added to fill holes and ruts or better the wearing surface. 192 EARTH ROADS 193 There are two general systems: the contract system which lets short strips of road not over 4 miles in length to farmers - long the road and the patrol system which is taken care of by a steady patrol gang which handles from 10 to 20 miles. The contract system is explained in the quotation from the 191 7 Year Book of the American Highway Association, page 196. The patrol system is referred to throughout the chapter in various quotations. Earth Roads. — Road machine blade scrappers are familiar to all readers. The road hones, planers, etc., are not so well known and their construction is shown in Figures No. 41-41 D. Steel drags ican now be obtained. Their use in earth or gravel road maintenance is explained in the following quotation from the United States Forest Road Manual. ^^v-1§" Fig:.4l.A Plank Drag S^-rg'' Fig.41-B Split Log or"King" Drag Fifir,41-C Lap Drag gp Smootber -***" Shod with Iron F.rfi:.41-D MAINTENANCE "Maintenance is the most important item of work to be considered in road management. The smaller allowances for systematic maintenance, as they are being included in the annual road budget alongside the unlimited number of those for periodical repairs, tend to give it a place of least con- sideration and again its consideration and planning is evaded as much as possible for it is the never-ending consideration of continuous annual work and expense. It is always admitted that the degree of efficient use we derive from anything constructed for practical utilization, depends on the amount of effective maintenance it receives. Therefore, roads which are most widely used and exposed in all their parts to the worst of elements relatively should receive the highest degree of such attention, and moreover the higher the type of construction and the more it costs, the more marked attention will it require. "However, it is most gratifying to find that the old ideas of taxpayer and user are rapidjy disappearing, _ making way for the installation of practical system for the efficient retention of the better roads — as they are now being constructed. Gradually are we beginning to learn that the stability and usefulness of a road is not forever established, even when the best of super- vision and authorities declare and approve or have made the construction strictly up to the standard and with ample drainage provided — but that each mile of construction should be followed immediately, with a mile of maintenance. Besides eliminating the difficulties and discomforts of travel. 194 MAINTENANCE which seems only a benefit to the traveler, but is in reality an economical benefit to everyone, directly or indirectly — maintenance will do away with all the worries to the management and effectively prevent so much of this misapplied criticism to construction features. Finally the results of main- tenance encourage more road-building, whereas its lack discourages it. "There is no type of road that can be considered permanent, and an earth road or one bedded in the natural material, which is wholly as im- portant as the higher grade roads, or even more so — is the cheapest to main- tain in its original condition. The complete maintenance of an earth road means simply the retention of the drainage facilities that were provided in a completed and properly constructed piece of road work. Furthermore the experience of and the attention given to the road in constant rnain- tenance will show where ample drainage was not sufficiently provided; and again showing its importance, constant maintenance secures this necessary drainage with the least costs and at the proper time — before serious damage is done and heavy repair costs result. The time to begin the maintenance is immediately after the road is constructed, and its degree of efficiency will depend on what in the way of money or assistance is con- stantly provided or made available to meet sudden contingencies. The work must be done at the right time and in the right way to get the best results. "Ample drainage begins with taking the water off the road and continues with taking it along the road and away from the road._ Constant main- tenance by dragging secures this primary step in the drainage system, and also a hard and smooth surface for travel. The dragging preserves the crown, which is kept in the traveled way for no other purpose than to shed water. It then follows that this water will be taken away from the road through the further efforts of constant maintenance in keeping the ditches and culverts open. ' * To properly and economically maintain -a certain road or set of roads an organization for doing the work should be effected. On a country or mountain road a patrol consisting of two teams and two men for one part and one team and one man for the other part of the season should be able to care for 15 to 20 miles. It will be found though that a newly constructed road will require heavier maintenance for the first year or two, thus re- ducing the number of miles for this patrol. One or more such outfits could be applied to a longer road or a larger system and kept under the same supervision. These patrols keep the ditches clean and the culverts open, haul surfacing materials, i.e., clay onto sandy portions and sand or gravel onto clay, keep the right-of-way open to sun and wind; and are on hand to drag the road after each rain. Two teams are provided only in cases where there is no extra help available along the road to^ assist in the dragging, otherwise one team would be sufficient. However, if the teams are govern- ment-owned, two teams should be had, as the added costs for the extra team are small and will in most cases prove cheaper than hiring. The two teams can be used on one drag or two depending on the ruling grades in the road. "In early spring when the winter snows are going off, the supervision and such extra assistance as is necessary should be made available early to see that the snow water is being cared for — that it is running down the ditches and into the culverts, and not down the wheel tracks and over the banks of the road. Later he should have a small gang of men making the necessary repairs that might occur while the frost is coming out of the ground and from wash and water-breaks. A light grader should be at hand especially on sidehill roads to clean the ditches of material broken off or rolled down the banks and to restore badly depleted crowns, after which the drag can be used for the remainder of the season to preserve this perfected condition. "A good foreman for this should be a man who as well as to take a hand in the work, should be able to plan the work and keep in touch with the maintenance needs and move his men economically to the first necessary pieces of repairs. " Dragging is the cheapest and most effective method of maintaining roads constructed of earth, top soil, sand-clay or gravel. The drag is a very simple and inexpensive implement and when used properly gives surprising results. "Properly used and at the right time the road drag performs four distinct offices, (i) By moving at an angle to the traveled way it tends to produce or preserve a crowned cross- section; (2) if used when the material of the DRAGGING 195 surface is not compact and .hard, it tends to reduce ruts and other irregu- larities in the road by moving material from points which are relatively- high to those which are relatively low; (3). when used after a rain it acceler- ates the drying out of the road by spreading out puddles of water and thus increasing the surfaces exposed to evaporation; (4) if the surface material is in a slightly plastic state, dragging smears over and partially seals the so-called pores which naturally occur in earthy material, and thus makes the road surface more or less impervious to water. "If used improperly or at the wrong time, the drag may do actual injury to a road. Dragging a very dry road, for example, serves to increase the quantity of dust and may do additional damage by destroying the seal produced during previous draggings.^ If, on the other hand, the road_ is very wet and muddy, the irregularities in the surface are likely to be in- creased rather than diminished. The common defect in road dragging is to regard the road drag as a road-building tool, and to expect one or two trips to put the road in shape for the season. Notes on Maintenance "i. In filling bad ruts and mud-holes, it is best to use the same material that the roadbed is composed of, otherwise an uneven surface will result, oftentimes, of course, the roadbed of clay can be improved by scattering sand or gravel over it more or less evenly, or if of sand by the same use of clay, but not by filling the ruts with these appHcations. ^ Filling with rock will effectively close a mud-hole but the next season will find two more mud-holes, one on either side of this hard place formed by filling the first. "2. On sidehill roads, after light snows have fallen during the season, the inside ditches should be opened of the snow immediately in order that the water from the melting snow will run down the ditches instead of the wheel tracks. This is especially necessary where steep grades occur to prevent heavy wash and loss of crown in the traveled way, and water break- ing over the outside bank. The snows, usually, being light, this can be done by drawing the drag down the ditch with a large skew angle or better with a small ditch-cleaner, the A-drag or go-devil. "3. In a grazing country very often it occurs that salting grounds have been used near or along the roads. These should be removed for cattle climbing up and down the banks and walking along the ditches can cause considerable unnecessary damage to the road. During the season of cattle or sheep drives the men on maintenance should see to it, that the herds or bands, if they have to use the road, use the traveled way and not the banks and do as little damage as possible. If serious damage is done they can make immediate reports, if owners are obligated to repair such damages on public roads. "4. Outer bank slopes of earth that are- continually eroding, should be protected by sowing to grass, or any other plant that will mat and not be objectionable to occupants of lands along the road. "S. Keep the ends of the culverts free from drifting weeds and d6bris and clean the catch-basins of silt and other deposits. "6. Remember that the chief repairs should be looked after in the spring when the soil, being moist and easily worked, will compact readily under the drag and traffic. There is little use in attempting to do much in July and August to the roadbed proper, for the soil is so dry that it is difficult to shape properly anctmost of that moved will blow away in the first wind. Notes on Dragging "i. Use the drag often and if the very best results do not come at first trial, do not quit. First-class results can be attained. "2. Dragging is always done after rains, melting snows, or thaws, just after the ground has lost its stickiness, when the material will slide easily along the face of the drag and pack well; but not when it becomes dry in any one place. Different road surfaces and varying conditions will demand different times of application, the knowledge of which will come through faithful and persistent use and observation. "3- It requires a careful and skilful operator to get good and quick results, one who knows or can learn how to hitch to it, and where and how to ride it. Hitch so that the drag will travel at an angle of 45° with the 196 MAINTENANCE center line of the road, and do not try to cut too much material at one operation. The amount moved depends wholly upon the length of hitch and position of driver. A long hitch will move more earth than a short one. When a hard spot must be cut, the driver throws all his weight on the front blade; when a low place must be filled he moves back. These operations on patented steel drags are facilitated by changing the angle of the blades from a vertical. Step quickly to the opposite end of the drag from which you wish to deposit material into low spots. "4. Drive the team at a walk and ride the entire distance. The drag should begin at the ditch line and proceed toward the center or crown. If the crown becomes too great, reverse the skew angle of the drag. Do not try to drag too wide a section at one operation. "S. Do not try to drag too long a section. So much depends on the time the drag is used, that there is danger of dragging the road too wet at - one end and too dry at the other. Learn to select those sections which dry before others and drag them first. "6. Drag the road during or directly after one of the light snow falls just before it freezes up for the first time, as it will be in better condition to go through the winter and better able to shed water during the spring thaw. "7. Very little improvement will be noticed after the first trial, and many trips will have to be made the first year after construction. The second year, less dragging will be required and the road ought to improve continually." The following quotation from the 191 7 Good Roads Year Book shows the Kentucky methods and approximate cost of maintenance. "Maintenance by dragging is most successful when well organized. The results obtained by good rnanagement in Hopkins County, Kentucky, are frequently cited as indications of this, and for this reason the following account of the work there is quoted from a report by the Kentucky depart- ment of highways. "In 191 2 a county engineer was appointed. The* county roads were pleasured under his supervision and 2 mile sections designated, and in January, 19 13. drags were started on about 100 miles of the county roads. This original contract was only for dragging the roads, which work was to be done four times between January ist and April ist, at a cost of $10 to $12 per mile. As the sections dragged were not continuous, the citizens at once appreciated the difference between the maintained road and that which was not maintained. Consequently the next contract, which called for dragging and also for cleaning the ditches for six months, until November, 1913, resulted in contracts for 150 miles of road and at a reduced cost. In November, 1913. a contract substantially like that now in use was adopted and the time of the contract was for one year, or until . November, 1914. Over 200 miles were maintained this year at an average cost of $28 per year per mile. For the year from November, 1914, to November, 1915. the benefit of the maintained roads was so well understood by the citizens that 560 miles were under contract at an average cost of $24.35 per mile per year. "In November, 1915, a two-year contract was entered into, which the county may revoke for non-performance of the obligation at the end of the first year. About 520 miles are now under contract, at prices ranging from $12 to $40 per mile per year, the average being $22.10. It is expected this mileage will soon be increased.^ Originally a contractor was allowed to have charge of 8 miles, but now he is not allowed to contract for more than 4 miles of road. Under the 191 5 contracts the contractor must trim the branches which overhang and interfere with travel on the roadway; keep the roadway between ditches free from shrubbery and weeds; keep ^e ditches clean, free from obstructions, and at all times capable of carrying the water. 'He shall by June ist each year grade the roads with dump scraper, grader, drag and ditcher, or in any way he may see fit, so that the center of the roadway shall be crowned so that the water will flow from the center of the road to the side ditches, and at no place will the water stand on the road or run down the road. The road shall be dragged from ditch to ditch at each dragging, when the road is wet, but not sticky.' "A record of the number of draggings is kept by the county engineer on cards which, before mailing by the contractor, are countersigned by the GRAVEL ROADS 197 rural route carrier or a reliable citizen. The contractor also hauls material and constructs all culverts and bridges of 10 ft. span or under, and keeps the approaches to and the floors and abutments of all bridges and culverts on his road in good traveling condition. An analysis of these contracts shows that where the contract has been faithfully executed there is a decrease each year in the cost per mile, mainly because the farmer contractor has learned from experience that continuous maintenance makes a lower cost of time and labor each succeeding year." Cost. — The cost of earth road maintenance ranges from $20 to $200 per mile per year. A fair average is approximately $50 per mile per year for ordinary farming county and $100 per mile per year for mountain roads. Sand -clay Roads. — The methods and character of work are the same for the sand-clay maintenance as for ordinary earth roads. The cost is generally less. The following quotation from the Alabama State Highway Report indicates the usual procedure. Sand-clay Roads "No cheap road can be maintained as easily and at as small an annual cost as a well constructed sand-clay road. It responds readily to a road machine and the surfacing material is usually very convenient. Like all others though it is neglected until extensive and expensive repairs become necessary. If a sand-clay road which has been intelUgently constructed is kept dragged at reasonable frequent intervals, say three times a month during December, January, February, March and April, and during rainy periods in the other months, it will give excellent service and serve all practical purposes. If too much sand is in the surfacing material the road will tend to ravel or disintegrate and it becomes necessary to add a small amount of clay to the sandy section. A thorough harrowing should then be given the surface, after which the road should be thoroughly machined or dragged until the proper cross-section is obtained. Likewise, too much clay may develop in wet weather and the addition of sand becomes necessary. Sand can be incorporated in like manner as the clay. In very wet weather, traffic will incorporate the sand fairly well and it frequently becomes nec- essary to add sand to prevent slipping, when artificial mixing would be difficult." Gravel Roads. — Gravel roads require patrol maintenance for good results. The road should be shaped with a road machine blade grader in the spring while soft and plastic and kept in shape by dragging. Gravel must be added continuously to fill holes and ruts. Shoulder, ditch and culvert routine cleaning is the same as for any maintenance. • The following quotation is from Instructions to Patrolmen in New Hampshire which is famous for its gravel roads. •'Each patrolman must supply a horse and dump cart, shovel, pick, hoe, rake, stone-hook, axe, iron bar, iron chain and tamp. Special tools are furnished by the State Highway Department. "One dragging in the spring is worth two in the summer. It is better to drag a mile of road several times and get it in good condition, than to drag 2 or 3 miles and not finish any part of it. Don't drag a soft section when it is so wet that the first vehicle to pass will rut it all up. First fill the holes and ruts with new material and then drag as the surface dries out. Every patrolman should have material dumped in small piles along the side of his section so that on a rainy day he can at once fill all holes and ruts in which water is collecting. "When the weather is unsuitable for dragging, as during a dry spell, all patrolmen should cart on all the new material possible in order to fill all ruts and holes and resurface worn sections. Carting is very essential 198 MAINTENANCE during dry periods and should never be neglected. Whenever a patrolman IS in doubt as to what to do next the general rule is to cart new material for all roads are wearmg out under travel and it is necessary that the surface be contmually renewed to take the place of the old material that is thrown out as mud or blown away as dust. "Save all the sods, leaves, rubbish, stones and refuse that you clean off your road and dump this waste material in places where the bank is steep so that by flattening the side slope there will be no need of a guard-rail or dump the material back of a present guard-rail so that later this guard- rail can be removed." The necessity for patrol maintenance is shown by the following extract from the Iowa Specifications. Maintenance of Gravel Roads V "iP^^*^ ^^^^^!^^^! and supervisors' attention is called to the fact that both Class A and Class B gravel roads require constant and systematic maintenance at all times. Special attention should be given such roads for the hrst year following their construction. During this period the gravel IS sure to become rutted, wavy, and scattered if it is not maintained in the most careful manner. "Haxiling gravel and dumping it on the road does not produce a gravel ^°i?- 1- 1^ "^°^^ important part of the construction work lies in the attention which the road received while the gravel is being compacted. A road newlv surfaced with gravel is nothing but a possibility. The success or failure of such a possibility depends very largely on the attention which it receives during Its first year. The frequent use of a planer or blade grader will prevent the formation of ruts and waves. This work should be done while the gravel is wet, as better results will be secured. ''The scattered gravel should be brought back on the surfacing and the ^?^^ i/u°^^^/^^^^^* "P *° ^°^^ *^^s material in place. Additional gravel should be added to replace that worn away and to fill any depressions due to settlement. u "The Commission strongly urges that the patrol system of maintenance be adopted for all gravel roads. The patrolman should spend all his time on the road. It is only by such a system that definite responsibility can be fixed. Patrol maintenance should extend not only over the first year after the gravel surface is placed, but also throughout the succeeding years. It should extend to the side ditches, earth shoulders, culverts, and all other parts of the road as well as to the gravel surfacing. "While the patrol system of maintenance is urged for all gravel roads, it is absolutely necessary for Class B gravel roads. These specifications have been prepared with that idea in mind. "The Commission will approve the construction of Class B gravel roads on the county system only on condition that an adequate patrol mainte- nance will be established promptly after such road is placed in service." Iowa Hiqhway Commission. Cost.-- We are indebted to Mr. F. R. White, Road Engineer of the Iowa Highway Commission for the following information in regard to the construction and maintenance cost of about 400 miles of Class B gravel roads (see Plate No. 39, page 140). These roads were constructed at a cost slightly above $1000 per mile. The cost of maintenance depends very largely on the volume of traffic and the location of gravel. However, where there is an average of 200 to 300 vehicles per day and the gravel can be obtained within 3 miles of the road the yearly cost of maintenance is about $150 per mile. In New York State where the roads are oiled to care for a some- what larger volume of traf&c 200 miles of high-class gravel roads cost approximately $550 per mile per year to maintain. MACADAM ROADS 199 A fair average maintenance cost per mile per year for double track gravel roads is probably from $200 to $300 under fairly heavy travel. HIGH TYPE ROAD MAINTENANCE In the development of any system of highways the methods and cost of maintenance become increasingly important. The rapid growth of motor traffic in the last few years has changed both methods and cost making it necessary to give new figures which are reliable for present traffic conditions. We have therefore confined ourselves in the discussion to recent costs with which we are familiar in order that in stating general conclusions proper allowance is made for unusual conditions not shown in the reports of various State Highway Departments. The discussion will be based on the general maintenance costs and methods employed on 6000 miles of New York State improved Highways of all types for the years 1915 and 191 7 and detail costs on 600 miles of roads in Western New York for a term of years. We are indebted to Mr. Frank Bristow for the following discus- sion of general maintenance methods and summarized costs. It should be borne in mind that the discussion and costs apply to territory subjected to severe winters. MAINTENANCE OF MACADAM AND RIGID PAVEMENT HIGHWAYS By Frank W. Bristow N. Y. S. Dept. of Highways, Division on Maintenance Maintenance comprises keeping the paved roadway surface in as nearly perfect condition as possible, keeping the earth shoulders smooth and safe for traffic; the drainage system free from obstruc- tions; all structures in good repair; removing obstacles to vision as brush or overhanging branches; and cutting tall weeds and grass. If the work of maintaining improved roadways is consistently performed through successive years it is certain that the efficient life of such roads will be lengthened. Maintenance should com- mence when construction leaves off, because in order to effectively and economically maintain improved roads it is necessary that the roadway be in a good state of repair at the time the maintenance work begins, and should the pavement be so worn as to be structur- ally weak it is not economy to postpone resurfacing. Maintenance work, including surface treatment with bituminous material and cover, should be distinguished from extensive repairs involving replacing of wearing course or reconstruction. Maintenance of Macadam Roads It is especially desirable that all surface treatments be completed as early in the season as possible; say by mid-summer to permit 200 MAINTENANCE traffic to enjoy the greatest benefit from such treatment, the season of heaviest motor traffic being from the middle of July to the middle of September. So far as practicable the correction of surface defects such as ruts and depressions should precede the surface treatments. While the elimination of dust on macadam roads is desirable as adding to the comfort of the traveling public, it is necessary from the maintenance point of view, inasmuch as dust means deterioration of the road which if permitted to continue results in a raveled condition and the macadam will disintegrate. Surface treatment with oil or tar also tends to seal or waterproof the pave- ment. Horse-drawn steel-tired traffic tends to destroy an oiled surface mat, while rubber- tired motor traffic is beneficial. It is good practice not to oil macadam roads upon which horse- drawn traffic greatly predominates or new waterbound macadam which has not been under traffic at least two months, or extremely shady roads. The usual foundation defects which develop in gravel and macadam surfaces are ruts, due to a soft condition in the earth sub-grade, depressions due to settlement of fills which commonly develop at locations where new culverts were constructed and frost boils. Shallow ruts and surface depressions are corrected by being filled in with crushed stone of as large size as the depth of depressions will permit, the same being well tamped into place, and piore lasting results are obtained if a proper grade of bituminous material is used to firmly bind the new stone; light asphaltic oils and tars have been used for this purpose with unsatisfactory results, in that patches made by this method do not endure, the experience being that the material forming the patch is pushed ahead by traffic leaving the original depression exaggerated by the bunch of new patching material at the end. Heavier binder grade material has been used; a patch by this method is durable but does not wear away as rapidly as the adjacent surface resulting in a high spot in time. To date our experience is that an asphaltic emulsion for cold patching is most satisfactory, being nearly fool proof and requiring no equip- ment but a broom and shovel. This material is not recommended for use with stone of greater size than will pass a one and a quarter inch ring. In using this material the depression to be repaired should be swept clean, so as to be free from mud or loose material, and tamped full of a mixture of the emulsion and broken stone. Such a patch will require an hour or two to set. The proportions of the mixture required are, where the stone used are uniform in size, about three-quarters of a gallon per cubic foot of stone ; jvhere the stone are graded about a gallon per cubic foot. This mixture may be made in moderate quantities as stock for use is required. Ruts in gravel surfaces may be eliminated by the use of a hone early in the season. Deep ruts indicate necessity of either sub- drainage or reinforcement of the foundation; an inspection should determine which is the proper remedy. On side hill roads frequently a deep drain in the upper side ditch to intercept the ground water OILING 20I will be effective; where reinforcement is decided as necessary, usually sub-base construction about eight feet in width will be sufficient. Field stone, quarry spalls, broken stone, slag or gravel are proper materials for such reinforcement. . Frost ooils so-called are caused by wet spots in the earth founda- tion freezing and heaving; later when the frost leaves and the foundation soil is soft the thin macadam crust tends to break through under loaded wheels. These spots which usually occur where the road construction is in a cut, should be excavated, and drained if practicable; any wet clayey soil or silt removed and replaced by gravelly material, field stone, quarry spalls or other good' material ; the macadam is then replaced. Ravel is the .term applied to describe the condition where the fragments of broken stone become loosened from the body of the road, due to the binding agent failing to perform its function. Bare, toothy or a pitted condition of surface are the varying degrees of a slightly rough surface due to the interstices between the frag- ments of stone not being filled flush with the binding material or when the wearing surface has innumerable extremely slight depressions. Dust, which is self-explanatory. The remedy for raveled, pitted or dusty condition is a surface treatment of bituminous material and cover. These treatments are generally made using a grade of asphaltic residuum oil or a refined tar product which can be applied cold, or which requires very little heating, and better and more uniform results are obtained where a pressure distributor is used. If a pressure machine is used not less than twenty pounds pressure ^should be required. Asphaltic base oils, or tar products having a bituminous content of from 40 to 60 per cent, may be applied by gravity sprinkler, but 60 to 75 per cent, asphaltic oils or tars containing 60 to 70 per cent, of pitch are preferably applied by pressure. Uniformity in application is important. As to the relative merits of asphaltic residuum oils, cut back asphalts, high carbon, or low carbon tars there is a diversity of opinion (see also page 210). Relative cost and durability will naturally be the considerations controlling the selection. The material which is the cheaper at one delivery point may not be at some other. As to the durability it is doubtful if there is any ad- vantage as between the asphalt and tar products. When applied, the tar material appears to take a set faster than the asphalt, which is a decided advantage, but more criticism is made as to slipperiness of the tarred surfaces during freezing weather. It is thought that the tars have the greater adhesive quality, but that the exposed surface due to evaporation of volatile constituents becomes crumbly or dead in a shorter time than a similar grade of asphalt. Regarding rate of application per unit area, this will vary with the porosity of the surface to be treated; for the cold, or light hot application ranging between one-sixth and one-third gallon per square yard. Experience is that from one-fifth to one-quarter gal- lon will produce good results on the average surface. 202 MAINTENANCE Preliminary to the applying of the bituminous material the surface to be treated should be swept clean if necessary, to free it from all loose and organic matter; after this has been done the application can proceed regardless of whether the surface is wet or dry, providing there are no pools of standing water on the surface, a slightly damp surface apparently gives better penetration than an absolutely dry surface, the object sought being to get the mate- rial into the texture of the road. The surface treatment should be confined to one side or half width of the road at a time, leaving the other side available for traffic. Some little time should be allowed for proper penetration, but within one hour after the application it should be lightly covered with suitable mg^terial. Traffic can now use this side and the treatment continued on the opposite side. The materials recommended for cover are crushed stone or slag which will pass a M-in. mesh and are free from dust; ore tailings, fine screened gravel or coarse sharp sand. The toughness of the mineral aggregate used for oiling cover is an element in the dura- bility of the mat formed by the treatment. Relative cost will determine the selection of material to be used for cover. The quan- tity of cover necessary will vary with the rate of application of the bituminous material and with the porosity of the surface treated. Where the rate of application of oil is from one-fifth to one-quarter gallon per square yard the range of cover may be stated as being between 35 and 70 cu. yd. per mile of road 16 ft. wide, and gen- erally 40 to 50 cu. yd. will be ample. This cover should be uniformly applied either by hand or by mechanical spreader; however, only sufficient to cover the oil lightly should be applied at one time. It will require two or three separate* spreadings from time to time as the surface becomes shiny and sticky to produce a perfect mat. Any excess unused material delivered for cover should finally be gathered up and stored in neat piles back of the ditch line where possible. These treatments do not require rolling, although rolling tends to turn any coarse sharp fragments of cover material onto their broader sides, reducing danger of tire cuts to a minimum. Thick mats^ formed of binder and %-inch stones while durable are not generally satisfactory; they are expensive, costing from $1000 to $2000 per mile and frequently become rough under traffic, although they do serve at times to carry a road along for a few years which would otherwise be a resurfacing matter. This treatment also is used to restore a crown to a road worn flat. On gravel and new waterbound macadam and upon roads where there is little motor traffic, maintenance by calcium chloride is effective. Where this treatment is used the applications may be of the granulated crystals applied by hand or by a mechanical spreader, at the rate of i lb. to i J^ lb. per square yard; preliminary sweeping is not necessary unless there is excessive dust say M-in. depth or more upon the surface proposed to be treated. Should 1 The authors wish to emphasize the danger of using thick mats for ordinary maintenance. RIGID PAVEMENTS 203 this treatment be made immediately preceding a rain, a consid- erable quantity of material would be lost. Two or three treat- . ments as above should suffice for the average season, and the width treated may be confined to the width of the traveled way. This treatment has cost in New York State about $150 a mile a year. Surfaces which have previously been oiled are not recommended for calcium chloride treatment. In cases where continued surface treatments of bituminous material through successive years has built up an excessive depth of mat, which has a tendency to be unstable and rut, it is suggested that such mat be removed and spread upon the shoulders, which will cost from $50 to $150 a mile, and that surface treatments be again^made upon the macadam itself. Should it be found that the macadam has become uneven, as to crown and grade, or is badly worn or has numerous holes, it is suggested that the road be scari- fied and thoroughly dragged with a heavy spike-tooth harrow, after which an agricultural weeder should be repeatedly hauled over the road, the object sought being to work all of the finer particles to the bottom of the scarified course, leaving fairly clean coarse stone at the surface; this should be shaped up by hand or scraper and rolled to develop any irregularities in the surface which should be corrected by the addition of new crushed stone. Any pockets of fine material should be removed and replaced by new top course stone, the weeder should again be used to loosen the stone, which will then be ready for the first application of binder, which may be at the rate of three-quarters of a gallon per square yard, application being made by a pressure distributor, the surface then to be covered with a layer of M-in. broken stone and thoroughly rolled. During the rolling, additional ^^-in. stone shall be applied and broomed about until the voids in the top course are well filled; all loose stone shall then be swept from the surface and a sealing cost of one-half gallon of binder per square yard shall be applied and immediately covered with a layer of J-^-in. stone and again rolled; surface will then be ready for traffic. This treatment is probably better adapted to waterbound macadam than to the penetration bitumi- nous type; however, if found necessary to break up and reshape penetration macadam, it is suggested that the latter loosening by the weeder qe omitted and a spread, one stone thick, of 2-in. broken stone be applied and the first application of binder be increased to one gallon or one and a quarter gallons. This method is not ap- plicabe to an extended mileage as it is generally better to resur- face Iwhen a road reaches this stage. Concrete Roads with Thin Bituminous Surfaces. — The second- class concrete with thin bituminous wearing surface is a difficult type to maintain; the bituminous surface under traffic patches off, and as the concrete is usually not strong enough to resist abrasion, holes develop in the concrete; patching results in a rough riding surface and probably the best way to secure a smooth riding road is to resurface, using a 2-in. bituminous mixing type top. Asphalt, Topeka Mix, Amiesite, Etc. — The holes which develop in the bituminous mixing method type wearing surfaces should be 204 MAINTENANCE repaired as follows: Excavate the old material at the defective spot the entire depth of course, so that the edges will present clean, vertical surfaces, these surfaces and the exposed foundation to be swabbed or painted with hot asphaltic cement or paving pitch, the hole then to be filled, with a mixture similar to that used in original construction, whenever practicable, using sufficient quantity so that after consolidation by rolling (or tamping in case • the extent of repairs is limited) the surface of the new patch will be flush with the adjacent pavement. In case there is no local mixing plant available, or the limited extent of repairs do not jus- tify expense of treatment as above, holes may be repaired with the mixture of crushed stone and cold patch asphaltic emulsion, as outlined for macadam surfaces. Concrete Pavements. — The cracks which develop in concrete pavements may be the result of either frost action, settlement of foundation or contraction, and are properly treated by being poured with hot paving pitch or asphalt binder. If spots disinte- grate, the defective material should be removed and replaced by new concrete. Brick Pavements. — Block pavements of brick, stone, asphalt, etc., properly constructed should not require repairing for a considerable term of years; cracks which develop should be grouted with hot paving pitch or asphalt binder; areas which settle, thereby breaking the bond of the grouted joints resulting in crushing or cobbling the blocks, should be taken up, the sand cushion reformed, all sound blocks cleaned and relaid, being turned over where necessary, any broken blocks to be replaced by new whole ones, joints then to be grouted with Portland cement grout preferably, if the original pavement was so constructed, otherwise the joints may be poured with hot paving pitch. It should be noted that repairs with fresh cement grout require to be protected by barricades for a period of about a week, so that such repairs should be confined to one side of the pavement in long stretches, leaving the other side available for traffic; where the repairs are limited in extent and barricades are especially undesirable, the patch may be covered with two inches of earth and further protected by planking during the time required for the grout to set. Where joints are poured with paving pitch, traffic need be diverted only during the time of actually making the repair; this is a decided advantage. Observation demonstrates that horse traffic on steep grades leave the pavement and seek the earth shoulder, so that so far as prac- ticable these shoulders should be improved by widening, and by graveling or covering with broken stone to avoid excessive rutting, also that on sharp curves the tendency of motor vehicles is to cut close to the inner edge, making it well for this reason to stone or gravel the shoulders at these points. Along the edges of the rigid types of pavement, block and con- crete especially, traffic usually develops a deep rut which if neg- lected becomes dangerous, to rapidly moving traffic; this rut should be kept filled with gravel or broken stone. Excess material when removed from the shoulders should be so disposed of as to widen embankments and flatten slopes. MAINTENANCE COSTS 205 General Organization Methods. — There are three general plans for performing the work of general maintenance, the patrol system, the repair gang and by contract. The nature of the work renders it difficult to estimate in terms of labor and material with precision, so that except in the case of surface treatments, repair by contract is not advised. By the patrol system the roads patrolled are under • constant supervision and the responsibility for neglect is 'fixed. The repair gang may be used to supplement the patrol system when it is desired to expedite extensive small repairs, and also to perform all necessary repairs upon any roads not patrolled. A patrolman living in the vicinity of his work, equipped with a single horse, one- yard wagon and small tools, costing $3.00 a day," can make all minor repairs on. a section of between 5 and 7 miles of macadam. The repair gang should be equipped with a small motor truck, say of one and a half tons capacity, to be used in transporting the men and tools within a radius of about 25 miles from their headquarters base; this truck can also assist by hauling some material required in the work. It is concluded that a combination of the patrol and repair gang systems is an improvement over the adoption of either plan of or- ganization exclusively, also that the success of either plan depends entirely upon the experience, good judgment and ability of the man in direct charge and control of this work. As nearly all of the hauling in connection with maintenance work is over hard-surfaced roads, motor equipment for delivering stone, oil, etc., would natu- rally be considered. The writers' opinion is that for short hauls teams are economical, also that the motor tractor and trailers sys- tem of equipment are more efficient than the complete single unit system. ' Summarized Costs for the Season of 1915 New York State. — 1 In order that the following figures may be more easily understood, I it is well to outline the development of the use of the different types of pavement. ' From 1898 when State highway improvement began until 1909 [ to which time 1787 miles had been constructed, practically the I entire mileage consisted of waterbound macadam. Up to this I time there had been no systematic maintenance, which resulted in a large mileage of road requiring more than ordinary expenditure I to bring it up to standard. Beginning in 1909, penetration bituminous macadam was gener- j ally used on the main roads with brick near cities and villages. About 191 2 the department tried out concrete roads with thin I bituminous oil tops. . This type proved unsatisfactory in that the bituminous surface peeled in spots and the concrete used was not sufficiently strong to stand the traffic directly. The high cost of I maintenance can be seen from the following table. The type has \ not been used since 19 14. The department is now designing ( first-class concrete roads where roads of that class are economical. I In the following tabulation of maintenance and renewal costs, I therefore, the average per mile represents approximately a fair ( sample of both yearly maintenance and renewal for waterbound i 2o6 MAINTENANCE « ^ rj O (U >» (U'T^ M OS O U < w o < M o tn 6 s 0) (u*-; :::: fJ S? 5 a ^ « rt t cs On On O lO M O H M fOOO t^ CO ^O Tf M On ONCX3 vO O^00 On M «N CO CS CS O (L) O > Its o es= ^ -^O CO O . O CO lOOO cs 00 CO vo t^ M O^, O LO cr 00 M M H O M lO o M rf o H o O MAINTENANCE COSTS 207 macadam, gravel and concrete bituminous and represents only ordinary yearly maintenance for bituminous macadam, concrete pavements, brick and other high -class rigid pavements; none of these latter classes have been down long enough to yet require renewal, which makes their cost as sho\\Ti much less than will ulti- mately be required. Of the mileage shown in the preceding table, the following table shows the amount of resurfacing. Table Showing Resurfacing Costs 191 5 ^ Type of Road Resurfaced No. Miles Total Cost Cost per mile Gravel 12.88 176. 29 43-72 24-85 0.36 258.10 $ 77,686.27 997,776.66 243,760.22 160,321.37 4,003.40 $ 6,000 6,000 6,000 6,400 12,000 Waterbound Macadam Penetration Bituminous. . . Concrete Bituminous top . . Block Pavements Totals. $1,483,547-92 1 The type of resurfacing is not necessarily the same type as the original road as shown in column No. i. Supplementary Explanation of Mr. Bristow's General Costs and Discussion The authors wish to call attention to two points in the general cos t tabulation. The average cost of maintenance and renewal for 191 5 is given as $750 per mile for the total system. This system includes approximately 1000 miles of road recently built on which there is practically no charge except minor repair aggregating not over $200 per mile per year. For a completed system of this char- acter all of which is under normal maintenance and renewal, the average cost per mile would be approximately $900 per mile, as is evident by excluding the thousand miles from the tabulation of total cost. In the resurfacing table it is evident from the cost per mile that better grades of top courses were generally placed on the water- bound and gravel roads than originally constructed; this means that in some cases the original design was not proper for the class of traffic the road served. The most evident faults of the usual maintenance are in delaying the work till late in the season and in careless mending of ruts and depressions before the application of surface treatments. It is well to emphasize the necessity of using a coarse grade of stone preferably ij^^" to 2}^." size in mending noticeable depressions. The hole should be dug out, the edges squared up, the depression 208 MAINTENANCE filled, bound with heavy binder and screened and rolled. Careless- ness in this regard has resulted in a large amount of justifiable com- plaint. The following quotation from the 191 7 report of Mr. Fred Sarr, 2d Deputy Highway Commissioner of New York State is very reliable and up to date data as the bookkeeping on which it is based is of a high order. "The cost of maintenance, repair and reconstruction of a large mileage has been segregated and charged against the roads of various types of im- provement, following the plan of the last two years in order to determine the cost of maintenance of the several types of pavements which have been used in the improvement of the New York State and county highways, and the results are indicated in the following tables. "The pavements are arranged in two groups. In the first group are the types represented by at least 100 miles, or those that by reason of the large mileage and wide distribution should represent with a reasonable degree of accijracy the average cost of maintenance of pavements of the particular typed. In the second group are the types represented by less than 100 miles and too much weight should not be given to the tabulated costs of maintenance of such mileage, in that the results of one year with a small mileage do not fairly represent the actual average cost per mile of mainte- nance of the particular type. First Group Type of Improved Surface Miles of Improved Highways of Each Type Expenditures per Mile dur- ing 191 7 for Maintenance and Repair, Exclusive of Reconstruction to Different Type Total Expendi- tures per Mile during 191 7, Including Re- construction to a more Per- manent Type of Surface Bituminous macadam, penetration method, as- phalt binder Waterbound macadam. . . Brick pavements Concrete: First Class 2,793.77 2,534.34 280. II 257.46 226.48 167.72 164.34 $412.00 970.00 222.00 1 1 2 . 00 1,127.00 918.00 352.00 504 . 00 1,154.00 1,443- 00 Second Class Grave] Bituminous macadam, penetration method, tar binder "An expenditure of ^34,392 which was required to restore to normal con- dition sections of improved highways that were damaged by cloudbursts and floods, has not been distributed to the particular type of pavement in- volved, in that the type of construction had no bearing upon this extra- ordinary expense. MAINTENANCE COSTS 209 Second Group Type of Improved Surface Miles of Improved Highways of Each Type Expenditures per Mile dur- ing 1 91 7 for Maintenance and Repair, Exclusive of Reconstruction to Different Type Total Expendi- tures per Mile during 191 7, Including Re- construction to a more Per-' manent Type of Surface Block pavements: Asphalt, concrete base. , Asphalt macadam base. Wood Stone Brick cubes, macadam base . Concrete : Hassam Bituminous Macadam: Mixing Method: Amiesite, concrete base. . Amiesite, macadam base, Topeka, concrete base. . . Topeka, macadam base. . Open mixed, concrete base Open mixed, macadam base Bitulithic, concrete base Henderson, macadam base Sheet asphalt, concrete base Gravel mixed, gravel base Penetration Method: Asphalt binder, concrete base Sub-base, bituminous. . Kentucky rock asphalt. . . . Rocmac Total all types 13-55 2.52 o. 24 2.93 58.52 3-73 4.33 33-74 12.64 13.32 3-58 13.63 I . II 1 .22 11.47 4.80 14-39 17-55 1-39 $240 . 00 163.00 30 . 00 76.00 619.00 32 .00 1,131.00 245 - 00 393- 00 29.00 109.00 2 I 6 . 00 1,380.00 738.00 I 74 . 00 1,079.00 387.00 3,884.00 $9,811 .00 6,639.21 $643 . 00 $767.00 The cost of maintenance having been segregated and charged against the various types of -Davement for the past three years, in order to secure a more reliable comparison of maintenance costs, the experience of the three years has been combined for the types having a material mileage in our system of improved highways with the following results: 2IO MAINTENANCE Type Average of the Past Three Years Experience Average Mileage Maintained Average Expendi- ture per Mile-year Bituminous penetration method Waterbound macadam Gravel. Brick pavement First Class concrete 2,6s9 2,408 178 280 164 2S3 $464 . 00 976.00 824.00 196.00 124.00 1,082 .00 Second Class concrete All types 6,099 678.00 General "Efficient maintenance of macadam pavements, particularly of the water bound type, of which there are 2535 miles in the State system of improved highways, necessitates frequent surface treatments with bituminous mate- rials or constant patching of the holes that rapidly develop under the present day motor vehicle traffic. "Frequent surface treatments are objectionable not only from a traffic standpoint, but from the fact that such treatments tend to build up an un- stable mat of bituminous material and mineral aggregate on the surface of the pavement that is displaced by the fast moving motor vehicle traffic, and develops a rough and uneven surface. , "It has, accordingly, been the policy of this Bureau to restrict the use of surface treatments and wear the surface mat down as this is possible before giving another general surface treatment. ^ "This method, while tending to provide a smoother surface, requires constant patching during the latter stages of the wearing down process. " Much time and thought have been given to the study of the results ob- tained by various methods of manipulation and materials used in patching macadam surfaces. "In making these patches to pavements carrying any considerable amount of motor vehicle traffic, it is necessary to bind the mineral aggregate with some form of bituminous material. "Light asphaltic oils and refined tar products, similar to those used for surface treatments, have been used extensively for light, thin patches, paint- ing the area to be patched with the bituminous material and covering with stone chips or sand. "Heavy binders that require heating have been used in the same manner. "The most satisfactory results have been obtained, where the required patch must be cme-half inch or more in depth, by mixing the mineral aggre- gate with a heavy asphalt or tar binder, cut back with light voltaic oils to a consistency that will mix readily with the mineral aggregate when cold, also with an emulsified asphalt binder used in the same manner. '' The bituminous material and stone aggregate, being mixed either by hand or in a small concrete mixer, permits of a proper ijrcportioning of the mate- rials which has been demonstrated to be about 6 % in weight of solid biturnen or mineral aggregate used, or about one gallon of the cut bacK or emulsion per cubic foot of crushed stone. "With asphalt cut back the best results have been obtained by using a material made from an asphalt binder, having a penetration of about 165, cut back with about 33 % in weight of naphtha. "With tar cut back the best results have been obtained with a material made from a refined tar binder having a melting point of about 70°C., cut back with about 40 % in weight of tar oils, of which at least 60 % shall distil up to 235°C. MAINTENANCE MATERIALS 21 1 "A very satisfactory material for patching purposes is an emulsified asphalt containing about 65% of asphalt binder having a penetration of about 165. ' ' This material may be diluted with water if desired, and may be mixed with wet mineral aggregate when found in that condition. It readily sepa- rates from the emulsified state when combined with crushed stone in the so-called open mix. "The resultant adhesive qualified of an emulsified asphalt appear to be better than can be obtained by the same asphalt in any other form. "The only tangible reason advanced for this result is that the water in the emulsion may carry the binder into the pores of the material or pavement to which it is applied. * ' The patch made with emulsified asphalt hardens to a condition of stabil- ity much quicker than one made with cold oils or tars or cut back binder that we have used, and is, for this reason, preferable to those materials for patching work on heavy traffic highways. "Very good results have been obtained with the cut back tar cold patch material, particularly on medium to light traffic highways, where the patch- ing material is not thrown about by traffic to any great extent. "In order to obtain efficient results in patching with a tar binder, it is necessary to make a so-called close mix, by using a graded mineral aggre- gate having arninimum amount of voids, which, however, will not permit the volatile oils to evaporate as fast and the patch to become stable as quickly as may be obtained with asphalt emulsion when used in the open mix. It is, accordingly preferable when using tar, to mix same with the mineral aggregate and leave in shallow piles for about two days before apply- ing to the road surface. . "The necessity for using the close mix with tar binders, is due to the fact that tar products are more susceptible to the heat and cold than asphalts. •' ' In other words, if starting with the two materials of the same consistency at 6o°F. and the temperature is raised to that of a pavement on a hot sum- mer day, say I30°F., the tar is much more fluid than the asphalt and tends to flow away from the open mineral aggregate, and the open patch will show a tendency to ravel. Again when the temperature is reduced to that of a pavement on a winter day, the tar becomes much more brittle than the asphalts and again the open patch with tar binder is more liable to ravel out than one made with asphalt binder. ' [ A comparison of the result obtained with the two materials each of which contains a quantity of the semi-volatile oils sufficient to permit them to be applied to the surface of the pavement at 6o°F. as a surface treatment, demonstrates that the tar, by reason of its greater fluidity en a hot summer day, will penetrate the old pavement to a greater extent than the asphalts, and thereby serves more as a binder to the old pavement. It is for this reason that cold tars are generally used as the first and second treatment of a waterbound macadam pavement, subsequent treatments of heavy as- phaltic oils carrying about 65 % of solid bitumen, will give more efficient and lasting results if used conservatively, that is, if the successive treatments do not follow each other too closely. "_When successive treatments are given every year as a dust layer or to obviate the necessity for patching, cold tar is preferable in that it does not build up a mat on the surface of the pavement to the extent obtained with asphaltic oils. "Providing a mat is built up with successive tar treatments, the same will generally lie flat and not shove u«ider traffic, and develop a wavy and corru- gated surface as is often obtained with too frequent surface treatments with asphaltic oils. "This resulting difference is due to the aforesaid difference in consistency at summer temperatures of the pavements. "The tar being so fluid at summer temperature, it appears to retain a smooth surface by the effect of gravity, while the asphalt simply softens sufficiently to permit the surface mat to be displaced by traffic, which dis- placement increased from day to day and often necessitates the entire removal of the old mat. ' ' Another factor to be considered in deciding upon the material to be used for the surface treatment is the condition of the old pavement. Where the old macadam is composed largely of small particles of crushed rock and dust, and is in a more or less loosened condition, and is subject to displacement by traffic, a light asphaltic oil is preferable to cold tar for 212 MAINTENANCE surface treatments. The asphaltic oil treatment develops into a mat or carpet over the macadam which remains more or less plastic, even at low temperatures, and displacement of the macadam under traffic does not result in the shattering and the ultimate destruction of the mat to the extent ob- tained under similar conditions with tar treatments. "Also for the same reason, asphaltic oils give the best results on pavements where steel shod traffic predoniinates. ' ' The best results obtained with tar treatments are where the old macadam pavement is clean or free from dust and where the pavement is firm and sound, and the stone fragments do not displace under traffic, and where motor vehicle traffic predominates, also where a minimum amount of cover material is used in conjunction with bituminous material. "Macadam pavements surface treated with tar are, however, much more slippery for horse traffic in cold weather than those treated with asphaltic oils. "In my report of a year ago, I discussed to some length the subject of the extensive breaking through of many of the pavements during the spring months. "Referring to such report it will be noted that the total area actually broken during the spring of 19 16 was equivalent to 82 miles of pavements 16 feet wide, and that the broken areas were distributed over many projects aggregating to a total of i939 miles, of which an average of 4.2% was broken through. "During the season of 1916, about 75% of the total broken areas were substantially repaired, and about 238 miles of the weaker pavements were resurfaced. "The spring of 191 7 appeared to be a repetition of the previous year as to the amount of broken pavements. "The result of a survey to determine the extent of the broken pavements when tabulated indicates that the total broken areas were, however, but 60 % of the total of the previous year. "The total length of the various projects involved aggregating 2090 miles about 9 % larger than those reported in the previous year. _ Of this total length the equivalent of about 48 miles of pavement 16 feet wide was broken »up or about 23^ % of the total length involved." Snow Removal. — On main roads between large cities snow removal in winter has become part of the regular program. In many districts automobile trucking relieves rail congestion and is needed even more in winter than in summer. The Maintenance Departments are in a position to handle this work with their organized forces and equipment which are idle at this time of year and the necessary expense is certainly worth while to make the main roads passable for trucks the year round. Typical Maintenance Costs of Different Types. — From a detailed study of 600 miles of road in Western New York with which we are personally familiar, the following typical costs are derived. It is assumed that the type used is suitable for the class of traflfic . served as indicated on page 164. The maintenance system is a combihation of patrol, gang work and contract. A one man patrol with horse and wagon is used to keep the shoulders in shape, the ditches and culverts clean and small holes in the pavement repaired. Gang work with proper machinery under State control to paint guard rail and make more extensive surface repairs and contract work for oiling and surfacing. Detail oiling costs are given under cost data (page 653). This system is not highly efficient as the executive heads are changed at short intervals for partisan reasons; the department is a con- venient means of dispensing minor patronage and the maintenance money is rarely available early enough in the spring to be used to DETAIL COSTS 213 advantage, but it represents about as good a method as can be expected in doing public work on a large scale and as such is of more practical value as a guide of costs than figures based on maximum efficiency. Patrol Work Macadam Roads. Regular patrol labor '. $70 per mile per year Extra labor 40 " '' '' " Maintenance material 45 " '' '^ " Guard rail, incidentals, etc 20 " " '' " Total per mile per year $175 " *' *' " Say $200 for waterbound roads Say $150 for bituminous penetration roads. Patrol Work Rigid Pavements. Regular patrol labor $30 per mile per year Extra labor 15 " " " " Shoulder material, etc 30 " " " " Guard rail, incidentals, etc 20 '' " '^ " Total per mile per year $95 Say $100 15' Waterboimd Macadam, Class n and IV Traffic. Life of top course 4 to 12 years; Say 7 years Class II and 9 years Class IV. Class 11 Traffic. Yearly patrol including materials for minor repairs and painting guard rail at $200 per mile per year $1400.00 Calcium chloride, ist and 8th years @ $125 per mile per year 250 . 00 Cold oiling, 2d year 200 . 00 " 3d '' 200.00 " ;^- 5th '' 250.00 Hot oiling 6th '' 1000 . 00 Cold oiling 7th '' 250 . 00 • Resurfacing with waterbound macadam 8th year 4000.00 Eight year total $755o . 00 Cost maintenance and renewal per mile per year 950.00 Cost of ordinary maintenance per mile per year 450.00 Class IV Traffic. 10 years total approx $8000 . 00 Cost of maintenance and renewal per mile per year 800.00 Cost of ordinary maintenance 400.00 214 MAINTENANCE 15' Penetration Bituminous Macadam Class 11 and IV Traffic. Life of top course 6 to 12 years. Say 10 year average. Yearly patrol @ $150 per mile per year $1,500.00 Cold oil 3d year 200 . 00 " "5th '' 250.00 . " "7th " 300.00 Hot " 9th '* 1,000.00 Cold '' loth '' 250.00 Resurfacing nth year with bituminous macadam 6,000.00 1 1 year total $9,500 . 00 Cost maintenance and renewal per mile per year 900.00 Cost ordinary maintenance 350.00 18' Cement Concrete Pavement Class I and 11. Class I Traffic (12 year life). Yearly patrol and incidentals @ $150 $1,800.00 Resurfacing the 13th year with either asphalt, brick, clay cubes or rebuilding with concrete @ $10,000 to $16,000 per mile 14,000.00 13 year total $15,800.00 Cost maintenance and renewal per mile per year 1,220.00 Cost ordinary maintenance 150.00 Class n Traffic (15 year period). Yearly patrol and incidentals $ 1,500.00 Resurfacing 13,000 . 00 16 year total 14,500.00 Cost of maintenance and renewal per mile per year $ 900 . 00 Cost of ordinary maintenance 100.00 18' Brick Pavement Class I Traffic Probable life 15 years based on reports from 80 cities. Range of life 10 to 25 years. Yearly patrol and incidentals $ 2,250.00 Replacing brick surface 18,000.00 16 year total $20,250.00 Cost of maintenance and renewal per year $ 1,250.00 Cost ordinary maintenance 150.00 Maintenance Conclusion. — The indications are that the yearly cost of maintenance and renewal of a well designed high-class road system will run about $900 per mile per year. The effect of bad design is evident from resurfadng costs, for if waterbound macadam is built on a Class I traffic road the life is easily halved, increasing the maintenance and renewal cost to $1500 per mile per year and causing continual inconvenience to the traveling public by repairs and reconstruction. Probably the most feasible method of reducing maintenance cost will be the utilizing prison labor to manufacture and in a limited way apply the maintenance materials. CHAPTER VIII MINOR POINTS Under this heading are included right-of-way widths, guard rail, bridge rail, snow fences, retaining walls, toe walls, curbs, guide and danger signs, cobble gutters; rip rap, catch basins, grates, dykes, storm sewers; flow of water in ditches and cattle guards. Right-of-way Widths. — Many of the older communities are handicapped in road improvement by narrow right-of-ways which require widening at a large expense and considerable legal difficulty. Where right-of-way is acquired for new locations future develop- ment should be considered. The width acquired must be sufficient to include all cut and fill slopes. Where these considerations do not increase the normal width the following normal widths are recommended : Mountainous regions (cheap land) loo ft. Farming country (moderately cheap land) 80 ft. Thickly settled districts (expensive land) 60 ft. Clearing Widths. — Clearing of trees, brush, etc., depends on height and thickness of growth; the object of clearing is first to (TopandBofhm No.9^ allofher Wires No.lh dSirands-fedf-ausperRod, Locusi- Posis, leasi- Piame-her cdl&wecf is 'finches. All Corner and End Po^H are 12 inches in leasf Diameter and Braced as shown above. Pig. 42.— jRight-of-way fence. remove growth within the slope lines, second to provide a clear view and third to clear sufficient width to allow the sun to reach the road and dry it out and melt snow. This last depends a good deal on the direction in. which the road is running and the altitude and geographical location. It is entirely a matter of judgment but should be liberal in the forest districts and ranges from 30 ft. for low scrub growth to 150 ft. in adverse location and thick 215 2l6 MINOR POINTS high growth. In high altitudes the roads are at their best closed in winter and if careful location and liberal clearing will increase the length of open season it is well worth while as in effect it increases the usefulness of the road by 15% to 25%. Guard Rail Wooden Guard Rail. — The construction generally used is shown in the following sketch. 7nis Jign every lOOft(approx.)wifh BfacHram t \ii ^ Rails and Posts Painted uJ .=% 3 Coats White Lead and Oii. Lj 2 "Steel or Wt. Iron Pipe -. >6< ..1> fieinforcemenf.} Mesh Reinforcement Pig. 44. — Concrete guard rail. The rail was invented by J. Y. McClintock, County Engineer of Monroe County, N. Y. It is neat in appearance, durable and strong, and is specially adapted for a combination bridge and ap- proach rail. The old design of an iron bridge rail connected with a wooden road rail has been an eyesore. The actual cost of manufacture and setting was from 50 to 60c. per foot. The contract price for such rail would, probably, run from 8dc. to $1.00, depending upon the length of the haul, freight rate, and difficulty of digging post holes but even at the high figure it is cheaper in the end than wooden rail and is a 2l8 MINOR POINTS safe construction. The anchor and rod shown on the sketch is used on curves or even on straight stretches where new fill is en- countered, to prevent the posts being torn out by impact from runa- way machines. y. 2.. Q U:. >k— ... S-'-—^ Cedar, Chesfnuf, Locust, OahfSf one or Concrete. dark Removed belowSurface. ^XpbleWfre} 4- vmn ASirandsofHo£ 1^2' EijeboH-nv^and Washer,Thread9dt6'.^ OnSecHons oiRaitin^LessfhanlOOFf. eakWire.-.^^ \ , GakmrtClips. \\ in Unqth the Pandas shown shall be \ H--- —10 ;^--- -H :. UsedafOne End and on fh9 other £nd ^~^^—\^^''6alv.Shel or IronWlre Cable. ^ jjjjij;, the Pipe Brace and 4 Strand wire \ Brace mau be omitted and 3' Eue bolts substituted for I'Eyebolfs ^ ■ Not Less than 12 Strands of NoA / 6a I V. Wire. "^ "" jT' OeadHan. wmTTTPr:^ • *■ After Erection, Posts and Parts not \ J \^ 6a Ivan ized to hare two coats o^ White j ; \ Lead and Linseed Oil Painf. \ ■ ^ V^ ^^ I I Poststol>€ not Less than d'Round or 6%q. | dark to be removed from Posts and Knots hewn flush mth Surface. 1 I \MPbsh tobeHtavtj'Bnish^^'^'^.^^ r^\/J \ Coated with Creosote T'^"^ 1 fbint on Bottom anct Sides . .^ / \ up not less than 4^ Feet. ^^ Area of Face to be not Lessthan4S Guard rail has two distinct purposes; first as merely a warning, at culverts, curves, low embankments, etc., where the danger is not great and second, as an actual protection in dangerous places. □ffi -7'Q "U..... End Ekvafion. Section C-JX Pig. 47. — Showing raised parapet on skew bridge extended over straight parapet retaining wall. Concrete guard rail is not advocated where warning alone is sufficient. Wire Cable Guard Fence. — Figure 45 illustrates this construction. Snow Fences. — Sketch No. 46 shows a typical snow fence used to prevent drifting in bad locations. Bridge Rail and Raised Parapets. — Bridge rail for small span bridges is of two types, iron pipe rail (see Figure 43) or solid raised parapets (see Figure 47). The solid parapet is to be preferred. Retaining Walls. — In unusual cases retaining walls are needed in road construction. Plain or reinforced concrete walls are gener- ally used, the selection depending upon the relative cost. The plain concrete wall is considered the best type for heights up to 12 ft.; the reinforced cantilever form from 12 to 18 ft. and above 18 ft. the buttressed design. We give, page 220, examples and rules for the plain and reinforced cantilever types only, as the necessity for walls higher than 18 ft. is very rare. For the design of buttressed walls the reader is referred to the standard works of reinforced concrete. Retaining walls are usually built in monolithic sections of 20' to 25' in length; expansion joints are provided between these sec- tions. The expansion joints may consist of simply a plane of weak- ness between the sections produced by allowing one section to set 2 20 MINOR POINTS RoundiolfRad.-^. k^-^ ^ ffoundtolkRad.^^ . * ,Weep-Hole5of3"7ife ; /o i4?f Spaced 6' ■C.toC. Pig. 2> Type R. 48. — New York State standard retaining walls. H Reinforcing Steel Bars of Deformed Section SXEMl Heel Toe Net Area Spacing C-C Length Net Area Spacing C-C Length Net Area Spacing C-C - Length 11' 0.601 6r I2'-2 ' 0.442 i¥ 4'-iir' 0.442 Qr ,s'-3r 12' 0.601 5r i3-3i" 0.442 6r 5'-5r' 0.442 H" ,^-8" 13' 0.601 5" i4'-5 " 0.442 sV 6'-o" 0.442 i¥ 4'-oi" 14' 0.601 ^V' i5'-6|" 0.601 6F 6'-6" 0.601 8/ 4'-44'' i.S' 0.601 a" i6'-8 " 0.601 s¥ 7'-o'' 0.601 1-" 4'-q" 16' 0.994 6' i7'-9 " 0.601 aV i'-(>¥ 0.601 6/ s'-ir 17' 0.994 5r iS'-ioi" 0.785 $¥ ^'-o¥ 0.785 i¥ sr^" . 18' 0.994 ,s" 20'-0 " 0.785 a¥ 8'-7" 0.785 6/ S'-ioi" iq' 0.994 4^' 2l'-ir' 0.785 a¥ 9'-i" 0.785 6i" 6'-2i" 20' 0.994 a¥ 22'-3 " 0.785 A " 9'-f 0.785 sr d'-?" 1 In each set of 3 bars in stem, first bar which is of length given, extends to top of wall, second bar to height f H, third bar to height | H. When Type W is used as a bank wall (that is, above the roadway), max. H = 20'; min. X = 2' for H of 5 to 10'; and 0.2 H for H greater than 10'. When Type W is used as a sustaining wall (that is, below the roadway), max. H = 13'; and min. X = 3', except where foundation is rock or entirely below frost. When Type R is used as a bank wall, max. H = 20'; min. X = 0.15 H for H greater than 10'. When Type R is used as a sustaining wall, max. H = 13'; min. X = 0.25 H for H greater than 10'. RETAINING WALLS 221 H M O o 1 eg pq ? eq 1 CO 1 T CO J o y H y t y ? :? 2 ffi :? "3 :? 00 :? OS I 1° m ? fe ? J J CO & ^:i J CO J CO H ft: z 2 % 2 2 ? ffi 5; 5: I :? 00 7 1 >< % o n • > oi Q 1 pq CO :? ft: fc T o H ft: ft: o :? CO :? CO W 00 OS 1 ISIS ;i o o pq ■ :? CO CO lb H C<1 :? CO CO CO ffi o 5: «3 CO 00 ft: :? o oi < H o pq 7 c>q CO o CO ? ^ :? lb % ^r ^ e^ ? cq ft: CO CO CO w . ft: o ? 00 ft^ ? bi 3 PQ oo CO CO ft: 2 *: cq :? CO CO CO lb :? oo bi o C! (^ c ^ s ts Tl rU « o 'd Xi ^ 'd ^ n •s •+J ^ u ^ w rt o ;3 ^ O o ,^ ^ f^ a a ft -^ 11^ Q> 0) rt 4^ ^ ^ rt o o TT f) oV. 05 ^ ^ ..2 ^ ^^ 1 'd a . a ■■2§ O (U c.25.?'^^ S (U C _, -, w Ph ^ ft 222 MINOR POINTS before building the adjacent wall, or it may be a key joint as shown in Figure 49A and the plane of separation may be made more pro- nounced by coating the concrete with a thin layer of asphaltum or pitch. Cemen+ and Dry Rubble. Pig. 49. — State of Pennsylvania retaining walls. Plan. Key Expansion Joint. Fig. 49A. Toe Walls. — Toe walls are nothing more than low retaining walls or very substantial curbs. They are used in cuts on the out- side of the gutters to prevent unstable side slopes from filling the gutters or heaving them out of shape by sliding pressure. Figure CURBS 223 50 gives a section of Eden Valley Hill near Buffalo, N. Y. where a clay quicksand cut was successfully protected in this manner. Curbs. — Curbs are constructed of stone and of concrete. Stone Curbs. — The cuts given show the methods of setting; the size of curbstones for first-class work range from 16" to 22" in depth, 5" to 6" in thickness and 3' to 5' in length. For small villages, curbstone of 4" width set in the simplest manner shown, Brick Outter.^ miosl- Drain Fig. 50. — Showing concrete toe wall. is satisfactory. The stones most used are granites, bluestones of New York State, and the tougher sandstones such as Medina, Berea, Kettle River, etc. The prices range widely, depending on the locality of the work. Mr. William Pierson Judson, in his "Roads and Pavements," gives the following range of costs: Cinders, Oravelor Crushed^ ^fone-'"' K/55{ Simple Stone Curb for Light Traffic Village Streets. Round to ("i^ad.^. Sand- J<6\ .'Round to I 'Rad. ! fe, Cinders, Oravelor Crushed ... ^ «»« Stone Cinders, Onrvel Z'Porous '^^"^' orCrushe^Stone'i ''^^ 2"PorousVie" Concr.Curb and Gulter. 'Round to TRad. . ■^.A'i'Joints Filled with Paving Fitch '^ J.4..^ i|^S^ \ilOli ^5" Concrete Ba^e Simplest Form of Concrete Curb. (Shbwing also Form of Expansion Joint where Brick are Laid Longitudinally in Gutter.) ' Fig. 51. Straight curbs set, cost about as follows: with 30% to 50% added for curves; granite, $0.50 to I0.90, unusual case $1.25 per foot. Ulster and Oxford bluestone, $0.40 to $0.80, unusual case $1.00 per foot. Medina and Berea sandstone, I0.35 to I0.90. Concrete usually costs from I0.40 to $0.50 with $0.35 added for a combined gutter, though combined gutter and curb have been built for $0.50. Simple concrete curb (Figure No. 51) has been built during 191 1 in different parts of Western New York at a cost of $0,30 to $0.40 per foot. 224 MINOR POINTS Where stone curbs can be built for less than $0.70 per foot, it seems good policy to use them through the business sections of small villages. For the residential Dortions or where the cost of stone curbing is high, a concrete curb of the simplest design is the best practice, as city conditions and require- ments are neither necessary nor expected. Curb Radii. — A good radius for drives is 4 ft. For right angle Main Street intersections 13 ft. For acute or obtuse angles 10 to 20 ft. /.^"Kd'C/eafs CJMei- Boh-s- •^^^^^"'' <22m-HUDS0N >: ALBANY lOi^J l^ <4^M-NA5SAUT>'^""^-^^^^^ I^^"^ I5.H.N0.37: ' ' A Cylinder of 2"J Clas$ „ Concrete; Diam. 6 , , Letters to be of '^^ ^ Aluminum on a Black Field. • /. 9 "Galv. Iron Pipe, (Outside Diam.) ; P- HI \ Iron Pin \ tiiroughPipe K- 6"--- — >i Cast Iron. Filler. <-^:^ -:i jRivet ^"Carriage Bolt •Upset Thread after Nut is in Place. Fig. 52. Guide Signs and Danger Signs. — A good sign must be easy to read, pleasing in appearance and permanent. The drawing (Figure ; 52) shows one of the designs in use; the posts are of galvanized iron and cost about $5.00 in place; the background for the alumi- 1 num is a japanned metal; the signs cost approximately $0.15 per COBBLE GUTTERS 225 letter including the board. Danger signs should be used only where no doubt exists as to their necessity, as their indiscriminate use decreases their effec^veness. Riprap and Dykes. — Well constructed riprap protects stream banks and bridge approaches from stream wash except in unusual cases where a solid masonry or concrete protection is required. ^{^ou/der 4cSand Cushion ( Sand-Cushion not Required in Sandy Soil Size of Stone 5-9") Cobble Gu-tter. Third Class Concrete Ditch Lining. • tiuisuai %idth)'y Concrete orSand Foundation; Grouted orSandJo/nts. Brick Gutter. No.4 Crushed Stone Ditch Protection. Fig. 53. I The sizes of stone suitable for riprap are usually specified at a i minimum of 3^ cubic foot and 50% or more of the material to be over 2 cubic feet. Where the road is located in bottom land and is covered with backwater in the Spring, it can be protected by riprap paving i on both sides or a dyke and riprap paving on one side as shown J in Figures No. 55 and No, 56, 226 MINOR POINTS Cobble Gutters, Brick Gutters, Ditch Linings, Etc. Cobble gutters are used to protect the ditches from wash on steep grades and at entrances to intersecting roads where there is not sufficient headroom for a culvert. Also at the entrances to private property where the grade line of the ditch might be badly cut by vehicles. Fig. 54. The usual cost of such construction ranges from $0.40 to $1.00 per square yard. Where cobblestones are not available, ordinary building brick may be used or No. 4 crushed stone as shown on page 225. Fb odElev. of Back Watery q^^^ l^aterial Coarse Oravel Preferred. '*ri7pT777r7T7ff^^''''" ' Fig. 55. — Method of protection where road can be built above flood level. Grates. — Cost of cast-iron grates about $0,065 per pound. Cost of wrought-iron grates about $0.08 per pound. Repointing Masonry and Refacing Old Walls. — Old masonry structures can often be used complete or in part by repointing the ,' Layer of Dead Water ( Prevents Wash) Elevation of Flood Water •Stone Fill Fig. 56. — Method of protection where road cannot be raised above flood level. joints; they should be cleaned out thoroughly with a chisel and filled flush with a i to i Portland cement mortar. The author does not believe in facing up old masonry abut- ments if it can be avoided; however, if it seems advisable, because of shortage of funds, the old joints should be weil cleaned out and STORM SEWERS 227 hook dowels used as shown in cut No. 58. One dowel every 6 sq. ft. is good practice. The concrete facing should be at least 12 in. thick, have a good footing course and be reinforced to prevent settlement and tem- perature cracks. Storm Sewers on Hills. — For the convenience of designers the approximate flow capacity of ordinary sized pipes on different grades are given below in Table 23. C 6„o-'g|&-o-Ji-<:?-0 -Q-&-0-:j| P'?" ri^f^oundBars j<...27---->i;<> Standard Orating hr"-^'fi Upset Ends ofBars and f fat- ten to f \ III ^'>-Z7V Section. ^ Standard Onating- Standard Orate. Leachin9 5asin. Table No. 23. Circuhr Opening''' Catch Basin. Fig. 57. -Approximate Flow Capacity in Cubic Feet Per Second Value oi N = 0.013 Grade Capacity of Flow of Different Sized Pipe 12" 15" 18" 20" 24" 36" 0.5% I.O I si 2.0 30 4.0 6.0 7.0 8.0 2 3 4 4 5 6 7 8 8 9 4 3 2 8 8 I I 8 5 4-4 6.3 7.6 8.8 II. 13.0 14.0 15.0 16.0 17.0 7.5 10.5 13.0 150 18.0 22.0 24.0 26.0 27.0 28.0 9-5 14.0 17.0 19.0 24.0 27.0 30.0 330 350 38.0 16.0 23.0 27.0 31.0 390 46.0 Si.o 56.0 60.0 65.0 42.0 60.0 75.0 86.0 105.0 122 .0 137.0 1500 162.0 1730 1 Computed from diagram Ogden's Sewer Design. 228 MINOR POINTS Flow of Water in Ditches. — Multiply area of flow by velocity. Velocity can be roughly approximated by the formula R V velocity in feet per second constant = 60 for ordinary cases , , ,. ,. cross-sectional area of flow in sq. ft. hydraulic radms = — ^ -. — : — : — r; — ~ wetted perimeter in lin. ft. S = slope of stream per foot. J Reinforcing Bars-^ Spaced IZ"C.toC. Pig. 58. — Facing tor old masonry. Yling Fence Guards Pit with 51 af Oraf/nj. Cattle guard driveway. Cattle Guards. — In western territory ranch owners will often grant road right-of-ways for a nominal sum but stipulate that the right-of-way shall not be fenced as it would cut off part of their range from water. The boundaries of these ranges are generally fenced and where the road passes this fence a gate must be used to prevent straying of cattle; it is more or less of a nuisance for every user of the road to open and close the gate and generally a gap is left in the fence across which a shallow pit 2' to 3' deep is dug and this is covered with a slat grating which cattle will not walk but which can be driven over by automobiles. CHAPTER IX MATERIALS The selection of materials is an important part of the design. Most municipal and State Departments have well equipped labora- tories for testing stone, gravels, brick, bitumens, cements, etc. The object of these tests is to determine the physical and chemical prop- erties that have a particular bearing on the action of the materials under construction conditions. While these conditions are not attained they are approximated and by a comparison of the labora- tory results with the actual performance of the different materials in practice a relation can be established that is useful as a basis for judgment : We are greatly indebted in this edition to Mr. H. S. Mattimore and Mr. J. E. Myers who have rearranged and brought up to date much of the material on tests and their significance. This chapter gives a brief statement of the desirable qualities and ' the tests for: I. Top course, macadam stone. • ! 2. Screenings, i 3. Bottom course, macadam stone. j 4. Bottom course and sub-base fillers. ; "- 5. Brick. I 6. Bituminous binders. 7. Concrete materials. I. STONE FOR THE SURFACING OF MACADAM ROADS Stone for use in the surfacing of a macadam road should be hard and tough to withstand the abrasive action of team traffic and the , vibratory action of high-speed motor vehicles and should not contain any minerals that are likely to disintegrate rapidly under influence of weather conditions. I To determine the relative hardness, toughness and power to resist abrasive and impact action of traffic, stones are subjected to the following tests: 1. Abrasion. 2. Hardness. 3. Toughness. 4. Specific gravity. 5. Absorption. 6. Fracture. 7. Geological classification. 229 230 MATERIALS Abrasion Test.^" — The machine shall consist of one or more hollow iron cylinders; closed at one end and furnished with a tightly fitting iron cover at the other; the cylinders to be 20 cm. in diameter and 34 cm. in depth, inside. These cylinders are to be mounted on a shaft at an angle of 30 deg. with the axis of rotation of the shaft. At least 30 lb. of coarsely broken stone shall be available for a test. The rock to be tested shall be broken in pieces as nearly uniform in size as possible, and as nearly 50 pieces as possible shall constitute a test sample. The total weight of rock in a test shall be within 10 g. of 5 kg. All test pieces shall be washed and thoroughly dried before weigh- ing. Ten thousand revolutions, at the rate of between 30 and S3 per minute, shall constitute a test. Only the percentage of mate- rials worn off which will pass through a 0.16 cm. (J^g in.) mesh sieve shall be considered in determining the amount of wear. This may be expressed either as the percentage of the 5 kg. used in the test, or the French coefficient, which is in more general use, may be given; that is, coefficient of wear = 20 X — = ■ — , where w is the WW weight in grams of the detritus under 0.16 cm. (J^g in.) in size per kilogram of rock used. Conversion Table % of Wear to French Coefficient F. Coef. % of Wear F. Coef. % of Wear 20 13.3 10 2 3 4 8 6.7 5.7 5 6 7 Deval rattler. Hardness. — Hardness is determined by a Dorry machine. A stone cylinder 25 cm. in diameter, obtained by a diamond core drill from the material to be tested, is weighed and placed in the machine so that one end rests on a horizontal cast-iron grinding disk with a pressure of 25 grams per sq. cm. Th« disk is revolved 1000 times during which standard crushed quartz sand about ij^ mm. in diameter is automatically fed to it. The cylinder is then removed and weighed and the coefficient of hardness obtained by the formula 20 — }i the loss in weight, expressed in grams. In order to get 1 American Society of Testing Materials. ROCK TESTS 231 reliable results two cylinders are generally used, each one being reversed end for end during the test. Test for Toughness.^ — i. Test pieces may be either cylinders or cubes, 25 mm. in diameter and 25 mm. in height, cut perpendicular to the cleavage of the rock. Cylinders are recommended as they are cheaper and more easily made. 2. The testing machine shall consist of an anvil of 50 kg. weight, placed on a concrete foundation. The hammer shall be of 2 kg. weight, and dropped upon an intervening plunger of i kg. weight, which rests on the test piece. The lower or bear-surface of this plunger shall be of spherical shape having a radius of i cm. This plunger shall be made of hardened steel, and pressed firmly upon the test piece by suitable springs. The test piece shall be adjusted, so that the center of its upper surface is tangent to the spherical end of the plunger. 3. The test shall consist of a i cm. fall of the hammer for the first blow, and an increased fall of i cm. for each succeeding blow until failure of the test piece occurs. The number of blows necessary to destroy the test piece is used to represent the toughness, or the centi- meter-grams of energy applied may be used. Determination of the Apparent Specific Gravity of Rock.^ — The apparent specific gravity of rock shall be determined by the following method: First, a sample weighing between 29 and 31 g. and approximately cubical in shape shall be dried in a closed oven for I hour at a temperature of no degrees C. (230 degrees F, ) and then cooled in a desiccator for i hour; second, the sample shall be rapidly weighed in air; third, trial weighings in air and in water of another sample of approximately the same size shall be made in order to determine the approximate loss in weight on immersion; fourth, after the balances shall have been set at the calculated weight, the first sample shall be weighed as quickly as practicable in distilled water having a temperature of 25 degrees C. (77 degrees F.); fifth, the apparent specific gravity of the sample shall be calculated by the following formula: W Apparent specific gravity = :^ ^jr- in which W = the weight W — W I in grams of the sample in air and Wi = the weight in grams of the sample in water just after immersion. Finally, the apparent specific gravity of the rock shall be the average of three determinations, made on three different samples according to the method above described. Determination of the Absorption of Water per Cubic Foot of Rock.^ — The absorption of water per cubic foot of rock shall be determined by the following method: First, a sample weighing between 29 and 31 g. and approximately cubical in shape shall be dried in a closed oven for i hour at a temperature of no degrees C. (230 degrees F.) and then cooled in a desiccator for i hour; second, the sample shall be rapidly weighed in air; third, trial weighings in air and in water 1 American Society of Testing Materials. 2 American Society of Testing Materials. 3 American Society of Testing Materials. 232 MATERIALS of another sample of approximately the same size shall be made in order to determine the approximate loss in weight on immer- sion; fourth, after the balances shall have been set at the calculated weight, the first sample shall be weighed as quickly as possible in distilled water having a temperature of 25 degrees C (77 degrees F.); fifth, allow the sample to remain 48 hours in distilled water maintained as nearly as practicable at 25 degrees C. (77 degrees F.) at the termination of which time bring the water to exactly this temperature and weigh the sample while immersed in it; sixth, the number of pounds of water absorbed per cubic foot of the sample shall be calculated by the following formula : ]^^2 — Wi Pounds of water absorbed per cubic foot = ^fz- — — — X 62.24 in W — Wi which W = the weight in grams of sample in air, Wi = the weight in grams of sample in water just after immersion, W2 = the weight in grams of sample in water after 48 hours' immersion, and 62.24 = the weight in pounds of a cubic foot of distilled water having a tem- perature of 25 degrees C. (77 degrees F.). Finally, the absorption of water per cubic foot of the rock, in pounds, shall be the average of three determinations made on three different samples according to the method above described. Fracture. — Stone suitable for- road work should crush in cubical shapes rather than in thin, flat pieces and preferably with rough, jagged fracture that it may interlock firmly under action of the roller. Geological Classification. — The geological classification is determined from an examination with a microscope or powerful hand glass, and a consideration of its origin. Great refinements are avoided as the general classification is all that is necessary to the highway engineer after the physical qualities are ascertained by test. Cost of Tests. — The cost of collecting and testing stone as given in the 1909 Report of the New York State Department of High- ways is $8.55' per sample. The following tables show tests on the more common rock: ROCK PROPERTIES 233 Table. 23a. Taken from Bulletin No. 31, United States Office of Pl^lic Roads Rock varieties Per cent wear Tough- ness Hard- Cementing value Granite Biotite-granite . . . . Hornblende-granite Augite-syenite . . . . Diorite Augite-diorite Gabbro Peridotite Rhyolite Andesite Fresh basalt . . Altered basalt . Fresh diabase . Altered diabase Limestone Dolomite Sandstone Feldspathic sandstone Calcareous sandstone Chert Granite-gneiss . . . . Hornblende-gneiss Biotite-gneiss . . . . Mica-schist Biotite-schist . . . . Chlorite-schist . . . Hornblende-schist Amphibolite Slate Quartzite Feldspathic quartzite Pyroxene quartzite . . Eclogite Epodosite 3-5 4.4 2.6 2.6 2.9 2.8 2.8 4.0 Z'7 4.7 Z'2> S'^ 2.0 2.5 5.6 5.7 6.9 2>'2> 7.4 10.8 3.8 2>'7 3-2 4.4 4.0 4.2 2>-7 2.9 4.7 2.9 3.2 2.4 3.6 15 10 21 10 21 19 16 12 20 II 17 30 24 10 10 26 17 IS 15 12 10 19 10 21 10 12 19 17 27 31 16 18.1 16.8 18.3 18.4 18.1 17.7 17.9 15.2 17.8 13.7 17.1 15.6 18.2 17-5 12.7 14.8 17.4 15-3 19.4 17.7 17.1 17.5 17.8 16.S 19.0 II. 5 18.4 18.3 18.6 17.4 16.0 20 17 30 24 41 55 29 28 48 189 III 239 49 156 60 42 90 119 60 27 26 30 41 30 16 24 53 29 102 17 21 17 21 47 *NoTE. — To convert % of wear to French coefficient, see Table on page 230. 234 MATERIALS Table 2^b From Annual Report N. Y. State Highway Comm. 1914 County Number of com- plete tests Number of . partial tests (no core piece) Weight lbs. per cu. ft. Water ab- sorbed, lbs. per cu. ft. French coeffi- cient of abrasion Hard- ness Tough- ness Erie Saratoga. . . Steuben . . . Clinton Dutchess Essex Franklin . . . Fulton Herkimer . . . Monroe Montgomery Niagara Saratoga .... St. Lawrence Washington . Dutchess . . , Herkimer . . . Montgomery Niagara .... St. Lawrence Washington Wayne .... Essex... Warren. Clinton Dutchess Essex Franklin Fulton Hamilton . . . Jefferson .... Lewis Orange Putnam St. Lawrence W^arren Washington. Westchester. Essex Franklin. . . . Hamilton . . . Jefferson. . , . Lewis ... Oneida St. Lawrence Warren 46 4 Calcareous Sandstone 167 I 0.65 169 0.31 162 I 1.44 Dolomite s 167 0.65 95 12.9 13-4 6 169 0.31 lO.I 15-9 13-8 4 I 162 1.44 9.4 15. 1 13.1 6 175 0.41 11.9 15.8 12.7 4 I 174 0.43 12.4 17-3 11.9 4 173 0.42 13.5 16.9 15.8 4 174 0.51 9-5 14.9 12. 1 4 176 0.15 II. 8 16.1 14.4 17 173 0.67 8.4 131 6.7 13 171 1.07 10.3 14.8 8.2 8 Hi 0.39 10.6 14.7 II-3 II 168 1.50 6.5 14.0 7.0 8 174 0.33 8.6 15.5 9.2 ^l 174 0.65 lo.S 15.7 9.9 6 175 0.29 10.7 iS-i lo.s Dolomitic Limestone 8 I 176 0.46 9.0 14.9 10.9 4 I 170 0.47 II-3 16.7 8.2 8 I 175 0.41 13.0 IS.8 12.4 7 166 2.19 95 13.I 7.8 7 168 0.38 9.2 16.8 6.8 4 175 0.36 13-7 16.1 10.8 4 173 059 10.2 15.S 8.7 Gabbro 176 I 0.29 183 1 0.37 Gneiss 7.6 lO.I 17.3 17.7 Granite 6.9 9.8 5 i8s 0.27 10.5 17.2 11.3 8 172 0.58 7.0 17. 1 9.1 29 176 0.31 8.4 17. 1 8.1 8 178 0.50 6.2 16.1 7^ii 12 169 0.2s II. I 17.8 ii.S II 173 0.37 8.2 17.0 5.8 26 171 0.23 II. I 17.3 12.0 6 167 0.27 9.6 17.9 10.6 7 179 0.38 7-1 17. 1 6.4 10 172 0.32 8.5 16.6 7-5 7 180 0.20 lO.O 17.0 8.5 52 172 0.27 9.7 17.5 10.2 30 2 173 0.30 7-5 17.3 6.5 4 170 0.29 8.5 17. 1 10.9 37 2 171 0-39 8.3 16.9 7.8 S ... 171 0.38 7.5 18.0 5.1 6 165 0.31 8.7 17.9 9.4 5 165 0.36 9.9 18.1 9.0 23 I 166 0.23 12. 1 18.4 lO.I 8 166 0.36 10.9 18.4 9.2 6 166 0.13 10.2 18.9 8.2 30 . . . 165 0.2s 9.9 18.3 8.1 s ... 165 0.45 7-9 17.9 7.7 ROCK PROPERTIES 235 From Annual Report N. Y. State Highway Comm. 191 4 County Number of com plete tests Number of partial tests (no core piece) Weight, lbs. per cu. ft. Water ab- sorbed, lbs. per cu. ft. French coeffi- cient of abrasion Hard- ness Tough- ness Weighted value Albany Cayuga Clinton . . . . . Columbia . . . Erie Fulton Genesee. . . . Greene Herkimer. . . Jefiferson. . . . Lewis Madison. . , . Monroe Montgomery Niagara Oneida Onondaga . . . Ontario Otsego Rensselaer. . Saratoga .... Schoharie . . . Seneca Ulster Warren Washington , Dutchess... Allegany. . Broome. . . Cayuga. . . Chenango. Clinton. . . Delaware . . Erie .... Franklin. . . Greene . . . Herkimer . Jefferson. . . Livingston . Madison . Niagara . . Orleans. . Otsego.. . Saratoga . 14 53 8 S 6 4 8 4 5 7 Limestone 13 7 168 0.60 7-9 14.3 6.4 34 6 170 0.49 8.8 14.9 7.8 14 2 170 0.28 8.2 14.1 5-3 12 170 0.28 9.1 15-3 9.2 9 3 167 0.57 8.1 16.6 8.3 6 I 168 0.21 7-7 15-5 6.5 6 3 169 0.26 8.0 I5-0 8.2 II 160 0.36 II. I 16.4 8.9 17 9 169 0.26 8.7 14.8 8.2 105 44 169 0.28 7.6 15.1 6.4 26 20 169 0.32 6.9 14.1 6.2 16 I 169 0.23 8.4 14.7 7-7 4 168 0.27 8.1 14.1 7-4 12 2 169 0.24 8.5 15-3 8.0 II I 168 0.84 7-1 12.8 6.5 31 19 169 0.29 7.8 13.8 6.6 25 I 170 0.38 8.9 15-7 8.4 II 169 0.39 10.2 15-9 10.2 7 2 169 0.32 8.1 14.1 6.3 4 I 171 0.21 7-5 I5-0 5-3 5 170 0.24 8.7 13-7 7.0 29 2 169 0.34 8.1 14.9 6.7 7 3 169 0.21 ?-^ 15-3 7.9 12 3 170 0.25 8.1 is.o 7.4 5 170 0.24 8.9 1S.7 7-4 S 3 169 0.34 7.9 15.5 6.9 Marble 178 I ^.30 7.3 I 14.2 Sandstone 156 i6s 167 164 163 167 159 157 169 160 156 160 163 158 155 162 163 2.10 1.29 1.16 1.58 0.71 1.4s 2.10 1.06 0.62 2.50 1.46 3-02 2.15 1.78 2.18 1.75 0.36 8.4 7.8 7.8 8.7 II. 7 7.0 6.3 9.7 8.6 10.9 8.3 8.8 9.9 9.0 11.8 8.4 IO-7 13.4 12.9 12. 1 11. 2 18.5 12.7 5-1 17.9 14-5 16.4 16.2 9.6 13.9 16.4 14.4 11.9 18.0 6.0 Quartzite Columbia . . . Dutchess Rensselaer. . Washington . 16 8 10 12 2 168 166 166 167 0.28 0.36 0.49 0.40 I6.S 13-5 12. 1 14.6 18.3 18.8 18.7 18.9 17. 1 II. 8 14.8 16.3 9.1 10.5 10.5 10.4 II.O 8.5 7.8 7.1 8.1 10.7 6.3 8.8 8.6 8.2 8.1 9.6 8.7 236 MATERIALS From Annual Report N. Y. State Highway Comm. 19 14. — Cont, County Number of com- plete tests Number of partial tests (no core piece) Weight, lbs. per cu. ft. Water ab- sorbed, lbs. per cu. ft. French coeffi- cient of abrasion Hard- ness Tough- ness Weighted value Schoharie . . Schuyler. . . Seneca Steuben St. Lawrence Sullivan . . . Ulster Wyoming . . Albany ..... Columbia . . . Dutchess .... Greene Montgomery Rensselaer . , Saratoga.. . . Schenectady Ulster Essex Franklin .... Herkimer. . . Jefferson. . . . Rockland . . . Sandstone . — Continued 6 3 i6s 1. 21 9.4 15.2 II. 7 4 162 2.14 8.1 II.6 10.6 5 165 0.86 IT.O 13.9 IS.8 22 3 157 2.79 8.3 9.3 lO.O 16 I5Q 0.79 lO.O 17.8 7.2 30 4 164 1.26 6.5 14.9 8.2 8 166 0.64 8.0 14-3 8.1 7 159 2.54 6.0 5.1 7.9 Sandy Grit 5 167 0.75 7-5 13.2 7.2 12 168 0.32 10.7 15.9 11.7 10 2 168 0.57 8.1 16.2 II-5 13 169 0.48 7.1 1S.6 9.5 4 166 1-39 lO.I II. 3 11.8 10 169 0.44 9.1 15-9 9.4 5 168 0.99 11.8 15.2 11.9 4 165 1. 10 9.2 14.6 95 7 169 0.59 7-5 13.8 10.2 183 Syenite 0.5: 0.4: O.K 0.3^ Trap I 0-39 7 184 0.52 7.7 17.1 6.7 4 171 0.45 lO.I 18.3 8.0 13 174 0.16 12.5 18.0 11.6 7 176 0.34 12.4 18.1 14.5 70 S8 77 54 73 58 61 36 56 76 68 62 65 69 78 66 60 64 75 85 13.2 I 17.6 I 1.64 I Table 2^bb Geological Classification Class Type Family I Igneous I Intrusive Cplutonic) f a Granite b Syenite i c Diorite d Gabbro I e Peridotite 2 Extrusive (volcanic) I [ a Rhyolite 1 b Trachyte ' c Andesite [ d Basalt and diabase I Calcareous f a Limestone \ b Dolomite II Sedimentary f a Shale 2 Siliceous \ b Sandstone [ c Chert (flint) I Foliated f a Gneiss \ b Schist [ c Amphibolite III Metamorphic \ [ a Slate ■ 2 Nonfoliated 1 b Quartzite 1 c Eclogite [ d Marble 1 Bulletin No. 31, United States Department of Public Roads. IGNEOUS ROCKS 237 The following quotation from bulletin No. 31 O. P. R. & R. E. describes the characteristics of the three groups: Igneous Rocks. — "All rocks of the igneous class are presumed to have solidified from a molten state, either upon reaching the earth's surface or at varying depths beneath it. The physical conditions, such as heat and pressure, under which the molten rock magma consolidated, as well as its chemical composition and the presence of included vapors, are the chief features influencing the structure. Thus, we find the deep-seated, plutonic rocks coarsely crystalline with mineral constituents well defined, as in case of granite rocks, indicating a single, prolonged period of development, whereas the members of the extrusive or volcanic tj^es, solidifying more rap- idly at the surface, are either fine-grained or frequently glassy and vesicular, or show a porphyritic structure. This structure is produced by the development of large crystals in a more or less dense and fine-grained ground mass, and is caused generally by a recurrence of mineral growth during the effusive period of magmatic consolidation. "In the arrangement of the rock families from a mineralogical standpoint it will be noted that the plutonic rock types, granite, syenite, and diorite, are represented by their equivalent extrusive varieties, rhyolite and andesite, and that diabase has been included, I somewhat arbitrarily, with basalt, as a volcanic representative of I gabbro. These latter rocks are of special interest, owing to their ; wide distribution and general use in road construction. They occur ; in the forms of dykes, intruded sheets, or volcanic flows, and vary [ in structure from glassy-porphyritic (typical basalt) to wholly crys- ! talline and even granular (diabase). Their desirable qualities for I road-building are caused to a large extent by a peculiar interlocking of the mineral components (t)phitic structure) , yielding a very tough I and resistant material well qualified to sustain the wear of traffic. \ "Igneous rocks vary in color from the light gray, pink, and brown I of the acid granites, syenites, and their volcanic equivalents (rhyo- lite, andesite, etc.) to the dark steel-gray or black of the basic gab- bro, peridotite, diabase, and basalt. The darker varieties are I commonly called trap. This term is in very general use and is ' derived from trappa, Swedish for stair, because rocks of this kind j on cooling frequently break into large tabular masses, as may be seen in the exposures of diabase on the west shore of the Hudson ! River from Jersey City to Haverstraw. I Sedimentary Rocks. — "The sedimentary rocks as a class repre- 1 sent the consolidated products of former rock disintegration, as in ' the case of sandstone, conglomerate, shale, etc., or they have been , formed from an accumulation of organic remains chiefly of a cal- I careous nature, as is true of limestone and dolomite. These frag- \ mental or clastic materials have been transported by water and j deposited mechanically in layers on the sea or lake bottoms, pro- I ducing a very characteristic bedded or stratified structure in many ! of the resulting rocks. j "In the case of certain oolitic and travertine limestones, hydrated i iron oxides, siliceous deposits, such as geyserite, opal, flint, chert, 238 MATERIALS etc., the materials have been formed chiefly by chemical precipita- tion and show generally a concentric or colloidal structure.^ Oolitic and pisolitic limestones consist of rounded pealike grains of calcic car- bonate held together by a calcareous cement. Travertine is the so-called 'onyx marble' of Mexico and Arizona. It is a compact rock, concentric in structure and formed by the precipitation of car- bonate of lime from the waters of springs and streams. "Loose or unconsolidated rock debris of a prevailing siliceous nature comprise the sands, gravels, finer silts, and clays (laterite, adobe, loess, etc.). Shell sands and marls, on the other hand, are mainly calcareous, and are formed by an accumulation of the marine shells and of lime-secreting animals. Closely associated with the latter deposits in point of origin are the beds of diatomaceous or infusorial earth composed almost entirely of the siliceous casts of diatoms, a low order of seaweed or algae. *'This unconsolidated material may pass by imperceptible grada- tions into representative rock types through simple processes of in- duration. Thus clay becomes shale, and that in turn slate, without necessarily changing the chemical or mineralogical composition of the original substance. "Such terms as flagstone, freestone, brownstone, bluestone, gray- stone, etc., are generally given to sandstones of various colors and composition, while puddingstone, conglomerate, breccia, etc., apply to consolidated gravels and coarse feldspathic sands. "The calcareous rocks are of many colors, according to the amount and character of the impurities present. Metamorphic Rocks. — "Rocks of this class are such as have been produced by prolonged action of physical and chemical forces (heat, pressure, moisture, etc.) on both sedimentary and igneous rocks ahke. The foliated types (gneiss, schist, etc.) represent an advanced stage of metamorphism on a large scale (regional meta- morphism), and the peculiar schistose or foliated structure is due to the more or less parallel arrangement of their mineral components. The non-foliated types (quartzite, marble, slate, etc.) have resulted from the alteration of sedimentary rocks without materially affect- ing the structure and chemical composition of the original material. "Rocks formed by contact metamorphism aftd hydration, such as hornfels, pyroxene marble, serpentine, serpentineous limestone, etc., are of great interest from a petrographical standpoint, but are rarely of importance as road materials. "The color of metamorphic rocks varies between gray and white of the purer marbles and quartzites to dark gray and green of the gneisses, schists, and amphibolites. The green varieties are com- monly known as greenstones, or greenstone schists." Interpretation of Tests. — It has been found impractical to specify definite qualities of stone for use in macadam highways. Economy and practical engineering demand that all available sources be con- sidered. Tests are made to determine the relative qualities of stone from these different sources and the results used as a guide for selection. 1 G. P. Merrill's "Rocks, Rock Weathering, and Soils," 1897, PP- 104-114. ROAD VAI.UE OF ROCKS 239 In the work of the New York State Highway Commission all tests are tabulated geographically, using a county as a unit. Table No. 23& is compiled from the records of this department. It will be noted that comparisons are made in different classifications only, as it is considered that conclusions should not be drawn from a comparison of tests procured from materials having different origins and composed of different minerals. For the purpose of ready comparison, there has been introduced a figure known as the ''weighted value." (See last column Table 236.) This is computed by giving relative weights of three to the French coefficient, two to the hardness, one to the toughness values and adding the three together. These relative weights were determined from a consideration of the amount of material used in the different tests and the personal equation in running them. By consulting these tables the available rocks of different classi- fications in various sections throughout New York State can be determined readily, and as new tests are completed they are com- pared with good average material from that section. Conclusions. — Trap (diabase), granite, gneiss, quartzite, sand- stone and limestone are the most common rocks and w^hen found in a good state of preservation make good surfacing materials. As generally found, trap is uniform in hardness and toughness, making an excellent material for use in top course. Granite and gneiss, where they occur with hornblende replacing a large percentage of the quartz, make an excellent surfacing stone. Quartzites when found in good State of preservation are hard and i tough. They should not be confused with crystalline quartz which I is hard but brittle. Sandstones are extremely variable and only the better varieties should be used. Limestones range from the fine grained dense products whick are hard and tough to the coarse grained soft products which are not suitable for surfacing. Screenings. — Screenings act as a filler and binder for waterbound macadam and as a partial filler for bituminous macadam. For use in waterbound construction the main mineral constituent is the most essential feature to be considered as this must be a material that will from a binder and "puddle" readily when subjected to the action of a road roller and water. I Limestone screenings have proved the most efficient as a binder in I j waterbound construction, although trap and some other igneous I I rocks can be bound with their own dust by repeated puddling. Screenings consisting mainly of quartz have never been used suc- cessfully in waterbound construction except by the addition of some ': i limestone screenings. The use of a percentage of clay or loam as a *i binder is not advisable except where the cost of limestone screenings (would be prohibitive. I Laboratory methods for testing the cementing power of rock 'powders are available but the results obtained are erratic and unde- pendable. In plain waterbound roads it is often necessary to mix some lime- 240 MATERIALS stone screenings, fine sandy loam, or even a small percentage of clay loam with trap, granite, sandstone, quartzite, or gneiss screen- ings to get a good bond and prevent raveling in dry weather. 3. BOTTOM COURSE MACADAM STONE As the bottom stone simply spreads the wheel loads transmitted through the top course and is not directly subjected to the traffic action, almost any stone that breaks into cubical irregular shapes that will not air or water slake and that is hard enough to stand the action of the roller during construction will be satisfactory. Any of the materials listed above in Table 24 except shale and slate can be used, provided that they are not rotten from long ex- posure in the air. The different available varieties are usually tested in the same manner as for top stone in order to pick the best. Acid blast furnace crushed slag makes an excellent bottom course but s not uniform enough for top course, 4. FILLERS Fillers are used in the bottom course to fill the voids between the crushed stone and to prevent rocking or sidewise movement of the larger pieces. They should be easy to manipulate in placing, should not soften when wet, or draw water up from the subgrade by capillary action. The materials most used are Coarse sandy loam Coarse sand Gravel with large excess of fine material Stone screenings The fitness of the material can be determined by inspection and by wetting a handful; if it gets sticky or works into a soft mud it should not be used. 5. VITRIFIED BRICK Bricks must withstand the same destructivelagenciesjas described for top stone. They must be uniform in size, tough, hard, dense, evenly burned, and, on account of their peculiar shape, must have a high resistance against rupture. These properties are tested by the standard methods adopted by the American Brick Manufacturers' Association, as described in the New York State specifications on page 730- It should be understood that bricks suitable for paving are manu- factured in a different way and of different materials than ordinary building bricks. "The materials for molding any paving brick must be of a peculiar character which will not melt and flow when exposed to an intense heat for a number of days but will gradually fuse and form vitreous combinations throughout while still retaining its form. *^The resulting brick must be a uniform block of dense texture in BITUMENS 241 which the original stratification and granulation of the clay has been wholly lost by fusion which has stopped just short of melting the clay and forming glass. "The clay while fusing must shrink equally throughout, thus causing the brick to be without laminations or of any exterior vitrified crust differing from the interior."^ The great majority of paving brick are made in Ohio, Illinois, Indiana, Pennsylvania, West Virginia, and New York. They are classed as shale or fire-clay brick. 6. BITUMINOUS BINDERS The subject of bitumens is an intricate one and the reader is re- ferred to the works of Clifford Richardson, Prevost Hubbard, and others, for detailed information, as a book of this character can give only an outline. There are a number of dust preventives and road binders on the market which depend for their effectiveness on a bituminous binding base. The term bitumen is applied to a great many substances. Hubbard arbitrarily defines bitumens as "consisting of a mixture of native or pyrogenetic hydrocarbons and their derivatives, which , may be gaseous, liquid, a viscous liquid, or solid, but if solid melting ^ more or less readily upon the application of heat, and soluble in I chloroform, carbon bisulphide, and similar solvents."^ ( The bitumens may be classified as native and artificial. The ( native bituminous materials, that are used in road work, are the asphaltic and semi-asphaltic oils (dust layers). Malthas (the binding base of Rock Asphalts), Trinidad, Bermudez California, and Cuba asphalts, Gilsonite, and Grahamite (which, however, are too brittle in their natural state and require fluxing with a suitable residual oil I before they can be used as binders). The natural asphalts are refined to remove water and any objectionable amount of impurities by heating until the gases are driven off, skimming the vegetable matter which rises to the surface, and removing the mineral constitu- ents which fall to the bottom. The artificial bituminous materials are derived by the destructive distillation of coal, or by fractional distillation of crude coal tars, or the native petroleum oils. They comprise the crude coal and water gas tars, the refined tars, the residual oils and semi-solid binders derived from the petroleum oils. They vary greatly in consistency and binding power. The following material is briefed from Bulletin No. 34, United States Office of Public Roads : The light oils and tars have a rela- tive small percentage of bituminous base and are effective only so long as it retains its binding power; the more permanent binders contain a larger percentage of bitumen; these are the heavy oils and \ semi-solids. Artificial Bitumens Crude Tars. — Coke ovens and gas plants produce most of the coal tars in use. These tars contain various complex combinations 1 Judson's "Roads and Pavements," page 87. 2 " Dust Preventives and Road Binders." John Wiley & Sons. 242 MATERIALS of carbon, hydrogen, and oxygen and small amounts of nitrogen and sulphur. They vary in composition according to the material from which they are made and the temperature at which they are distilled. The percentage of free carbon ranges from 5 per cent, to 35 per cent., and the bitumen from 60 per cent, to 95 per cent., depending on the temperature of manufacture. Tars produced at high temperatures contain free carbon in excess which weakens their binding power; they, also, contain a large amount of anthracine and naphthalene, two useless materials from the standpoint of road work. Tars produced at low temperatures are to be preferred. Coke tar is low temperature tar; gas tar is high temperature tar. Refined' Tars. — Much of the road tar is refined tar — that is, it has been subjected to fractional distillation to remove the valuable volatile compounds. The residuum from this process is a thick viscous material known as coal-tar pitch, and if the crude tar from which it is obtained was produced at a low temperature it is nearly pure bitumen; the dead oils obtained from the distillation are of little value and are often run back into the pitch, which makes it liquid when cold. The following table gives the approximate com- position of water-gas tar, crude coal tar, and refined tar. Table 23c. Specific Gravity and Composition of Tar Products Table from Bulletin No. 34 United States Ofiice of Public Roads Kind of Tar Water-gas tar . . Crude coal tar . Refined coal tar Specific Gravity 1. 04 1 1. 210 1. 177 Ammo- niacal Water % 2.4 2.0 0.0 Total Light Oils to 170° C. % a2i.6 ^17.2 612.8 Total Dead Oils 170° 270° C. % 652.0 626.0 ^47.6 Residue (by Difference) % C24.O /54.8 a Distillate mostly liquid. b Distillate all liquid. c Pitch very brittle. d Distillate mostly solid. e Distillate one-half solid. / Pitch hard and brittle.^ g Distillate one-third solid. Table 23 J gives a more up-to-date analysis of the coal tars on the market. The tests and detailed requirements for light, medium, and heavy bitumens are given in specifications, page 721. ; If the tar is used as a temporary dust-layer only, it should be a , low-temperature, dehydrated tar, liquid when cold. If used as a more permanent binder and applied hot, it should have a larger percentage of pitch, should contain no water, and be free from an excessive amount of free carbon. If used as a mastic in butuminous macadam, it should contain a high percentage of pitch and be free from the defects mentioned. BITUMENS 243 Natural Bitumens and Artificial Residual Oils and Semi-solids. — Mineral oils can be classed as paraffin petroleums, mixed paraffin and asphaltic petroleums, and asphaltic petroleums. The relative value of oils as a source of supply for road materials depends on their percentage of asphaltic residue. The eastern oils found in New York, Pennsylvania, West Virginia, etc., are paraffin petro- leums; the western oils vary from light to heavy asphaltic petro- leums, and the southern oils have a mixed paraffin and asphaltic base. The crude petroleum is refined by fractional distillation to obtain its valuable products, such as kerosene, etc. The character of the residue depends, as for the tars, on the crude material and the method of manufacture; the operation known as ''cracking," which is used to increase the yield of the inflammable oils, produces an excess of free carbon. The paraffin petroleum residuums are soft and greasy and are not suitable for road work; they contain a large amount of the paraffin hydrocarbons and paraffin scale (crude paraffin). The California petroleum residuums resemble asphalt, and if care- fully distilled without cracking should contain little or no free carbon. They are suited to road work. The Texas, or semi-asphaltic petroleums contain some paraffin hydrocarbons and about i per cent, of paraffin scale. Residuums from these oils, if containing a relatively small amount of paraffin, can be successfully used. The tests and required properties of residuum bituminous binders used on the New York State roads in 1914 are given in specifications, page 721. The following tables give a general idea of the relative character- istics of the crude petroleums and petroleum residuums. Results of Tests of Crude Petroleum Tables from Bulletin No. 34 United States Office of Public Roads Kinds of Oil II h -So Volatility at 110° C. 7 Hours Volatility at 160" C. 7 Hours Volatility at 205° C. 7 Hours Pennsylvania, paraffin Texas, semi-asphaltic California, asphaltic 0.801 .904 .939 (a) 43 26 % 47.3 20.0 % 58.0 27.0 % 68.0 49.0 J42.7 &32.O C51.O CS7.3 a Ordinary temperature b Soft c Quick flow e Soft maltha; sticky d Volatility at 200*, 7 hours. {Continued on page 248) 244 MATERIAI.S Table 23(f. Circular No. 97, U. S. OrricE of Public Roads Analysis of crude coke-oven tars produced in the United States and Canada- Serial No. S126 S123 S124 S137 5x21 512s S128 5200 5189 5 160 5074 5081 5095 5083 S159 S107 S086 S078 S087 S109 S122 5188 5404 5 108 S089 GeDeral Information Company and location Solvay Process Co., Syracuse, N.Y.. Semet-Solvay Co., Pennsylvania Steel Co., Steelton, Pa Semet-Solvay Co. National Tube Co., Benwood, W.Va Semet-Solvay Co., Milwaukee Coke & Gas Co., Milwaukee, Wis Semet-Solvay Co. Pennsylvania Steel Co., Lebanon, Pa By-Products Coke Corporation, South Chicago, 111 Semet-Solvay Co., Detroit, Mich Semet-Solvay Co., Empire Coke Co, Geneva, N.Y Semet-Solvay Co., Dunbar Furnace Co., Dunbar, Pa Semet-Solvay Co., Central Iron & Coal Co., Tuscaloosa, Ala I Philadelphia Suburban Gas & Electric [ Co., Chester, Pa Semet-Solvay Co., Ensley, Ala , The N. E. Gas & Coke Co., Everett,Mass I Lackawanna Steel Co., Lackawanna Iron ( & Steel Co., Lebanon, Pa Dominion Tar & Chemical Co., Sydney, Nova Scotia Hamilton Otto Coke Co., Hamilton, Ohio Carnegie Steel Co., South Sharon, Pa.. . Maryland Steel Co., Sparrows Point, Md. Citizens' Gas Co., Indianapolis, Ind \ Pittsburg Gas & Coke Co., The United [ Coke & Gas Co., Glassport, Pa Zenith Furnace Co., Duluth, Minn. Illinois Steel Co., Joliet, HI I Illinois Steel Co., Indiana Steel Co., ^ Gary, Ind Camden Coke Co., Camden, N.J. Type of Oven Semet-Solvay Otto Hoffman }••••■' United Otto Maximum temperature of firing retorts }.,..".... .Koppers , Cambria Steel Co., Johnstown, Pa.. Lackawanna Steel Co., Buffalo, N.Y. Otto Hoff. man United Otto Otto Hoff- man United Otto United Otto Rotbb erg 1650-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1050-1450° C. 1250° C. 1050° c. 1250° c. iiioo°C. ( 1000° C. I (1800° F.) (2) (iiii°C. I (2000° F.) ( 1666° C. i(30oo°F.) 1 1333° c. ( (2400 F.) (I222°C. ( (2200 F.) { (. ( I222-I277°C. ( 2200-2300°F. I 1444** C. ((2600° F.) 1100° c. ( 1000° c. ( (1800° F.) I 1222° C. ( (2200° F.) (iiii°C. 1(2000°F.) (iiii°C. \ (2000° F.) ( 1000° C. ((i8oo°F.) ( 1000° C. l(i8oo°F.) BITUMENS Table 2^(1. Continued 245 Answers to Questions Examination Per Maximum temperature Specific gravity Per cent of free carbon in tar Specific gravity Per cent Per cent cent soluble in CS2, includ- ing to which coal of crude tar of tar, of free of is brought 25° c. carbon ash H2O 950-1150° C. I. 12-1. 21 3-12 1.195 7.76 0.12 92.12 950-1150° C. I. 12-1. 21 3-12 1.206 8.77 .07 91.16 950-1150° C. I. 12-1. 21 3-12 1. 176 7.14 .04 92.82 950-1150° C. I. 12-1. 21 3-12 1. 168 6.10 .OS 93.8s 950-1150° C. I. 12-1. 21 3-12 1. 173 4.71 .06 95.23 950-1150° C. I. 12-1. 21 3-12 1. 191 7-49 ■03 92.48 950-1150° C. I. 12-1. 21 3-12 1. 169 6.56 .11 93.33 950-1150° C. I. 12-1. 21 3-12 1.159 6.07 .08 93.8s 950-1150° C. I. 12-1. 21 3-12 1.181 8.85 .02 91.13 1150° C. I. 17 ( 1. 16 1 (20° C.) S.72 1.159 5.05 .02 94.93 1000° c. — 1. 141 3.96 .05 95.99 1150° c. { 1.17 ( (iS°C.) 8 1.175 6.90 .06 93.04 ll200°C. 1. 17 8-10 1. 160 13.94 .00 86.06 1000° C. ) (1800° F.) } 1. 10 16-24 1. 214 14.05 •13 85.82 (2) 1. 170 10-15 1. 143 10.81 .05 89.14 1111° C. (2000° F.) 1 1. 14 616.0 1. 160 8.37 .06 91-57 1444° c. (2600° F.) 1 - 7. 09-10.64 1. 191 7.89 .03 92.08 1222° C. (2200° F.) } ' I.I9 3 8-10 1. 179 8.49 .03 91.48 1222° C. (2200° F.) 1 I. I4-I. IS f (50° F.) 4-5 1 1. 133 S.21 .07 94.72 (2) -j 1.207 I 10° c. 16.59 1. 176 10.53 .04 89.43 (2) (2) (2) 1. 195 12.18 •OS 87.77 1388° C (2500° F.) 1 I. 16-I. 20 12-15 1. 171 3.89 .06 96.0s { 880-950° *i.i74 1. 169 1 4.35 1. 169 2.73 .04 97.23 Sas'^C. {1500° F.) 1055° c. I. 20-1. 30 M1.221) 7-9 1 1.182 11.30 .06 88.64 (i900°F.) iiiii°C. (2000° F.) iiiii°C. 1. 12 ^IS 1. 211 12.40 .16 87.44 (2000° F.) 1000° c. (1800° F.) 1000° c. 1.16 16-24 1. 210 16.80 .00 83.20 {1800° F.) J '246 MATERIALS Table 22,d. Continued Serial No. 5126 5123 S124 5137 5I2I 512s 5128 5200 5189 SI60 S074 S081 5095 5083 5159 5107 5086 5078 S087 5109 5122 5188 5404 5108 SI27 5089 Company and Location Solvay Process Co., Syracuse, N.Y. . Semet-Solvay Co., Pennsylvania Steel Co., Steelton, Pa Semet-Solvay Co., National Tube Co., Benwood, W.Va Semet-Solvay Co., Milwaukee Coke &: Gas Co., Milwaukee, Wis Semet-Solvay Co., Pennsylvania Steel Co., Lebanon, Pa By- Products Coke Corporation, South Chicago, 111 ., Semet-Solvay Co., Detroit, Mich. . .. Semet-Solvay Co., Empire Coke Co., Geneva, N.Y Semet-Solvay Co., Dunbar Furnace Co., Dunbar, Pa Semet-Solvay Co., Central Iron & Coal Co., Tuscaloosa, Ala .Philadelphia Suburban Gas & Electric Co., Chester, Pa Semet-Solvay Co., Ensley, Ala „ . . . The New England Gas & Coke Co. Everett, Mass Lackawanna Steel Co., Lackawanna Iron & Steel Co., Lebanon, Pa Dominion Tar & Chemical Co., Sydney, Nova Scotia Hamilton Otto Coke Co., Hamilton, O.. . Carnegie Steel Co., South Sharon, Pa.. . . Maryland Steel Co., Sparrows Point, Md. Citizens' Gas Co., Indianapolis, Ind Pittsburg Gas & Coke Co., The United Coke & Gas Co., Glassport, Pa Zenith Furnace Co., Duluth, Minn Illinois Steel Co., Joliet, III Illinois Steel Co., Indiana Steel Co., Gary, Ind Camden Coke Co., Camden, N.J Cambria Steel Co,, Johnstown, Pa. . . Lackawanna Steel Co., Buffalo, N.Y. . Examination, Public Roads Distillation results Water I.O I.O l.I 1.8 .6 (n 6.9 4.0 2.0 3.2 2.3 3.3 2.2 5.4 3-2 3-4 I.O 1.6 1.2 I.I 3.6 1.9 3.5 2.2 lO.I 2.7 I.O 1.5 •5 5.9 3.4 1-7 2.8 2.0 2.8 2.8 3-0 I.O I.I I.O 3.0 1.6 3.0 1.9 8.3 2.2 Light oils up to 110° C. "0.3 .4 1.9 1.4 1.6 •4 92.8 2.6 1.7 2.4 2.3 81.4 2.9 «i.4 [1.9 31 9 1.6 1.3 I.I I.I 1-7 9 1.7 ^1.3 1.8 «3.l 0.3 .3 1.5 1.2 1.3 •3 2.3 2.1 1.4 1.9 T^i 1.0 2.3 1.4 IS 2.5 1.2 .9 .9 1-3 1.2 1.0 1.4 2.3 .3 References to Table 23 4 1 Approximately. 2 No information. 3 Varies with coal. Coal with 28 per cent of volatile matter used. 4 With H20. 5 At present. 6 Variable. 1 Trace. 8 Trace of solids. 9 Distillate, solid. 10 Distillate, one-fourth solid. " Distillate, nine-tenths solid. 12 Distillate, three-fourths solid. Distillate, eight-ninths solid. w Distillate, one-half solid. BITUMENS Table 2^d, Continued 247 Examination, Office of Public Roads Distillation results Middle oils, iio°-i7o C. Heavy oils, i70°-27o C. Heavy oils, 27o°-3i5° C. Pitch Serial No. {1 ^-0 ^.1 ^1 ^1 0.8 0.7 12 13. 1 11.5 19 8.2 7-3 25 76.6 79.1 S126 82.0 1.7 814.0 12.3 20 7.9 6.9 2674.7 77.6 5123 .7 .6 14.9 13.2 21 II.9 10.6 27 69-5 73.1 5124 .8 .6 13 21. 1 18.9 2° 5.5 4.9 25 69.4 72.5 5137 .8 .6 " 17.5 15.5 19 9.4 8.4 25 70.I 73.7 5121 12 I.I ' -4 •9 .3 16 23.6 11 14.6 20.7 13.0 8 9.8 8 6.9 8.9 5-7 27 65.1 26 68.4 68.9 72.0 5125 5128 .6 •S 10 17.6 15.5 22 II.4 10.4 27 63.8 67.7 5200 .2 .2 w 20.0 17.8 " 6.5 5-7 25 69.6 73-1 S189 .3 .3 18.6 16.3 ^°7.S 6.8 27 68.0 71.5 5160 1.2 .2 .8 .2 22.8 " 16.S 19-5 14.1 i^i3.6 " 9-3 12. 5 8.2 57.8 2^69.3 62.0 73.2 5074 5081 .6 •S 23.5 20.4 17 15-6 14.4 2755.2 59-7 509s 9 .1 .1 "13.0 10.9 21 9.4 8.1 25 70.7 74.6 5083 .6 .5 .6 .4 27.2 27.9 W 12. 1 24.2 24.4 10.2 » 7.3 1^ 3-8 19II.O 6.7 3-5 9-7 2759.8 27 61. 1 2573.7 63.5 64.9 77-5 5159 5107 5086 .6 •4 1217.2 151 21 9-6 8.5 2869.7 73-2 5078 1.4 ■5 .4 9 .2 »2.2 1-3 .4 •3 .2 •3 •5 .2 1.7 23-9 18 26.9 " 18.I 8 20.0 820.6 " 20.5 «7.i 811.7 21.4 23.6 15.9 18.0 18.5 18.2 6.1 9.9 10 II.6 14 6.9 "12.5 "13.4 » 7.1 23 8.5 12 7-4 24 II.8 10.4 6.3 II. I 12.0 6.5 7.5 6.9 10.2 27 60.8 27 63.5 27 63.7 26 62.8 2667.1 25 66.4 26 72.0 27 71. 1 64.7 67.6 67.8 66.3 70.2 70.1 74.8 1 75.0 5087 5109 5122 5188 5404 5108 5127 5089 References to Table 23 d w Distillate, two-thirds solid. " Distillate, four-fifths solid. _ 17 Distillate, seven-eighths solid. 18 Distillate, one-ninth solid. 18 Distillate, one-third solid. 20 Distillate, one-sixth solid. » Distillate, one-fifth solid. « Distillate, two-fifths solid. 23 Distillate, one-seventh solid. 24 Distillate, three-fifths soHd. 25 Pitch, soft and sticky. 26 Pitch, very soft and sticky. 27 Pitch, hard and brittle. » Pitch, plastic. 248 MATERIx^S Results of Petroleum Residuum Kinds of Oil 1. ^•2 ?8« V 'in -1 n3 c/)0 P4 1^- P^ Ph ^u Pennsylvania, paraffin 0.920 186 % % % % Texas, semi-asphaltic •974 214 . 14.2 085.8 II.O 3.0 California, asphaltic 1.006 191 6.2 093-8 1-7 1-^ 17.3 082.7 0.0 6.0 a Soft. Tests of Bitumens and Their Significance. — Bitumens for use as the cementing material in road construction may, according to their source and characteristics, be divided into the two general classes of asphalts and tars. The asphalts suitable for use as the cementing agent in road con- struction are produced either by reducing asphaltic base petroleum to a suitable consistency by the distillation process or by softening the so-called solid asphalts to a suitable consistency by the addition of flux produced by the partial distillation of petroleum. The different grades, relative to consistency, of road oils are usually produced by the partial reduction of asphaltic base petroleum. By the destructive distillation of bituminous coals or the "crack- ing" of petroleum oils during the carburetting process in the manu- facture of water gas, crude tars are produced. These crude tars are refined or reduced by distillation to a suitable consistency for use in road construction. Bitumens are used in road construction for the purpose of water- proofing the surface and adding to the mechanical bond of the min- eral aggregate by cementing together the finer particles of mineral matter, thus preventing their displacement under the action of traffic and retaining them in the road surface where they fill the interstices between the larger stone and bind them together. The desirable characteristics of bituminous material for road building purposes are, first, Adhesiveness, second, Non-Susceptibility to changes in temperature, and third, Stability or "life.'' The chief object of bituminous material specifications is to make imperative these desirable qualities of the material. In connection with testing bituminous materials the thought should be kept in mind that the laboratory results obtained in the different tests are largely for comparative purposes. By this means new or but little used materials may be compared with materials which have proven satisfactory under service tests. Also laboratory results furnish an accurate means to specify the exact characteristics of the material desired for any given purpose. Adhesiveness. — The adhesiveness of the material is provided for in specifications by suitable requirements of ductility and toughness. TESTS OF BITUMENS 249 The ductility and toughness tests are made for the purpose of determining the adhesive and binding quahties of the material under different conditions of temperature. The ductility test is made by determining the distance a briquette of the material, having a stand- ard cross-section (i sq. cm.) will draw out before breaking. Since temperature effects the results, a standard temperature of 77 degrees Fahrenheit, has been adopted generally for making this test. Expe- rience teaches that the greater the distance that a briquette of the material will stretch out before breaking the more sticky and adhesive the material. This test may be performed in a rough manner by pulling out a small roll of the material between the fingers. Material which will not pull out to a long thread before breaking is usually spoken of as " short. '* Such materials are not adhesive or sticky and it is extremely difficult to bind a road with them, even under the most favorable circumstances. As stated, the ductility test is usually made at a temperature of 77 degrees Fahrenheit and thus measures the adhesiveness of the mate- rial at a rather high temperature. To obtain an indication of the character of the material at a low temperature the Toughness test is made at a temperature of 32 degrees Fahrenheit. This test is per- formed by dropping a weight of 2 kilograms on a cylinder of the material i % inches in diameter by i ^^ inches in height. The first height of the drop is usually from a distance of 5 cm. and is gradu- ally increased until rupture of the cylinder occurs. A rough field test for toughness may be performed by noting whether a piece of the material will fracture under a sharp blow. If the temperature of the material is about 32 degrees Fahrenheit, the results will be more indicative of the character of the material. Bitumens which are brittle or which give a low toughness result, lose their binding value in cold weather and roads constructed by their use are apt to ravel and break up under traflSc. Bitumens which give good ductility and toughness results under the methods outlined, will give satisfactory results as the cementing medium when used in road construction provided the other con- struction details have been properly followed out. In connection with the stickiness and adhesiveness of bitumens the fact should always be kept in mind that their purpose in road construction as cementing medium, is most effective when used with a hard, clean, dry mineral aggregate. As the departure from these qualities of the mineral aggregate increased so also are increased the difficulties of getting a satisfactory road surface firmly bound together. Susceptibility to Changes in Temperature. — The susceptibility to changes in temperature is shown by the relative hardness as indicated by the penetration tests at different temperatures, as 32 degrees Fahrenheit, 77 degrees Fahrenheit and 115 degrees Fahrenheit. The consistency of asphalts is referred to as the "penetration." The penetration test is made by measuring the distance in hundredths of a centimeter that a standard needle under a stated load, applied 250 MATERIALS for a stated time, will penetrate into it vertically. These variable factors are usually as follows : Needle — R. J. Roberts' Parabola ''Sharps" No. 2. at 32° F. 200 gram weight, i minute, at 77^^ F. 100 gram weight, 5 seconds, at 115® F. 50 gram weight, 5 seconds. The material which is the most susceptible to changes in tempera- ture will show the greatest variation in penetration under varying conditions of temperature. Roads constructed by the use of mate- rials which are extremely susceptible to changes in temperature be- come soft in warm weather, mark easily, have a tendency to rut and become wavy. In cold weather this material becomes very hard and slippery and is apt to be brittle and become chipped from the road surface. In addition to the general qualities of bitumens which are shown by penetration tests, this test is used in specifications to define within narrow limits the consistency of the material. The consist- ency limits placed in specifications are governed by the climate and the type of construction to be followed, also the general size of the mineral aggregate to be used. When the penetration method of construction is followed it is necessary to use a relatively soft asphalt in order that it may be incorporated in the road surface. In the mixing types of construction a harder asphalt may be incorporated with the mineral aggregate. The use of a hard asphalt together with a graded mineral aggregate gives a dense wearing surface that does not readily become wavy under traffic. The information obtained by the penetration test is not readily checked in the field without the aid of laboratory apparatus, but as a general rule bitumens which are suitable for binders are plastic when ''worked" in the hands. Stability.— When the term "Stability'' or "Life" is used in ref- erence to bitumens it refers to the quality of the material by which it retains its characteristics, usually as defined by the specifications, over a long period of time. The laboratory tests which indicate this property are the evaporation test, the ratio of the penetration after evaporation to the original penetration, and the flash point The heating or evaporation test, is made by placing 50 grams of the material in a flat bottomed dish 2%6 inches in diameter by 1% inches in depth. This is placed in an oven maintained at a specified temperature, usually 325 degrees Fahrenheit for a period of 5 hours. This test may be considered as an accelerated test on the material. In a binder, the percentage lost by weight together with the result- ing hardening as shown by the relative penetration, i.e., the ratio of the original penetration to the penetration after evaporation, are indicative of the "life" of the material. The less the evaporation loss and the less the hardening as shown by the relative penetration the greater will be the "life" of the material. In an oil used for surface application the evaporation test shows the presence and quantity of light oils. This is indicative of the time required for the oil to "set up" after application to the road TESTS OF BITUMENS 251 surface; the evaporation from the large surface area of the oil as applied to the road being roughly comparable with evaporation from the smallest surface area of the oil exposed at the higher tem- perature at which the test is made. The open flash test is made by heating at the rate of about 10 degrees Fahrenheit per minute, a small quantity of the material, approximately 40 grams in a dish of approximately the same size as the dish used for the penetration tests, 2^{q inches in diameter by I % inches in depth. A small flame from a capillary tube is passed over the surface of the oil at each increase of 5 degrees in tem- perature. A slight ^'puff " or explosion indicates the flash point has been reached. The presence of light oils or distillates is indicated by a low flash point. The flash point together with the evaporation results give an indication as to the methods and materials used in the manufacture of the bitumen which is being tested. Unless "cut-back" materials are being tested, in which an exceed- ingly light distillate as naphtha or benzole has been used as the *' cut-back '* agent, considerable " smoke '^ will be given off from the sample before the flash point is reached. This feature should be kept in mind when material is being heated for application in the field. Material should never be heated in the field to a point when it smokes profusely, for at such a temperature the material is being "burned" or hardened to such an extent that it loses its adhesive- ness and becomes brittle when coid, thus failing to become a binding or cementing agent which binds the mineral aggregate of the road together. The same "burning" effect on the material is produced by keeping it at a temperature below the "smoking point" for a long period (several hours) as would be produced at a higher temperature for a shorter period of time. This important feature should always be kept in mind when heating material for applica- tion in the field. Such tests as those for water, specific gravity, purity, par affine, etc. are usually placed in specifications in addition to the tests which govern adhesiveness, non-susceptibility and stability for the purpose of identification of materials used, methods of manufacture, degree of refinement and care used in refining. The presence of water in bituminous materials causes frothing when heated to a temperature of about 212 degrees Fahrenheit. In addition to the difficulty experienced in heating material containing water, due to the frothing, an even application or distribution to the road of such material is extremely difficult, due to the presence of the froth which is apt to be applied rather than the liquid bitumen. Tests for specific gravity, purity, paraffine, etc. require laboratory apparatus to get results which indicate qualities of the material. The information obtained by these tests can not be obtained by field tests. If we assume that a suitable bitumen has been specified and ob- tained for construction work in which a bitumen is to serve as the 252 MATERIALS cementing material, the results obtained, relative to the bitumen, will depend upon: 1. Not over-heating (by high temperature or long time) the bitumen. 2. The use of hard, clean, dry stone. 3. Grading of the mineral aggregate to reduce the voids and obtain greater density. 4. Thorough and uniform incorporation of the bitumen with the mineral aggregate. 5. Maximum consolidation, by rolling when laid. When bituminous materials which may be applied cold are to be applied to a road surface, that surface should first be put in good condition. Surface application treatment is for the purpose of preserving a road which is in good condition and not repairing an un- even road. We do not repair a house by painting it; rather we repair the house and then paint it, in order that it may remain in good condition. An attempt to build up a road wearing surface by the use of bitumens which may be appied cold usually results in a surface which is easily marked, ruts alnd pushes into waves. Cement. — There are five different classes of cement, Portland, Natural, Pozzolan, Iron Ore, and Magnesia cements. Of these the Portland or Natural is usualy spiecified. Portland cement is the term lappled to the finely pulverized product resulting from the calcination to incipient fusion of an in- timate mixture of properly proportioned argillaceous and calcareous materials, and to which no addition greater than 3 per cent, has been made subsequent to calcination. (Amer. Soc. Testing Materials 1915— page 353.) Natural cement is the term applied to the finely pulverized prod- uct resulting from the calcination of an argillaceous limestone at a temperature only sufficient to drive off the carbonic acid gas. (Amer. Soc. Testing Materials 191 5 — p. 352.) Portland cements are usually heavier, stronger, slower setting, and more uniform than the natural cements and are generally used for road structures, such as culverts, retaining walls, etc. Portland cement is practically the only cement used to any extent in the United States at the present time. The few manufacturers of natural cement who were retaining a hold on the market some few years back when the production of Portland cement was expensive, are finding it difficult to compete with this latter product at its present price and quality. The following is the standard specification for Portland cement as adopted by the American Society of Civil Engineers and the American Society for Testing Materials: First: Specific gravity. The specific gravity of cement shall not be less than 3.10. Should the test of cement as received fall below this requirement, a second test may be made upon a sample ignited at a low red heat. The loss in weight of the ignited cement shall not exceed 4 per cent. Second: Fineness. It shall leave by weight a residue of not more than 8 per cent, on the number 100, and not more than 25 per cent, on the number 200 sieve. Third : Time of Setting. It shall not develop initial set in less than thirty minutes; and must develop hard set in not less than one hour, nor more than ten hours. CONCRETE MATERIALS 253 Fourth: Tensile Strength. The minimum requirements for tensile strength for briquettes one square inch in cross section shall be as follows and the cement shall show no retrogression in strength within the periods specified: Age Neat Cement Strength 24 hours in moist air 175 lbs. 7 days (i day in moist air, 6 days in water) 500 " 28 •* (i " " " " 27 " " ** ) 600 " One Part Cement — Three Parts Standard Ottawa Sand 7 days (i day in moist air, 6 days in water) 200 lbs. 28 " (i " " " •' 27 " " " ) 275 " Fifth : Constancy of Volume. Pats of neat cement about three inches in diameter, one-half inch thick at the center, and tapering to a thin edge, shall be kept in moist air for a period of twenty-four hours. (a) A pat is then kept in air at normal temperature and observed at in- tervals for at least 28 days. (b) _ Another pat is kept in water maintained as near 70 degrees F. as practicable, and observed at intervals for at least 28 days. (c) A third pat is exposed in any convenient way in an atmosphere of steam, above boiling water, in a loosely closed vessel for five hours. These pats, to satisfactorily pass the requirements, shall remain firm and hard, and show no signs of distortion, checking, cracking or disintegrating. Sixth: Chemical Composition. The cement shall not contain more than 1.75 oer cent, of anhydrous sulphuric acid (SO3), nor more than 4 per cent, of magnesia (MgO). The methods used in testing cement are standardized in detail and can be obtained in the "Year Book'^ of 1913, published by the American Society for Testing Materials or Committee report on "Uniform Tests of Cement"* of the American Society of Civil Engineers 191 2. CONCRETE MATERIALS Fine Aggregate. — Fine aggregate for use in concrete should con- sist of sand free from any deleterious matter. Any sand which shows a coating on the grains should not be used until satisfactorily cleansed by washing. The following tests are made on sand to determine its suitability for use in different classes of concrete: I St. Gradation. 2nd. Percentage of voids. 3rd. Percentage of loam or silt. 4th. Compressive or tensile strength in cement mortar. In order to secure suitable qualities, minimum requirements determined from the above tests should be definitely specified. The following specifications are now being used by Highway Departments in several of the States: Sand for use in Portland cement concrete roads shall be of the following gradation: 100 per cent, shall pass a }^" screen, not more than 20 per cent, shall pass a No. 50 sieve and not more than 6 per cent, shall pass a No. 100 sieve. Sand may be rejected for this class if it contains more than 5 per cent, of loam and silt. Mortar in the proportion of one part of cement to three parts of the sand, shall develop a compressive or tensile strength at least equal to the strength of a similar mortar of the same age, composed of the same cement and standard Ottawa sand. 254 MATERIALS Sand for use in foundations, culverts, retaining walls, etc. shall not contain more than 8 per cent, of loam and silt. Mortar in the proportion of one part of cement to three parts of the sand, when tested shall develop a compressive or tensile strength of at least 80 per cent, of the strength of a similar mortar of the same age, com- posed of the same cement and standard Ottawa sand. Screenings if substituted wholly or in part for the above sand, should meet the following requirements: They shall be free from dust coating or other dirt. 100 per cent, shall pass a 34'' screen and not more than 6 per cent, shall pass a No. 100 sieve. Mortar in the proportions of three parts of the screen- ings or mixed screenings and sand, with one part of cement shall develop a strength equal to a sand for which it is to be substituted. The best and safest way in the selection of a concrete sand is to have a fair representative sample from the deposit listed. After this is found to meet the requirements, it is necessary to have constant and careful field inspections and tests made as the deposit is worked. The use of screenings is not advisable on any concrete work, except where a good grade of sand is not available. When used the product must be constantly inspected and tested as it is likely to vary to a considerable degree. Screenings from the softer lime- stones should not be used as the fine material is apt to ^'ball" in the mixer. Sand used for grout in brick and stone block pavement must be fine enough to ensure it getting between the joints of the block, but an excessively fine sand should be avoided as it weakens the grout. Some states and many municipalities require the grout sand to pass a No. 20 sieve and not more than 30 per cent, pass a No. 100 sieve. Such sand should not contain more than 5 per cent, of loam and silt. Coarse Aggregate. — Coarse aggregate for use in structural concrete should be of hard durable stone gravel or blast furnace slag (see table of tests) free from coating of any kind. For use in concrete pavement, stone and gravel should be hard, tough and absolutely clean. For use in culverts, retaining walls, etc. stone, gravel or slag should be of sound, un weathered material, clean and free from coating. It should not contain more than 10 per cent, of soft stone or shale. Gravel containing a large percentage of thin flat stone should not be used. For reinforced concrete the size of the stone is usually }^i" to i" in order to facilitate the compacting of the concrete between the reinforcing bars or mesh. For plain concrete a mixed size is used ranging from 3^'' to 3M''; a scientifically graded stone reduces the amount of mortar required, but the structures in road work are so small that it does not pay to attempt to reduce the voids in this manner and the size that is available is used, varying the propor- tions of mortar to get a dense product. For extensive concrete pavement of the first class graded sizes are feasible. The use of slag in concrete is still a debatable matter but if proven to be reasonable will add materially to the source of concrete materials. The latest available tests by the Pittsburgh laboratory with an up to date discussion is quoted as follows: TESTS OF BLAST-FURNACE SLAG 255 TESTS OF BLAST-FURNACE SLAG AS COARSE AGGREGATE IN CONCRETE "[In order to secure definite authoritative data on the use of blast- furnace slag in concrete, a number of leading interests, which either produce or market slag, made a co-operative arrangement with the Pittsburgh Test- ing Laboratory of Pittsburgh to conduct a series of experiments and tests that would extend ultimately over a period of five years. "The reports of these tests will be of more than ordinary value, as the care involved in the preparation and testing of the specimens made the tests more expensive than would ordinarily be undertaken by a commercial labo- ratory, and the results are such as can be obtained only by having a very carefully organized research department. "Recognizing that these tests are of the utmost value to engineers in ac- quainting them with the performance of blast-furnace slag in concrete work, the Manufacturers Record publishes herewith extracts from the report com- piled by the Pittsburgh Testing Laboratory. — Editor Manufacturers Record.] "The purpose of this series of tests v/as to furnish information relative to the use of concrete materials, as follows: " (i) A comparison of the crushing strengths of air-cooled blast-furnace slag, crushed stone and gravel when used as the coarse aggregate in concrete, tests to be made at the end of 14, 30, 60 and 180 days, i year, 2 years, 3 years, 4 years and 5 years. " (2) To determine the granulometric analysis of the material as received, together with other physical characteristics. " (3) Determination of the corrosive tendency of sulphur in slag. "(4) Effect of sulphur and other elements on the durability of concrete up to the age of five years. "(5) Relative strength and durability of concrete made of high magnesia, low lime slag and low magnesia high lime slag. " The materials used as the coarse aggregates in these tests were secured from the following localities: P. T. L. Mark Slag: Cleveland Macadam Co., Cleveland, Ohio (from A. S. & W. Co., Central Fur., Cleveland, Ohio) 87410 Slag: Duquesne Slag Products Co., Pittsburgh, Pa. (from C. S« Co., Duquesne, Pa., slag bank) 87420 Slag: Carnegie Steel Co., Pittsburgh, Pa. (from Ohio Works, Youngstown, Ohio) 87430 Slag: Northwestern Iron Co., Mayville, Wis 87440 Slag: Standard Slag Co., Youngstown, Ohio (from S. F. Co., Sharpsville, Pa.) 87450 Slag: Cleveland Macadam Co., Cleveland, Ohio (from C. F. Co., Cleveland, Ohio) _. . ._ 87470 Slag: Birmingham Slag Co., Birmingham, Ala. (from T. C. & I. Ry. Co., Ensley, Ala 87480 Slag: Duquesne Slag Products Co., Pittsburgh, Pa. (from E. S. Co., Pottstown, Pa.) 87520 Slag: The France Slag Co., Toledo, Ohio (from T. F. Co., Toledo, Ohio) 87530 Gravel: Allegheny River, from Pittsburgh, Pa 87460 Trap Rock: from Birdsboro, Pa 87490 Gravel: from Akron, Ohio _ 87500 Crushed granite: from Stockbridge, Ga 87510 Limestone: from Gates City, Ala 87540 Dolomitic limestone: Kelly Island, from Cleveland, Ohio.. . 87550 It did not seem practicable to screen the fine aggregate and recombine to conform to Fuller's curve, or to use a combination of two or more sands which would make theoretically the best fine aggregate. The material selected was reasonably well graded, and the same sand was used throughout the series of tests, the whole aniount being secured at one time from the back channel of the Ohio River, at Neville Island. "The cement used was Alpha Portland, from Manheim, W. Va. This brand was selected by lot, being drawn from a list of several standard brands of Portland cement. All cement was purchased at the same time and sam- 2s6 MATERIALS pled and tested before the preparation of concrete test specimens was begun. The results of these tests are included in the report. "As the various aggregates were received, they were screened through sieves consisting of iron plates with circular holes of the following diameters: i^i inches, i inch, ^^ inch, 3^ inch and ^^ inch. "The portions retained on each of the above sieves were stored separately and labeled, to be later recombined to make the coarse aggregate used in the tests. "In accordance with the specifications, the coarse aggregate was recom- bined to conform to Fuller's curve. Since the portion of Fuller's curve representing coarse aggregate is a straight line, and since the curve is re- ferred to ordinates, of which the vertical ordinate is divided into equal parts, showing percentages by weight, and the abscissa is divided into equal parts, representing the diameter of the particles in inches, it follows that coarse aggregates, when so recombined, will consist of equal percentages of the four (4) gradings, which increase in size uniformly from ^^ inch to ij'i inches. All aggregates, therefore, were recombined by weighing equal quantities of the four gradings and shoveling them fogether, turning them until their appear- ance showed them to be thoroughly mixed. "In order to accurately proportion the concrete, the weight per cubic foot of all materials was determined. Since there is no generally accepted method for determining the weight per cubic foot of concrete materials, one was used which had been found in the past to give consistent results. A cubic foot measure was filled loosely with either sand or the recombined aggregate, after which the measure was dropped 10 times on a felt pad one inch thick from a height of three inches. The measure was again filled and smoothed off with a straight edge and weighed. The average of 10 determinations was taken as the weight per cubic foot of the material used. The variation of the individual determinations was usually within five-tenths of i per cent, and seldom over i per cent. The weight per cubic foot was frequently redetermined, to take into account any drying out of the material. The weight of the cement per cubic foot was taken at 100 pounds, this being in accordance with the generally accepted figures for cement. "Void determinations were made on the various aggregates after recom- bining. Each coarse aggregate was thoroughly wet, drained and a cubic foot measure filled and weighed, as given in the method for determining the weight per cubic foot. Water was then slowly added until the measure was level full. From the increase in weight the percentage of voids was computed. "It was not possible to combine the sand and cement with the slag, gravel and crushed stone, respectively, to strictly conform to Fuller's curve and still have tests which would be comparable with each other on the basis of equal proportions of cement. It was, therefore, necessary to determine the leanest mixture which would produce a dense concrete when using the coarse aggregate having the highest percentage of voids, and then using this mixture for all materials. ^ By this method the same quantity of cement was used to make each specimen, and the test data shows a comparison of the diffeient aggregates under the same conditions. "The proportions for the mortar were determined by making trial mortars of various proportions of cement and sand and selecting the mixture giving the maximum density as shown by increase in volume of the resulting mortar. After numerous tests, the proportions of i part cement and 2 parts sand were found to most nearly fulfill the tests for maximum density of the mortar. "The coarse aggregates used for these tests varied in weight per cubic foot from 64 to 104.5 pounds, and the percentages of voids from a minimum of 31.85 to 49.2 per cent. Since the percentage of voids in one case was 49, to obtain the maximum density, using this aggregate, the mixture should be almost exactly two parts of mortar and four of coarse aggregate; this pro- portion would give some excess mortar in all of the other cases. "The fact that a 1-2-4 mixture is one which is very commonly used — and a large amount of data may be found for comparison — was an additional reason for using it in these tests. , , , . , "These proportions by volume having been selected, the equivalent weight each of the materials for these proportions was determined, and throughout the series of tests all materials were weighed, and greater accuracy in propor- tioning thus obtained. The mixture, however, is by volurne, the method of weighing being used only to insure more accurate proportions. TESTS OF BLAST-FURNACE SLAG 257 "A quantity of material sufficient to make ten (10) cylinders was mixed at one time, the sand being spread in a flat pile and the cement placed over this. The two materials were turned by two men until the color appeared to be uniform, [.three or four turnings being required. The coarse aggregate was then shoveled on this material and the whole turned dry three times. During the fourth turn a weighed amount of water was added from a sprinkling can and three (3) additional turnings given the mixture. During the last three turnings small quantities of water were added as needed until a * quaking consistency * was obtained. In all mixtures an attempt was made to secure the same consistency, regardless of the amount of water used. For this reason, it was not possible to use a me- chanical mixer, as the quantity of water is very important, and in mechanical mixing the material may be made too wet and the whole batch spoiled for laboratory purposes. It is noteworthy that care must be used to obtain the correct consistency, and that the addition of I pound of water to a lo-specimen mixture would give a consistency too wet, usually de- scribed as 'mushy,' and the results of the tests would be unsatisfactory. *'The specimens were made in steel molds 8 inches in diameter by 16 inches high. The concrete was poured into these molds in layers 4 inches thick, and each layer tamped thirty (30) times with a J-^-inch round rod. After the second and fourth layers the sides were spaded with a large trowel. These cylinders were finally finished at the top by spading with a small trowel to form a smooth upper rim, and a piece of plate-glass placed on top to form a smooth surface. Since the concrete would settle slightly after a few hours, it was necessary to cap the top of the specimen with plaster-of-Paris and cement and again place the] plate-glass on the cap to make a smooth surface. ; "The specimens were kept in the molds for forty-eight (48) hours and then stored in damp sand for thirty-five (35) days. At the end of this time all specimens were removed and stored in air. Four (4) short pieces of rein- forcing steel were embedded in each of two (2) cylinders from every batch. "These pieces were 3, 6, 9 and 12 inches long, and were cut from }4 inch twisted rein- forcing bars furnished by the Carnegie Steel Co., Duquesne heat No. 99439. having the following chemical analysis: Carbon 20.0 per cent. Manganese 45-0 per cent. Phosphorus 0.018 per cent. Sulphur 0.046 per cent. "These specimens will be examined at the end of the five-year period to determine the corrosive action of the aggregates. " (i) It will be noted that one-half of the tests of the slag concrete were made using slag produced by the quick-cooling process^ in w u < "A (A P 2 Q w O o o OfOwiiOOOoOwroO 00 rO •-• f*5 O ^ w 00 O O 1000 O ^ 10 t^oo fOt^roO w oj M '^ 00 fO M "^ 000 \no "^o viroai^t^ rf O^ W O ro CO t^ '^oo 0 Per Cent. Passing ^ ^ C . o^ ""^ Sieve as Received _c 1^ Name of Material »-. rt ..^ '>> Weight -^ S^ 2s A Used p^S of ^ U ^^ «^^ " c Cylinder bo C ft \^'^ lb. oz. o.S rt a=c^ iK I H Vz Ya. S C w . Weight 2a '>. Weight ^S* 2c of ^v. Average Ci Strength ii per sq. in. of C/3 w O"" _: of m ^ O"^ _: g Cylinder lb. oz. .2 ^ ■a 1^ Cylinder lb. oz. Average < Strength per sq. ir ■a Cylinder lb. oz. Average < Strength per sq. ir 10 63 3 2461 1 8 63 00 2815 7 62 10 3740 33 63 10 2770 2525 13 62 15 2966 2930 5 62 5 3958 3753 28- 62 14 2343 26 62 13 3008 8 63 3560 10 66 00 242s 4 65 6 3143 7 64 12 4280 17 64 4 2983 2657 13 65 6 3402 3117 16 65 10 4464 431S 27 65 I 2562 22 65 4 2810 25 64 5 4200 10 65 8 2642 7 66 4 3625 2 65 10 3880 17 64 00 2568 2657 12 63 10 3220 3306 16 65 00 4130 4154 28 64 10 2761 22 65 12 3074 20 65 S 4452 3 63 00 2640 5 62 5 3523 I 62 IS 4146 13 62 12 2630 2653 21 63 00 3363 3403 4 62 8 4268 4309 23 63 4 2688 28 62 II 3320 6 63 4512 3 65 00 3127 10 65 II 3359 I 64 II 4906 13 65 00 2999 3075 18 65 00 3468 3365 5 65 3 4678 4803 27 65 00 3100 21 64 •13 3268 9 64 II 4824 3 68 13 2608 6 68 13 3427 7 68 14 4200 13 68 9 2514 2510 21 69 2 3170 329s 9 68 9 3816 3969 23 68 15 2409 27 68 13 3289 19 69 I 3892 I 62 2 2810 1 3 61 10 3167 6 61 15 4588 II 61 8 3057 2844 14 62 I 3126 3288 13 61 14 4422 4394 21 62 5 2666 24 61 2 3068 16 61 9 4172 I 66 9 2660 8 64 00 3270 3 66 2 4432 II 66 00 2800 2752 17 66 9 3354 3289 4 66 9 4460 4451 20 67 2 2796 [25 66 5 3244 7 66 7 4460 I 72 6 2454 9 72 6 3411 3 72 15 4814 II 73 5 2330 2386 ii5 72 12 3416 3360 6 72 12 4738 4819 21 72 9 2374 120 72 8 3256 7 72 14 4906 I 66 13 2040 i 8 67 12 2756 3 68 3 3636 II. 67 9 2040 2078 16 68 2 2378 2554 4 68 9 3840 3627 21 67 8 2153 28 67 14 2527 16 68 3404 I 69 00 2230 3 69 2 3112 8 69 6 4190 12 68 4 2334 2292 16 69 00 2760 3043 17 69 4016 41SI 22 69 8 2313 19 69 8 3258 23 69 5 4248 2 64 2 2738 5 63 8 3245 27 63 5 4210 II 63 6 2600 2650 14 63 00 3244 3289 4 63 6 4203 4184 21 63 00 2613 24 63 8 3378 3 63 4140 I 66 7 2527 7 66 3 3251 3 66 4 4130 II 65 4 2402 2536 16 66 5 2864 3103 9 66 15 4333 4164 22 66 4 2680 20 66 4 3195 13 65 6 4030 3 69 9 1985 2 69 6 3149 4 70 3936 10 69 8 1950 1988 15 68 13 3014 3082 8 69 6 4636 4127 23 69 8 2030 22 69 00 3072 9 68 12 3814 I 69 6 2269 2 70 00 3503 3 70 4640 12 69 14 2442 2360 17 69 12 3846 3604 19 70 5011 4724 24 69 00 2375 22 70 12 3462 27 69 4520 order as follows: 87410, 87420, 87430, 87440, 87450, 87460, 87470, 87480, 87490, selected by lot. Ohio River sand. Large aggregates as shown above. 26o MATERIALS O -rf O Tj- TtOO - TtOO rtoo 00 O O* fO t^ '*00 »O00 O •-" 00 Oi lO M roO M lOvO O moOOO poI^moOvO c^ O ■100 OOvO c^ -^N roioroc^ fOOj m m Ttcow 0\roO* •J 1^ "^ a o ^ :^ > U '^ o" a C) zi aJ I 1> 0) 53 O n c) bo o o o o O ll O 0) oJ > o O 2P^Q ^S>H W)0^ bort^ ^;^'^ bpi^jg MtjrS ^.ii -^ COO C^^ CB^ O^ CQ^ w^ h" l^ !>• t- t^ TESTS OF BLAST-FURNACE SLAG 261 fO fO a t> Tf- Tt »> ro ^ 00 ''t l> ro ro •* ^ ^ ^ rt 0\ Ov rj- Tt rf ro «> t^ t^ 10 t- rj- 1^0 lot-ot^iorororoooooo COfOfO'^"^'?f"^"^'^"^'^'^'=t-"*'^iO" t^vO ioOn OvO TfoO 0\ lOV "* re HH f^ »0 0' 1 (N i-H rt i-H (N :j 1 .^0 Co. 0, Ohio. Ala. C3 OJ SB hflTJ . . (U 0^ eSla Tole one — City itic L slsla eland Slag— Duqu Pott Slag— • Franc East Limest ■ Gates M (N ro Tt 10 10 10 10 10 10 10 j> !>• t^- t^ l^ i^ 00 00 00 00 00 00 < 262 MATERIALS pits, in which the slag is shipped within a few days from the time it comes from the furnace, and the remainder from slag which had been seasoned in banks for a period of six months in some cases and as much as 15 years in one case. "(2) The length of time during which this series of tests has been con- ducted does not warrant the drawing of any definite conclusions, but the general uniformity of the results of the crushing tests of the concrete should be observed. " (3) Slags coming from furnaces many hundred miles apart, varying quite widely in chemical analyses, and also varying considerably in the weight per cubic foot, do not vary in strength in proportion to either the weight or percentage of any chemical constituent. Since the following tests were published the one-year test has been completed, and in reporting on these the Pittsburgh Testing Laboratory states: *'In most cases the specimens show a considerable increase in strength over those tested at the age of 180 days, but in some cases the increase is very slight. Discussion of these tests will be withheld until the end of the two or three-year tests, but the discussion of results furnished with the 180- day tests^ stili holds trtie for these tests. In some instances, as will be noted, an exceptionally high compressive strength has been developed at the age of one year. Water. — The following quotation from the Concrete Highway Magazine of May, 191 8, by Duff A. Abrams shows the effect of excessive water on the strength of concrete. It should be borne in mind that this represents the laboratory point of view but shows very forcibly that excess water is injurious. ''It is commonly stated that concrete is composed of a mixture of cement, sand and pebbles or crushed stones. This conception of concrete overlooks one essential element of the mixture; namely, water. An exact statement of the ingredients of concrete would be: Cement, aggregate, and water. The last-named material has not yet received proper consideration in tests of concrete or in specifica- tions for concrete work. '* Early users of concrete centered their entire attention on the quality of the cement, and practically disregarded the characteristics of the other ingredients. During the past dozen years some atten- tion has been given to the importance of the aggregate, but it is only recently that we have learned that the water also requires consideration. ''A great deal has been said and written recently concerning the effect of water on the strength and other properties of concrete, but the full significance of this ingredient of concrete has not heretofore been pointed out. A discussion which appeared in the April, 191 7, issue of the Concrete Highway Magazine gave a brief review of results of some of the experimental work carried out along this line at the Structural Materials Research Laboratory, Lewis Institute, Chicago The relation between the water content and the compressive strength of the concrete for a wide range of con- sistencies was there pointed out and emphasis was placed on the injurious effect of too much water. ** Tests made in studies of the effect of size and grading of ag- gregates have shown that the only reason that concrete of higher strength and durability can be produced from well-graded aggregate WATER 263 as compared with a poorly graded aggregate is that the former can be mixed with less water. If this is not done no advantage is gained from using a coarse, well graded aggregate. The following dis- cussion shows that a similar conclusion can now be stated with reference to a rich concrete mix as compared with a lean one. *' While the injurious effects of too much water in concrete are apparent, tests made in this laboratory show that the truly funda- mental role played by water in concrete mixtures has been entirely overlooked in previous discussions of this subject. The relation referred to above is brought out by a series of compression tests of about 1600 6 by 12-in. concrete cylinders made up as follows: Mix Range of Sizes of n^^^:^-i- .. Cement- Aggregate Aggregates | -v......uc....y I- 9 I- 5 I- 3 I- 2 I— I Neat , > ' o-14-mesh sieve 0- 4-mesh sieve o-i %-inch o-i K-inch 0-2 -inch . ( 7^ different con- 1 sistenciesfor 1 each mix and [ aggregate *^The mixes used covered a wide range, as did also the grading of aggregate and consistency. The aggregates consisted of two sizes of sand and mixtures of sand and pebbles graded to the sizes shown. The mix is expressed in terms of volumes of dry cement and aggregate, regardless of grading; i.e., a i : 5 mix is made up of I cu. ft. cement (i sack) and 5 cu. ft. of aggregate as used, whether a sand or a coarse concrete mixture. " This series gives valuable information on the effect of changing the quantity of cement, the size of the aggregate and the quantity of water. The effect of many different combinations of these variables can be studied. One set of relations gives the effect of amount of cement using aggregates of different size and grading; another set of relations gives the effect of different quantities of water, varying both mix and size of aggregate, etc. In all respects these tests bear out the indications of both earlier and later series. These tests are of interest in that they reveal for the first time the true relation between the strength and the proportions of the con- stituent materials in concrete. ** The figure shows the relation between the compressive strength and the water content for the 28-day tests. The water content of the concrete has been expressed as a ratio of the volume of cement, considering that the cement weighs 94 lb. per cu. ft. Distinguishing marks are used for each mix, but no distinction is made between aggregates of different size or different consistencies. ** When the compressive strength is platted against the water in 264 MATERIALS n' this way, a smooth curve is obtained, due to the overlapping of the points for different mixes. Values from dry concretes have been omitted. If these were used we should obtain a series of curves dropping downward and to the left from the curve shown. It is seen at once that the size and grading of the aggregate and the quantity of cement are no longer of any importance except in so far as these factors influence the quantity of water required 8000 0.50 1.00 1.50 e.00 2.50 3.00 3.50 YVa+er-Rcj-t-jo +o Volume of Cement 4.oa to produce a workable mix. This gives us an entirely new con- ception of the function of the constituent materials entering into a concrete mix and is the most basic principle which has been dis- covered in our studies of concrete. ** The equation of the curve is of the form, 5 = A ■^ B- (i) where S is the compressive strength of concrete and x is the ratio of the volume of water to the volume of cement in the batch. A and B are constants whose values depend on the quality of the cement used, the age of the concrete, curing conditions, etc. ** This equation expresses the law of strength of concrete so far as the proportions of materials are concerned. It is seen that for given concrete materials the strength depends on only one factor — the ratio of water to cement. Equations which have been pro- posed for this purpose contain terms which take into account such factors as quantity of cement, proportions of fine and coarse aggregate, voids in aggregate, etc., but they have uniformly omitted the only item which is of any importance; that is, the water. ** For the conditions of these tests, equation (i) becomes, 14,000 (2) WATER 265 '' The relation given above holds so long as the concrete is not too dry for maximum strength and the aggregate not too coarse for a given quantity of cement; in other words, so long as we have a workable mix. " Other tests made in this laboratory have shown that the charac- ter of the aggregate makes little difference so long as it is clean and not structurally deficient. The absorption of the aggregate must be taken into account if comparison is being made of different aggregates. *' In certain instances a 1-9 mix is as strong as a 1-2 mix, depending only on the water content. The strength of the concrete responds to changes in water, regardless of the reason for these changes. **It should not be concluded that these tests indicate that lean mixes can be substituted for richer ones without limit. We are always limited by the necessity of using sufficient water to secure a workable mix. So in the case of the grading of aggregates. . The workability of the mix will in.all cases dictate the minimum quantity of water that can be used. The importance of the workability factor in concrete is therefore brought out in its true relation. *^The reason a rich mix gives higher strength than a lean one is that a workable concrete can be produced by a quantity of water which gives a lower ratio of water to cement. If an excess of water is used we are simply wasting cement. Rich mixes and coarse, well- graded aggregates, are as necessary as ever, but we now know just how these factors affect the strength of the concrete. *' Practical use may be made of the curve in estimating the rela- tive strength of concretes in which the water content is different for any reason. For example, a concrete mixed with 7.5 gallons of water (i cu. ft.) to one sack of cement (allowance being made for absorption of aggregate) gave a strength in this series of 2000 lb. per sq. in. (x = i.oo). For x = o.8o (6 gal. of water per sack of cement) we have 3000 lb. per sq. in.; for x = o.75 (5.6 gal.) 3300 lb. per sq. in. Concrete in a 1-4 mix (same as the usual 1-2-3 ^li^ with a coarse sand) should be mixed with 5 M to 6 gal. of water per sack of cement. " The importance of any method of mixing, handling, placing and finishing concrete which will enable the work to be done with a mini- mum of water is at once apparent. It now seems that practically all faulty concrete work can be traced to the use of too much water. ** Laboratory research performs its true function when it uncovers basic principles which have not been revealed by experience in construction, or observation of completed work.*' PART II PRACTICE OF SURVEY, DESIGN AND CONSTRUCTION CHAPTER X PRELIMINARY INVESTIGATIONS As stated in the introduction the object of all preliminary in- vestigation, either of new locations in unsettled districts or of high type pavement improvements in populous sections, is to se- cure data on which a reasonable program of work can be based. Work of this kind should be done only by experienced highway engineers as reliable results depend largely on the judgment of engineer which must be based on actual design and construction experience under conditions similar to those investigated. As a rule this portion of the engineering program is carelessly done due to hesitation in spending money before a project is assured but this policy is short sighted as there is no part of the work which is more important. The cost of first-class investigations of this kind range Irom $3.00 to $40.00 per mile. A cost of $5.00 to $10.00 per mile is a fair average for long mountain road projects similar in character to the work being done by the U. S. Office of Public Roads in the west and a cost of $5.00 to $15.00 per mile for high type road re- ports in the eastern states. Reconnaissance surveys in heavily timbered regions may cost as high as $40.00 per mile. HIGH TYPE ROAD INVESTIGATIONS IN WELL- SETTLED DISTRICTS The improvement generally consists of betterments to an existing road the location of which is fixed by existing rights-of-way. The choice of which road to improve is made by local boards or the State Highway Commissioner so that when the problem reaches the field engineer his work is confined to a definite engineering report on a definite road. The field work and report deal with the following main features. 1. Probable Traffic. — This forms the basis of decision as to general type (rigid or flexible) and the width of pavement (single or double track). 2. Local Materials, — This forms the basis for decision as to the most economical type of pavement of the general class required. 3. Cost Estimate. — This forms the basis of appropriations for survey, design, and construction and indicates the mileage that can be completed with the funds at hand. 266 FIELD METHODS 267 Field Work. — In any district the volume of traffic is entirely a matter of judgment. A traffic census can be taken but is of little value as the improvement of a road changes the amount and class of travel. The most reliable basis for decision is a study of the map of the locality and inquires of local residents to determine the probable routes of travel for farm traffic to markets or shipping points, for long distance truck traffic, and the location of summer re- sorts in relation to the improvement, etc. These considerations applied in a comparative way to previously built roads of different types serving districts of practically the same general character form the only reasonable basis for the selection of general type and width. See Chapter VI for traffic classification and the principles of general selection of type. See sample preliminary report page 274 for an example of this part of the work. See page 329 for traffic notes. Local Materials (Field Work). — The investigation for local material is very important. Careless work in this particular results in specifying impracticable or needlessly expensive sources of supply for materials and often in the selection of an unreasonable type of construction. A careless estimate of the quantity of avail- able local material also causes trouble during construction by a shortage in supply. It is important not only to determine the amount of local material but also its character as for example a local gravel may be suitable for a first-class bottom for macadam construction but not suitable for a concrete pavement, or it may be suitable for a concrete paving base but not for a concrete road taking the traffic directly. A local hard sandstone may be suitable when bound with bitumen and would not act well if waterbound with its own screenings, etc. The necessary properties of stones, gravels, sands, etc., are given in the Chapter on Materials, and in Specifications. Any preliminary report should cover the sources of supply and approx. cost at pit or switch of the following materials : t -Gravels. — Suitable for. Stone, Slag, Etc. — Suitable for Bottom courses. Top courses. Structural concrete. First-class concrete pavement. Concrete paving base. Sub-base filler. Sub-base. Bottom course. Waterbound macadam top. Bituminous macadam pave- ment. First-class concrete pave- ment. Concrete paving base. Structural concrete. 268 PRELIMINARY INVESTIGATIONS Sand. — Suitable for. Miscellaneous. Bottom course filler. Cushion sand. Structural concrete sand. First-class concrete paving sand. Fine and coarse sand for sheet asphalt. Bitumens. Tars. Paving brick. Stone block. Asphalt block. Wood block. Stone or brick cubes. Location and quality. A convenient method of recording the location of materials is as follows : Water Supply. Static Es+. /. Oeo.Barber /OOOcu.ycfs. Fence Bouiaers 20%6ranite ifo%SandsTorie /oxLimesfone 30% son rock SO'A of the Granite must he Blasfea or 4fcaff9i W 2. Patrick Donlin ZSOO cu.ycfs- same €fs apcye 3. MikeO'Donnell 500 cu VCfs / ya Lar^e Qramte Bould erd 7S% must 'be Blasted ^, Old Limestone Quarry 20^face Samples fakerj'^ looks ^ood for Top Stone Pig. 59. Unloading Points for Freight. — Provided U. S. geological maps are obtainable, the position of sidings may be marked on the sheets. The notes for each siding show its car capacity; whether or not an elevator plant can be erected, and if hand unloading is necessary whether teams can approach from one side or two. They should also show any coal trestle that can be utilized in un- SAMPLING MATERIALS 269 loading and the location and probable cost of any new sidings that will materially reduce the length of the haul. Canal or river unloading points are shown in the same manner. Sand, Gravel and Filler Material. — The position of sand and gravel pits and filler material are noted with their cost at the pit; if no local material is available the cost, f.o.b. at the nearest siding is given. Samples are taken and tests made. Stone Supply. — Provided imported stone is to be used the work is simplified to determining the rate, f.o.b. to the various sidings for the product of the nearest commercial stone-crushing plant that produces a proper grade of stone. In case local stone is available the location of the quarries or outcrops is shown; the amount of stripping, if any, and the cost of quarry rights. If the estimate will depend upon rock owned by a single person an option is obtained to prevent an exorbitant raise in price. In case of field or fence stone a careful estimate is made of the number of yards of boulder stone available, the owners' names, what they will charge for it, the position of the fences or piles relative to the road, or side roads, and if the fences are not abutting on a road or lane the length of haul through fields to the nearest road or lane. As fences are usually a mixture of different kinds of rock, the engineer estimates the percentage of granite, limestone, sandstone, etc., and the percentage that will have to be blasted or sledged in order to be crushed by an ordinary portable crusher. The amount of field stone required per cubic yard of macadam is given in estimates, page 593. If there is a large excess of stone a careful estimate need not be made, only enough data being collected to determine the probable position of the crusher set-ups and the average haul to each set-up. If a sufficient supply is doubtful a close estimate is made as outlined above, and options obtained from the various owners. Samples of the different rocks are tested (see "Materials"). Simple field tests can be made but if the department has a testing laboratory it is better to take samples and have a careful test made and recorded. As these tests are made the location of the sample and result of the tests are recorded on a large map of the district which in the course of a few years shows at a glance the different sources of supply of acceptable materials for the entire county or State and saves future duplication of work for reconstruction, maintenance and adjacent improvements. The method of sampling and the amounts of material required for a good test are quoted below from the New York State Instruc- tions for Sampling Materials, SAMPLING Samples of material will be taken by a duly authorized employee of the Department, in its place of occurrence or manufacture or delivery by carrier. These samples must be taken from different parts of the lot of material to be tested, so as to be fairly representative, and must be unmixed with foreign substances and placed in clean and safe receptacles; and they must conform in all respects to the requirements given under the special 270 PRELIMINARY INVESTIGATIONS headings. They must be carefully and securely packed, enclosing notifica- tion slip properly protected from wear and injury, and sent by express " collect " to the " Bureau of Tests, State Highway Commission, Albany, N. Y.'! a postal card notice being mailed at the same time. Envelopes, scoops, cans, thermometers, etc., for use in taking the samples, may be had from the Bureau of Finance and Audit at Albany. In the case of materials sampled at place of manufacture, check samples may be required; these are to be taken and treated the same as ordinary samples, except that the packages must be marked "Check Samples," and the use of the material needed not be prohibited pending the results of the check tests. Sand and Gravel. — The character of the supply, whether from stream bed, bank, crusher bins, etc., is to be stated; also the use for which it is intended, whether for concrete foundations or other structures, binder for waterbound macadam, filler or wearing carpet or blotter for bituminous macadam, or for aggregate in waterbound or bituminous macadam, etc. Material which will all pass through a H in. screen will be considered sand. Each sample of sand or screenings shall be H cu. ft. in volume; of gravel iH cu. ft. A small sample shall be taken from each test sample sent, and be kept on the contract as a measure of the quality of material. Each sample is to be shipped in a tight box or in a clean, closely woven bag from which there will be no leakage; the usual identification slip is to be enclosed. ^ In numbering samples, sand and gravel are to be treated as one material, not as two. Notification of acceptance or rejection may be expected to arrive at the Division office twenty days after the submission of the samples and data, providing the need of a retest does not cause delay. Cement. — One sample is to be taken from at least every ten barrels or every forty bags, care being taken to properly distribute the sampling over the lot. Each sample shall be not less than 27 cu. in. in volume or enough to fill a 3 in. cube. Whenever possible, samples should be forwarded in envelopes furnished by the Commission for that purpose, the envelopes being filled to the Une marked thereon. The individual samples are not to be numbered, but each group or lot of these samples representing a single boat load or car load is to be given a lot number, and these lot numbers are to run consecutively. Not more than one boat load or car load is to be reoresented by one lot number. Receipt of notification of acceptance or rejection of cement sampled at destination may be expected to arrive at the Division Engineer's office twelve days after the submission of the samples and data. ^ If cement is held for twenty-eight day tests the Division Engineer will be notified accordingly. Concrete. — The concrete on each highway must be sampled for testing, the samples being taken at rand om from the batches used and being molded at the place and time of mixing. The work need not be delayed pending the results of the tests. Each sample shall be a pair of cubes measuring 6 in. on the edge or of cylinders 8 in. in diameter and 16 in. long; the sample is to be made in such manner as to fairly represent the concrete going into the structure. ^ At least one sample is to be taken, and as many more as seem to be required by changes in the character of any ingredient or by any other consideration. In concrete pavement work (whether foundation or top course) one pair of cubes or cylinders should be sent for every 500 cubic yards. Not less than two pairs are to be sent, however small the pavement. The sample must remain in the mold two days, then be buried in clean sand to age under the same conditions as the material in the structure. On the twenty-first day the samples shall be taken out and shipped. Each sample is to have its number painted on each piece, and is to be shipped in a box, properly protected from breakage and surface chipping, accompanied by the usual included identification slip and the postal notifi- cation. ^ Especially must the class of concrete, the purpose for which it is used (kind of structure and portion), and the date and time of day when sample was mixed, be stated. Bituminous Material. — When material is shipped in barrels one sample is to be taken for every twenty or twenty-five barrels, the sampling being properly distributed over the lot. When material is shipped in tank cars one sample is to be taken from SAMPLING MATERIALS 271 every 2000 or 2500 gallons, the samples being taken from equally dis- tributed levels in the car. When mineral bitumen is shipped in loose bulk, one sample is to be taken for every five or six tons, the samples being taken from different levels and different vocations in the lot and never from the surface of the material. Each sample shall be not less than 14 cu. in. in volume, which volume is slightly less than one-half pine or about the size of a one pound paint can. It should be remembered that the bituminous material will flow at summer temperature or thereabouts, and consequently great care should be used in sealing cans and doing up packages. Whenever possible, samples should be forwarded in the cans furnished by the Commission for the purpose. The individual samples are not to be numbered, but each group or lot representing a single boat load or car load is to be given a lot numlDer, and these lot numbers are to run consecutively; not more than one boat load or car load of material is to be represented by one lot number. In order to check the weighing and marking of bituminous material shipped in barrels, one unopened barrel out of every car load of approxi- mately 65 barrels, or a proportionate number of barrels for each boat load, is to be selected at random and weighed. The gross weight found, and the gross weight marked on the barrel, are to be entered on the Monthly Bitu- minous Material Reports or the information rnay be recorded elsewhere and submitted to the Bureau of Tests. Any noticeable difference between the gallonage marked on a barrel and the gallonage found therein, must be reported to the Headquarters office at Albany.^ The unit of measure for bituminous material is the gallon measured at the temperature of 6o°P. If the volume of material is measured when hot, allowance should be made for expansion according to the following table, which will apply approximately to all of the different classes of bitu- minous material at present used oil the State highways: Increase in volume of various classes of bituminous material when heated from 6o°F. To 400°F. is approximately 12 per cent. To 350°F. is approximately 10 per cent. To 300°F. is approximately 8 per cent. To 250°F. is approximately 6 per cent. To 200°F. is approximately 4 per cent. To I50°F. is approximately 2 per cent. Stone. — Rotten or partially disintegrated stone, or weathered specimens from the surface of a quarry or ledge, are not to be submitted. Samples ot quarry or ledge stone must be representative of the sound, fresh, interior stone of the ledge or quarry. Such samples may be secured either by blasting or by breaking up with the sledge. If all material is of the same variety, texture, etc., one sample will suffice. If, however, there are different varieties, separate samples are to be taken of each and report made as to the extent, giving details as to location and position for use. All field stone, whether in walls, piles, or scattered over the ground, which might be used, must be examined and a representative sample taken. When two or more varieties of great difference in quality or texture are observed to exist, separate samples are to be taken of each, and report made as to the percentage of each kind, the amount of small stone which might run through the crusher without action, and the percentage of disintegrated or badly weathered rock present. In taking samples from the output of crushers, fifteen pounds of crushed material not smaller than i}4 in. in size shall be taken, and also one piece at least 3 X 4 X S in. shall be procured from the source of supply. Each sample shall weigh not less than twenty-five pounds nor more than thirty-five pounds. If the entire sample submitted is a single piece of stone, it should be remembered that a piece about the size of a man's head will weigh twenty-five or thirty pounds. While not less than twenty-five pounds are absolutely necessary in each sample, care should be taken to see that the samples do not weigh over thirty-five pounds. One piece of each sample shall be at least 3X4X5 inches. Each sample is to be given a number running consecutively in each Division. This number must contain both the Division number and the sample number; thus, sample No. 42 from Division No. i would be rnarked "1-42." Paint or Higgins drawing ink may be used to mark directly on the sample, or a label or tag may be securely fastened thereto. 272 PRELIMINARY INVESTIGATIONS Samples maj'- be shipped in boxes, burlap, grain bags, cement bags, etc. It is preferred that stone be shipped in a strong bag or in a double bag which may be formed by placing one bag inside of another. If shipping in a single ''>ag which the sample only partially fills, the bag should be securely tied just above the sample and the remaining unfilled part of the bag folded back so as to completely envelop the stone and the portion of bag contain- ing it; this folded back part should then be securely tied on the other side of the sample; this makes a tying of the bag on two sides of the stone, and permits two thicknesses of the bag to completely surround the stone, and if securely tied is as satisfactory as a double bag. Receipt of notification of acceptance or rejection of stone may be expected to arrive at the Division Engineer's office twelve days after the submission of the samples and data, provided acceptance or rejection is not deferred awaiting a retest. The location of source of supply is to be expressed by an index number according to the system used in the Government Office at Washington, which is, that each quadrangle of the U. S. Geological Survey Sheet is divided into nine sections numbered from i to 9 inclusive, as shown in the following plan: 1 2 3 4 5 6 T 8 9 The north and south sides of each section are then divided into 22 spaces designated from A to V and the east and west sides into 32 spaces designated I to 32, so that the location of the stone may then be closely defined, as for example, Quadrangle Albany, Section 7, Letter J, Number 13, which when abbreviated would read " Albany-7-J-i3." Paving Brick. — A sufficient number of samples in every case is to be taken to insure the use of brick of proper quality, but it should also be borne in mind that the charges for transportation and testing of brick are high, and only the smallest number of samples necessary for this purpose should be submitted. At least one sample is to be taken from every 200,000 brick or less. Each sample shall consist of 30 bricks. If in a shipment or several shipments of the same make and kind of brick there appear to be different classes of brick — such as brick of different de- grees of burning, for example — a full sample of each class is to be taken. Each brick selected for the sample is to be free from cracks or other defects which would prevent its passing inspection at the road, for the sample must represent bricks which will not be culled out. Especially is it for- bidden that any person financially interested in the manufacture or use of brick be present when samples are taken. Each sample (consisting of 30 bricks) shall receive a number, the numbers to run consecutively for each road. The sample shall be shipped in wooden boxes, not more than 10 or 12 bricks being put in one box on account of weight and strength of package. Notification of acceptance or rejection of brick sampled at destination may be expected to arrive at the Division Engineer's office nine days after submission of samples and data, providing the need of a retest does not cause delay. Asphalt Block. — A sufficient number of samples in every case is to be taken to insure the use of block of proper quality, but it should also be borne in mind that transportation and testing costs are high, and only the smallest COST ESTIMATES 273 number of samples necessary should be submitted. At kast one sample is to be taken from every 100,000 blocks or less. Each sample shall consist of 2 blocks. If in a shipment or several shipments of the same make and kind of block there appear to be different classes of block, a full sample of each class is to be taken. Each block selected for the sample is to be free from every defect that would prevent its passing inspection at the road, for the sample must represent blocks which will not be culled out. Each sample (consisting of 2 blocks) shall receive a number, the numbers to run consecutively for each road. The sample shall be shipped in a wooden box, with usual identification card and postal notice. Notification of acceptance or rejection of block sampled at destination may be expected to reach the Division Engineer's office fourteen days after submission of samples and data, providing the need of a retest does not cause delay. Acceptance Upon completion of the testing of any set of samples the Division Engi- neer is notified of the acceptance or rejection of the material, and transmits the statement to the engineer in charge of the contract. Estimates of Cost. — The length of the road can be obtained from maps (U. S. G. S. are convenient) or by autometer distances or pacing. Maps are generally available and serve as a convenient basis for notations. A field inspection by one man preferably on foot furnishes the necessary data on required drainage, founda- tion soils, approximate amount of excavation, condition of existing bridges and all special features. Minor drainage features can generally be lumped and assumed to run about $700 per mile. (For more detailed cost, estimate each culvert separately. See chapter on ''Drainage.") Special bridges must be figured in detail. (See chapter on " Drainage for 'Standard Design," etc.) The amount of excavation per mile for ordinary rolling topog- raphy is entirely a matter of judgment which can only |be developed by personal experience in similar work. For special long hills requiring a cut and fill reduction a rough profile can be run with an Abney level. However the item of excavation on macadam roads rarely exceeds 20% of total cost and considerable error in estimating the yardage will not greatly effect the value of the estimate. The character of the natural road soil has an important bearing on the depths of macadam and must be carefully recorded. This can best be done by giving the character of the soil; noting whether the improved road will probably be in cut or fill at the points recorded and specifying the recommended depths of macadam. The depths of macadam for different classes and traffic and dif- ferent soils were indicated in Chapter V, page 152. Sample notes on foundation soils are shown on page 330. Methods of computing pavement costs are given in Chapter XIV. The sample preliminary report following illustrates the method to be followed for high type roads. A report of this character will rarely differ from the final cost of construction by more than 15%. While photographs increase the value of these reports 274 PRELIMINARY INVESTIGATIONS they are not as essential as for new locations. Notes on photography are given in Chapter XII. PRELIMINARY DESIGN REPORT, NEW CONSTRUCTION December lo, 1914. Division Engineer Dept. of Highways, Dear Sir: In accordance with your request on Nov. 25th, find enclosed report on a reasonable cost for the Town Line-Manitou State-County Highway. General Report and Estimate, Town Line-Manitou State -County Highway With a proper use of local materials a satisfactory road can be built at a cost of $94,000 or approx. $11,000 per mile including Engineering and Contingencies. An expenditure of $1 2,000 per mile would not however be excessive. • The Braddocks Bay crossing is the expensive feature of this road; it raises the cost of the entire road about $1000 per mile. Design No. i is recommended (see page 280). A detail report follows. Signed, Designing Engineer. DETAIL REPORT AND ESTIMATE, TOWN LINE-MANITOU STATE- COUNTY HIGHWAY Length. — Eight and fifty-one hundredths miles from the Ridge Road to Manitou Beach. Foundation SoiL— ;-Heavy soil, not particularly good foundation Sta. o to 133; sandy soil balance of distance except across Braddocks Bay, A 9 in. thickness of some form of macadam is advisable Sta. o to 133; 7 in. or 8 in. the balance of the distance should be satisfactory except across Braddocks Bay where it is safe to figure on 12 in. to 15 in. of stone. Grade. — The present surface can be followed closely. The excavation should not exceed 2800 cu. yd. per mile except across Braddocks Bay; a rough estimate of borrow excavation for this fill is 15,000 cubic yards. Alignment. — Good; no right-of-way required except possible at Sta. 350 near the schoolhouse at the turn to Manitou. Traffic and_ Section. — There is a heavy volume of automobile pleasure traffic and a light volume of heavy hauling traffic on this road. The large amount of pleasure travel requires from 16 ft. to 18 ft. of stone surface; the heavy hauling does not require over 12 ft. to 14 ft. full depth rnetaling. We recommend a graded section 26 ft. to 28 ft. wide between ditches in cut with a 12 ft. width of full depth metal with 6 ft. of extra width of local crusher run on the shoulders Sta. o to 133; a 14 ft. width with 4 ft. of stone on shoulders 5ta. 133 to 260; a width of 12 ft. of full depth metal with 6 ft. of stone on shoulders the balance of the distance except across Braddocks Bay where the entire width of metaling 16 ft. should have the full depth. This road carries so much high speed traffic that it requires some form of bituminous macadam or if Waterbound is selected, it should be treated with calcium chloride immediately and have a surface coat of bitumen applied early in the next year. SAMPLE REPORT 275 Railroad Crossings. — Sta. 223 R. W. & O. Ry. crossing; no gates or flag- man. In the summer time the crossing should have a flagman as the orchards cut off the view. The crossing is not particularly dangerous, but during the season of the year the traffic on this road is entitled to better protection at this point. The approach grade from the south should be made easier. Drainage. — No special features; approximate cost $3500 exclusive of bridges above 5 ft. span to be built by the towns. Dangerous Places. — The Braddocks Bay crossing is a dangerous one as the fill is high and the swamp is full of semi-fluid muck from 6 ft. to 12 ft. deep; a first-class concrete guard rail protection should be provided. Materials Filler Sand. — In abundance along road and from roadbed excavation. Gravel. — The only good gravel is lake gravel; this can be obtained up to approximately 6000 cu. yd. i3^ miles north of Sta. 350 and 3000 cu. yd. 3^^ mile west of Sta. 450. Probably this can be used to advantage (screened or selected beach run) as bottom course Sta. 350 to 450 or as filler for sub- base bottom and on the shoulders. Stone. — Fifteen thousand cubic yards of fence stone are available within a mile and a half of the road Sta. o to 133. There is practically no local stone Sta. 133 to 350. Four thousand cubic yards of fence stone are available within i3^ miles of Sta. 350. This material runs about 20 % granite fit for top and the balance soft sandstone fit for bottom either as a sub-base bottom or crushed stone bottom. There is sufficient stone at the south end of the road to build a sub-base bottom with crushed stone filler; a local granite top with crushed stone on the shoulders from Sta. o to 133 and a local crushed stone bottom 5 in. thick Sta. 133 to about Sta. 200. There is sufficient stone at the north end to build about 1% miles of crushed stone bottom with stone on shoulders or ij^i miles of sub-base bottorn with crushed stone filler and crushed stone on shoulders. I do not think there is enough granite to make it worth while to try and use a local top on any part of the north end. It is probably better to use an imported top from Sta. 133 to 450 and imported bottom Sta. 200 to 280. (See detail Stone Statement and Com- putations following.) Crusher Set up at Sta. 100. — Fifteen thousand cubic yards field stone available within 3 miles maximum haul. Average haul 1}^ miles. Assume for safety that only 11,000 cu. yd. are available with an average haul to crusher of i mile. Of this 11,000 cu. yd. field stone. 3000 cu. yd. used for sub-base bottom average haul 3^^ mile. xooo cu. yd. used for crushed stone filler { l^, f^^^^ctle^ « mile. ,00 cu. yd. used for crushed stone shoulders { h^i ^^.^crushe^^ H^e. .500 cu. yd. used for top course { ^-1 t^^-^tYh^ri' mile. 7200 CU. yd. field stone used for local macadam, from Sta. o-to 133, leaving 3800 cu. yd. available for crushed bottom and shoulder stone for road north of Sta. 133. Three thousand eight hundred cubic yards will produce approximately 3000 cu. yd. of crushed bottom loose measure or about 2300 cu. yd. of rolled measure. This will build 10,600 lin. ft. of 5 in. bottom 14 ft. wide. We can therefore safely specify local bottom to Sta. 200 which will leave enough shoulder stone to use as far north as Sta. 300 if necessary. Crusher Set up at Sta. 350. — Four thousand cubic yards available within 1 3'^ miles say average haul i mile. Assumefor safety that 3000 cu. yd. only are available, average haul i mile. This will produce about 2400 cu. yd. crushed bottom stone loose measure or approximately 1800 cu. yd. rolled measure. One thousand eight hundred cubic yards will build approximately 90 Sta. of 12 ft. bottom 5 in. deep which makes it safe to specify a local bottom using crushed stone and lake gravel as far south as Sta. 280 with either gravel or crusher run the entire length of road on the shoulders. Imported bottom should be used Sta. 200 to 280. 276 PRELIMINARY INVESTIGATIONS Imported Stone. — One dollar and twenty-five cents per ton f.o.b. switch. Switch can be built at Sta. 233 for I300 to $400. Water. — Can be obtained at all seasons at intervals from i mile to 11^2 miles all along the road. Cost of Different Types Grubbing and clearing $ 300 . 00 23,000 cu. yd. roadbed excavation @ $0.50 11,500.00 15,000 cu. yd. brow exc. across Braddocks Bay @, $0.45 6,750.00 800 cu. yd. sub-base @ $1 .25 1,000.00 4,000 lin. ft. concrete G. R. across Braddocks Bay @ $1 .00.. . . 4,000.00 Drainage of system 3,500 . 00 Minor points @ 400 per mile 3,400 . 00 Engineering and contingencies ^ 8,000 .00 Total cost of items other than metaling $38,450 .00 Schedule of Unit Prices Imported waterbound top Sta. 133 to 450 $5 .00 per cu. yd. rolled Imported bit. mac. top Sta. 133 to 450 7.30 per cu. yd. rolled iLocal granite bit. mac. top Sta. o to 133 6.00 per cu. yd. rolled ^Imported limestone water mac. Sta. o to 133 5- SO per cu. yd. rolled Sub-base bottom crushed stone filler o to 133 i .50 per cu. yd. rolled Local crushed bottom Sta. 133 to 200 2 ,50 per cu. yd. rolled Imported mac. bottom Sta. 200 to 280 3 .20 per cu. yd. rolled Local crushed bottom Sta. 280 to 350 2 .30 per cu. yd. rolled Lake gravel bottom Sta. 350 to 450 i .90 per cu. yd. rolled Crushed stone or gravel on shotilders i . 50 per cu. yd. loose Tarvia B 0.08 per gal. in place Table of Comparative Cost 1 Type Approx. Cost Including Eng. and Contingencies Cost per Mile Total Cost Design No. i (for details see Cost Estimate Sheet) $11,000 11,300 12,000 12,500 ■■$ 93,500 96,200 102,200 106,000 Design No. 2 (for details see Cost Estimate Sheet) Design No. 3 (for details see Cost Estimate Sheet) Design No. 4 (for details see Cost Estimate Sheet) Computation of Unit Prices Overhead approximately 30c. per cubic yard of bottom and top stone* No overhead estimated on other items. Sub-base Bottom Course Crushed Stone Filler Sta. to 133 Cost of stone in fences $0.10 Loading 0.15 Hauling 3^^ mile 0.12 Placing and sledging o . 20 Rolling 0.05 Crushed stone filler. (See Filler) 0.35 cu. yd. . : o .40 $1.02 20 % profit O . 20 Overhead . 30 Estimate ' $1 .52 Say $1.50 1 There is no difference in cost Sta. o to 133 between a local granite bit. mac. top and an imported limestone waterbound top when treated with Tarvia B, SAMPLE REPORT 277 Crushed Stone Filler (Crusher Run) Per Cu. Yd. Cost of stone in fences $0.10 Loading 0.15 Haul to crusher i mile 0.35 Crushing o.io Cost in bins $0 . 70 Loading to wagons o. 01 Haul to road f^ mile 0.22 Spreading and brooming o. 20 I1.13 0.35 cu. yd. per yard of sub-base = $0.40 Local Crushed Stone Bottom Sta. 133 to 200 Cost in bins $0.70 Loading to wagons o.oi Hauling to road i^^i miles o .40 Spreading o. 06 Rolling 0.05 $1 .22 Consolidation 0.3 o .37 Si. 59 Filler 0.20 $1.79 20 % profit o. 36 Overhead 0.30 Say I2.50 I2.45 Stone on shoulders %i .50 per cu. yd. loose. Local Granite Bit. Mac. Top Sta. to 133 Stone in fences So . i o Loading 0.15 Blasting and sledging 0.15 Hauling to crusher ^ 0.35 Crushing 0.15 $0 . 90 in bins Loading to wagons o.oi Hauling to road ^^ mile . . 0.22 Spreading o . 06 Rolling 0.08 Si. 27 Consolidation 0.38 Si. 65 Screenings No. 2 and Bit 3 . 10 Profit o. 90 Overhead 0.30 Estimate Ss • 95 Say S6.00 ^ No. 2 Screenings and Bitumen. Note: There should be enough local screenings for about ^^3 of the top course. Use imported for the balance. Cost o .45 cu. yd. screenings and No. 2 at bin $0.40 Hauling ^^ mile o . 10 Spreading 0.12 Manipulation 21 gal. bitumen @, i^^c 0.32 Cost 21 gal. bitumen on road @ 8>^c i . 82 $2 . 74 278 PRELIMINARY INVESTIGATIONS Imported Screenings and No. 2 Cost o . 45 cu. yd. f.o.b. switch @ $1.25 per ton $0 . 70 Unloading o . 05 Hauling 3 miles . 90 Spreading 0.12 Manipulation 21 gal. bitumen @ ij'^c o .32 Cost 21 gal. bitumen on road @ Sj'^c i . 80 13-89 Average price $3 ■ 10 Imported Limestone Waterbound Mac. Sta. o to 133 Materials: 4400 lb. of stone @ $1 . 25 per ton I2 . 75 6 % profit . 0.15 I2.90 Labor: Unloading |o . 10 Hauling 3 miles @ |o . 25 o . 75 Spreading 0.08 Rolling and puddling o . 10 $1 .03 Consolidation 0.3 0.31 $1.34 Screenings 0.55 20 % profit 0.38 Overhead o . 30 Materials 2 . 90 Estimate $5-47 Screenings: Unloading |o . 05 Hauling 3 miles o . 40 Spreading and brooming o . 10 I0.55 Imported Limestone Waterbound Mac. Sta. 133 to 450 Materials S2 . 90 Labor: Unloading o.io Hauling 90 sta. iH miles 9.55 Spreading 0.08 Rolling and puddling o.io I0.83 Consolidation o . 25 $1.08 Screenings 0.45 20 % profit o . 30 Overhead 0.30 Materials 2 . 90 Estimate $5 . 03 Say S5.00 Screenings: Unloading $0.05 Hauling i^i miles. 0.30 Spreading and brooming o.io $0.45 SAMPLE REPORT 279 Imported Limestone Bituminous Macadam Sta. 133 to 450 Materials: 4200 lb. @, $1.25 f.o.b. per ton $2 .62 6 % profit 0.15 $2.77 Labor: Unloading $0.10 Hauling 0.55 , Spreading 0.08 Rolling 0.08 $0.81 Consolidation 0.3 . 24 $1.05 Screenings and bitumen $2 . 52 20 % profit o . 70 Overhead 0.30 Materials 2.77 Estimate I7 • 34 Screenings No. 2 and Bitumen Unloading $0 . 05 Hauling * 0.25 Spreading and brooming 0.12 21 gal. bitumen A. @ S}r^c i . 78 Manipulation of bitumen 0.32 $2.52 Imported Limestone Bottom Sta. 200 to 280 Materials: 3200 lb. stone @ I1.25 per ton $2 .00 profit o . 10 Total materials $2.10 Labor: Unloading $0.10 Hauling average distance, 20 sta 0.15 Spreading o . 06 Rolling o . OS $0.36 Consolidation 0.3 o . 1 1 $0.47 Filler o . 20 $0.67 20% profit . 0.13 Overhead o . 30 Materials 2.10 $3 . 20 28o PRELIMINARY INVESTIGATIONS Local Stone Mac. Bottom Sta. 280 to 350 Stone in fences $0.10 Sledging o . 05 Loading 0.15 Hauling to crusher i mile o .35 Crushing 0,12 Cost in bins $0.77 Loading to wagons o . 01 Haul to road o . 7 mile 0.22 Spreading o. 06 Rolling 0.05 $1.11 Consolidation 0.3 o. 33 $1.44 Filler o. 20 $1.64 20 % profit 0.33 Overhead 0.30 Say $2.30 $2.27 Lake Gravel Bottom Sta. 350 to 450 Assume j^i material from Manitou Beach. Assume % material from beach 1}^ miles north of Sta.'^^so. Selected Beach Run of Gravel Cost on beach |o . 10 Loading 0.15 Hauling average 2 miles 0. 70 Spreading 0.05 Rolling o. 04 Loam and flushing o. 05 |i .09 Consolidation 0.2 0.22 $1.31 20 % profit o. 26 Overhead 0.30 $1.87 Say $1.90 Approximate Cost Estimates Design No. i. ii2' wide 6'' sub-base 3" bit. mac, local top 6' of stone on shoulders. Treated with Tarvia B or No. 4 road oil. Sta. o to 133. 14' wide 5" local mac. bot. 3" waterbound imported lime- stone top. Treated with Tarvia B. 4' stone on shoulders. I Sta. 133 to 200. c, ^ / 14' wide 5" imported bottom; same top as from Sta. 133 to £»ec. iNO. 3 ^ 200 Sta. 200 to 260. 4' stone on shoulders, c ^ / 12' wide 5" imported bottom 3" water imported top Tarvia B. oec. iNO. 4 <, ^, q£ g^Qj^g Qj^ shoulders. Sta. 260 to 280. c: M c / 12' wide 5" local mac. bottom 3" water imported top Tarvia aec. iNO. 5 \ ^ 5/ stone on shoulders. Sta. 280 to 310. q ]ST /- f 16' wide 9" sub-base bottom 3'' water mac. top Tarvia B.- vsec. iNO. o j j^Q stone on shoulders. Sta. 310 to 335- q ATp, « / 12' wide 5" local mac. bottom 3" water mac. top Tarvia B. oec. iNO. 7 ^ j> f 12' wide s" lake gravel bottom 3" water mac. top Tarvia B. C5ec. iNO. 5 ^" bit. mac. top 23,800 .00 Increased cost Design No. 2 over No. i $ 2,700 .00 Design No. 3. 16' road entire distance local bottom Sta. o to 200 and 280 to 450 and imported bottom Sta. 200 to 280 with 3" imported water- bound macadam treated with 0.4 gal. Tarvia B. or 0.25 gal. No. 4 Road Oil. 9,200 cu. yd. local bottom 5" thick @ $2 . 25 $20,700 .00 1,970 " " imported bottom 5" thick @ $3.20 6,300.00 6,700 " " imported top 3" thick @ $5.10 34,200.00 32,000 gal. Tarvia B. @ $0.08 2,560.00 $63,760.00 Items other than metaling 38,450 .00 $102,210,00 282 PRELIMINARY INVESTIGATIONS Design No. 4. Substitute a 2J4" bit. mac. top for the 3" waterbound top of Design No. 3. This increases the cost approx. $4,000. Signed, Designing Engineer. PRELIMINARY INVESTIGATIONS FOR ROADS IN UN- SETTLED DISTRICTS Reports of this nature can not be figured as accurately as for high type roads but if carefully done should not vary over 25% from the final construction cost. The cost of preliminary investigations depends very largely on the character of the country, the methods employed, and the travel necessary to get to the work and will range from $2 to $40 per mile. A fair average cost for work similar to that done by the U. S. Office of Public Roads in the mountainous districts of the west is $5 per mile for ordinary cases and $30 per mile for a plane table sketch survey in difficult country. Ordinary Preliminary Investigations. — The improvement to be investigated generally consists of a combination of betterments of existing roads with a large percentage of relocation of the old road or the new location of a highway where no road of any kind traverses the territory. The length of these projects range from 5 miles to 150 miles. The engineer generally receives orders to report on the best general route and approximate cost of a road between definite terminals which requires more general investigation than called for in the preliminary reports on high type roads previously discussed. The field work is usually made by one or two men on foot or horseback. All possible different routes are examined. As a rule this general examination eliminates all but one or two possibilities which are examined with care; sufficient notes, photographs, etc., being taken to make a reasonably close estimate of cost. The selection of general route is based on a comparison of the following factors for the different routes. 1 . Best location for the development of the country. 2. Longest open season for use. 3. Least rise and fall. 4. Feasible ruling grades. 5. Length and cost. The following engineering equipment will cover all requirements for obtaining the general data and the detailed information required for a reasonably close cost estimate. 2 Aneroid barometers 2j^"or3''' dial in leather carrying cases. Tested for range of altitude needed. I Abney level reading to degrees and per cent. I Pocket compass 2" floating card dial or, if desired, I Prismatic compass (card dial preferred). I 4 A Kodak with folding tripod. Note books, existing maps, etc. In rolling topography it makes no difference in which direction the line is traced but where elevation is developed on a ruling grade the work should be done from the highest point down hill. FIELD METHODS 283 Where aneroid elevations must be depended on considerable care must be exercised. If one aneroid can be left at a stationary point and its fluctuations read at intervals during the day very accurate results can be obtained when the field aneroid is corrected for the fluctuations but this is not feasible for work of this kind as a rule and aneroid elevations are to say the least uncertain. Where used two instruments should be carried; when reading they should be held horizontal and the crystal rapped sharply with the finger nail to free the needle if caught which often happens. Any important elevations should be determined at least twice and a return trip made to the original datum point to check the instrument. The general rise and fall can be determined by the aneroids. The approximate location of the road for different ruling grades can be traced with the Abney level. A rough traverse can be run with the pocket compass or pris- matic compass. Distances can be obtained by pacing (pedometer or hand counter) by timing if on horseback; by scaling from reliable maps or by auto- meter if on an existing road. Cross-sections are determined by the Abney level and are taken and recording at sufficient intervals to show the general slope of the sidehill. Classification of excavation and the cut slopes at which excava- tion will stand depends on the judgment of the engineer but must be systematically recorded. Drainage should be carefully estimated particularly the larger structures as this item forms a large percentage of the cost of low type roads. Clearing and grubbing is recorded by section. Each engineer has his own ideas about notes and it makes little difference how the data is recorded so long as it is clearly and definitely set down in such a way that anyone can retrace the route and reestimate the cost without additional field work. The main faults of reports and notes are that they are not suffi- ciently clear on facts; they generally run strong on generalities and judgment and are not worth the paper they are written on if the author is not available to explain in detail. A well arranged report should either summarize the conclusions at the beginning and explain in detail later or be indexed so that the conclusions can be readily located. A preliminary estimate should be rounded out to even figures as amounts figured to single yards or costs figured to odd figures of less amount than 10% of the total cost are merely ridiculous and show that the estimator has lost track of the relative accuracy of his work. The following form of notes serve in a satisfactory way when supplemented by photographs, sketches and text descriptions. Detail suggestions on photography are given in Chapter XII. Table 25 and 26, pages 286 and 296, serve to give a rough ap- proximation of the amount of excavation required. Drainage costs can be estimated on the standard structures required by the State or Government for whom the work is being 284 PRELIMINARY INVESTIGATIONS r rs ■Mis 00 a: 1 >< CD i - - Is y i 111 -^ 8 1 III iis 1 5 1 1 i <51 10 oc COV 5>c 9 5 _ _ _ - _ — — — ~: 5 > its J 1 7 _ :S|3> h h hi ■> 2 ^-§o^^ 0^ "^H. b •;::»- 5 ^^^'S # o 2° W 0) •+J o W O d .-* ^ «-i 6^ ^ CJ a 6 TJ Ci (N >> LO d :3 00 w M M rovO .2 *b ^ ^ H '^':: :: CO 0) >% H ft 3':: :: fi "^ CJ >. to 0^ 10 d CO to M H ^ [z< 1 -d^ ^ U >,- - 1 6z z Pfi ^ 000 w >» to to Pk ;3 ,- - C4 ft 3:: :: W Oh '^ CJ 2: >. Th M ;3 > to lo 1 H d !>• »0 H H CO — ^^ • Cii Oh Oh T^^ ^ < CO u 0) ft >r ^ 6z z ^ CJ >. <^'0 vi M rovO W U oi C OC50 c/} w u H Qo Ph ;z; J ;dc/2 S ^ oS 1 0^ w ^0 I 'oj g ^ > lo '-' 5 Q a ^ EXCAVATION AMOUNTS 287 •iy > u a 10 a a 0; 8 ^ 4-> 0^ Tl CO (U W) 6 (1) ^ Fi j-J %^ C3 -M > (!) CJ < 1 II 1) C« ^ I. ■♦J >. >. (4 -=3tJ ^ (1) a ^^ ^ r" i!i n ^ C 13 C oca .2 61 PK TWi "1 14 f^'^ 9^IUI J9(i 'ipA 'UQ ^001 jad *piC -xiQ 9s ^^O 9^iin J9d 'pA -riQ ^001 J9d -pA -riQ sdois nid: 9dOIS ^HQ 9;nn J9d -pX -nQ ^001 J9d '-pA TIQ ^^oiS m^i 9dOXS ^HQ 9^TIU J9d 'pX 'UQ ^001 J9d 'p^C 'UQ 9dois m^!^ 9do^S ^^O §2 Geo 'O 000 00 10 10 to 00 (N M N ro (N 000 000 O Omo 10 10 O O O sO *-• CO 10 t^ iLO c^ H M w ro ^ 00 N^N^^ ^N^:^ :^ 000 000 ^o o 000 M cs re 1000 r-KH\i-K l-r\F^r4 10 o o 000 00 O -^ l> M 00 M (N fOvO O \0 OvO O vr O \i-Ki-K i-Kr-Ni-K 000 00 O 10 o 00 \(N\(N\IN \IN\,-*^ ?s|| o o ^ ^ ^ "^ o >> O -u O M- "^ 3 ^:4 s ^s » M adoiS ^^0 ::i^:i:f:it ^:^:^ ::i^ 9im -is^i -pA '^0 ,001 J9d 'pj^ -UQ 3^oiS IIM 9(Jo|s :^nQ 9im -laci -pj^ -no /OOi J9d -p^ -no 3^ois m^ 3do][S ^^O 91IK -19^ -PA '^0 ooo OOO CMiT: O OOO OOO OOO ooo ooo 0^ O ro O t^ P< OOO O O 00 O O O O Ci ro lo 0\ ,001 J9d -p^ -no 3,« w rt Q> C ^^ CO (u ^^^ ^^^ ^^ W g CO '^ o ^ rt to 43 -M Onoo r- H M vO ^-00 Tt t-00 000 l/JO »o M M 000 li^ too fOTt ^^■2 Sots o Z. ^ ^ E o f'5 Q. 5P O O C 5 u^To S f^ 53 " «-4 .52^i5^coa^ C3 ^ TO -^ Q *7^ O 2 6 w w5 o ^-^^ ° S^ ° O 3 tu O O loOO OO OnvO O CO O 00 O lO M ro -^vOOO (N 00 9doiS TIM 9dots ^^O ^d^IS IIM 9doxs ;riQ 9dois TIM 9dois ^^O 9niM ^9^ 'PA '^O ,ooi J9d -p^ -riQ 3doiS Illvil 9dois ^UQ 9tTp\I J9d -p^ -TIQ ,001 J9d -p^ -UQ 3^ois m^i 9dots ^nQ 3im ^9d 'PA *T^o ,001 J9d -pji^ -UQ 9^oiS TIM 9dOtS ^HQ ; 5^ (/) u Oi ^ (/) S HgSS •saa (N i/^O l> O On wo (N lo OOO OOO ooo ooo O t^ ro O 00 M M M ro lo t^ P< OOO ooo r^ o o ooo (N ro O Ol vO lO M c^ rt C^O 0\ ^rj-ir> r^O 00 M Tj- 1^ ro O vO OOO OOO fO O O O O Q ro lO ro Onoo vO H N lO t^ CN O t-i \0 M (N rt OOO O o 00 o o o o ro t-- I^ O Tf OOO ro lO O '^OO o ^^^ ^^^ ^^ ooo OOO o o q^ O ^ '^^ EXCAVATION AMOUNTS 291 .B £.2 ^^ § O J3 tH o ij rj u rr a >. n3 T3 ^ ^ a 03 n ti Ih >^ < 1 <-M >1 ^ Xi ^ 1 M H 1 ID to to ri rt ^ (N 1 > to 3 <-• D^G OT3 -M 9IIIM -13^ 'PA *^0 ,001 jad -pj^ -UQ 9doiS IIT^ adoxs %n^ 9UN ^9^ 'PA '^O ,001 J3d •pA*"nO 3^oiS IIM adots ^HQ 31II\[ -19^ -PA '"^O ,001 jad -pj^ -TiQ »^oi3 IIM 9doxs :;n3 3UH -19^ 'PA 'f^O ^001 J9d -pA -113 9dois ni^ ado^s :^n3 ^VM -la^ 'PA '"^O ^001 J9d -pA -UQ 9doiS TIM adots :^nQ 9IIH -19(1 -pA '^0 ^001 J9d -pj^ 'UQ 3«loiS IlTd 9do^S ^^O "^ iz ^ w e^ t^ 75 S •S9a 000 000 00 0000 000 00 ro O 00 t^OO ro '^^ M M M (S -^ 000 000 O ro O O 000 O rf CI c^ CJO 00 t^ M H Ci -^ vO 0\ "^ -^ i-^ i-H O 00 10 00 (N TtOO N 00 l> M M r< 000 000 o 10 o 000 i> On O O 00 0\ M \0 "^ O cs I/: 000 000 000 000 r^ Ci Tt 00 ■^oo f< O c< 10 CN ro rOO O 00 OiO COO 00 10 o o 00 r- Tj-oo M T}- ro 'cJ-O O »o rovo t-" 1-1 O 000 10 O O M rOvO O\oo l> \0 t^oO O "^ H N ro '^10 t-00 000000 00 (U t/5 ^ o -4 4J O 'S CJ '^'^ •-1 ft to -M o tl ^ ^ ^ a y ^ d c« d 5 toJ3 )- J:^ oj o rt 0) (u "rt fe to-^^ S^ 292 PRELIMINARY INVESTIGATION S99A39Q ui spisiuH JO adois ssojq QUANTITIES 293 -Table 25. — Approximate Quantities Wall Section Minimum I Single Track Road Section W-8 r Double '' '' '' W-12 1.5 or 2.0 TYPICAL SECTIONS 30° & 35° Slopes Ditch Excavation Makes Fill Back of Wall TYPICAL SECTIONS 40 & 45 Cross Slopes Borrow Fill Required Note. — Rough rubble masonry walls ,to have outside face batter of 3" to i' and a bottom width of 3^ the height. The foundation to be carried to a firm strata. Natural Ground Cross Slope Approximate Quantities per 100' of Road for W-8 SEcnoN Wall Masonry Ditch Excavation Used in Fill Borrow Excavation for Balance ^ of Fill Wall^ Excavation Waste Total Excavation •30° 40° 45° 46cu.yd. I 55 " ** 100 *• " 135 •* " 55 cu. yd. 80 " " 30 " •• 45 •• " None None 90 cu. yd. 100 " " 15 cu. yd. 20 " " 35 " '• 45 '* " 70 cu. yd. 100 " " 155 " " 200 " " Table for Minimum Double Track Section W-12 1 Approximate Quantities per 100' Natural Ground Cross Slope Wall Masonry Ditch Excavation Used in Fill i - Borrow Excavation for Balance of Fill Wall r^ . 1 *30° 1 K 40° 45° 65 cu. yd. 90 ♦* " 180 •' " 250 " •' 1 100 cu. yd. 140 " ** 30 " " 45 " " None None 200 cu. yd. 250 " '* 15 cu. yd. 1 115 cu. yd. 20 " " 1 160 " *• 45 " " ; 275 " " 80 " " 375 *' ** Note. — Above 45° ground slope use Rock Bench Sections, except in un- usual cases. * Retaining wall section on 30° cross slope is not usually economical. 294 PRELIMINARY INVESTIGATION Table 25. — Table of Approximate Quantities Road Benched out of Rock TYPICAL BENCH SECTION Using S-8, S-io, S-12, S-14, S-16 Natural Slope of Face of Rock Ledge Cut Slope Approximate Excavation in Cu. Yd. per loo' for Different Sections *S-8 S-IO **S-I2 • S-14 S-16 50° 60° 70° 80° Vertical Half Tunnel 350 cu yd 500 cu yd 600 *• " 850 '• *• 560 " " 800 " " 460 " " 550 •' " 660 cu yd 1,200 " •* 1,050 " " -680 " " 870 cu yd 1,550 " " 1,400 *' " 1,100 cu yd 2,000 ** •* 1,800 " " * Minimum width single track in rock. ** Minimum width double track in rock. Table 26. — Approximate Amounts of Embankment and Ex- cavation for Different Center Line Cuts and Fills Ground Surface Assumed Level (See page 295.) Ground Surface Level \^-W= 12 to 22— >j \<—W^ 14 to 24^' ' f H I Ground Surface Level EXCAVATION' 295 CI c* B NiOMOOO OOMIONO CiMoorO'^ (MooroOM rtoo PO t^ 00 rooo mvOioOm MMN csroro-^io O t^oo O •-• »ooo M O m M M M M CS (N fO '^OO fOOO fO OMOMt^Tt oO'^OoOt^ t^P0C<«\OiO M M Cil^«0O MMM MC<(NrOf*5 +> n, M 4^ oooOOrOoO OioOoOro CO 0\ OsvO O pO -^ "^ fO <^ oOt~-WOO vo O lO O O t^ 0\ O vjoooOO O>t-t^r0P0 rooo o MMCs 0 m oj « loO O O O ^n-- ro^OO^fOt^ m lo O '^oo oo CM-" roO tJ-ioOOvO ^C/D ' M M M (S CI HI MiOMMCO QO-O lO OMO \Ol-O-00P« Tt Tt M o 00 ONoorooo jair.. (N looo M lo oo(NvOoio Tf'^irjvooo loiot^ro*-" r>J=.M i I-"*-! M(N(Nroro ^t lOO t^oo m -^ t^ m lo ^C/3 1 M hH M ci CI i ^1? l^t^OO-^ vcOO loco MioO'O'^ (NiompoOn i-'t^ (NMiofOiO MM (N (N M fO ro »OvO l^ 0\ O ^00 M t^ Ci M M M (N cs ro 5&" rooo lo-^Tj- t>Mt^ir>io 0(NNO\"<^ t^oo COO CS-'^t^OfO OOfOt^M 00\0\0\M o •^o O t^ MM M » « (V) M m -"t O 0» M vO ro '^O fOMOO rOMfOOM (Nioi^MTt 00 t^ m 10 OvnO •'tvO 00 100 t-00 vO O PO POOO II §5 10 10 t-< r^ CO t^ Tl- (N t^ -"t N M M 10 POvO PO 't M M W CS ro TfTj-iovO t- 0\ M po »0 0> TfOi 10 M M M M M p< Ci PO Tf ^ § "^ "V s (^ ^ " 100 OvO ^ro Ci PO Tj-t^O -^ l>vO -'to 11 TtOv ""to 10 MOO TtMOO P0O\vO »o -^ vO fO -"to M M N ro f*5 -^J^ »0 t^oo Pi "^ 00 POOO ■^ M H M M Pi N PO Tt ^ S -« ft _ CS r^ rJ-M ro t^ i/^ t^ OwO ^ MOO t^O t^ PO rf lOPOO §■5 -^O -^O rf <>< o>.o MVC PO M (N 00 00 PO PI M M C» ro f*5 "St Tt 10 t^oo N •^ 00 CI t^ PO 0\ M p« e< PO PO & fe "" *e< a. N ^. N t^»O»O00 Tfrl-rJ-OsO a N r^po 00 MvOO C« II ■^00 fOOO CO 0\ to M l>. Tf 00 TfOoO t^ t^PO N >/^ M M OJ .po PO rooo 0 M t^ M M M CS CI PO PO ^ g" 'a 0*^ ^ r! t^OOO rfO M 100 Oi p* '^o\ PO T^lo t^ t^ o\ — < i-N fO t^MvO M \0 M\0 N 0\ MvO MOO 10 rt t^ TfO CI M M (N rl- rj- t^ 0\ N tOOO M M M N N ro PO & S "" 00 0) 04_ M S - 10 M C«lO M N VC C< C^ 00 o\ P< POOO 10 _ .-N fO t^M 10 10 »o M r^ POOO 10 PI cioo >o H M CS 0 »0 10 M 0> PO M fOsO "^0\ rooo Tf CMo t^ M\0 M 00 10 t^ C« POOO II CN N roPO -^ 10 t^OO M »o 0\ 'tO\ Tf M M M C« PO & s i a M M JO M M ro 000 10 CMO vO t^O P< 00 M 0\0\>0 t* roO ^00 N l^ CNJ l^PO lOOO POOO •^ M mOO n M M M c< w PC ro ^ lOvO 00 0\ M 10 0\ rooo Tf M M (M PS PO ^ I/) 0) 0< H ^. 0\ M lOTfro vO POO NO PO M 0\ H t^O PO fsvO ro t- MVO wvO M roO rfM vOO M PO II §5 N N PO PO •^ »/5vO 00 0\ M tJ-oO POOO PO M M C< PI PO ^ fej "^ V ^ t^ t^oo •^ vo 00 1000 M 1000 >* C« 10 M PO Oi ^ II W\« M M N M N PO PO lovO t^ 0\ ■^00 « t^ c« — < "-f^ M M Pi C« PO ^ fe 6^ U^ »0 »>^ 10 10 00000 00000 M M «N CS PO fO't'^iO vO t^oO 0\ c* Tj-ooo M M M M PS UNIT PRICES 297 Miscellaneous Information of Value in Making Preliminary Investigations and Estimates Conversion Per Cent, of Grade to Degrees of Vertical Angle (For use in tracing grade with transit or Abney Level) Per cent. Degrees 1 o°3s' 2 1° 09' 3 1:43' 4 2° 18' 5 2°S2' 6 3° 26' 7 4° 00' 8 4° 35' 9 5° 09' 10 5° 43' 11 6° 17' 12 6° si' 13 7° 24' 14 7°S8' 15 .8°32' Table 27. — Table or Acres Per Station of 100 Feet and Per Mile for Different Widths of Clearing OR Right-of-way — Acreage Width of Strip Per 100' Per Mile 30 ft 40" 50" 60" 70" 80" . 069 acres 0.092 ** 0.115 " 0.138 '' 0.161 " 0.184 " 3 4 6 7 8 9 636 acres 849 " 061 ** 273 '' 485 " 697 " 90" 0.207 *' 10 909 '' 100 " 0.230 " 12 121 *' Range in Unit Estimate Prices Clearing and Grubbing. Sage brush $ lo to $'50 per mile Light clearing $ 20 '* $ 60 per acre Medium clearing. . $ 60 " $150 '' " Heavy clearing $150" $300 '^ ** 298 PRELIMINARY INVESTIGATION Excavation. Common. Machine turnpiking $0.15 to $0. 25 per cu. yd. Wheel scrapper and machine finish $0.25 " $0.35 " '' '' Wagon haul and machine finish $0.40 '' $0.60 '' '' " Side hill plow, scrapper and machine $0.35 '' $0.75 " '' '' Disintegrated Rock or Dry Hard Clay. Considerable hand work or shooting $0.75 "• $1.00 '' '' '' Solid Rock. Blasting open cut, per cu. yd. $0.80 '^ $2.00 '' " " Tunnel work $4.00 '' $5.00 '' '* " Retaining Walls. Rough dry rubber masonry $1.00 '' $3.00 " '* '' Mortar rubber $4 . 00 '' $8 . 00 '' " *' Concrete $6.00 "$20.00 " '' "■ Timber and Lumber S30.00 ''$80.00 '' " '' Carpenter Work. Simple structures $5.00 " $10.00 " M ft. B.M. Truss framing, etc $10.00 '' $20.00 '' " '* Table 28. — Approximate Cost Per Foot of Length Small Drainage Structures Size of Opening Kind of Structures Corru- * Vitrified gated Cas t Iron Concrete Log Pipe Metal Pipe r *ipe Boxes Culverts 12" $0.60 $1.25 $^ 2.00 IS-" or 16" 90 I •50 2.90 18" I 10 I .80 5.40 24" 2 00 2 •75 )-50 36" 3 75 4 .00 48" 6 •50 2' X2' 3.75 $1.50 2;x3' 4.80 1.70 3'X3' 5.40 2.30 3'X4' 6 . 00 2.80 4'X4' ... 6.75 3.00 4'XS' . 8.00 3.60 S'XS' 8.70 4.00 * Based on $50 per ton in place. **Based on $10 per cubic yard in place. SMALL BRIDGES 299 Culvert Data. — ^Local conditions must be considered in prices of materials, haul, etc., for a close estimate. Table 50, page 559, gives weights of corrugated pipe. Table 49, page 558, gives weights of cast iron pipe. Quantities of concrete can be figured from standard designs given in Chapter III. Timber in superstructures can be figured from standard designs in Chapter III. The summarized data shown in Table 28 will however act as a rough guide. Amounts of masonry in two abutments and four wings for various heights of abutment for small span timber bridge super- structures with 16' Roadway. H = height from bottom of foundation to bridge seat. Cubic Yards H in Feet Concrete Masonry 6 24 cu. yd. 29 CU. yd. 7 32 \ ^^\ 8 40 49 9 52 60 ' 10 62 ' 74 ' i 12 90 ' 105 ' 14 133 153 16 18 Ti^O * 200 * 260 * 230 ' 20 295 '' *' 325 '' '' Compiled from Plate 29, page 119. Approximate amoimt of timber in small span stringer bridge su- perstructures having 16' roadway and figured to carry a 20 ton load. (Figured from Plate 21, page 104) Clear Span 1 Feet B. M. Pounds Hardware 6 ft. 8 '' 10 '' 14 " 18 '' 1000 1400 1700 2500 3300 70 pounds 90 '^ no " 130 " 150 '' Note. — For timber spans 30' to 50', see Plates 22 and 23, pages 107 to 108. Pile abutments can be figured from Plate 21, page 104. 300 PRELIMINARY INVESTIGATION Net Volume of Logs in Board Measure. — A convenient approxi- mate rule for computing the net number of feet board measure of sawed timbers in logs is as follows: Diameter in inches X radius in inches _ Feet (board measure) ^ per foot of log. Example. Suppose you have a log lo' long 12" in diameter. Diameter X radius , rr.T^AT e ^ e ^ = number of feet B. M. per foot of log. 12 11^^ = 6 ft. B. M. per ft. X 10' = 60 ft. B. M. 12 Steel Bridges. — The following diagrams taken from various sources will serve as a basis for rough estimates on longer span steel highway bridges. They are figured for a live load of 100 lb. per square foot and presumably for a plank floor. They are of much lighter construction than called for on heavy traffic roads where solid floors and a heavier loading are gaining favor. Magnetic Declination. — The following isogonic charts give the approximate magnetic declination for States east and west of the Mississippi for January i, 191 5. The yearly change is given. These charts will give a value close enough for preliminary investi- gation purposes. For meridian determination for location surveys, see Chapter XI. ''Polaris" and ''Solar Meridians." Explanation of Plates ^7 and 38 (Taken from U. S. Coast and Geodetic Chart) The solid lines on these charts are lines of equal magnetic de- clination. The dot and dash lines are lines of equal yearly rate of change in the magnetic declination. The charts show the magnetic declination for Jan. i, 191 5. Lines marked East Declination mean that the north end of the magnetic needle points east of true north. Lines marked West Declination mean that the north end of the needle points west of true north. For localities east of the line of no annual change the north end of the magnetic needle is moving west. For localities west of this line it is moving east at the rate shown by the lines of annual change. The location of the line of no annual change is shown on Plates 38 and 37G. STEEL BRIDGES 301 •I '11 >< a. - E I I 18000 16000 14000 12000 lOOOO 8000 6000 4000 2000 ■ 1 - / - '< '• 1 > ;^^ > / A pO V M / ^ /" ^ ^ X ^,15', /^ Wight of Steel in Bridges, exclusive of Joists and fznce, Warren yRiveted Low Truss, Half Hip, Tee Chords, L ive I oad 1600 lb. per lin. ft' of Bridge, RoadwoL/ 16'0". 3P' LV X ^* .^ f ^ ^ -J 1 1 1 1 1 1 1 1 1 1 1 30 40 50 60 70 80 Span of Bridge inFee-t*. — T" ' 1/ ' / / / / J- ' , /^ jVI i<^' /^ ' >' 20' Road,2,e' Sidewalks ~/8' '^ 2,5' »'. ! ■^ ,oof y .^ / l^'- .^ ^ le' 9y 2,5' ri ' ~ / , y 'y^ ■' ' ' / b5^:^ > '''.'' >' ^-^ ;i.>^: .JLl^-^ ^^. 85,000 80,0 00 75,000 J) 70,000 ■§ 65,000 § G0,000 '^- 55,000 g^ 50,000 ^ 45,000 °^ 40,000 o 35,0 00 ^ 30,000 .?^ 25,000 ^ 20,000 - 15,000 -H 10,000 5,000 4-0 50 60 70 80 90 100 110 120 130 140 150 160 Panele> 302 PRELIMINARY INVESTIGATION Plate 37A. MAGNETIC DECLINATION 303 Plate 37B. 304 PRELIMINARY INVESTIGATION Plates 37 C and D. I -25« — 24° /' .^■^2- ,2,0 20, ,9, ./ ^S: MAGNETIC DECLINATION Plates 37E and F. 305 3o6 PRELIMINARY INVESTIGATION Plate 37G. Plate 37 H. MAGNETIC DECLINATION Plate 37I. 307 3o8 PRELIMINARY INVESTIGATION Plate 38. V .. X'-.,\\X 3^ ■•V ♦ ^'« \\^ ^ i^ •k- w '^•l£\\ '5\ ^^' l\%- 0< ••-1 I V , [Oo ±s. V, ■> \ \ N- \ \ r-- \ \V On \ \\ "^ ^^^^- W j D£C L\//VAT\d(A/ \\ \\ \\ \ ' \)s\ V\ \ \\ H\ \3° \ V \V^ \\.0° SAMPLE REPORT 309 The following sample report shows a form in ordinary use for Preliminary Investigations which covers the information required. REPORT ON PRELIMINARY INVESTIGATION OF THE RED GAP-BIG BEAR RANCH HIGHWAY IN PATERSON AND GRANT COUNTIES, STATE OF , 1919 State Commissioner of Highways, Dear Sir: Complying with your request of May loth, a preliminary investi- gation of the proposed Red Gap-Big Bear Ranch Highway was made June ist to June loth. There is only one feasible route via Clear River Ranch, Coal Basin, Stray horse Divide, See Creek and Blackwater river a total distance of 30 miles. This route is free from ^now seven months in the year. A double track road from Red Gap to Coal Basin and a single track road with turnouts and permanent drainage structures for the remaining distance will cost approximately $175,000. In case the entire project can not be undertaken by one appro- priation, I recommend the following order of construction of the various sections shown on the accompanying map (page 317). First in importance G 4, G 5, Second '' '' G 7, Third '' " G6, Fourth " " G 2, G 3, Fifth " " G I, P I, P 2, Sixth " '' ..^ P3, P4, Seventh " '' P 5, The report in detail follows. Signed, Field Engineer. Table of Contents Page 1. Introduction 310 2. Length in Counties and Benefits .... = 310 3. Metiiods of Investigation 310 4. Present Condition Roads and Trails 310 5. General Topography. 311 6. Proposed General Route 312 7. Controlling Points 313 8. Description between Controlling Points 313 9. Recommendations and General Costs 315 10. Detail Estimate 315 {a) Classification of Material 315 {h) Unit Prices Used 316 (c) Division into Sections 316 {d) Estimate by Sections 316 11. Maps and Photographs The field notes on which this report is based can be found in Field Book No. 153 Preliminary Investigation file. 3IO PRELIMINARY INVESTIGATION I. Introduction It is proposed to build a new road over Stray Horse Divide con- necting the valleys of the Clear and Blackwater Rivers and to improve the location, grade and width of the existing roads in these valleys. The highway will extend from Red Gap in Paterson County to Big Bear Ranch in Grant County a distance of approxi- mately 30 miles. It will open up a valuable farming section on the upper Blackwater River and will afford more direct communi- cation between these two counties. 2. Length in Counties and Benefits Paterson County. — Red Gap to Stray Horse Divide 8 miles. Grant County. — Big Bear Ranch to Stray Horse Divide 22 miles. Paterson County will be benefited by a better and quicker con- nection with communities to the south and by the large amount of tourist travel which will undoubtedly use this road. Grant County will gain a more direct route to an isolated por- tion of its territory and will help the development of a promising farming section on the upper Blackwater River. While none of this road lies in Socorro County, this county will be more directly benefited than Paterson County as the natural outlet for trade and produce up the Blackwater lies toward Lochiel. 3. Methods of Investigation Field Work.— The entire line was covered twice on foot June ist to loth, noting the controlling points (aneroid elevations) the general classification of materials, the sidehill slopes and reason- able ruling grades. Office Work. — The office estimate is based on paced distances checked by Forest Service maps and maps of the Clear River Railroad. The excavation per running foot on sidehill work is based on cross slopes taken with an Abney level at frequent intervals and is figured on the principle of balanced sidehill sections adding dif- ferent percentages for inequalities in profile. The classification of excavation is made roughly from notes on the general character of the formations. The drainage is approximated for the smaller structures. The larger bridges are noted in more detail. Estimates have been prepared for various widths of roadway. 4. Present Condition of Roads and Trails Paterson County (Red Gap to Stray Horse Divide). — There is a fair wagon road from Red Gap to Clear River Ranch about 2 miles south; a solid but poor wagon road from this point to Coal Basin; a fair road from Coal Basin to Stray Horse Station and a well SAMPLE REPORT 311 marked but steep trail from this point to the top of Stray Horse Divide. Grant Comity (Stray Horse Divide to Big Bear Ranch). — There is an easy trail from Stray Horse Divide to Blackwater River ap- proximately 8 miles; a very poor wagon road down Blackwater River from See Creek to Adams Ranch approximately 9 miles. The road between these points crosses the river eight or ten times by fords and can not be used at all if the water is much above low stage. Under the best conditions a good 'team can not haul over I ton. From Adams Ranch to Big Bear Ranch (about 5 miles) the road is poor and dangerous in many places. It is so steep that one and a half tons is about the maximum load for an exceptionally good team under the best conditions. While this project ends at Big Bear Ranch it should be noted that if the road from this point to Lochiel in Socorro County, the nearest railroad point, is not improved the value of this project will be practically lost. The present road to Lochiel is dangerous, limits a team load to about 1 3^ tons and will be an expensive road to improve. I estimate roughly that $40,000 will be required to put it into reasonably good shape. 5. General Topography Paterson County (Red Gap to Stray Horse Divide) (See photo- graphs No. I to No. 10). — From Red Gap south for about 2}/^ miles the topography is abrupt. Red sandstone and conglomerate clilBfs and dykes hold the road location closely to the Clear River. From this point to about one-half mile south of Coal Basin occa- sional cliffs occur but a careful location will avoid them and it will be possible to gain some elevation along the sides of the valley. From the point to Stray Horse Divide and for a couple of miles south of the pass there are no cliffs and while the slopes are steep averaging 25° to 40° the location can be placed at any desired eleva- tion. This strip of country is fortunately favorable to location. Grant County (See photos No. 11 to 30). — From Stray Horse divide to Thompson's Ranch the formation is favorable for location on any desired grade. Few rock outcrops occur. The slopes aver- age 20° to 25°. • From Thompson's Ranch down See Creek is an ideal road loca- tion. No solid rock, very little loose rock, easy water grade. The side slopes average 10° for one-half the distance and 20° for the balance of the way. From the junction of See Creek and Blackwater River down the east side of the Valley to Buck Creek the location is easy on a side- hill averaging 25° side slope. There are no rock outcrops and very little loose rock. An easy grade can be obtained. From Buck Creek to Spring Creek along the sidehOl on the east side of Blackwater River the following conditions prevail. Average sidehill slope 30°; one-half mile of rock ledge slope of face approx. 60°. Expensive work can not well be avoided but an easy grade can be obtained. 312 PRELIMINARY INVESTIGATION From Spring Creek to Adams^ Ranch the formation on the east side of the valley is favorable for location at some distance away from the River. A ruling grade of 5 % can be obtained at the worse places and ordinarily the grade is light. Benches and sidehill slopes are easy averaging 15° for 3^ the distance and 30° for the remainder. From Adams' Ranch to Big Bear Ranch the best location lies on the west side of the valley. Difficult country is encountered, heavy scrub oak brush, many large boulders and considerable solid rock. The River changes its channel frequently and any permanent road location must be placed beyond its reach necessitating ex- pensive work. The natural soil from Big Bear Ranch to Adams' Ranch is very slippery when wet. To get a good safe road Creek Gravel should be used as surfacing. Unless the roadbed is sloped toward the hill (one way crown) any of this location will be dangerous in wet weather. This same condition applies in a less marked degree all the way up Blackwater River to See Creek. 6. Proposed General Route Paterson County. — From Red Gap, the proposed road follows the present road with some modifications to avoid unnecessary WATERFAL'L. rise and fall to the first crossing of the Clear River about 1% miles south of Red Gap. From this point to the mouth of the Canyon about 14 niile the location is open to argument. The existing road crossed the river twice (see sketch above). Both of these bridges were wrecked by the flood of 19 18 and temporarily the travel is using the railroad track between these points. With the permission of the railroad, it would be possible to widen out the cut on the west side of the track and tunnel or half tunnel SAMPLE REPORT 313 for about 500 feet around the rock bluff point, eliminating the two bridges and two railroad crossings. On the other hand the road would be very close to the track for 34 mile and would in my opin- ion be more dangerous for horse traffic than the old location re- quiring two bridges. The bridge location is recommended. From the mouth of the gorge the road will follow approximately the location of the present highway to the top of canyon hill and thence on a new location along the west side of the Clear River Valley to Stray Horse Divide. Grant County. — Beginning at the County line at Stray Horse divide a new location will follow down the north side of See Creek to a point about 2j^ miles southwest of Thompson's Ranch and thence along the south and east side of See Creek and Blackwater River to Adams' Ranch. At Adams' Ranch the road will cross to the west side of the valley and remains on this side to Big Bear Ranch the end of the proposed improvement varying somewhat from the location of the present road to better short sharp grades and to avoid Creek flood areas. 7. Controlling Points (Aneroid Elevations) Paterson County. Stray Horse Divide 9200 Bench between CliJBfs at Coal Basin 8200 Top of Canyon Hill 8100 Bottom of Canyon Hill 7930 Red Gap , 7800 Grant County. Stray Horse Divide 9200 Thompson's Ranch 7900 23^ miles S. W. of Thompson's 7500 (See Creek Crossing.) Bench between Cliffs between Buck and Spring Creek 7150 Adams Ranch 6780 Big Bear Ranch 6600 8. Description of Location Problems Between Controlling Points Paterson County Stray Horse Divide to Coal Basin. — The difference in elevation of these two points is approximately 1000 feet. The direct dis- tance is about 1 3-2 miles. In order to get a good grade and come somewhere near Coal Basin, which is probably desirable, it will be necessary to run south from Stray Horse Divide and then turn north. In this way any required ruling grade can be obtained and the length of road will depend entirely on the grade selected. The switchback can be made without too great cost by a careful loca- tion. I recommend a 5 % grade with a length of 4 miles. The road in general will follow the corftours. Two pronounced gulleys are 314 PRELIMINARY INVESTIGATION crossed which can be bridged or filled as determined on the location survey. By the use of a 6% to 7% grade it is possible to run direct from Stray Horse Divide to the top of Canyon Hill. This solution should be carefully investigated but does not appeal to me to be as good as the 5 % location as the topography is not as favorable for location and while it is shorter the lighter grade is to be preferred and the extra length of road south of the divide will be utilized in the future as a part of the road to Stone Quarry. Coal Basin to Top of Canyon Hill. — Approximate length 1% miles. Along contour of steep sidehill for approx. % mile and then along bench cut up by small swales and knolls. No special features. Grade any convenient to fit topography. No grade problem on this section. Excavation largely earth and loose rock. One lo' span bridge required. Top of Canyon Hill to Bottom of Canyon Hill at Mouth of Gorge. — Approximate length 0.6 mile. Along side of Canyon following present highway closely. Largely a question of equalizing grade by cut and fill. From Aneroid elevations and Abney level, I judge that a 6% grade can be obtained. Certainly a 7% can be built. This section of the road will be expensive and will govern the ruling grade from Red Gap to Stray Horse Divide. The excavation will be approximately 50% solid rock. One 20' span bridge will will be required. Mouth of Gorge (at Bottom of Hill) to Red Gap. — Approximate length 2 miles. From mouth of gorge J^ mile south to wagon road on the west side of the river the location is the most expensive of the entire project. This strip will require either two bridges or heavy rock work as previously discussed. The bridges are recommended. From this point to Red Gap there are no difiicult problems as the road will follow in general the present location and can be cheaply built. Another bridge at Red Gap will better the location and increase the convenience of the road. Grant County Stray Horse Divide to Thompson's Ranch. — The difference in elevation is approximately 1300 feet. It is desirable to get down to a natural bench at Thompson's ranch. The length of road between these points will depend on the ruling grade selected. As it is a long climb I recommend 5% with a length of 5 miles which can be obtained with one switchback turn. The country is favorable for location. Excavation is largely earth and some loose rock. Thompson's Ranch to See Creek Crossing. — Approximate length 2 3^i miles. Ideal road location on bench. Easy grade. Excava- tion practically all earth. Plow and machine scrapper work. No grade problem. One 20' span bridge required. See Creek Crossing to Buck Creek. — Easy sidehill location except for }/2 mile of rock ledge near Buck Creek. The location should keep upon the sidehill to avoid abrupt river banks and slides due to freshet scour. SAMPLE REPORT 315 Buck Creek to Adams* Ranch. — Easy sidehill and bench location. No difficulty in obtaining grades less than the maximum. Ex- cavation earth and loose rock. Adams' Ranch to Big Bear Ranch. — ^Location problem one of protecting road from River floods, also avoiding ledge and large boulder rock work. No hard grade problem. Excavation 50% loose rock, boulders and solid ledge. 9. General Recommendations and Costs The cost of construction under present conditions is uncertain. The prices used in the following detail estimates should be carefully noted in considering the possibility of cheapening the work by the use of convict labor. The costs used are for contract work and may vary greatly in a short time. I recommend for this project a double track sidehill section (S-14O from Big Bear Ranch to Coal Creek; a single track. sidehill section (S-io) with turnouts from Coal Creek up to Blackwater River, See Creek over the Divide and down to the top of Canyon hill in Paterson County. A double track road from this point to Red Gap. Permanent culverts and bridges. Ruling grades of short 7% and long 5%. Alignment limited as a rule to a minimum curvature of 100' radius with a few 40' radii at exceptionally bad places. The cost of this type of road is estimated at approximately $175,000 divided as follows: Clearing and excavation $108,000 Permanent culverts - • ■ ■ - 20,000 Permanent bridges over 10' span 35j000 Engineering . 12,000 Total $1 75,000 If it is not possible to construct the entire project by one ap- propriation it would be well worth while to build from Big Bear Ranch to See Creek at once to open up the new farming section on the Upper Blackwater. The cost of this portion of the road would be about $70,000. For details and various combinations of design see the following estimates by sections. 10. Detail Estimates Classification of Materials. — The classification of excavation can not be accurately made; it is based on the following assumptions. Where the road is located on a bench near the bottom of a slope which appears to be slide or wash formation and no rock outcrops are visible the excavation is classed as 99 % common and i % rock. Where the location is on a steep main mountain slope of 25° to 35° covered with loose rock but no solid rock outcrops are visible the assumption has been that solid rock will be encountered 6 feet back of the slope surface. 3l6 PRELIMINARY INVESTIGATION Where occasional outcrops occur rock is assumed 4 feet back of the surface. Any extended rock ledge has been noted. Unit Prices Clearing Sage brush $ 30 per mile Light brush and trees $ 30 '' acre Medium brush and trees $100 '* *' Excavation Solid rock $1 . 00 to $1 . 50 per cu. yd. Tunnel rock .....4.00 '* ^' " Common Exc. Turnpike in earth 0.18" '' " Sidehill plow and scrapper o . 30 to 0.40 *' ^' " Wagon haul and scrapper 0.40 " " " Concrete $12.00 '' " " 18'' corrugated pipe 2 . 00 " foot Rough rubber retaining wall 2 . 00 ** cu. yd. Division into Sections. — For the purpose of estimating the road is divided into the following sections. Paterson County Sec. P-i Stray Horse Divide to Coal Basin 4.0 miles Sec. P-2 Coal Basin to top of Canyon Hill 1.8 " *Sec. P-3 Canyon Hill 0.6 '' *Sec. P-4 Canyon Hill to Clear River Ranch 0.25 " *Sec. P-5 Clear River Ranch to Red Gap i . 75 " Total Paterson Co 8.40 " Grant County Sec. G-i Stray Horse to Thompson's Ranch 5.0 miles Sec. G-2 Thompson's Ranch to See Creek Crossing. ... 2.5 *' Sec. G-3 See Creek Crossing to Blackwater River i .0 *' *Sec. G-4 See Creek and Blackwater to Buck Creek 2.5 *' *Sec. G-5 Buck to Spring Creek 2.0 *Sec. G-6 Spring Creek to Adams' Ranch 4-5 *Sec. G-7 Adams' Ranch to Big Bear Ranch 4.3 *' Total 21.8 '' Note. — See map for location of these sections. The sections marked with a * have a poor wagon road at present which however can be used. Sections having no star require new construction to permit wagon traffic. Estimate of Sections. Section P-i. — (Length 4.0 miles.) Clearing. — Six acres per mile for 3 miles = 18 acres @ $100 = $1800. SAMPLE REPORT 317 Drainage. — Say 10 culverts per mile for 4 miles @ $700 per mile = $2800. Excavation for Double Track Road. — Sidehill slope averages 27°. Excavation per mile for balanced section S = 14 equals approxi- mately 13,000 cu. yd. for a 1:1 cut slope which is considered /Big Bear Ranch \. :'^^ 0- xV /' S+one ©-6 / Adams "^U^ Quarry g CO 8 = ^^^ -.Ranch /\ ^5 \-.^ PjlCKCMff ..'-'' r Y^ A5n^ 0^ W /\ , W^ --^©-2 V<. 1 J/ Its k^' y ^- t ptON t 1 f la. \ 10 \ m ^^ M Hi ■- j^> K-. -_..r^ Clear Xv^' River .-^ ^ •--,.P-4 Ranch |^ P-5 Red 6a p ^ .-' safe for this material. Add 25% for inequalities of profile giving 16,200 cu. yd. per mile or 55,000 cu. yd. for 4 miles. It is estimated that 20% of this or 11,000 cu. yd. are rock excavation and the balance 44,000 cu. yd. are common. 3i8 PRELIMINARY INVESTIGATION 44,000 cu. yd. common @ $0.40 « . $17,600 11,000 " " rock @ 1.20 13,200 Total excavation $30,800 Excavation for Single Track Road S-io. Exc. per mile balanced section. . . 7,400 cu. yd. Add for profile 25% 1,850 '' " 9,200 '* " Assume 10% rock 900 " '' per mile Assume common exc 8,300 '* " " ** Cost of Excavation for 4 miles. 3,600 cu. yd. rock @ $1 . 50 $5,400 33,000 " '' common @ $0.33 11,000 Add for turnouts 5 to the mile 500 cu. yd. rock @ $1 , 20 600 1,500 " " common @ $0.40 600 Total $17,600 Summary of Cost Section P-i. Double Track Road Single Track Road Clearing $ 1,800 Clearing $ 1,800 Drainage 2,800 Drainage 2,800 Excavation 30,800 Excavation 17,600 $35,400 $22,200 Contingencies, wall, etc 2,600 Contingencies 1,800 $38,000 $24,000 Equals $9500 per mile Equals $6000 per mile Estimate Section P-2. — (Length 1.8 miles.) o . 8 miles similar to section P-i 1 .0 miles average side slope 15° Estimate of the easy mile (side slope 15°) Clearing 6 acres @ $50 $300 . 00 Drainage (ordinary) 500 . 00 20' span bridge 800 . 00 Excavation (see S-14) 3300 cu. yd. per mile Add for profile 25% 800" " '' " 4100 " " '^ " Rock excavation 100 *' " ©1.50 $150.00 Common excavation 4,000 '^ " " 0.30..... 1200.00 $2950.00 Contingencies 150 . 00 Total $3100.00 SAMPLE REPORT 319 Summary P-2. Double Track ^^^^ Single and Part Double . 8 miles similar to P-i @ $9500 per mile = $7,600 @ $6000 per mile = $4800.00 1 . o miles as per estimate above.... 3,100 , 3100.00 $10,700 $7900.00 Say 11,000 Say... 8000.00 Estimate Section P-3. — (Length 0.6 miles.) Double track road based on hand level profile. Clearing 3 acres @ $100 $ 300 . 00 3000 cu. yd. common @ $0.40 1200.00 3000" " rock® $1.25 3750.00 Ordinary drainage 500 . 00 1 20' span bridge 800 . 00 $6550.00 Contingencies 150.00 Total : $6700 . 00 Estimate Section P-4. — (Length 0.25 miles.) Estimate No. i. — Based on location requiring two bridges over the Clear River. Clearing $ 20 . 00 1000 cu. yd. common exc. @ $0.40 400.00 200 " " rock (^$1.50 300.00 400 " " rip-rap @ $1 . 00 400 . 00 2 (80' span solid floor steel truss bridges) 16,000.00 I (20' span concrete bridge) 800.00 $17,920.00 Say 18,000 . 00 Estimate No. 2. — Based on half tunnel west of track. Clearing $30 . 00 5000 cu. yd. of common exc. @ $0.40 2,000.00 4500 '^ ^' rock tunnel work @ $4.00 18,000.00 Stone wall between track and road 900.00 $20,930.00 Say $21,000.00 Estimate Section P-5. — (Length i . 75 miles.) Double track road. Approximately same cost per mile as Section P-2 on the easy mile. 1.75 miles @ $3100 per mile $ 5,425.00 Possible bridge at Rip Gap 8,000.00 $13,425.00 Say $14,000 . 00 320 PRELIMINARY INVESTIGATION Summary of Costs, Paterson County Section Double Track Single Track Road WITH Turnouts P-i $38,000 $24,000 P-2 $11,000 8,000 »P-3 7,000 iP-4 18,000 ^P-5 14,000 $88,000 Engineering 4,000 Total appropriation $92,000 Estimated total cost for double track road Sec. P-3, P-4 and P-5 and single track road to the divide Sec. P-i, and P-2 is $75,000. Estimated cost of cheap single track road connecting present road to the divide Sec. P-i and P-2, with temporary drainage structures and 6% ruling grade instead of 5% $25,000. Cost Estimate, Grant County In a similar manner detail estimates are made for the sections in Grant County as summarized below. These estimates can be found in computation file F-32. They are not included in this re- port as they are bulky. i|L j Summary of Costs, Grant County Section Double Track (S-14) Single Track (S-io) With Turnouts (S-14) G-i $ 32,000 $ 22,000 G-2 33,000 3,000 G-3 5,000 3,000 G-4 10,000 7,000 G-5 20,000 12,000 G-6 26,000 20,000 G-7 36,000 — ■ $132,300 25,000 $ 92,000 Engineering. . . . Appropriation . . 7,700 8,000 $140,000 $100,000 Total Summary of Recommended Construction Paterson County $ 75,ooo Grant County 100,000 Total $175,000 1 Sections have usable wagon road at present. SAMPLE REPORT 321 RECONNAISSANCE SURVEYS The methods described for ordinary investigations can be used for most cases but for heavily wooded country or extremely difficult and rough topography a more careful survey is desirable. Methods. — For open barren country the transit stadia method is preferred by the author using magnetic bearings, stadia distance, vertical angle profile and cross slopes and ordinary note book sketches and recording. The map is plotted up on a scale 1000 ft. to the inch and the profile 100' to the inch. The line is marked in the field by tall stakes or lathes with a strip of cloth attached. Work of this kind can be done by two men with very simple equipment. In remote regions a third man to move and care for camp equipment is required (see Chapter XII). Engineering Equipment Light mountain transit with stadia and verticle circle. Light stadia rod, 8' to 10' long. Camera. Note books, maps, etc. 100' steel tape. 2 aneroid barometers. For heavily wooded country the U. S. Geological methods are the cheapest and most satisfactory using a light 15" sketch plane table and tripod oriented with a magnetic needle; 6'' gun sight alidade; 500' linen tape coated with paraffin for distance. Aneroid inter- mediate elevations checked by flying lines of spirit levels or stadia levels along trails. The main advantage of this method is that it requires no cutting as direction is obtained by sighting by ear to a yell or whistle. It also gives a complete contour map of all the territory that the road can possibly traverse and makes it possible to lay out a better final location than any amount of scouting where the engineer depends on his memory and sense of direction for his final location. The projected line is then followed with a rough plane table traverse, slopes, etc., taken and the estimate made. Work of this kind can be done by two men with very simple equipment for a cost ranging from $10 to $30 per square mile mapped. A convenient scale to work on is 2000' to the inch and a contour interval ranging from 10' to 50'. A third man to move and care for camp is desirable. Engineering Equipment 15'' Plane table with tripod. 500' Linen tape. 6" Gun sight alidade in leather case. 100 Steel tape. Plane table map paper. 322 PRELIMINARY INVESTIGATION 2 Aneroid barometers Light mountain transit with stadia (for flying levels). Stadia rod. Conclusion. — It should be borne in mind that if engineering is to be of value it must be thorough and that new locations will often fix roads for generations. % Screws to hold Double Mourrhed Plane Table Paper firm I u in Place. ^ I (ah Area Heavilcj Wooded ; I excepf Portion Harked \ \CI earing. '^^ i Proposed Locaiion of Road \shown in Oo-ffed Lines. \^^ i Areas nof Favorable for -^ *' \Locafion Hatched ihus ^ Pig. 6 1. — Sample plane table map. There should be no hesitation in spending what ever is needed even if it seems all out of proportion to the cost of the actual con- struction work to be performed within a year or so. Government programs carry out this principle and they are often criticised for high engineering cost but it is well worth while looking to the future. The engineering program must be complete or it might just as well be discarded entirely. CHAPTER XI THE SURVEY The chapter on survey will be handled under two main divisions : (a) Improvement of existing roads. (b) Location of new roads. (a) FOR THE IMPROVEMENT OF EXISTING ROADS As the survey furnishes the information for the design, it must be carefully made in regard to the essential features. These are alignment, levels and cross-sections, drainage, information con- cerning foundation soils, available stone supply, available sand, gravel, filler, etc.; direction and amount of traffic, railroad un- loading points, the location of possible new sidings, and such topography along the road as will have a bearing on the design. The survey should be made not more than a year before construc- tion starts and during the open season, as a snowfall of any depth makes the work unreliable and only fit for a rough estimate. When contracts based on winter surveys are awarded it is always necessary to take new cross-sections to insure a fair estimate of the excavation. A party of five men is a well-balanced force for surveys of this character. Force Engineer Instrument man Three helpers Equipment Transit Level 2 I go' steel tapes 3 50' metallic tapes 3 pickets 2 level rods Pocket compass Hatchet Sledge Axe Keel Stationery Reports Pencils Notebook U. S. G. S. map. Stakes For preliminary survey no stakes per mile For construction 220 stakes per mile The Center Line. — The placing of the center-line hubs (transit points) requires good judgment and should be done by the chief of the party. In locating them he considers the principles of align- ment discussed in Chapter I. The hubs are placed at tangent intersections and sometimes at the P. C.'s and P. T.'s of curves and are referenced to at least three permanent points that will not be disturbed during construction. (See sample page of notes. Fig. 62.) The deflection angles at the tangent intersections are usually read to the nearest minute, taking a double angle to avoid mis- 323 324 THE SURVEY takes; the magnetic bearing of each course is recorded. For all deflection angles over 4° it is good practice to figure and run in on the ground the desired curve. Curves with central angles of less than 4° can be run in with the eye during construction. The center line is marked at intervals of either fifty or one hundred feet (see cross-section, page 325) in any convenient manner; the alignment of these points should be correct to within 0.2 and the distance along the line to within o.i per ioo feet of the length; any attempt to get more accurate stationing is a waste of time. The chaining may be done on the surface of the ground up to a grade of 5 % with no objectionable error; beyond that slope, however, the tape should be leveled and plumbed. ^ Steel tapes should be used for chaining the center line and referencing the hubs ^ Deflection Angle Curve ^ P.l Sta.S-hZdA rL-'dW I^S Angle 3''Z0'\ J P.L 5fu. O-hOO V J I5"0ak - Z%^' O- TeleqraphPole ^45kz^ <*-. ^^ Cor- Post i in Fence l^ '■^^' Bam ^- l2"MapleTree ^^<>. ^s< -'>ol5"0ak Fig. 62. — Alignment notes. A convenient method of marking the actual center line sta- tions is to use a nail and piece of flannel; red flannel for the 100' stations and white flannel for the intermediate 50' stations, if needed. Where the soil is sandy, or muddy, and these nails would be kicked out or covered, a line of stakes can be set outside of the traveled way on a specific offset from the center line. However, if an offset line is used the chaining of all curves should be done on the center line to insure a correct center line distance and the stakes placed radially on the desired offset.^ Railroad spikes make good permanent transit points and are easily placed. At the same time that the line is run it is just as well to paint the 100' station numbers on any convenient place where they can be readily seen, as stations marked in this manner make it much easier to sketch in the topography than if marked in chalk on stakes. Also, if the stations are permanently marked it is LEVELS 32s easier for the construction engineer to pick up the transit points at some future time. A party of j&ve men will run from two to four miles of center line a day, the speed depending upon the number of curves and length of tangents, if the hubs have been previously placed and referenced. If the hubs are placed at the same time the line is run, the work is greatly delayed. Two men can place and reference the transit points at the tangent intersections at the rate of from four to ten miles per day. Sta. P.M.^^1 B.S. F. S. H.I. Elev. V" Spike m 15" Elm, l^ight of 5fa.5-h6Q _/^ Fig. 63. — Bench level notes. Levels and Cross -Sections. — Bench levels are run in the usual manner; the levels will be sufficiently accurate if the rod is read to the nearest o.oi'; for such work any good level and a self-read- ing rod graduated to hundredths are satisfactory. Benches are established at intervals of 1000-1500 feet; they must be substantial, well marked, and so situated as not to be disturbed during construc- tion. A small railroad spike in the root of a tree, a large boulder, or the water table of a building make good benches. The bench levels may be referred to some local datum in general use or to the U. S. levels, or the datum can be assumed. In run- ning bench levels it is better to use each bench as a turning point, as side-shot benches may be wrong even if the line of levels is correct. Cross-sections are taken at either 100' or 50' intervals, at all culverts, possible new culvert sites, and any intermediate breaks not shown by the normal interval. Enough sections are taken to show the constantly changing shape of the road. The distance of the shots from the center line of the road is read to the nearest 1,0' where the ground has no abrupt change of slope 326 THE SURVEY and to the nearest 0.5' where there is a well-defined abrupt change. The elevations are read to the nearest o.i'. The sections should extend from fence line to fence line, or in villages from sidewalk to sidewalk, and the position of the pole lines, tree lines, curbs, etc., noted. Engineers differ as to whether the sections should be taken at a normal interval of 50' or 100'. Table 29 gives the difference in the computed quantity of earth- work using 50' and 100' sections with intermediate sections at well- defined breaks in the grade. Table 29 Name of Road Length Figured Charac- ter of Road Excava- tion 50' Section Excava- tion 100' Section Appro- ximate Differ- ence Per cent of Differ- ence Scottsville Mumford . . . Scottsville Mumford . . . Leroy Caledonia *Leroy Caledonia Clarence Center Clarence Center Lockport Tonawanda . . . *East Henrietta Rochester I mile I " I " ! '' I " I " I " I " flat hilly rolling flat rolling eat flat rolling Cu. Ft. 61,444 111,109 57,840 77,841 73,727 38,037 59,096 37.275 Cu. Ft. 61,995 111,700 60,560 78,659 73,048 39,415 59,470 36,07s Cu. Ft. 550 600 2700 800 700 1400 400 1200 + I«0% + h% + 4i% + 1 % -I % + 3x\% + /tj% -3i% The following tabulation shows the variation for shorter sections of the starred roads. Name Station Quantities Quantities Approx- of and to by 50' Sec- by 100' imate Difference road Station tions Sections Difference Cu. Ft. Cu. Ft. Cu. Ft. Leroy Caledonia, 80- 90 . . . 19,151 19,525 400 t' Z^ *' 90-100 . . . 21,915 23,415 1500 + 7 % " lOO-IIO . . . 21,555 20,689 900 -4 % " 110-120 . . . 15,220 15,030 200 - iA% Total and averages . 77,841 78,659 800 + 1 % East Henrietta Rochester, 0-19 . . . 14,625 14,300 300 -2 % 32-49 . . • 11,950 11,575 350 -3 % 49-66 . . . 10,700 10,200 500 -5 % Total and averages . 37,275 36,075 1200 -3i % CROSS SECTIONS 327 The question of quantities is not the only factor in determining the interval. Where it is important to fit the local conditions, as in a village, or to utilize an old hard foundation, the designer is helped by 50' sections. In taking cross-sections the work becomes mechanical, and un- less the engineer in charge is unusually alert to all the inter- mediate changes better results will be obtained by the use of the shorter interval. For these reasons the author believes that a 50' interval is advisable except on long uniform stretches of road. A party of three men will run from 4000 to 7000 feet of 50' cross-sections per day; a party of four men from 5000 to 9000 feet, depending on the country. Sta. lOtOO lOtSO r.p.tes Rock on lltOO B.S. 5.41 I.ZZ F.S. Z.IO H.I. esi.75 3S0.35 Elev. "V eze.sz eze.6s Leff < ^ ^ ^ ^^ >« 2:4 ^ tvj «M cvj 0^ CJi 505Z605ZS\j 40 14 IZ 5 C CVJ M C^ C^ C^ (Si S£ 6.0 6S 6.5 6.0 60 «(i ►O ©J cvi >j. iq f\4 PVl CVJ C\j <\4 tVj 8Z 61 9J 63 6.6 30 ZO IS & 5 C 10 14 Id 30 >v. Right Ki 04 00 ^ CV* v£> vo u6 ^ to CV4 CM £4 J^ tVi Oi C^ C^ 0^ O B.4 5.5 S3 S5 6.5 5 9 II 19 Z4 >h N N ^ ^v If) >*I M^ ^ ►O CM r?j cs^ c5i 04 CT) CXS ^ 0^ ci 6.5 7.0 7.0 7.6 8.0, 26 20 14 II 6 O 6 n /2 ZO 23 dS ^ N > ^ CU ^' CM Ni w rulvfift .Ne.edeU^. 5ta. 55-i-IO Drainai^e? Arffa 300 A. Q Ro/finq Farm Landj 'laq. ^ilopG ahout^O' per 1000 U.o\^e 3. Mike O'Donnelf 500 cu yds. J yd- ^ Large Qranite Boulderd 75% must he Blasted -4-. CId Limestone (Quarry 2o'^ face Samples taken- looks good for Top Stone Scafe l"=IMiIe Fig. 68. the nearest road or lane. As fences are usually a mixture of different kinds of rock, the engineer estimates the percentage of granite, limestone, sandstone, etc., and the percentage that will have to be blasted or sledged in order to be crushed by an ordi- nary portable crusher. The amount of ^ field stone required per cubic yard of macadam is given in estimates, page 593. If there is a large excess of stone a careful estimate need not be made, only enough data being collected to determine the probable position of the crusher set-ups and the average haul to each set- up. If a sufl&cient supply is doubtful a close estimate is made as outlined above and options obtained from the various owners. Samples of the different rocks are tested. (See materials.) RIGHT OF WAY SURVEYS 333 Preliminary surveys of the above description should be made at a speed of from two to four miles per week at a cost of from $35 to $70 per mile, allowing $6 per day for the engineer; $3.50 for the instrument man; $2 per man for three laborers; $1 per day board per man and $4 per day for livery. Right-of-way and diversion line surveys are often needed but are usually not made at this time; if the, designer believes that additional land must be acquired or that a diversion line is necessary, he indicates the information desired and the surveys are made. RIGHT-OF-WAY SURVEYS These surveys are used not only to show the amount of land to be acquired but, also, the damage to property from altering the shape of a field, cutting a farm in two, changing the position of a house or barn relative to the road, etc. The acreage to be taken is shown by an ordinary land survey in which the road lines, property lines, corners, etc., are located in relation to the proposed center line of the improvement, and their lengths and bearings carefully determined. It is often difficult to locate the road boundaries, as town records are care- lessly kept and there is a general tendency to encroach on the road. As the amount paid for new right-of-way is rarely settled on an acreage basis, it is customary to take the existing fence lines as the road line unless it is very evident that the fence has been moved. This produces better feeling on the part of the property owner and does not affect the price paid. The lines between adjoining properties are usually well defined. In cases where an orchard is damaged the position and size of the trees are noted; where a field or farm is cut the whole field is shown, with the shape and acreage of the pieces remaining after the land actually appropriated has been taken out. As is usually done in all land surveys, the parcel to be bought is traversed and the survey figured for closure error to insure the description against mistakes. The standard form of map and description of the N. Y. State Department is shown in the folio mng illustration: 334 THE SURVEY ^ S o U O sT . O'O O 0) *> O a^ ^ oil I g! ^ J. J ao" ^ > <^^ ^ ^ '" tJ « iJ.SP, 1 « 9 *Jh k'C 3"^ rtri* p g 3 P =^ S 2 r 4, =3 U7^ ^,t3 0.J2 *- .-: i-?^ >» ?^ s o M cj ?^, fl " *^ ° •• 1,637.1 . 01.05 — — 52.5 3 40' . . 1,562.7 01. 1 — — 55.0 4° 00' . . 1,432.5 01.2 — — 00.0 4° 20' . . 1,322.3 01.3 — — 05.0 4"" 30' • • 1,273-3 01.35 — — 07.5 4° 40' . . 1,227.9 01.4 — — lO.O 5° 00' . . 1,146.0 01.5 — — 15.0 5:3°:-- 1,041.8 01.65 — 22.5 6° 00' . . 955.0 01.8 — — 30.0 6° 30' . 881.5 01.95 — — 37.5 7° 00' . 818.6 02.1 — — 45.0 7° 30'.. 764.0 02.25 — 52.5 8° 00' . . 716.3 02.4 — — 2 00.0 8° 30' . . 674.1 02.55 — — 2 07.5 9° 00' . . 636.6 02.7 — — 2 15.0 9° 30' . . 10 00 . . 603.2 573.0 02.85 — — 2 2 22.5 30.0 03.0 — 10° 30' . . 545.7 03.15 — — 2 37.5 11° 00' . . 520.9 03.3 — — 2 45.0 11° 30' . . 498.3 03.45 — — 2 52.5 12° 00' . . 477-5 03.6 — — 3 00.0 12° 30' . . 458.4 03.75 — — 3 07.5 13° 00' . . 440.8 03-9 — — 3 15.0 13° 30' . . 424.4 04.05 — — 3 22.5 14° 00' . . 409.3 04.2 — ■ — 3 30.0 14° 30' . . 395.2 04.35 — — 3 37-5 15° 00' . . 382.0 04.5 — ' — 3 45.0 15° 30' . . 369.6 04-65 — — 3 52.5 16° 00' . . 358.1 04.8 2 00.0 4 00.0 16° 30' . . 347.3 04.95 2 03.8 4 07.5 17° 00' . . 337.0 05.1 2 07.5 4 15.0 17° 30' . . 327.4 05.25 2 II. 2 4 22.5 18° 00' . . 318.3 05.4 2 15.0 4 30.0 18° 30' . . 309.7 05.55 2 18.7 4 37.5 348 THE SURVEY Table 31. — Continued Degree of Radius of Deflection per ft. of Arc Deflection per 25' of Arc Deflection per Curve Curve so' of Arc Minutes Degree Minutes 19° 00' 301.6 05.7 2 22.5 19° 30' 293.8 05.85 2 26.2 20° 00' 286.5 06.0 2 30.0 20° 30' 279.5 06.15 2 33.7 21° 00' 272.9 06.30 2 37.5 21° 30' 266.5 06.45 2 41.2 22° 00' 260.5 06.6 2 45.0 22° 30' 254.7 06.75 2 48.7 23° 00' 249.1 06.9 2 52.5 23° 30' 243.8 07.05 2 56.2 24° 00' 238.8 07.2 3 00.0 24° 30' 233.9 07.35 3 03.7 25° 00' 229.2 07.5 3 07.5 26° 00' 220.4 07.8 3 15.0 27° 00' 212.2 08.1 3 22.5 28° 00' 204.6 08.4 3 30.0 29° 00' 197.6 08.7 3 37.5 30° 00' 191.O 09.0 3 45.0 Deflection per 10' of Arc 31° 00' 184.8 09.3 3 52.5 32° 00' 179.1 09.6 4 00.0 1° 36; 33° 00' 173.6 09.9 — — 1° 39 34° 00' 168.5 10.2 — — 1° 42' 35° 00' 163.7 10.5 — — 1° 45' 36° 00' 159.2 10.8 — — 1° 48; 37° 00' 154.9 II. I — — 1° 5^ 38° 00' 150.8 II.4 — — 1° 5< 39° 00' 146.9 II. 7 — 1° 57 40° 00' 143.2 12.0 — — 2° 00' 42° 00' 136.4 12.6 — — 2° 06' 44° 00' 130.2 13.2 — — 2° 12' 46° 00' 124.6 13.8 — — 2° 18' 48° 00' I19.4 14.4 — — 2° 24' 50° 00' I14.6 15.0 — — 2° 30' 52° 00' II0.2 15.6 — 2° 36; 54° 00' I06.I 16.2 — — 2° 42' 56° 00' 102.3 16.8 — ~ "~" 2° 48' CURVE FORMULAE 349 For all practical purposes the value of 5730 can be used. In the same manner a two-degree curve is one having such a radius that 100 feet of arc will subtend two degrees of central angle, and its radius is 27r i^ = ^— X 100 2 _ 18,000 or }4. of the radius of a one-degree curve. The radius of a three-degree curve will be J-^ of 5730. The radius of a four-degree curve will be J^ of 5730. The formula for the radius of any degree of curve is therefore (2) R = 5730 D The degree of curvature for any specified radius is therefore (3) In general the degree of curvature is expressed by the central angle subtended by 100 feet of arc, and the radius for that degree of curve is found by dividing 5730 feet, the radius of a one-degree curve, by the degree of curve desired expressed in degrees and decimals of a degree. That is, if the radius of a 3° 30' curve is wanted, divide 5730 by :2^.^, which equals 163 7.1'. The radii given in Table 31 are computed in this manner. Length of Curve. — For a 5° curve a central angle of 5° subtends 100' of arc; a central angle of 10°, 200' of arc; a central angle of 12° 30', 250' of arc. That is, for a specified central angle the length of any specified curve equals that central angle expressed in degrees and decimals of a degree divided by the degree of curve expressed in degrees and decimals multiplied by 100; i.e., the length 20.7^ • of a 10° 15' curve for a central angle of 20° 45' = — '■ — X 100' = 10.25 202.4' 3-nd is expressed by the formula (continued on page 376) Table 32. Functions of a One-Degree Curve Figured on A Basis of 1^ = 5730' and Tabulated to Tenths of Feet Use 100' chords up to 8° Curves Use 25' chords up to 32" Curves Use so' chords up to 16° Curves Use 10' chords above 32° Curves 5 0° 1° " 3° g 5 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. 0.0 0.0. 0.2 50.0 0.9 lOO.O 2.0 . 150-1 10 0.0 8.3 0.3 S8.3 I.O 108.4 2.2 158.4 10 20 0.0 16.7 0.4 66.7 1.2 116.7 2.4 166.8 20 30 0.1 25.0 0.5 7S.O 1.4 125.0 2.7 175.1 30 40 0.1 33.3 0.6 83.3 ! 1.6 1334 2.9 183.4 40 §° 0.2 41.7 0.7 91.7 1.8 141.7 3.2 191.7 so 60 0.2 50.0 0.9 lOO.O 2.0 150.1 3.5 200.1 60 350 THE SURVEY Use loo' chords up to 8" Curves Use 50' chords up to 16" Curves Use 25' chords up to 32° Curves Use 10' chords above 32° Curves 1 c 4 5 ° 6 7 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 3-5 200.1 5.5 250.2 7.9 300.3 10.7 350.4 I .0167 3-5 200.9 5.5 251.0 7-9 301. 1 10.8 351.3 I 2 •0333 3-6 201.8 5-5 251.8 8.0 302.0 10.8 352.1 2 3 .0500 3.6 202.6 5.6 252.7 8.0 302.8 10.9 352.9 3 4 .0667 3.6 203.4 5.6 253-5 8.0 303.6 10.9 353.8 4 s •0833 3.6 204.3 5.6 254-3 8.1 304.5 II.O 354.6 5 6 .1000 3-7 205.1 5.7 255.2 8.1 305.3 II.O 355-5 6 7 .1167 3-7 205.9 5.7 256.0 8.2 306.1 II. I 356.3 7 8 .1333 3.7 206.8 5.8 256.8 8.2 307.0 II. I 357.1 8 9 .1500 3.8 207.6 5.8 257.7 8.3 307-8 11.2 358.0 9 10 .1667 3.8 208.4 5-8 258.5 8.3 308.6 II. 2 358.8 10 II .1833 3.8 209.3 5.9 259.3 8.4 309.5 11.3 359-6 II 12 .2000 3.9 210.1 5.9 260.2 8.4 310.3 11.3 360.5 12 13 .2167 3-9 210.9 5-9 261.0 8.4 3II.I 11.4 361.3 13 14 .2333 3-9 211.8 6.0 261.9 8.5 312.0 11.4 362.2 14 IS .2500 3.9 212.6 6.0 262.7 8.5 312.8 11.5 363.0 15 16 .2667 4.0 213.4 6.1 263.5 8.6 313.7 ii.S 363.8 16 17 •2833 4.0 214.3 6.1 264.4 8.6 314-S 11.6 364.7 17 18 .3000 4.0 2I5-I 6.1 265.2 8.7 315-3 II. 7 365.5 18 19 .3167 4.1 215-9 6.2 266.0 8.7 316.2 11.7 366.3 19 20 .3333 4.1 216.8 6.2 266.9 8.8 317.0 11.8 367-2 20 21 •3500 4.1 217.6 6.2 267.7 8.8 317-8 11.8 368.0 21 22 .3667 4.2 218.4 6.3 268.5 8.9 318.7 11.9 368.8 22 23 .3833 4.2 219.3 6.3 269.4 8.9 319.5 11.9 369.7 23 24 .4000 4.2 220.1 6.4 270.2 9.0 320.3 12.0 370.5 24 ^ .4167 4-3 220.9 6.4 271.0 9.0 321.2 12.0 371.4 25 26 .4333 4-3 221.8 6.4 271.9 9.0 322.0 12. 1 372.2 26 ^l .4500 4-3 222.6 6.5 272.7 9-1 322.8 12. 1 373.0 27 28 .4667 4.4 223.5 6.5 273.5 9-1 323.7 12.2 373.9 28 29 .4833 4.4 224.3 6.5 274.4 9.2 324-5 12.2 374.7 29 30 .5000 4.4 225.1 6.6 275.2 9.2 325-4 12.3 375.S 30 31 •5167 4-5 226.0 6.6 276.1 9-3 326.2 12.4 376.4 31 32 •5333 4.5 226.8 6.7 276.9 9-3 327-0 12.4 377.2 32 33 .5500 4-5 227.6 6.7 277.7 9-4 327-9 12.5 378.1 33 34 .5667 4.6 228.5 6.8 278.6 9.4 328.7 12.S 378.9 34 35 .5833 4.6 229.3 6.8 279.4 9.5 329.5 12.6 379.7 35 36 .6000 4.6 230.1 6.8 280.2 9-5 330.4 12.6 380.6 36 37 .6167 4.7 231.0 6.9 281. 1 9.6 331.2 12.7 381.4 H 38 .6333 4-7 231.8 6.9 281.9 9.6 332.0 12.7 382.2 38 39 .6500 4.7 232.6 7.0 282.7 9.7 332.9 12.8 383.1 39 40 .6667 4.8 233.S 7.0 283.6 9-7 333.7 12.9 383.9 40 41 .6833 4.8 234-3 7.1 284.4 9.8 334.6 12.9 384.7 41 42 .7000 4.8 235.1 7-1 285.2 9.8 335.4 13.0 385.6 42 43 .7167 4.9 236.0 7.1 286.1 9.9 336.2 13.0 386.4 43 44 .7333 4.9 236.8 7.2 286.9 9.9 337.1 13.1 387.3 44 45 .7500 4.9 237.6 7.2 287.7 lO.O 337.9 13.1 388.1 45 46 .7667 S.o 238.5 7.3 288.6 1 0.0 338.7 13.2 388.9 46 47 .7833 5.0 239-3 7.3 289.4 lO.I 339.6 13.2 389.8 4^ 48 .8000 5.0 240.1 7.3 290.3 lO.I 340.4 13.3 390.6 48 49 .8167 5.1 241.0' 7.4 291. 1 10.2 341.2 13.4 391.4 49 SO .8333 5-1 241.8 7.4 291.9 10.2 342.1 13.4 392.3 SO 51 .8500 5.1 242.6 7.5 292.8 10.3 342.9 13.5 393-1 51 S2 .8667 5.2 243.5 7.5 293.6 10.3 343.7 13.5 394-0 52 53 .8833 5.2 244.3 7.5 294.4 10.4 344.6 13.6 394-8 53 54 .9000 5-2 245.2 7.6 295.3 10.4 345.4 13.7 395-6 54 55 .9167 5.3 246.0 7.6 296.1 lo.s 346.3 13.7 396.5 55 56 .9333 5.3 246.8 7.7 296.9 10.5 347.1 13.8 397.3 56 57 .9500 5.3 247.7 7.7 297.8 10.6 347.9 13.8 398.1 57 58 .9667 5.4 248.5 7.8 298.6 10.6 348.8 13-9 399.0 58 59 .9833 5.4 249.3 7.8 299.4 10.7 349.6 13.9 399.8 59 FUNCTIONS OF ONE-DEGREE CURVE Use loo' Chords up to S° Curves Use 25' Chords up to 32° Curves Use 50' Chords up to 16° Curves Use 10' Chords above 32° Curves 351 3 g » 9° 10° 11° i Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 .i4^o 400.7 17.7 450.9 21.9 501.3 26.5 551-7 I .0167 14.0 401.5 17.8 451-8 21.9 502.2 26.6 552.6 I 2 •0333 14.1 402.4 17.8 452.6 22.0 503. 26.7 553.4 2 3 .0500 14.2 403.2 17.9 453.4 22.1 503-8 26.7 554-3 3 4 .0667 14.2 404.0 18.0 454^3 22.2 504.7 26.8 555.1 4 5 .0833 14-3 404.8 18.0 455^1 22.3 505.5 26.9 555-9 5 6 .1000 14-3 405.7 18.1 456.0 22.3 506.4 27.0 556.8 .6 7 .1167 14.4 406.5 18.2 456.8 22.4 507-2 27.1 557-6 7 8 .1333 14-5 407.4 18.3 457.7 22.5 508.0 27.2 558.5 8 9 .1500 14-5 408.2 18.3 458.5 22.6 508.9 27.2 559.3 9 10 .1667 14.6 409.0 18.4 459.3 22.6 509.7 27-3 560.1 10 II •1833 14.6 409.9 18.4 460.2 22.7 510.6 27.4 561.0 II 12 .2000 14.7 410.7 18.5 461.0 22.8 511-4 27-5 561.8 12 13 .2167 14.8 4II-5 18.6 461.8 22.9 512.2 27.6 562.7 13 14 .2333 14.8 412.4 18.7 462.7 22.9 513.1 27.7 563.5 14 15 .2500 14.9 413.2 i8.r 463.5 23.0 513.9 27.7 564-3 IS 16 .2667 14.9 414.1 18.8 464.4 23.1 514.8 27.8 565.2 16 17 •2833 15.0 414.9 18.9 465-2 23.2 515.6 27.9 566.0 17 18 .3000 15^1 415.7 18.9 466.0 23.2 516.4 28.0 566.9 18 19 •3167 15.I 416.6 19.0 466.9 23.3 517.3 28.1 567.7 19 20 •3333 15.2 417.4 19.1 467.7 23.4 518.1 28.1 568.5 20 21 •3500 15-2 418.2 19.1 468.5 23.5 519.0 28.2 569.4 21 22 .3667 15^3 419.1 19.2 469.4 23.5 519-8 28.3 570.2 22 23 .3833 1S.4 419.9 19-3 470.2 23.6 520.6 28.4 571.1 23 24 .4000 15-4 420.8 19.3 471. 1 23.7 521.5 28.5 571.9 24 ^^ .4167 15^5 421.6 19.4 471.9 23.8 522.3 28.6 572.8 25 26 .4333 15.6 422.4 19.5 472.8 23-8 523-2 28.6 573-6 26 27 .4500 15.6 423.3 19^5 473-6 23.9 524.0 28.7 574-4 27 28 .4667 15.7 424.1 19.6 474-4 24-0 524.9 28.8 575-3 28 29 .4833 IS.7 424.9 19.7 475-3 24.1 525.7 28.9 576.1 29 30 .5000 I5^8 425^8 19.8 476.1 24.1 526.5 29.0 577.0 30 31 .5167 159 426.6 19.8 476.9 24.2 527-4 29.1 577-8 31 32 •5333 iS-9 427.5 19.9 477-8 24-3 528.2 29.1 578.6 32 33 •5500 16.0 428.3 20.0 478.6 24.4 529.0 29.2 579.5 33 34 .5667 16.0 429.1 20.0 479-5 24-5 529.9 29-3 580.3 34 35 .5833 16.1 430.0 20.1 480.3 24.S 530.7 29-4 581.2 35 36 .6000 16.2 430.8 20.2 481. 1 24.6 531.6 29-5 582.0 36 37 .6167 16.2 431.7 20.2 482.0 24-7 532.4 29.6 582.8 37 38 •6333 16.3 432.5 20.3 482.8 24.8 533-3 29-7 583.7 38 39 .6500 16.4 433.3 20.4 483.6 24.8 S34.I 29.7 584.5 39 40 .6667 16.4 434.2 20.S 484.S 24.9 534 9 29.8 58S-4 40 41 .6833 16.5 435.0 20.S 485-3 25.0 535-8 29-9 586.2 41 42 .7000 16.6 435-9 20.6 486.2 25.1 536.6 30.0 587.1 42 43 .7167 16.6 436.7 20.7 487.0 25.1 537-5 30.1 587.9 43 44 .7333 16.7 437^5 20.7 487.9 25.2 538.3 30.2 588.7 44 "^1 .7500 16.7 438.4 20.8 488.7 25.3 S39.I 30.3 589.6 45 46 .7667 16.8 439-2 20.9 489.6 25-4 540.0 30.3 590.4 46 "^l .7833 16.9 440.0 21.0 490.4 25-5 540.8 30.4 591.3 47 48 .8000 16.9 440.9 21.0 491.2 25.5 541.7 30.S 592.1 48 49 .8167. 17.0 441.7 21.1 492.0 25.6 542.5 30.6 592.9 49 50 .8333 17.I 442.5 21.2 492.9 25-7 543-3 30.7 593.8 50 51 .8500 17.1 443.4 21.2 493.7 25.8 544-2 30.8 594-6 51 52 •^^^7 17.2 444.2 21.3 494-6 25-9 545.0 30.9 595-5 52 S3 •8833 17-3 445-1 21.4 495.4 25-9 545-9 3I.O 596.3 53 54 .9000 17.3 445-9 21.5 496.3 26.0 S46.7 31.0 597-2 54 55 .9167 17^4 446.7 21.5 497-1 26.1 547.5 31.1 598.0 55 56 •9333 17.5 447-6 21.6 498.0 26.2 548.4 31.2 598.8 56 57 .9500 17.5 448.4 21.7 498.8 26.3 549.2 31.3 599-7 57 58 .9667 17.6 449.3 21.8 499-6 26.3 550.1 31-4 600.5 58 59 .9833 17.6 450.1 21.8 500.4 26.4 550.9 31-S 601.4 59 352 THE SUR VEY Use loo' Chords up to 8 ° Curves Use 25' Chords up to sa** Curves Use 50 Chords up to 16 ° Curves Use 10' Chords above 32° Curves T d 12° 13° i^ 15° 1 3_ Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 31.6 602.2 37.1 652.9 43.0 703.5 49-4 754.4 I .0167 31.7 603.1 37.2 653-7 43-1 704-4 49-6 755.2 I 2 .0333 31-7 603.9 37.3 654-6 43-2 705.2 49-7 756.1 2 3 .0500 31.8 604.7 37-4 655.4 43-3 706.1 49.8 756.9 3 4 .0667 31-9 605.6 37-5 656.3 43.4 706.9 49.9 757.7 4 5 .0833 32.0 606.4 37.6 657.1 43.5 707.8 50.0 758.6 S 6 .1000 32.1 607.3 37.7 657-9 43-7 708.6 50.1 759-4 6 7 .1167 32.2 608.1 37.7 658.8 43-8 709.5 50.2 760.3 7 8 .1333 32.3 609.0 37.8 659-6 43-9 710.3 50.3 761.1 8 9 .1500 32.4 609.8 37.9 660.5 44.0 711.2 50.5 762.0 9 10 .1667 32.5 610.7 38-0 661.3 44.1 712.0 S0.6 762.8 10 II .1833 32.S 611.S 38.1 662.2 44.2 712.9 50.7 763-7 II 12 .2000 32.6 612.4 38.2 663.0 44.3 713-7 50.8 764-5 12 13 .2167 32.7 613.2 38.3 663.8 44.4 714.6 50.9 765-4 13 14 .2333 32.8 614.0 38.4 664.7 44.5 715.4 51.0 766.2 14 IS .2500 32.9 614.9 38.5 665.5 44.6 716.3 Si.i 767.1 15 16 .2667 33-0 615-7 38.6 666.4 44.7 717. 1 51.2 767-9 16 17 .2833 33-1 616.6 38.7 667.2 44.8 718.0 51.3 768.8 17 18 .3000 33.2 617.4 38.8 668.1 44-9 718.8 S1.5 769.6 18 19 .3167 33.3 618.3 •38.9 668.9 45.0 719.6 S1.6 770.5 19 20 .3333 33.4 619.1 39.0 669.8 45-1 720.5 ^H 771.3 20 21 .3500 33.4 619.9 39.1 670.6 45.2 721.3 51.8 772.2 21 22 .3667 33-5 620.8 39.2 671.4 45.3 722.2 51.9 773.0 22 23 .3833 33.6 621.6 39.3 672.3 45.4 723.1 j2.0 773.9 23 24 .4000 33.7 622.5 39.4 673.1 45.5 723.9 S2.I 774.7 24 25 .4167 33.8 623.3 39.5 674-0 45-6 724.7 523 775.6 25 26 .4333 33-9 624.2 39-6 674-8 45-8 725-6 52.4 776.4 26 27 .4500 34-0 625.0 39-7 675-7 45-9 726.5 52.5 777-3 27 28 .4667 34.1 625.9 39.8 676.5 46.0 727-3 52.6 778.1 28 29 .4833 34-2 626.7 39.9 677.4 46.1 728.1 52.7 778.9 29 30 .5000 34-3 627.6 40.0 678.2 46.2 729.0 52.8 779.8 30 31 .5167 34.4 628.4 40.1 679-0 46.3 729.8 52.9 780.6 31 32 .5333 34.5 629.2 40.2 679-9 46.4 730.7 53.1 781.5 32 33 .5500 34.5 630.1 40.3 680.7 46.5 731.5 53.2 782.3 33 34 .5667 34.6 630.9 40.4 681.6 46.6 732.4 53.3 783.2 34 35 •5833 34.7 631.8 40.5 682.4 46.7 733.2 53.4 784.0 n 36 .6000 34-8 632.6 40.6 683.3 46.8 734-0 53-5 784.9 36 37 .6167 34.9 633-5 40.7 684.1 46-9 734-9 53-6 7?|-7 H 38 .6333 35-0 634-3 40.8 685-0 47.0 735-7 53-7 786.6 38 39 .6500 35.1 635.1 40.9 685.8 47.2 736.6 53.9 787.4 39 40 .6667 35.2 636.0 41.0 686.6 47.3 737.4 54.0 788.3 40 41 .6833 35.3 636.8 41. 1 687.5 47.4 738.3 54-1 789.1 41 42 .7000 35-4 637-7 41.2 688.3 47.5 739.1 54.2 790.0 42 43 .7167 35.5 638.5 41.3 689.2 47.6 740.0 54.3 790.8 43 44 .7333 35.6 639.4 41.4 690.0 47.7 740.8 54.4 791.7 44 45 .7500 35.7 640.2 41-5 690.9 47.8 741.7 54-6 792.5 45 46 .7667 35.8 641. 1 41.6 691.7 47-9 742.5 54-7 793-4 46 47 .7833 35.8 641.9 41.7 692.5 48.0 743-4 54-8 794-2 47 48 .8000 35.9 642.7 41.8 693.4 48.1 744-2 54-9 795-1 48 49 .8167 36.0 643.6 41.9 694-2 48.2 745.1 55-0 795.9 49 50 .8333 36.1 644.4 42.0 695-1 48.3 745.9 55.1 796.8 50 51 .8500 36.2 645-3 42.1 695.9 48.5 746.7 55-3 797.6 51 52 .8667 36.3 646.1 42.2 696.8 48.6 747.6 55.4 798.5 52 53 .8833 36.4 647.0 42.3 697.6 48-7 748.4 55.5 799.3 53 54 .9000 36.S 647.8 42.4 698.5 48.8 749.3 55.6 800.2 54 55 .9167 36.6 648.6 42.5 699.3 48.9 750.1 55.7 801.0 55 56 .9333 36.7 649-5 42.6 700.1 49.0 751.0 55.8 801.9 56 57 .9500 36.8 650.3 42.7 701.0 49-1 751.8 56.0 802.7 57 58 .9667 36.9 651.2 42.8 701.8 49.2 752.7 56.1 803.6 58 59 .9833 37.0 652.0 42.9 702.7 49.3 753.5 56.2 804.4 59 FUNCTIONS OF ONE-DEGREE CURVE 353 Use loo' Chords up to 8° Curves Use 50^ Chords up to 16° Curves Use 25' Chords up to 32° Curves Use 10^ Chords above 32° Curves 1 .0000 I e'' 17° I 8° 19^ 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. 56.3 805.3 63.6 856.4 71.4 907.5 79-7 958.9 I .0167 56.4 806.2 63.8 857.2 71.6 908.4 79.8 959.7 1 2 •0333 56.5 807.0 63.9 858.1 71.7 909.2 79-9 960.6 2 3 .0500 56.7 807.8 64.0 858.9 71.8 9ib.i 80.1 961.4 3 4 .0667 56.8 808.6 64.2 859.8 72.0 910.9 80.2 962.3 4 5 .0833 56.9 809.S 64-3 860.6 72.1 91 1. 8 80.4 963.2 5 6 .1000 57^o 810.4 64.4 861.5 72.2 912.7 80.5 964.0 6 7 .1167 57.1 811. 2 64-5 862.3 72.4 913.5 80.7 964.9 7 8 •1333 57^3 812. 1 64.7 863.2 72.5 914.4 80.8 965.7 8 9 .1500 57.4 812.9 64.8 864.0 72.6 915.2 80.9 966.6 9 10 .1667 57^5 813.8 64.9 864.9 72.8 916.1 81.1 967.4 10 II .1833 57.6 814.6 65.0 865.7 72.9 916.9 81.2 968.3 II 12 .2000 57^7 815.5 65.2 866.6 73.0 917.8 81.4 969.2 12 13 .2167 57.9 816.3 65.3 867.4 73.2 918.6 81.5 970.0 13 14 .2333 58.0 817.2 65.4 868.3 73.3 919.5 81.7 970.9 14 IS .2500 58.1 818.0 65.6 869.1 73.4 920.3 81.8 971.7 IS 16 .2667 58.2 818.9 65.7 870.0 73.6 921.2 81.9 972.6 16 17 .2833 58.3 819.7 65.8 870.8 73.7 922.0 82.1 973.4 17 18 .3000 58.5 820.6 65.9 871.7 73-9 922.9 82.2 974-3 18 19 .3167 S8.6 821.4 66.1 872.5 74.0 923.8 82.4 975.1 19 20 •3333 58.7 822.3 66.2 873.4 74.1 924.6 82.5 976.0 20 21 .3500 58.8 823.1 66.3 874.2 74^3 925.5 82.7 976.9 21 22 .3667 58.9 824.0 66.4 875.1 74.4 926.3 82.8 977.7 23 23 .3833 59-1 824.8 66.6 875.9 74.5 927.2 82.9 978.6 23 24 .4000 59.2 825.7 66.7 876.8 74.7 928.1 83.1 979.4 24 ^1 .4167 59^3 826.5 66.8 877.6 74.8 928.9 83.2 980.3 25 26 •4333 59-4 827.4 67.0 878.5 74.9 929.8 83.4 981.2 26 27 .4500 59-6 828.2 67.1 879.3 75.1 930.6 83-5 982.0 27 28 .4667 59-7 829.1 67.2 880.2 75.2 931-5 83.7 982.9 28 29 .4833 59.8 829.9 67.3 88x.o 75.4 932.3 83.8 983.7 29 30 .5000 59.9 830.8 67.5 881.9 75.5 933.2 84.0 984.6 30 31 .5167 60.0 831.6 67.6 882.7 75.6 934-0 84.1 985.4 31 32 .5333 60.2 832.5 67.7 883.6 75.8 934-9 84-3 986.3 32 33 .5500 60.3 833.3 67.9 884.5 75.9 935-7 84.4 987.2 33 34 •5667 60.4 834.2 68.0 885.3 76.1 936.6 84.6 988.0 34 35 .5833 60.S 835.1 68.1 886.2 76.2 937.5 84.7 988.9 35 36 .6000 60.7 835.9 68.2 887.0 76.3 938.3 84.8 989.7 36 37 .6167 60.8 836.8 68.4 887.9 76.5 939-2 85.0 990.6 37 38 .6333 60.9 837.6 68.5 888.7 76.6 940-0 85.1 991. 5 38 39 .6500 61.0 838.5 68.6 889.6 76.7 940.9 85.3 992.3 39 40 .6667 61.1 839.3 68.8 890.4 76.9 941.7 ?5-4 993-2 40 41 .6833 61.3 840.2 68.9 891.3 77.0 942.6 85.6 994.0 41 42 .7000 61.4 841.0 69.0 892.2 77^1 943.5 85-7 994.9. 42 43 .7167 61.S 841.9 69.2 893.0 77.3 944-3 85.9 995-8 43 44 .7333 61.6 842.7 69-3 893.9 77.4 945.2 86.0 996.6 44 45 .7500 61.8 843.6 69.4 894.7 77.6 946.0 86.2 997-5 45 46 .7667 61.9 844.4 69.6 895.6 77.7 946.9 86.3 998-3 46 47 .7833 62.0 845.3 69.7 896.4 77.8 947-7 86.5 999.2 47 48 .8000 62.1 846.1 69.8 897.3 78.0 948.6 86.6 1 000.0 48 49 .8167 62.3 847.0 70.0 898.1 78.1 949.4 86.8 1000.9 49 50 .8333 62.4 847.8 70.1 899.0 78.3 950.3 86.9 1001.8 50 51 .8500 62.5 848.7 70.2 899.8 78.4 951.1 87.1 I003.6 51 52 .8667 62.6 849.5 70.4 900.7 78.5 952.0 87.2 1003.S 52 53 .8833 62.8 850.4 70.5 901.5 7?-7 952.9 87.4 1004.3 53 54 .9000 62.9 851.2 70.6 902.4 78.8 953.7 87.5 1005.2 54 55 .9167 63.0 852.1 70.8 903.3 79.0 954-6 87.7 1006.0 55 56 •9333 63.1 852.9 70.9 904.1 79.1 955.4 87.8 1006.9 56 57 .9500 63-3 853.8 71.0 905.0 79.2 956.3 88.0 1007.7 57 S8 .9667 63.4 854.7 71.2 905.8 79.4 957.2 88.1 1008.6 S8 59 .9833 63.S 855.5 71.3 906.7 79.5 958.0 88.2 1009.5 59 354 THE SURVEY Use 100' Chords up to 8 " Curves Use 25' Chords up to 32° Use 50 ' Chords up to 16 ° Curves Use 10' Chords above 32 .a QQ 20° 21° 22° 23'' 1 Ext. Tan. Ext. Tan. ^ Ext. Tan. Ext. Tan. o .0000 88.4 1010.4 97.6 1062.0 107.2 1113.8 117.4 1165.8 I .0167 88.5 1011.2 97.7 1062.8 107.4 1114.6 117.6 1166.6 I 2 .0333 88.7 1012.1 97.9 1063.7 107.6 1115.5 117.7 1167.5 2 3 .0500 88.8 1012.9 98.1 1064.5 107.7 1116.4 117.9 1 168.3 3 4 .0667 89.0 1013.8 98.2 1065.4 107.9 1117.3 118.1 1169.2 4 5 .0833 89.1 1014.6 98.4 1066.3 108.0 1118.1 118.3 1170.1 S 6 .1000 89.3 IOI5-S 98.5 1067.2 108.2 1119.0 118.4 1171.0 6 y .1167 89.4 1016.3 98.7 1068.0 108.4 1119.8 118.6 1171.8 7 8 .1333 89.6 1017.2 98.8 1068.9 108.6 1120.7 118.8 1172.7 8 9 .1500 89.7 1018.1 99.0 1069.7 108.7 1121.5 118.9 1173.S 9 lO .1667 89.9 1019.0 99.2 1070.6 108.9 1122.4 119.1 1174.4 10 II .1833 90.0 1019.8 99.3 1071.5 109.0 1123.3 119.3 1175.3 II 12 .2000 90.2 1020.7 99-5 1072.4 109.2 1124.2 119.5 1176.2 12 13 .2167 90.3 1021.5 99.6 1073.2 109.4 1125.0 119.7 1177.0 13 14 .2333 90.5 1022.4 99.8 1074.1 109.6 1125.9 119.8 1177.9 14 IS .2500 90.6 1023.2 99.9 1074.9 109.7 1126.7 120.0 1178.8 IS i6 .2667 90.8 1024.1 lOO.I 1075.8 109.9 1127.6 120.2 1179^7 16 17 .2833 90.9 1024.9 100.2 1076.6 IIO.O 1128.5 120.4 1180.S 17 i8 .3000 91.1 1025.8 100.4 1077.5 II0.2 1129.4 120.5 1181.4 18 19 .3167 91.2 1026.7 100.5 1078.4 1 10.4 1130.2 120.7 I182.2 19 20 •3333 91.4 1027.6 100.7 1079.3 II0.6 1131.1 120.9 1183.1 20 21 •3500 91.6 1028.4 100.9 1080.1 II0.7 1131.9 121.0 1184.0 21 22 .3667 91.7 1029.3 lOI.I 1081.0 II0.9 1132.8 121. 2 1184.9 22 23 .3833 91.9 1030.1 IOI.2 1081.8 III.O 1133.7 121.4 1185.7 23 24 .4000 92.0 103 1. IOI.4 1082.7 III. 2 1134.6 121.6 1186.6 24 25 .4167 92.2 103 1. 8 IOI.5 1083.5 III.4 1135.4 121.7 1187.5 25 26 •4333 92.3 1032.7 IOI.7 1084.4 III.6 1136.3 121.9 1 188.4 26 27 .4500 92.5 I033-S IOI.8 1085.3 III. 7 1137.1 122. 1 1189.2 27 28 .4667 92,6 1034.4 102.0 1086.2 111.9 1138.0 122.3 1 1 90. 1 28 29 •4833 92.8 1035.2 102. 1 1087.0 112. 1 1138.8 122.4 1 190.9 29 30 .5000 92.9 1036.1 102.3 1087.9 112. 3 1139.7 122.6 1191.8 30 31 .5167 93-1 1037.0 102.5 1088.7 112.4 1140.6 122.8 1192.7 31 32 •5333 93-2 1037.9 102.7 1089.6 112.6 1141.5 123.0 1193.6 32 33 .5500 93.4 1038.7 102.8 1090.4 112. 7 1142.3 123.2 1194.4 33 34 .5667 93-5 1039.6 103.0 1091.3 112.9 1143.2 123.3 1195.3 34 35 .5833 93.7 1040.4 103. 1 1092.2 113.1 1 144.0 123.5 1196.2 35 36 .6000 93.9 1041.3 103.3 1093. 1 113.3 1 144.9 123.7 1197.1 36 3t .6167 94.0 1042. 1 103.4 1093.9 113.4 1145.8 123.9 1197.9 37 38 .6333 94.2 1043.0 103.6 1094.8 113.6 1146.7 124.1 1 1 98.8 38 39 .6500 94-3 1043.9 103.8 1095.6 II3-7 1147.S 124.3 1199.6 39 40 .6667 94-5 1044.8 104.0 1096.5 113.9 1 148.4 124.4 1200.5 40 41 .6833 94.6 1045.6 104. 1 1097^4 114.1 1149.2 124.6 1201.4 41 42 .7000 94.8 1046.5 104.3 1098.3 114.3 1150.1 124.8 1202.3 42 43 .7167 94.9 1047.3 104.4 1099.1 114.4 1151.0 124.9 1203. 1 43 44 .7333 9S.I 1048.2 104.6 1 1 00.0 114.6 1151.9 125.1 1204.0 44 ^1 •^12° 95^2 1049.0 104.7 1 100.8 114.8 1152.7 125^3 1204.9 45 46 .7667 95.4 1049.9 104.9 1101.7 115.0 1153.6 125.5 1205.8 46 ^J .7833 95^6 1050.8 105. 1 1102.5 115. 2 1154.5 125.7 1206.7 47 48 .8000 95.7 1051.7 105.3 1103.4 115.3 1155.4 125.8 1207.5 48 49 .8167 95-9 1052.5 105.4 1 104.3 115.5 1156.2 126.0 1208.3 49 SO •8333 96.0 1053.4 105.6 1105.2 115.7 1157.1 126.2 1209.2 50 51 •55^° 96.2 1054.2 105.7 1106.0 115.8 1157.9 126.4 •1210.1 51 52 .8667 96.3 1055.1 105.9 1106.9 116.0 1158.8 126.6 1211.0 52 53 •8833 96.5 1055.9 106. 1 1107.8 116.1 1159.7 126.7 1211.8 53 54 .9000 96.7 1056.8 106.3 1108.6 116.3 1160.6 126.9 1212.7 54 55 .9167 96.8 1057.7 106.4 1 109.4 116.5 1161.4 127.1 1213.6 55 S6 .9333 97.0 1058.6 106.6 1 1 10.3 "5-7 1162.3 127.3 1214.5 56 57 .9500 97.1 1059.4 106.7 mi. 2 116.8 1163.1 127.5 1215.3 57 S8 .9667 97^3 1060.3 106.9 1112.1 117.0 1164.0 127.6 1216.2 58 59 .9833 97.4 1061.1 107.0 1112.9 117. 2 1164.9 127.8 1217.1 59 FUNCTIONS OF ONE-DEGREE CURVE Use loo' Chords up to 8° Curves Use 25' Chords up to 32° Cui-ves Use so' Chords up to 16° Curves Use 10' Chords above 32" Curves 355 to Si g 24° 25" 26"* 27"* 1 .2 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 128.0 1218.0 139.1 1270.3 150.7 1322.9 162.8 1375.6 I .0167 128.2 1218.8 139-3 1271.1 150.9 1323.7 163.0 1376.5 I 2 •0333 128.4 1219.7 139-5 1272.0 151.1 1324.6 163.2 1377.4 2 3 .0500 128.5 1220.5 139-7 1272.9 151-3 132^-5 163.5 1378.3 3 4 .0667 128.7 I22I.4 139.9 1273.8 iSi-5 1326.4 163.7 1379.2 4 5 .0833 128.9 1222.3 140.1 1274.6 151.7 1327.3 163.9 1380.0 5 6 .1000 129.1 1223.2 140.3 1275.5 151.9 1328.1 164.1 1380.9 6 7 .1167 129.3 1224.0 140.4 1276.4 152.1 13290 164-3 1381.8 7 8 .1333 129.5 1224.9 140.6 1277.3 152.3 1329.9 164.5 1382.7 8 9 .1500 129.7 1225.8 140.8 1278.2 152.5 1330.7 164.7 1383.6 9 10 .1667 129.8 1226.7 141.0 1279.1 152.7 1331.6 164.9 1384.5 10 II .1833 130-0 1227.5 141.2 1279-9 152.9 1332.5 165.1 1385.3 11 12 .2000 130.2 1228.4 141-4 1280.8 153.1 1333-4 165-3 1386.2 12 13 .2167 130.4 1229.3 141.6 1281.6 153.3 1334.3 165-5 '^^^' 13 14 .2333 130.6 1230.2 141.8 1282.5 153.5 1335-2 165.7 1388.0 14 15 .2500 130.7 1231.0 142.0 1283.4 153.7 1336.0 '?|-^ 1388.9 15 16 .2667 130.9 I23I.9 142.2 1284.3 153.9 1336.9 166.1 1389-8 16 17 .2833 13I.I 1232.7 142.3 1285.2 154.1 1337.8 '^<'3 1390.6 17 18 .3000 I3i^3 1233-6 142.5 1286.1 154-3 1338.7 166.5 1391.5 18 19 .3167 131.S 1234-5 142.7 1286.9 154-5 1339.5 166.7 1392.4 19 20 .3333 131-7 1235-4 142.9 1287.8 154.7 1340.4 167.0 1393-3 20 21 .3500 131-9 1236.2 143.1 1288.7 154-9 1341.3 167.2 1394-1 21 22 .3667 132.0 1237.1 143.3 1289.6 155.1 1342.2 167.4 1395-0 22 23 .3833 132.2 1238.0 143-5 1290.4 155.3 1343.0 167.6 1395-9 23 24 .4000 132.4 1238.9 143.7 1291.3 155-5 1343.9 167.8 1396.8 24 25 .4167 132.6 1239.7 143.9 1292.2 155-7 1344-8 168.0 1397-7 25 26 26 •4333 132.8 1240.6 144.1 1293.1 1SS.9 1345-7 168.2 1398.6 27 .4500 I33-0 1241.5 144.3 1293.9 156.1 1346.5 168.4 1399-4 27 28 .4667 I33^i 1242.4 144-5 1294.8 156.3 1347.4 168.6 1400.3 28 29 .4833 I33^3 1243.2 144-7 1295.7 156.5 1348.3 168,9 1401.2 29 30 .5000 133-5 1244.1 144.9 1296.6 156.7 1349.2 169.1 169.3 169.5 169.7 169.9 1402.1 30 31 .5167 133.7 1244.9 145-1 1297.4 15^-9 1350.1 1403-0 31 32 •5333 133-9 1245.8 145-3 1298.3 157-1 1351.0 1403-9 32 33 .5500 134.0 1246.7 145-5 1299.2 157.3 1351.8 1404-7 33 34 .5667 134-2 1247.6 145-6 1300.1 157.5 1352.7 1405.6 34 35 .5833 134-4 1248.4 145.8 1300.9 157-7 1353.6 170.1 1406.5 35 36 .6000 134.6 1249.3 146.0 1301.8 157.9 1354.5 170.3 1407-4 36 37 .6167 134-9 1250.2 146.2 1302.7 158.1 1355.3 170.5 1408.3 37 38 •6333 135-0 1251-1 146.4 1303.6 158.3 1356.2 170.8 1409.2 \^l 39 .6500 135.2 1251.9 146.6 1304.4 158.5 1357.1 171.0 1410.0 39 40 .6667 135-4 1252.8 146.8 1305.3 158.7 1358.0 171.2 1410.9 1411.8 40 41 .6833 135.6 1253-7 147-0 1306.2 158.9 1358.9 171.4 41 42 .7000 135-7 1254.6 147-2 1307.1 159.1 ^^IPi 171.6 1412.7 1413-6 42 43 .7167 135.9 1255.4 147-4 1307.9 159-3 1360.6 171.8 43 44 .7333 136.1 1256.3 147-6 1308.8 159.5 1361.5 172.0 1414-5 44 45 .7500 136.3 1257.2 147.8 1309.7 159.7 1362.4 172.2 1415-4 45 146 46 .7667 136.5 1258.1 148.0 1310.6 160.0 ^S^S'S 172.5 1416.3 47 .7833 136.7 1258.9 148.2 1311-5 160.2 1364.2 172.7 1417.1 47 '48 48 .8000 136.9 1259.8 148.4 1312.4 160.4 1365.1 172.9 1418.0 49 .8167 137.1 1260.7 148.6 1313-2 160.6 1365-9 173-1 1418.9 49 50 •8333 137.2 1261.5 148.8 1314-1 160.8 1366.8 173.3 1419.8 50 51 .8500 137.4 1262.4 149.0 1315-0 161.0 1367-7 173-5 1420.7 51 52 .8667 137.6 1263.3 149.2 1315-9 161. 2 1368.6 173-7 1421.6 52 53 •8833 137.8 1264.1 149.4 1316.7 161.4 1369-5 173-9 1422.4 ;53 54 .9000 138.0 1265.0 149-5 1317-6 161.6 1370.4 174-1 1423-3 |54 55 .9167 138.2 1265.9 149-7 1318.5 161.8 1371-2 174.4 1424.2 55 '56 56 •9333 138.4 1266.8 149-9 1319.4 162.0 1372.1 174-6 1425-1 57 .9500 138.6 1267.6 150.1 1320.3 162.2 1373-0 174-8 1426.0 1426.9 57 58 58 .9667 138.7 1268.5 150.3 150.5 1321.1 162.4 1373.9 175.0 59 .9833 138.9 1269.4 1322.0 162.6 1374.7 175.2 1427.7 59 356 THE SURVEY Use loo' Chords up to 8" Curves Use 25' Chords up to 32" Curves 1 Usesc ' Chords up to 16° Curves Use 10 ' Chords above 32"* Curves | 1 6 S) ^0 28° 29° 30« 31° 1 a Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 175-4 1428.6 188.S 1481.9 202.1 1535.3 216.3 1589.0 1' .0167 175.6 1429.5 188.7 1482.8 202.3 1536.2 216.5 1589-9 I 2 .0333 175.8 1430.4 189.0 1483.7 202.6 1537.1 216.8 1590.8 2 3 .0500 176.0 1431.3 189.2 1484.5 202.8 1538.0 217.0 1591.7 3 4 .0667 176.3 1432.2 189.4 1485.4 203.1 1538.9 217.2 1592.6 4 S .0833 176.S 1433.1 189.6 1486.3 203.3 1539.8 217.4 1593.5 5 6 .1000 176.7 1434.0 189.9 1487.2 203.5 1540.7 217.7 1594.4 6 7 .1167 176.9 1434-8 190.1 1488.1 203.7 1S41.6 217.9 1595.3 7 8 .1333 177.1 1435.7 190.3 1489.0 204.0 1542.5 218.2 1596.2 8 9 .1500 177.3 1436.6 190.5 1489.9 204.2 1543.4 218.4 1597.1 9 10 .1667 177.6 1437.5 190.8 1490.8 204.5 1544.3 218.7 1598.0 10 II .1833 177.8 1438.4 191.0 1491.7 204.7 1545.2 218.9 1598.9 11 12 .2000 178.0 1439.3 191.2 1492.6 204.9 1546.0 219.2 1599.8 12 13 .2167 178.2 1440.2 191.5 1493.4 205.1 1546.9 219.4 1600.7 13 14 .2333 178.4 1441.1 191.7 1494.3 205.4 1547.8 219.6 1601.6 14 IS .2500 178.6 1441.9 191.9 1495.2 205.6 1548.7 219.8 1602.5 IS 16 .2667 178.9 1442.8 192.1 1496.1 205.9 1549.6 220.1 1603.4 16 17 .2833 179.1 1443-7 192.3 1497.0 206.1 1550.5 220.3 1604.3 17 18 .3000 179.3 1444.6 192.5 1497.9 206.3 1551.4 220.6 1605.2 18 19 .3167 179.5 1445.5 192.7 1498.8 206.5 1552.3 220.8 1606.1 19 20 .3333 179.7 1446.4 193.0 1499.7 206.8 1553.2 221.1 1607.0 20 21 .3500 179.9 1447.3 193-2 1500.6 207.0 1554.1 221.3 1607.9 21 22 .3667 180.2 1448.2 193-5 1501.S 207.3 1555.0 221.6 1608.8 22 23 .3833 180.4 1449.0 193-7 1502.3 207.5 1555.9 221.8 1609.7 23 24 .4000 180.6 1449.9 193.9 1503.2 207.7 1556.8 222.1 1610.6 24 25 .4167 180.8 1450.8 194.1 1504.1 207.9 1557.7 222.3 1611.5 25 26 .4333 181.0 1451.7 194.4 1505.0 208.2 1558.6 222.6 1612.4 26 27 .4500 181.2 1452.6 194-6 1505.9 208.4 1559.5 222.8 1613.3 27 28 .4667 181.S 1453.5 194.8 1506.8 208.7 1560.4 223.0 1614.2 28 29 •4833 181.7 1454.3 195.0 1507.7 208.9 1561.3 223.2 1615.1 29 30 .5000 181.9 1455.2 195.3 1508.6 209.1 1562.2 223.S 1616.0 30 31 .5167 182.1 1456.1 195.5 1509-5 209.3 1563.1 223.7 1616.9 31 32 .5333 182.3 1457.0 195.7 1510.4 209.6 1564.0 224.0 1617.8 32 33 .5500 182.S 1457-9 195-9 1511-2 209.8 1564.9 224.2 1618.7 33 34 .5667 182.8 1458.8 196.2 1512.1 210.1 1565.7 224.5 1619.6 34 35 .5833 183.0 1459.7 196.4 1513.0 210.3 1566.6 224.7 1620.5 35 36 .6000 183.2 1460.6 196.7 1513.9 210.5 1567.5 225.0 1621.4 36 37 .6167 183.4 1461.4 196.9 1514.8 210.7 1568.4 225.2 1622.3 H 38 •6333 183.6 1462.3 197.1 1515.7 211.0 1569.3 225.5 1623.2 38 39 .6500 183.8 1463.2 197.3 1516.6 211.2 1570.2 225.7 1624.1 39 40 .6667 184.1 1464.1 197.6 1517.5 211.5 1571.1 226.0 1625.0 40 41 .6833 184.3 1465.0 197.8 1518.4 211.7 1572.0 226,2 1625.9 41 42 .7000 184.5 1465.9 198.0 1519-3 212.0 1572.9 226.5 1626.8 42 43 .7167 184.7 1466.8 198.2 1520.1 212.2 1573.8 226.7 1627.7 43 44 .7333 185.0 1467.7 I98.S 1521.0 212.4 1574.7 227.0 1628.6 44 4| .7500 185.2 1468.6 198.7 1521-9 212.6 1575.6 227.2 1629.5 45 46 .7667 185.4 1469-5 198.9 1522.8 212.9 1576.5 227.5 1630.5 46 47 .7833 185.6 1470.3 199.1 1523-7 213.1 1577.4 227.7 1631.4 47 48 .8000 185.9 1471.2 199.4 1524-6 213.4 1578.3 228.0 1632.3 48 49 ,8167 186.1 1472.1 199.6 1525.5 213.6 1579.2 228.2 1633.2 49 50 .8333 186.3 1473.0 199.8 1526.4 213.9 1580.1 228.4 1634.1 50 SI .8500 186.5 1473.9 200.0 1527.3 214.1 1581.0 228.6 1635.0 51 52 .8667 186.8 1474.8 200.3 1528.2 214-4 1581.9 228.9 1635-9 52 53 .8833 187.0 1475.7 200.5 1529.1 214.6 1582.8 229.1 1636.8 53 54 .9000 187.2 1476.6 200.8 1530.0 214-8 1583.7 229.4 1637.7 54 55 .9167 187.4 1477.4 201.0 1530.9 215.0 1584.6 229.6 1638.6 H 56 •9333 187.6 1478.3 201.2 1531.7 215-3 1585.5 229.9 1639.5 56 57 .9500 187.8 1479.2 201.4 1532.6 215.5 1586.3 230.1 1640.4 H 58 .9667 188.1 1 480. 1 201.7 1533.5 215.8 ^S?7.2 230.4 1641.3 S8 59 .9833 188.3 1481.0 201.9 1534.4 216.0 1588.1 230.6 1642.2 59 FUNCTIONS OF ONE-DEGREE CURVE 357 Use loo' Chords up to 8° Curves Use 50' Chords up to 16" Curves Use 25' Chords up to 32° Curves Use 10' Chords above 32° Curves 1 .a 32** 1 33" 34° [ sf 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 230.9 1643.1 246.1 1697-3 261.8 1751.8 278.1 1806.7 I .0167 231.1 1644.0 246.3 1698.2 262.0 1752.7 278.4 1807.6 I 2 •0333 231.4 1644.9 246.6 1699. 1 262.3 1753-7 278.6 1808.5 2 3 .0500 231.6 1645.8 246.8 1700.0 262.6 1754-6 278.9 1809.4 3 4 .0667 231-9 1646.7 247.1 1700.9 262.9 1755.5 279.2 1810.3 4 5 .0833 232.1 1647.6 247.4 1701.8 263.1 1756.4 279.4 1811.2 5 6 .1000 232.4 1648.5 247.7 1702.7 263.4 1757.3 279.7 1812.2 6 7 .1167 232.6 1649.4 247.9 1703.6 263.7 1758.2 280.0 1813.1 7 8 •1333 232.9 1650.3 248.2 1704.5 264.0 I759-I 280.3 18140 8 9 .1500 233.1 1651.2 248.4 1705.4 264.2 1760.0 280.6 1814.9 9 10 .1667 233-4 1652.1 248.7 1706.4 264.5 1761.0 280.8 1815.8 10 II .1833 233-6 1653.0 248.9 1707.3 264.7 1761.9 281.1 1816.7 II 12 .2000 233.9 1653.9 249.2 1708.2 265.0 1762.8 281.4 1817.7 12 13 .2167 234-1 1654-8 249.4 1709.1 265.3 1763.7 281.6 1818.6 13 14 .2333 234.4 1655.7 249-7 1710.0 265.6 1764.6 281.9 1819.5 14 IS .2500 234-6 1656.6 249.9 1710.9 265.9 1765-S 282.2 1820.4 IS 16 .2667 234.9 1657-5 250.2 1711.8 266.1 1766.4 282.5 1821.3 16 17 .2833 235.1 1658.4 250.5 1712.7 266.4 1767.3 282.7 1822.2 17 18 .3000 235.4 1659-3 250.8 1713-6 266.7 1768.3 283.0 1823.2 18 19 .3167 235-6 1660.2 251.0 1714.5 266.9 1769.2 283.3 1824.1 19 20 .3333 235-9 1661.1 251-3 1715.5 267.2 1770.1 283.6 1825.0 20 21 .3500 236.1 1662.0 251.5 1716.4 267.4 1771-0 283.9 1825.9 21 22 .3667 236.4 1662.9 251.8 1717.3 267.7 1771-9 284.2 1826.8 22 23 .3833 236.6 1663.8 252.0 1718.2 268.0 1772.8 284.4 1827.7 23 24 .4000 236.9 1664.7 252.3 1719.1 268.3 1773.7 284.7 1828.7 24 25 .4167 237-1 1665.6 252.6 1720.0 268.6 1774.6 285.0 1829.6 25 26 .4333 237-4 1666.5 252.9 1720.9 268.8 1775.6 285.3 1830.5 26 27 .4500 237-6 1667.4! 253.1 1721.8 269.1 1776.5 285.6 1831.4 27 28 .4667 237.9 1668.3 253.4 1722.7 269.3 1777.4 285.9 1832.3 28 29 .4833 238.1 1669.2 253-6 1723.6 269.6 1778.3 286.1 1833.2 29 30 .5000 238.4 1670.1 1 253-9 1724.6 269.9 1779.2 286.4 1834.2 30 31 .5167 238.7 1671.0 254.1 1725.5 270.1 1780.1 286.7 1835.1 31 32 .5333 239.0 1671.9 254-4 1726.4 270.4 1781.0 287.0 1836.0 32 33 .5500 239.2 1672.8 254.7 1727.3 270.7 1781.9 287.2 1836.9 33 34 .5667 239-5 1673.7 255.0 1728.2 271.0 1782.9 287.5 1837.8 34 35 .5833 239.7 1674.6 255-2 1729-1 271.2 1783.8 287.8 1838.7 35 36 .6000 240.0 1675.5 255.5 1730.0 271.5 1784.7 288.1 1839.7 36 37 .6167 240.2 1676.4 255.7 1730.9 271.7 1785.6 288.4 1840.6 37 38 .6333 240.S 1677.4 256.0 1731.8 272.0 1786.5 288.7 1841.5 38 39 .6500 240.7 1678.3 256.2 1732.7 272.3 1787.4 289.0 1842.4 39 40 .6667 241.0 1679-2 256.5 1733.6 272.6 1788.4 289.2 1843.4 40 41 .6833 241.2 1680.1 256.8 1734-5 272.9 1789-3 289.5 1844.3 41 42 .7000 241.5 1681.0 257.1 1735.5 273.1 1790.2 289.8 1845.2 42 43 .7167 241.7 1681.9 257-3 1736.4 273-4 1791.1 290.1 1846.1 43 44 .7333 242.0 1682.8 257-6 1737.3 273-7 1792.0 290.4 1847.1 44 45 .7500 242.2 1683.7 257.8 1738.2 274-0 1792.9 290.6 1848.0 45 46 .7667 242.5 1684.6 258.1 1739.1 274-2 1793-9 290.9 1848.9 46 47 .7833 242.7 1685.5 "5?-| 1740.0 274-5 1794.8 291.2 1849.8 ^? 48 .8000 243.0 1686.4 258.6 1740.9 274.8 1795.7 291.5 1850.7 48 49 .8167 243-2 1687.3 258.9 1741.8 275.0 1796.6 291.8 1851.6 49 50 .8333 243-5 1688.2 259.2 1742.7 275.3 1797.5 292.0 1852.6 50 51 •?i5° 243-8 1689.1 259.4 1743-6 275.6 1798.4 292.3 1853.5 51 52 .8667 244.1 1690.0 259.7 1744.6 275.9 1799.3 292.6 1854.4 52 53 .8833 244-3 1690.9 259.9 1745.5 276.1 1800.2 292.9 1855.3 53 54 .9000 244.6 1691.8 260.2 1746.4 276.4 1801.2 293-2 1856.3 54 55 .9167 244.8 1692.7 260.5 1747-3 276.7 1802.1 293-4 1857.2 55 56 •9333 245.1 1693.7 260.8 1748-2 277-0 1803.0 293.7 1858.1 56 57 .9500 245-3 1694.6 261.0 1749-1 277-3 1803.9 294.0 1859.0 57 58 .9667 245.6 1695.5 261.3 1750.0 277.5 1804.8 294.3 1859.9 58 59 .9833 245.8 1696.4 261.5 1750.9 277-8 1805.7 294.6 1860.8 59 558 THE SURVEY Use 100' Chords up to 8 ° Curves Use 25' Chords up to 32® Curves Use so' Chords up to 16 ° Curves Use 10' Chords above 32" Curves o ^1 36^ 37** 38'' 39** i i Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 294-9 1861.8 312.3 1917.3 330.2 1973.0 348.7 2029.1 I .0167 295-2 1862.7 312.5 1918.2 330.5 1973.9 349.0 2030.0 I 2 .0333 295.4 1863.6 312.8 1919.1 330.8 1974.9 349.3 2031.0 2 3 .0500 295.7 1864.5 313-1 1920.0 331. 1 1975.8 349.6 2031.9 3 4 .0667 296.0 1865.5 313.4 1921.0 331.4 1976.7 349.9 2032.9 4 5 .0833 296.3 1866.4 313-7 1921.9 331.7 1977.6 350.3 2033.8 5 6 .1000 296.6 1867.3 314.0 1922.8 332.0 1978.6 350.6 2034.7 6 7 ,1167 296.9 1868.2 314-3 1923.7 332.3 1979.5 350.9 2035.6 7 8 •1333 297.2 1869.2 314.6 1924.7 332.6 1980.5 351.2 2036.6 8 9 .1500 297-5 1870.1 314.9 1925.6 332.9 1981.4 351.5 2037.S 9 lO .1667 297-7 1871.0 315.2 1926.S 333.2 1982.3 351.8 2038.5 10 II .1833 298.0 1871.9 315.5 1927.4 333.S 1983.2 352.1 2039.4 II 12 .2000 298.3 1872.9 315.8 1928.4 333.8 1984.2 352.4 2040.4 12 13 .2167 298.6 1873.8 316. 1 1929.3 334.2 1985.1 352.8 2041.3 13 14 .2333 298.9 1874-7 316.4 1930.2 334.S 1986.1 3S3.I 2042.3 14 IS .2500 299.2 1875-6 316.7 1931.1 334.8 1987.0 353.4 2043.2 IS i6 .2667 299.5 1876.5 317.0 1932. 1 335.1 1987.9 353-7 2044.1 16 17 .2833 299.7 1877.4 317.2 1933.0 335.4 1988.8 354.0 2045.0 17 i8 ^000 300.0 1878.4 317.5 1933.9 335.7 1989.8 354.3 2046.0 18 19 .3167 300.3 1879.3 317.8 1934.8 336.0 1990.7 354.6 2046.9 19 20 .3333 300.6 1880.2 318.1 1935.8 336.3 1991.7 354.9 2047.9 20 21 .3500 300.9 1881.1 318.4 1936.7 336.6 1992.6 355.3 2048.8 21 22 .3667 301.2 1882. 1 318.7 1937.6 336.9 1993-6 355.6 2049.8 22 23 .3833 301.5 1883.0 319.0 1938.5 337.2 1994.5 355.9 2050.7 23 24 .4CK)0 301.8 1883.9 319.3 1939.5 337.S 1995.4 356.2 2051.7 24 25 .4167 302.0 1884.8 319.6 1940.4 337.8 1996.3 356.6 2052.6 25 26 •4333 302.3 1885.8 319-9 1941.3 338.1 1997.3 356.9 2053.5 26 27 .4500 302.6 1886.7 320.2 1942.2 338.4 1998.2 357.2 2054.4 27 28 .4667 302.9 1887.6 320.5 1943.2 338.7 1999.2 357.5 2055.4 28 29 .4833 303.2 1888.S j 320.8 1944.1 339.1 2000.1 357.8 2056.3 29 30 .5000 303.5 1889.5 321.1 I94S-0 339.4 2001.0 358.1 2057.3 30 31 .5167 303.8 1890.4 321.4 1945-9 339.7 2001.9 25^4 2058.2 31 32 .5333 304.1 1891.3 j 321.7 1946.9 340.0 2002.9 358.8 2059.2 32 33 .5500 304.3 1892.2 322.0 1947.8 340.3 2003.8 359.1 2 060. 1 33 34 .5667 304.6 1893.2 322.3 1948.8 340.6 2004.8 359.4 2061. 1 34 35 .5833 304.9 1894.1 322.6 1949.7 340.9 2005.7 359.8 2062.0 35 36 .6000 305.2 1895.0 322.9 1950.6 341.2 2006.6 360.1 2063.0 36 37 .6167 305.5 1895-9 323.2 1951.5 341.5 2007.5 360.4 2063.9 37 38 •6333 305.8 1896.9 323.5 1952.5 341.8 2008.5 360.7 2064.8 38 39 .6500 306.1 1897.8 323.8 1953.4 342.1 2009.4 361.0 2065.7 39 40 .6667 306.4 1898.7 324.2 1954.4 342.4 2010.4 361.3 2066.7 (40 41 .6833 306.7 1899.6 324.5 1955.3 342.8 201 1. 3 361.6 2067.6 41 42 .7000 307.0 1900.6 324-8 1956.2 343.1 2012.3 362.0 2068.6 42 43 .7167 307.2 1901.5 325.1 1957.1 343.4 2013.2 362.3 2069.5 43 44 .7333 307.5 1902.4 325.4 1958.1 343-7 2014.1 362.6 2070.5 44 45 .7500 307.8 1903-3 325.7 1959.0 344-0 2015.0 363.0 2071.4 45 46 .7667 308.1 1904.3 326.0 1960.0 344-3 2016.0 363.3 2072.4 46 47 .7833 308.4 1905.2 326.3 1960.9 344-6 2016.9 363.6 2073.3 47 48 .8000 308.7 1906. 1 326.6 1961.8 344-9 2017.9 363.9 2074.2 48 49 .8167 309.0 1907.0 326.9 1962.7 345-3 2018.8 364.2 2075.1 49 50 •8333 309.3 1908.0 327.2 1963.7 345-6 2019.7 364.S 2076.1 50 51 .8500 309.6 1908.9 327.5 1964.6 345-9* 2020.6 364.9 2077.0 51 52 .8667 309.9 1909.8 327.8 1965-5 346.2 2021.6 365.2 2078.0 52 53 .8833 310.2 1910.7 328.1 1966.4 346.5 2022.5 365.5 2078.9 53 54 .9000 310.5 1911.7 328.4 1967.4 346.8 2023.5 365.8 2079.9 54 55 .9167 310.8 1912.6 328.7 1968.3 347-1 2024.4 366.2 2080.8 55 56 .9333 311.1 1913.5 329.0 1969.3 347-4 2025.4 366.5 2081.8 S6 57 .9500 311.4 1914.4 329.3 1970.2 347.8 2026.3 366.8 2082.7 57 58 .9667 311.7 1915.4 329.6 1971.1 348.1 2027.2 367.1 2083.7 58 59 .9833 312.0 1916.3 329.9 1972.0 348.4 2028.1 367.4 2084.6 59 FUNCTIONS OF ONE-DEGRFE CURVE 359 Use loo' Chords up to 8° Curves Use so' Chords up to 16" Curves Use 25' Chords up to 32° Curves Use 10' Chords above 32° Curves a ^1 40'' 41 42" 43° ^ .s Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 367-7 2085.5 387.4 2142.3 407.7 2199.5 428.6 2257.1 I .0167 368.0 2086.4 2?Z-^ 2143.2 408.0 2200.4 429.0 2258.0 I 2 .0333 368.4 2087.4 388.1 2144.2 408.3 2201.4 429-3 2259.0 2 3 .0500 368.7 2088.3 2??-5 2145.1 408.7 2^2.3 429.7 2260.0 3 4 .0667 369-0 2089.3 388.8 2146.1 409.0 2203.3 430.0 2261.0 4 5 •0833 369-4 2090.2 389.1 2147.0 409.4 2204.3 430.4 2261.9 5 6 .1000 369-7 2091.2 389-4 2148.0 409.7 2205.3 430.7 2262.9 6 7 .1167 370.0 2092.1 389.8 2148.9 410.1 2206.2 431. 1 2263.8 7 8 .1333 370.3 2093.1 390.1 2149.9 410.4 2207.2 431.4 2264.8 8 Q .1500 370.7 2094.0 390.4 2150.9 410.8 2208.1 431.8 2265.7 9 ro .1667 371.0 2095.0 390.7 2151.9 411.1 2209.1 432.1 2266.7 10 II •1833 371.3 2095.9 391.1 2152.8 411.5 2210.0 432.4 2267.7 ii 12 .2000 371.6 2096.9 391-4 2153.8 411.8 2211.0 432.8 2268.7 12 13 .2167 372.0 2097.8 391-8 2154.7 412.2 2211.9 433.2 2269.6 13 14 .2333 372.3 2098.8 392.1 2155.7 412.5 2212.9 433.5 2270.6 14 15 .2500 372.6 2099.7 392.4 2156.6 412.9 2213.9 433.9 2271.5 15 16 .2667 372.9 2100.7 392.7 2157.6 413.2 2214.9 434.2 2272.5 16 17 .2833 373-3 2101.6 393-1 2158.5 413.6 2215.8 434.6 2273.5 ^l 18 .3000 373.6 2102.6 393.4 2159.5 413.9 2216.8 434-9 2274.5 18 19 .3167 374.0 2 103. 5 393.7 2160.4 414.3 2217.7 435.3 2275.4 19 20 •3333 374-3 2104.5 394-1 2161.4 414.6 2218.7 435-6 2276.4 20 21 •3500 374.6 2105.4 394-4 2162.3 415-0 2219.6 436.0 2277.3 21 22 .3667 374.9 2106.3 394.7 2163.3 415.3 2220.6 436.3 2278.3 22 23 .3833 375-3 2107.2 395-1 2164.2 415-7 2221.5 436.7 2279.2 23 24 .4000 375-6 2108.2 395.4 2165.2 416.0 2222.5 437.0 2280.2 24 25 .4167 375.9 2109. 1 395.8 2166.1 416.3 2223.4 437-4 2281.2 25 26 •4333 376.2 2110.1 396.1 2167. 1 416.6 2224.4 437.8 2282.2 26 27 .4500 376.6 2111.0 396.5 2168.0 417.0 22254 438.2 2283.1 27 28 .4667 376.9 2 II 2.0 396.8 2169.0 417.3 2226.4 438.5 2284.1 28 29 .4833 377.2 2112.9 397-2 21^9.9 417.7 2227.3 438-9 2285.0 29 30 .5000 '377^5 2113.9 397.5 2170.9 418.0 2228.3 439-2 2286.0 30 31 •5167 377.9 2114.8 397-8 2171.8 418.4 2229.2 439-6 2287.0 31 32 •5333 378.2 2115.8 398.1 2172.8 418.7 2230.2 439-9 2288.0 32 33 .5500 378.S 2116.7 398.5 2173.7 419.1 2231. I 440-3 2288.9 33 34 •5667 378.8 2117.7 398.8 2174.7 419.4 2232.1 440.6 2289.9 34 35 •5833 379.2 2118.6 399.2 2175.6 419.8 2233.0 441 -o 2290.8 35 36 .6000 379.5 2119.6 399.5 2176.6 420.1 2234.0 441-4 2291.8 36 37 .6167 379-8 2120.5 399-9 2177.5 420.5 2235.0 441.8 2292.8 37 38 •6333 380.1 2121.5 400.2 2178.5 420.8 2236.0 442-1 2293.8 38 39 .6500 380.5 2122.4 400.6 2179.4 421.2 2236.9 442.5 2294.7 39 40 .6667 380.8 2123.4 400.9 2180.4 421.5 2237.9 442.8 2295.7 40 41 .6833 381. 1 2124.3 401.2 2181.4 421.9 2238.8 443-2 2296.7 41 42 .7000 381.4 2125.3 401.5 2182.4 422.2 2239-8 443.5 2297.7 42 43 .7167 381.8 2126.2 401.9 2183.3 422.6 2240.7 443.9 2298.6 43 44 •7333 382.1 2127.2 402.2 2184.3 422.9 2241.7 444.2 2299.6 44 45 .7500 382.5 2128.1 402.6 2185.2 423.3 2242.6 444.6 2300.5 45 46 .7667 382.8 2129.1 402.9 2186.2 423.6 2243.6 445.0 2301.5 46 47 •7833 383-1 2130.0 403.3 2187.1 424.0 2244.6 445.4 2302.5 47 48 48 .8000 383.4 2131.0 403.6 2188.1 424.3 2245-6 445-7 2303.5 49 .8167 383.8 2131.9 404.0 2189.0 424-7 2246.5 446.1 2304.4 49 SO •8333 384.1 2132.9 404.3 2190.0 425-0 2247-5 446.4 2305.4 50 SI .8500 384.5 2133.8 404.6 2190.9 425-4 2248.4 446.8 2306.3 51 52 .8667 384.8 2134-7 404.9 2191.9 425-7 2249-4 447.1 2307.3 52 53 .8833 385.1 2135^6 405.3 2192.8 426.1 2250.3 447-5 2308.3 53 54 .9000 385.4 2136.6 405.6 2193.8 426.4 2251.3 447.8 2309.3 54 55 .9167 385.8 2137.5 406.0 2194.7 426.8 2252.3 448.2 2310.2 55 56 •56 .9333 386.1 2138.5 406.3 2195.7 427.1 2253.3 448.6 2311.2 57 .9500 386.5 2139.4 406.7 2196.6 427.5 2254.2 449.0 2312. 1 ^l 58 .9667 386.8 2140.4 407.0 2197.6 427.8 2255.2 449.3 2313.1 58 59 •9833 387.1 2141.3 407-4 2198.5 428.2 2256.1 449.7 2314.1 59 360 THE SURVEY Use 100' Chords up to S" Use so' Chords up to 16° Curves Curves Use 25' Chords up to 32° Curves Use 10' Chords above 32* Curves G s 44" 45 46 V 47** 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 450.0 2315-1 472.1 2373.4 494.8 2432.2 518.3 2491.S I .0167 450.4 2316.0 472.5 2374-4 495.2 2433.2 S18.7 2492.4 I 2 •0333 450.7 2317.0 472.9 2375-4 495.6 2434.2 519.0 2493-4 2 3 .0500 45I-I 2318.0 473.3 2376.3 496.0 2435.1 519.4 2494-4 3 4 .0667 451.5 2319.0 473.6 2377-3 496.4 2436.1 519.8 2495.4 4 5 .0833 451-9 2319.9 474.0 2378.3 496.7 2437.1 520.2 2496.4 5 6 .1000 452.2 2320.9 474.4 2379-3 497.2 2438.1 520.6 2497.4 6 7 .1167 452.6 2321.8 474.8 2380.2 497.6 2439.1 521.0 2498.4 7 8 .1333 452.9 2322.8 475.1 2381.2 497-9 2440.1 521.4 2499.4 8 9 .1500 453.3 2323.8 475.5 2382.2 498-3 2441.1 521.8 2500.4 9 10 .1667 453.7 2324.8 475-9 2383-2 498.7 2442.1 522.2 2501.4 10 II .1833 454.1- 2325.7 476.3 2384.2 499-1 2443.0 522.6 2502.4 II 12 .2000 454.4 2326.7 476.6 2385.2 499-5 2444.0 523.0 2503.4 12 13 .2167 454-8 2327.7 477-0 2386.1 499-9 2445.0 523-4 2504.4 13 14 •2333 455.1 2328.7 477-4 2387.1 500.3 2446.0 523.8 2505.4 14 IS .2500 455.5 2329.6 477-8 2388.1 500.7 2447.0 524.2 2506.3 IS 16 .2667 455-9 2330.6 478.1 2389.1 501.0 2448.0 524.6 2507.3 16 17 .2833 456.3 2331.6 478.5 2390.0 501.4 2449.0 525.0 2508.3 17 18 .3000 456.6 2332.6 478.9 2391-0 501.8 2449.9 525.4 2509.3 18 19 •3167 457-0 2333-5 479-3 2392.0 502.2 2450.9 525.8 2510.3 19 20 •3333 457-3 2334-5 479-6 2393-0 502.6 2451.9 526.2 2511.3 20 21 .3500 457-7 2335-4 480.0 2393-9 503.0 2452.9 526.6 2512.3 21 22 .3667 458.1 2336.4 480.4 2394.9 503-4 2453.9 527.0 2513.3 22 23 .3833 458.5 2337-4 480.8 2395.9 503.8 2454.9 527.4 2514.3 23 24 .4000 458.8 2338.4 481. 1 2396.9 504. 1 2455.9 527.8 2515.3 24 25 .4167 459-2 2339-3 481.S ^397.8 S04-5 2456.8 528.2 2516.3 25 26 .4333 459-5 2340.3 481.9 2398.8 504-9 ^457-8 528.6 2517.3 26 27 .4500 459-9 2341-3 482.3 2399-8 505.3 2458.8 529.0 2518.3 27 28 .4667 460.3 2342.3 482.6 2400.8 505-7 2459.8 529-4 2519.3 28 29 .4833 460.7 2343-2 483-0 2401.8 506.1 2460.8 529-8 2520.2 29 30 .5000 461.0 2344-2 483-4 2402.8 506.5 2461.8 530.2 2521.2 30 31 •5167 461.4 2345 -X 483.8 2403.7 506.9 2462.8 530.6 2522.2 31 32 .5333 461.7 2346.1 484.2 2404-7 507-3 2463.8 531.0 2523.2 32 33 •5500 462.1 2347.1 484-6 2405.7 507-7 2464.7 531.4 2524.2 33 34 .5667 462.5 2348.1 484-9 2406.7 508.0 2465-7 531.8 2525.2 34 35 .5833 462.9 2349.0 485-3 2407.6 508.4 2466.7 532.2 2526.2 35 36 .6000 463.2 2350.0 485-7 2408.6 508.8 2467.7 532.6 2527.2 36 37 .6167 463-6 2351-0 486.1 2409.6 509.2 2468.7 533.0 2528.2 37 38 •6333 463.9 2352.0 486.5 2410.6 509.6 2469.7 533.4 2529.2 38 39 .6soo 464.3 2352.9 486.9 2411.6 510.0 2470.7 533-8 2530.2 39 40 .6667 464.7 2353.9 487.2 2412.6 S10.4 2471.7 534-2 2531.2 40 41 .6833 465.0 2354.9 487.6 2413-5 510.8 2472.6 534-6 2532.2 41 42 .7000 465.4 2355.9 4?^° 2414-5 511.I 2473.6 535.0 2533.2 42 43 .7167 465.8 2356.8 488.4 2415-5 511.5 2474.6 535.4 2534.2 43 44 .7333 466.2 2357.8 488.7 2416.5 511.9 2475.6 535.8 2535.2 44 45 .7500 466.5 2358.8 489.1 2417-5 512.3 2476.6 536.2 2536.2 45 46 .7667 466.9 2359-8 489-5 2418.5 512.7 2477.6 536.6 2537-2 46 47 .7833 467.3 2360.7 489-9 2419-4 513.I 2478.6 537.0 2538.2 47 48 .8000 467.7 2361.7 490.3 2420.4 513.5 2479.6 537.4 2539.2 48 49 .8167 468.0 2362.7 490.7 2421.4 S13.9 2480.6 537.8 2540.2 49 50 .8333 468.4 2363.7 491.0 2422.4 514.3 2481.6 538.2 2541.2 SO SI .8500 468.8 2364.6 491.4 2423.4 514.7 2482.5 538.6 2542.2 SI 52 •?^^7 469.1 2365.6 491.8 2424.4 515.I 2483.5 539.0 2543.2 52 S3 .8833 469.5 2366.6 492.2 2425.3 S15.5 2484.5 539.4 2544-2 53 54 .9000 469.9 2367.6 492.5 2426.3 515.9 2485-5 539.8 2545.2 54 SS .9167 470.3 2368.5 492.9 2427-3 516.3 2486.5 S40.2 2546.2 5| S6 •9333 470.6 2369.5 493.3 2428.3 516.7 2487.5 540.6 2547.2 56 57 .9500 471.0 2370.5 493.7 2429-2 517. 1 2488.5 541.0 2548.2 ^l 58 .9667 471.4 2371.5 494.1 2430.2 517.5 2489.5 541.4 2549.2 58 59 .9833 471.8 2372.4 494.5 2431.2 517.9 2490.5 541.9 2550.1 59 FUNCTIONS OF ONE-DEGREE CURVE Use loo' Chords up to 8" Curves Use 25' Chords up to 32" Curves Use so' Chords up to 16" Curves Use 10' Chords above 32° Curves 361 1 G *S8 48" 49^ 50° 51** .s Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 542.3 255I-I 567.0 2611.3 592.4 2671.9 618.5 2733.0 I .0167 542^7 2552.1 567-4 2612.3 592.8 2672.9 618.9 2734.1 I 2 .0333 543-1 2553.1 567.8 2613.3 593.2 2673.9 619.3 2735.1 2 3 .0500 543.5 2554^1 568.3 2614.3 593.7 J!675.o 619.8 2736.1 3 4 0667 543-9 2555.1 568.7 2615.3 594.1 2676.0 620.2 2737.1 4 5 •0833 544-3 2556.1 569.1 2616.3 594.5 2677.0 620.7 2738.2 5 6 .1000 544-7 2557.1 569-5 2617.3 594.9 2678.0 621. 1 2739.2 6 7 .1167 545-1 2558.1 569.9 2618.3 595-4 2679.0 621.6 2740.2 7 8 .1333 545-5 2559.1 570.3 2619.3 595.8 2680.0 622.0 2741.2 8 9 .1500 546-0 2560.1 570.8 2620.4 596.2 2681.1 622.5 2742.3 9 10 .1667 546-4 2561.1 571.2 2621.4 596.7 2682.1 622.9 2743.3 10 II .1833 546-8 2562.1 571.6 2622.4 597.1 2683.1 623.3 2744.3 II 12 .2000 547.2 2563.1 572-0 2623.4 597.5 2684.1 623.7 2745.3 12 13 .2167 547-6 2564.1 572.4 2624.4 598.0 2685.1 624.2 2746.4 13 14 .2333 548.0 2565.1 572.8 2625.4 598.4 2686.1 624.6 2747.4 14 IS .2SOO 548.4 2566.1 573-3 2626.4 598.9 2687.2 625.1 2748.4 15 16 .2667 548.8 2567.1 573-7 2627.4 599.3 2688,2 625.5 2749.4 16 17 •2833 549-2 2568.1 574-1 2628.4 599.7 2689.2 626.0 2750.5 17 18 .3000 549-6 2569.1 574.5 2629.4 600.1 2690.2 626.4 2751.5 18 19 .3167 550.1 2570.1 574.9 2630.4 600.6 2691.3 626.9 2752.5 19 20 •3333 550.5 2571-1 575.3 2631.4 601.0 2692.3 627.3 2753.5 20 21 .3500 550.9 2572.1 575.8 2632.5 601.S 2693.3 627.8 2754.6 21 22 .3667 551-3 2573-1 576.2 2633-5 601.9 2694.3 628.2 2755.6 22 23 .3833 5SI-7 2574-1 576.6 2634-5 602.3 2695.3 628.7 2756.7 23 24 .4000 552.1 2575-1 577.0 2635-5 602.7 2696.3 629.1 2757.7 24 25 .4167 552-5 2576.1 577.5 2636.5 603.2 2697.4 629.6 2758.7 25 26 •4333 552.9 2577-1 577.9 2637.5 603.6 2698.4 630.0 2759.7 26 27 .4500 553-3 2578.1 578.3 2638.5 604.1 2699.4 630.5 2760.8 27 28 .4667 553.7 2579-1 578.7 2639-5 604.5 2700.4 630.9 2761.8 28 29 .4833 554-2 2580.1 579.2 2^40.5 604.9 2701.4 631.4 2762.8 29 30 .5000 554.6 2581.1 579-6 2641.S 605.3 2702.4 631.8 2763.8 30 31 .5167 55S.O 2582.1 580.0 2642.5 605.8 2703.5 632.3 2764.9 31 32 .5333 555.4 2583.1 580.4 2643-5 606.2 2704-5 632.7 2765.9 32 33 •SSoo 555.8 2584.1 580.9 2644.6 606.6 2705.S 633.2 2766.9 33 34 .5667 556.2 2585.1 581.3 2645.6 607.0 2706.5 633.6 2767.9 34 35 .5833 556.6 2586.2 581.7 2646.6 607.5 2707.6 634.1 2769.0 35 36 .6000 557.0 2587.2 582.1 2647.6 607.9 2708.6 634.5 2770.0 36 37 .6167 557.4 2588.2 582.6 2648.6 608.4 2709.6 634-9 2771.0 H 38 .6333 557.8 2589.2 583.0 2649.6 608.8 2710.6 ^JH 2772.0 38 39 .6500 558.3 2590.2 583.4 2650.6 609.3 2711.6 635.8 2773.1 39 40 .6667 558.7 2591.2 583.8 2651.6 609.7 2712.6 636.2 2774.1 40 41 .6833 559-1 2592.2 584.3 2652.7 610.1 2713.7 636.7 2775.2 41 42 .7000 559-5 5593.2 584.7 2653-7 610.S 2714.7 637.1 2776.2 42 43 .7167 559-9 2594.2 585.1 2654^7 611.0 2715.7 637.5 2777.2 43 44 .7333 560.3 2595-2 585.5 2655-7 611.4 2716.7 638.0 2778.2 44 45 .7500 S60.8 2596.2 586.0 2656.7 611.9 2717.8 638.5 2779.3 "^l 46 .7667 561.2 2597.2 586.4 2657-7 612.3 2718.8 638.9 2780.3 46 47 •7833 561.6 2598.2 586.8 2658.7 612.8 2719.8 639.4 2781.3 47 48 .8000 562.0 2599.2 587.2 2659.7 613.2 2720.8 639.8 2782.3 48 49 .8167 562.4 2600.2 587.7 2660.8 613.7 2721.8 640.3 2783.4 49 SO •8333 S62.8 2601.2 588.1 2661.8 614.1 2722.8 640.7 2784.4 50 SI .8500 563-3 2602.2 588.5 2662.8 614.5 2723.9 641.2 2785.4 51 52 .8667 563-7 2603.2 588.9 2663.8 614.9 2724.9 641.6 2786.4 52 53 .8833 564-1 2604.2 589.4 2664.8 615.4 2725.9 642.1 ^7^2'^ 53 54 .9000 564.5 2605.2 589.8 2665.8 615.8 2726.9 642.S 2788.S 54 55 .9167 564.9 2606.2 590. 2 2666.8 616.3 2728.0 643.0 2789.6 H 56 .9333 565-3 2607.2 590.6 2667.8 616.7 2729.0 643.4 2790.6 56 H •9500 565.8 2608.3 591.1 2668.9 617.2 2730.0 643.9 2791.6 57 58 .9667 566.2 2609.3 591.5 2669.9 617.6 2731.0 644.3 2792.6 58 59 •9833 566.6 2610.3 592.0 2670.9 1 618.1 2732.0 644-8 2793.7 59 362 THE SURVEY Use 100' Chords UD to 8 ° Curves Use 25' Chords up to 10' Chords above K^""" ves Use 50' Chords up to 16 ° Curves Use J 32" Curves "3 52° 53*" 54° 55° "3 c Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 645^2 2794-7 672.7 2856.9 700.9 2919.S 729.9 2982.8 2983.9 1 .0167 .0333 .0500 645-7 2795-8 673.2 2857.9 701.4 2920.6 730.4 I 2 646.1 2796.8 673.7 2858.9 701.9 2921.6 730.9 2984.9 2 3 4 646.6 2797.8 674.2 2860.0 702.4 2922.7 731.4 2986.0 3 .0667 647.0 2798.8 674.6 2861.0 702.8 2923.8 731.9 2987.1 4 c .0833 .1000 647.5 2799-9 675.1 2862.1 703.3 2924.9 732.4 2988.2 5 6 647-9 2800.9 675-5 2863.1 703.8 2925.9 732.9 2989.2 6 7 8 .1167 .1333 648.4 2802.0 676.0 2864.2 704.3 2927.0 733-4 2990.3 7 648.9 2803.0 676.4 2865.2 704.8 2928.0 733.8 2991.3 8 9 .1500 649^4 2804.0 676.9 2866.3 705.3 2929.1 734.3 2992.4 9 10 .1667 649.8 2805.0 677-4 2867.3 705.7 2930.1 734.8 2993.4 10 II .1833 .2000 650-3 2806.1 677-9 2868.4 706.2 2931.2 735-3 2994.5 II 12 650.7 2807.1 678.3 2869.4 706.7 2932.2 735-8 ^^^H 12 13 .2167 651.2 2808.2 678.8 2870.5 707.2 2933.3 736.3 2996.6 13 14 .2333 651.6 2809.2 679.2 2871.5 707.7 2934.3 736.8 2997-7 14 ;^ .2500 .2667 652.1 2810.2 679-7 2872.5 708.2 2935.4 737.3 2998.8 15 652.5 2811.2 680.2 2873.5 708.6 2936.4 737.8 2999-8 16 17 18 .2833 ."^OOO 653.0 2812.3 680.7 2874.6 709.1 2937-5 738-2 3000.9 ^l 653-4 2813.3 681. 1 2875.6 709.6 2938.5 738.7 3001.9 18 19 .3167 653-9 2814.4 681.6 2876.7 710.1 2939.6 739.2 3003.0 19 20 •3333 654-3 2815.4 682.0 2877.7 710.5 2940.6 739.7 3004.0 20 21 .3500 654-8 2816.4 682.5 2878.8 711.0 2941.7 740.2 3005.1 3006.2 21 22 .3667 655-2 2817.4 683.0 2879-8 7II-5 2942.7 740.7 22 23 24 .3833 .4000 655.7 2818.5 683.5 2880.9 712.0 2943-8 741.2 3007.3 23 656.2 2819.5 683.9 2881.9 712.S 2944-8 741.7 3008.3 24 25 .4167 656.7 2820.6 684.4 2883.0 713-0 2945.9 742.2 3009.4 25 26 •4333 657-1 2821.6 684.9 2884.0 713-4 2946.9 742.7 3010.4 26 27 .4500 657.6 2822.6 685.4 2885.1 713-9 2948.0 743-2 3011.5 27 28 28 .4667 658.0 2823.6 685.8 2886.1 714-4 2949.0 743-7 3012.5 3013.6 29 •4833 658.5 2824.7 686.3 2887.1 714.9 2950.1 744.2 29 30 .«;ooo 658.9 2825.7 686.7 2888.1 71S-3 2951.1 744-7 3014.7 30 31 •3 T^ .5167 659.4 2826.8 687.2 2889.2 715.8 2952-2 745-2 3015.8 31 32 33 34 •5333 .5500 .5667 659.8 2827.8 687.7 2890.2 716.3 2953-2 745-7 3016.8 32 660.3 2828.8 688.2 2891.3 716.8 2954-3 746.2 3017.9 33 660.7 2829.8 688.6 2892.3 717-3 2955-3 746.7 3018.9 34 35 36 37 38 39 .5833 .6000 661.2 2830.9 689.1 2893.4 717.8 2956.4 747.2 3020.0 35 36 66x6 2831.9 689.6 2894.4 718.2 2957.S 747.7 3021.1 .6167 .6333 .6500 662.1 2833.0 690.1 2895-5 718.7 2958.6 748.2 3022.1 11 662.5 2834.0 690.5 2896.5 719.2 2959.6 748.7 3023.2 663.0 2835.1 691.0 2897.6 719-7 2960.7 749.2 3024.3 39 40 .6667 663.5 2836.1 691.5 2898.6 720.2 2961.7 749.7 3025.3 3026.4 40 41 42 43 •6833 .7000 .7167 664.0 2837.2 692.0 2899.7 720.7 2962.8 750.2 41 664.4 664.9 2838.2 2839.2 692.4 692.9 2900.7 2901.8 721.1 721.6 2963.8 2964.9 750.7 751.2 3027.5 3028.6 3029.6 42 43 44 •7333 665.3 2840.2 693.4 2902.8 722.1 2965.9 751.7 44 45 .7500 665.8 2841.3 693.9 2903.9 722,6 2967.0 752.2 752.6 3030.7 46 46 .7667 666.2 2842.3 694-3 2904.9 723.1 2968.0 3031.7 3032.8 3033.8 47 •7833 666.7 2843.4 694.8 2906.0 723-6 2969.1 753.1 753.6 47 48 48 .8000 667.2 2844.4 695-3 2907.0 724-1 2970.1 49 .8167 667.7 2845-5 695-8 2908.1 724.6 2971.2 754.1 3035.0 49 50 .8333 668.1 2846.5 696.2 2909.1 725.0 2972.2 754.6 3036.0 50 51 .8500 668.6 2847.5 696.7 2910.2 725-5 2973.3 75S-I 755-6 3037.1 3038.1 51 52 .8667 669.0 2848.5 697.1 2911.2 726.0 2974.4 52 S3 .883J 669-5 2849.6 697.6 2912.3 726.5 2975.S 756.1 3039.2 53 54 .9000 669.9 2850.6 698.1 2913.3 727.0 2976.5 756.6 3040.2 54 u •9167 •9^33 .9500 .9667 .9833 670.4 670.9 2851.7 2852.7 698.6 699.0 2914.4 2915.4 727.S 728.0 2977-6 2978.6 757-1 757-6 3041.3 3042.4 11 57 58 59 671^4 671.8 2853.8 2854.8 699-5 700.0 2916.5 2917.5 728.5 729.0 2979.7 2980.7 758.6 3043.5 3044.5 3045.6 11 672.3 2855.9 700.5 2918.5 . 729-5 2981.8 759.1 59 FUNCTIONS OF ONE-DEGREE CURVE 363 Use icx)' Chords up to 8 ° Curves Use 2. ;' Chords up to 32° Curves Use 50 ' Chords up to 16 ° Curves Use 10' Chords above 32° Curves s 56'' 57° 58° 59** Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 759.6 3046.6 790.2 3111.1 821.4 3176.1 853-S 3241.9 I .0167 760.1 3047.7 790.7 3112.2 821.9 3177-2 854.0 3243.0 I 2 -0333 760.6 3048.8 791-2 3113.3 822.5 3178.3 854.6 3244.1 2 3 .0500 761. 1 3049.9 791.7 3114.4 823.0 3179.4 855.1 3245.2 3 4 .0667 761.6 3050.9 792.2 3115.4 823.5 3i'8o.5 855-7 3246.3 4 5 .0833 762.2 3052.0 792.8 3116.5 824.1 3181.6 856.2 3247.4 5 6 .1000 762.7 3053.1 793.3 3117.6 824.6 3182.7 856.8 3248.5 6 7 .1167 763.2 3054-2 793.8 3118.7 825.2 3183.8 857.3 3249.6 7 8 -1333 763.7 3055-2 794.3 3119.7 825.7 3184.9 857-9 3250.7 8 9 .1500 764.2 3056.3 794-8 3120.8 826.2 3186.0 858.5 3251.8 9 10 .1667 764.7 3057-4 795.3 3121.9 826.7 3187.1 859.0 3252.9 10 II .1833 765.2 3058.5 795.8 3123.0 827.3 3188.2 859-S 3254-0 II 12 .2000 765-7 3059.5 796.3 3124.1 827.8 3189.2 860.0 3255.1 12 13 .2167 766.2 3060.6 796.9 3125.2 828.4 3190.3 860.6 3256.2 13 14 .2333 766.7 3061.6 797-4 3126.2 828.9 3191.4 861.1 3257.3 14 IS .2500 767.2 3062.7 797.9 3127.3 829.4 3192.5 861.7 3258.4 IS 16 .2667 767.7 3063.8 798.4 3128.4 829.9 3193.6 862.2 3259.5 16 17 .2833 768.2 3064.9 798.9 3129.5 830.5 3194.7 862.8 3260.6 17 18 .3000 768.7 3065.9 799.4 3130.6 831.0 3195.8 863.3 3261.7 18 19 .3167 769.2 3067.0 799-9 3131.7 831.5 3196.9 863.8 3262.8 19 20 .3333 769.7 3068.1 800.S 3132.7 832.1 3198.0 864.4 3263.9 20 21 .3500 770.3 3069.2 801.0 3133.8 832.5 3199.1 864.9 3265.0 21 22 .3667 770.8 3070.2 801.5 31349 833-1 3200.2 865.S 3266.1 22 23 .3833 771.3 3071.3 802.0 3136.0 833-6 3201.3 866.0 3267.2 23 24 .4000 771-8 3072.4 802.5 3137-0 834-2 3202.4 866.6 3268.3 24 ^1 .4167 772.3 3073.5 803.1 3138.1 834-7 3203.5 867.1 3269.4 25 26 .4333 772.8 3074.5 803.6 ■ 3139.2 835.3 3204.5 867.7 3270.5 26 27 .4500 773.3 3075.6 804.2 3140.3 835.8 3205.6 868.2 3271.6 27 28 .4667 773.8 3076.6 804.7 3141-4 836.3 3206.7 868.8 3272.7 28 29 30 .4833 .5000 774.3 774.8 3077.7 3078.8 805.2 805.7 3142.5 836.8 3207.8 3208.9 869.3 869.9 3273.8 3274.9 29 30 3143-5 837.4 31 -5167 775.3 3079.9 806.3 3144-6 837.8 3210.0 870.5 3276.0 31 32 -5333 775.8 3080.9 806.8 3145-7 838.4 3211.1 871.0 3277.1 32 33 .5500 776.3 3082.0 807.3 3146.8 838.9 3212.2 871.6 3278.2 33 34 .5667 776.8 3083.1 807.8 3147.9 839.5 3213-3 872.1 3279.4 34 35 .5833 777.3 3084.2 808.3 3149.0 840.0 3214.4 872.7 3280.5 35 36 .6000 777.8 3085.2 808.8 3150.0 840.6 3215.5 873-2 3281.6 36 H .6167 778.4 3086.3 809.4 3151-1 841. 1 3216.6 873.8 3282.7 37 38 .6333 778.9 3087.4 809.9 3152.2 841.6 3217.7 874.3 3283.8 38 39 .6500 779.4 3088.5 810.4 3153.3 842.1 3218.8 874-9 3284.9 39 40 .6667 779.9 3089.6 810.9 3154-4 842.7 3219.9 875.4 3286.0 40 41 .6833 780.4 3090.7 811. 5 3155.5 843.1 3221.0 876.0 3287.1 41 42 .7000 780.9 3091.7 812.0 3156.6 843.8 3222.1 876.5 3288.2 42 43 .7167 781.4 3092.8 812.5 3157.7 844.2 3223.2 877.0 3289.3 43 44 .7333 781.9 3093-9 813.0 3158.7 844.9 3224.3 877.6 3290.5 44 45 .7500 782.5 3095.0 813.6 3159.8 845.5 3225.4 878.1 3291.6 45 46 .7667 783.0 3096.0 814.1 3160.9 846.0 3226.5 878.7 3292.7 46 47 .7833 783.5 3097.1 814.6 3162.0 846.5 3227.6 879.2 3293.8 47 48 .8000 784.0 3098.2 815. 1 31.63 I 847.0 3228.7 879.8 3294.9 48 49 .8167 784.5 3099.3 815.7 3164-2 847.6 3229.8 880.3 3296.0 49 50 .8333 785.0 3100.3 816.2 3165.3 848.1 3230.9 880.9 3297.1 50 SI .8500 785.5 3101.4 816.7 3166.4 848.7 3232.0 881.5 3298 2 51 52 •?5^7 786.0 3102.5 817.2 3167.4 849.2 3233.1 882.0 3299.3 52 S3 •8833 786.6 3103.6 817.8 3168.5 849.8 3234.2 882.6 3300.4 53 54 .QCXXJ 787.1 3104.6 818.3 3169.6 850.3 3235.3 883.1 3301.5 54 55 .9167 787.6 3105.7 8x8.8 3170.7 850.9 3236.4 883.7 3302.6 55 S6 •9333 788.1 3106.8 819.3 3171.8 851.4 3237.5 884.2 3303.8 56 57 .9500 788.6 3107.9 819.9 3172.9 852.0 3238.6 884.8 3304.9 57 S8 .9667 789.1 3108.9 820.4 3174.0 852.5 3239.7 885.3 3306.0 58 59 1 .9833 789.7 3110.0 820.9 3175. 1 853.0 3240.8 885.9 3307.1 59 364 THE SURVEY Use loo' Chords up to 8° Curves Use 50' Chords up to 16° Curves Use 25' Chords up to 32* Curves Use 10' Chords above 32° Curves s a 60° 61" 62*^ 63° 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 886.4 3308.2 920.2 3375.2 954.8 3442.9 990.3 3511.3 I .0167 886.9 3309.3 920.8 3376.3 955.4 3444.1 990.9 3512.4 I 2 .0333 887.5 3310.4 921.4 3377.4 956.0 3445.2 991.5 3513.6 2 3 .0500 888.1 3311.5 922.0 3378.5 956.6 3446.3 992.1 3514.8 3 4 .0667 888.7 3312.7 922.S 3379.7 957.2 3447.5 992.7 3515.9 4 5 .0833 889.3 3313.8 923.0 3380.8 957-7 3448.6 993.3 3517.1 5 6 .1000 889.8 3314.9 923.6 3381.9 958.3 3449.7 993.9 3518.2 6 7 .1167 890.3 3316.0 924.2 3383.1 958.9 3450.9 994.S 3519.3 7 8 •1333 890.9 3317. 1 924.8 3384.2 959-5 3452.0 995.1 3520.5 8 9 .1500 891-5 3318.2 925.3 3385.3 960.1 3453.2 995.7 3521.6 9 10 .1667 892.0 3319.3 925.9 3386.4 960.7 3454.3 996.3 3522.8 10 II .1833 892.6 3320.5 926.5 3387.5 961.3 3455-4 996.9 3524.0 II 12 .2000 893.1 3321.6 927-1 3388.7 961.9 3456.6 997.5 3525.1 12 13 .2167 893.7 3322.7 927.6 3389.8 962.4 3457.7 998.1 3526.2 13 14 .2333 894.3 3323.8 928.2 3390.9 963-0 3458.8 998.7 3527.4 14 15 .2500 894.8 3324.9 928.7 3392-1 963-6 3460.0 999.3 3528.6 IS 16 .2667 895.4 3326.0 929.3 3393-2 964.2 3461.1 999.9 3529.7 16 17 .2833 895.9 3327.1 929.9 3394.3 964.8 3462.3 1000.5 3530.9 ^l 18 .3000 896.5 3328.3 930.5 3395-4 965.4 3463.4 lOOI.I 3532.0 18 19 .3167 897.0 3329.4 931.0 3396.6 966.0 3464.6 IOOI.7 3533.i_ 19 20 .3333 897.6 3330.5 931.6 3397.7 966.6 3465.7 1002.3 3534.3 20 21 •3500 898.2 3331.6 932.2 3398.8 967.2 3466.8 1002.9 3535.4 21 22 .3667 898.8 3332.7 932.8 3399.9 967.8 3467.9 1003.5 3536.6 22 23 .3833 899.3 3333.8 933.3 3401.1 968.3 3469.0 1 004. 1 3537-8 23 24 .4000 899.9 3334.9 933.9 3402.2 968.9 3470.2 1004.7 3538.9 24 25 .4167 900.5 3336.1 934.5 3403.3 ' 969.5 3471.3 1005.3 3540.0 25 26 .4333 901.0 3337.2 935.1 3404.4 970.1 3472.5 1005.9 3541.2 26 27 .4500 901.6 3338.3 935.7 3405-6 970.7 3473.6 1006.5 3542.3 27 28 .4667 902.1 3339.4 936.3 3406.7 971.3 3474.7 1007. 1 3543.5 28 29 .4833 902.7 3340.5 936.8 3407.8 971.9 3475.9 1007.8 3544.6 29 30 .5000 903.2 3341.6 937.4 3408.9 972.S 3477.0 1008.4 3545-8 30 31 •5167 903.8 3342.7 938.0 3410.1 973.0 3478.1 1009.0 3546.9 31 32 •5333 904.4 3343.9 938.6 3411.2 973.6 3479.3 1009.6 3548.1 32 33 •5SOO 904.9 3345.0 939.1 3412.3 974.2 3480.S I0I0.2 3549.2 33 34 .5667 905.5 3346.1 939.7 3413-5 974.8 3481.6 I0I0.8 3550.4 34 35 .5833 906.1 3347.2 940.4 3414.6 975-4 3482.7 IOII.4 3551.6 35 36 .6000 906.6 3348.3 940.9 3415-7 976.0 3483.9 I0I2.0 3552.7 36 37 .6167 907.2 3349.5 941.5 3416.8 976.6 3485.0 IOI2.6 3553.8. H 38 .6333 907.7 3350.6 942.1 3418.0 977.2 3486.2 IOI3.2 3555.0 38 39 .6500 908.2 3351.7 942.6 3419-2 977.8 3487.4 IOI3.9 3556.2 39 40 .6667 908.8 3352.8 943.2 3420.3 978.4 3488.5 IOI4.5 3557-3 40 41 .6833 909.4 3353.9 943.8 3421.4 979.0 3489.6 IOI5.I 3558.4 41 42 .7000 910.0 3355.0 944-4 3422.5 979.6 3490.7 IOI5.7 3559.6 42 43 .7167 910.6 3356.1 944.9 3423-6 980.2 3491.9 IOI6.3 3560.8 43 44 .7333 911.1 3357.3 945.5 3424-8 980.8 3493.0 IOI6.9 3562.0 44 45 .7500 911.7 3358.4 946.1 3426.0 981.4 3494.2 IOI7.5 3563.2 45 46 .7667 912.3 3359-5 946-7 3427-1 982.0 3495.3 IOI8.I 3564.3 46 47 .7833 912.8 3360.6 947.2 3428.2 982.6 3496.4 IOI8.7 3565.5 4? 48 .8000 913.4 3361.8 947.8 3429.3 983.2 3497.6 IOI9.3 3566.6 48 49 .8167 913.9 3362.9 948.4 3430.4 983.8 3498.7 1020.0 3567.7 49 50 •8333 914.S 3364.0 949.0 3431-6 984.4 3499.9 1020.6 3568.9 50 51 .8500 915.1 3365.1 949.6 3432.8 984.9 3501.0 I02I.2 3570.0 51 52 .8667 915.7 3366.2 950.2 3433-6 985.5 3502.2 I02I.8 3571.2 52 53 .8833 916.2 3367.3 950.7 3434-0 986.1 3503.3 1022.4 3572.3 53 54 .9000 916.8 3368.5 951.3 3436.1 986.7 3504.5 1023.0 .^573.5 54 55 .9167 917.4 3369.6 951.9 3437-2 987.3 3505.6 1023.6 3574.6 55 56 .9333 918.0 3370.7 952.5 3438.4 9?Z-9 3506.8 1024.2 3575.8 56 57 .9500 918.6 3371.9 953.0 3439-6 988.5 3507.9 1024.8 3576.9 H 58 .9667 919.1 3373.0 953-6 3440.7 989.1 3509.0 1025.4 3578.1 58 59 .9833 919.6 3374.1 954.2 3441.8 989.7 3510.1 IO26.I 1 3579.3 59 FUNCTIONS OF ONE-DEGREE CURVE 365 Use icx>' Chords up to 8° Curves Use 50' Chords up to 16** Curves Use 25' Chords up to 32° Curves Use 10' Chords above 32° Curves 1 64° 65'. 66'' 67*^ CO 0) .S. Ext. Tan. Ext. Tan. Ext. Tan Ext. Tan. .0000 1026.7 3580.4 1064.0 3650.4 1102.2 3721.1 1141-5 3792.6 I .0167 1027.3 3581.6 1064.6 3651.6 1102.9 3722.3 1142.2 3793.8 I 2 .0333 1027.9 3582.8 1065.2 3652.8 1103.5 3723.4 1142.8 3795.0 2 3 .0500 1028.6 3583.9 1065.9 3654.0 1104.2 3724.6 1143.5 3796.2 3 4 .0667 1029.2 3585.1 1066.5 3655.1 1 104.8 3725.8 1144.1 3797.4 4 S .0833 1029.8 3586.3 1067.1 3656.3 1105.5 3727.0 1144.8 3798.6 5 6 .1000 1030.4 3587.4 1067.7 3657.5 1106.1 3728.2 1145.4 3799.8 6 7 .1167 1031.1 3588.6 1068.4 3658.6 1106.8 3729.4 1146.1 3801.0 7 8 .1333 1031.7 3589.7 1069.0 3659.8 1107.4 3730.6 1146.7 3802.2 8 9 .1500 1032.3 3590.9 1069.6 3661.0 1108.1 3731.7 1147.4 3803.4 9 10 .1667 1032.9 3592.1 1070.2 3662.2 1108.7 3732.9 1148.1 3804.6 10 11 .1833 1033.S 3593.3 1070.9 3663.4 1109.4 3734.1 1148.8 3805.8 11 12 .2000 1034.1 3594.4 1071.5 3664.5 IIIO.O 3735.3 1 149.4 3807.0 12 13 .2167 1034.8 3595.5 1072. 1 3665.7 III0.7 3736.5 1150.1 3808.2 13 14 .2333 1035.4 3596.7 1072.7 3666.9 1II1.3 3737.7 1150.7 3809.4 14 IS .2500 1036.0 3597.9 1073.4 3668.0 I1I2.0 3738.9 1151.4 3810.6 15 16 .2667 1036.6 3599.1 1074.0 3669.2 III2.6 3740.1 1152.0 3811.8 16 17 .2833 1037.3 3600.3 1074.6 3670.4 III3-3 3741.3 1152.7 3813.0 17 l8 .3000 1037.9 3601.4 1075.2 3671.6 1113.9 3742.4 1153.3 3814.2 18 19 .3167 1038.5 3602.6 1075.9 3672.8 1114.6 3743.6 1154.0 3815.4 19 20 .3333 1039.1 3603.7 1076.6 3673.9 1115.2 3744.8 1154.7 3816.6 20 21 .3500 1039-7 3604.8 1077.2 3675.0 1115.9 3746.0 1155.4 3817.8 21 22 .3667 1040.3 3606.0 1077.8 3676.2 1116.5 3747.2 1156.0 3819.0 22 23 .3833 1 041.0 3607.2 1078.5 3677.4 1117.2 3748.4 1156.7 3820.2 23 24 .4000 1 041. 6 3608.4 1079.1 3678.6 1117.8 3749.6 1157.4 3821.4 24 25 .4167 1042.2 3609.5 1079.8 3679.7 1118.5 3750.7 1158.1 3822.6 25 26 ■4333 1042.8 3610.7 1080.4 3680.9 1119.1 3751.9 1158.7 3823.8 26 27 .4500 1043. 5 3611.9 io8i.i 3682.1 1119.8 3753.1 1159-4 3825.0 27 28 .4667 1044. 1 3613.0 1081.7 3683.3 1120.4 3754.3 1160.1 3826.2 28 29 .4833 1044.7 3614.1 1082.4 3684.5 1121.1 3755.5 I160.8 3827.4 29 30 .5000 1045.3 361S.3 1083.0 3685.6 1121.7 3756.7 I161.4 3828.6 30 31 .5167 1045.9 3616.5 1083.6 3686.8 1122.3 3757.9 1162. 1 3829.8 31 32 •5333 1046.5 3617.7 1084.2 3688.0 1123.0 3759.1 1162.8 3831.0 32 33 .5500 1047.2 3618.9 1084.9 3689.2 1123.7 3760.3 1163.5 3832.2 33 34 .5667 1047.8 3620.0 1085.5 3690.4 1124.3 3761.5 1164.1 3833.4 34 35 .5833 1048.4 3621.1 1086.2 3691.6 1125.0 3762.7 1164.8 3834-6 35 36 .6000 1049.0 3622.3 1086.8 3692.7 1125.6 3763.9 I165.5 3835.9 36 H .6167 1049.7 3623.5 1087.5 3693.9 1126.3 3765.1 I166.2 3837.1 37 38 .6333 1050.3 3624.7 1088.1 3695.1 1126.9 3766.3 1166.8 3838.3 38 39 .6500 1050.9 3625.8 1088.8 3696.2 1127.6 3767.5 1167.5 3839.5 39 40 .6667 1051.5 3627.0 1089.4 3697.4 1128.3 3768.7 1168.2 3840.7 40 41 .6833 1052. 1 3628.2 1090.0 3098.6 1129.0 3769.9 1168.9 3841.9 41 42 .7000 1052.7 3629.4 1090.6 3699.8 1129.6 3771.0 1169.5 3843.1 42 43 .7167 1053.4 3630.5 1091.3 3701.0 1130.3 3772.2 1170.2 3844.3 43 44 .7333 1054.0 3631.7 1091.9 3702.2 1 130.9 3773.4 1170.9 3845.5 44 4^ .7500 1054.6 3632.8 1092.6 3703.3 1131.6 3774.6 I171.6 3846.7 45 46 .7667 1055.2 3634.0 1093.2 3704.5 1132.2 3775.8 I172.2 3847.9 46 ^l .7833 1055.9 3635.2 1093.9 3705.7 1132.9 3777.0 1172.9 3849.1 47 48 .8000 1056.5 3636.4 1094.5 3706.9 1133.5 3778.2 1173.6 3850.4 48 49 .8167 1057.1 3637.5 1095.2 3708.1 1134.2 3779.4 1 1 74.3 3851.6 49 SO .8333 1057.7 3638.7 1095.8 3709.3 1134.9 3780.6 1174.9 3852.8 SO SI .8500 1058.4 3639.9 1096.4 3710.5 1135.6 3781.8 1175-6 3854.0 51 52 •?5^7 1059.0 3641.1 1097.0 3711.6 1136.2 3783.0 I176.3 3855.2 52 S3 .8833 1059.6 3642.3 1097.7 3712.8 1136.9 3784.2 1177.0 3856.4 53 S4 .9000 1060.2 3643.4 1098.3 3714.0 1137.5 3785.4 1177.6 3857.6 54 H .9167 1060.9 3644.6 1099.0 3715.1 1138.2 3786.6 1178.3 3858.8 55 S6 .9333 1061.5 3645.7 1099.6 3716.3 1138.8 3787.8 1179.0 3860.0 S6 H .9500 1062. 1 3646.9 1100.3 3717.5 1139.5 3789.0 1179.7 3861.2 57 S8 .9667 1062.7 3648.1 1100.9 3718.7 1140.1 3790.2 1180.3 3862.S S8 59 .9833 1063.4 3649.2 1101.6 3719.9 1140.8 3791.4 1181.0 3863.7 S9 366 THE SURVEY Use loo' Chords up to 8** Curves Use 25' Chords up to 32° Curves Use so' Chords up to 16° Curves Use 10' Chords above 32 Curves 1 .a 68° 69° 1 70° 71° Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 1181.6 3864^9 1222.9 3938.1 1265.0 4012. 1 1308.4 4087.1 I ,0167 1182.3 3866.1 1223.6 3939.4 1265.7 4013.4 1309.2 4088.4 I 2 .0333 1183.0 3867.3 1224.3 3940.6 1266.4 4014.6 1309.9 4089.7 2 3 4 .0500 1183.7 3868.5 1225.0 3941.8 1267.2 4015.9 1310.6 4091.0 3 .0667 1184.4 3869^7 1225.7 3943.0 1267.9 4017. 1 1311.3 4092.2 4 K .0833 1185.1 3870.9 1226.4 3944.2 1268.6 4018.4 1312.1 4093.5 S 6 .1000 ii85^7 3872.2 1227. 1 3945.5 1269.3 4019.6 1312.8 4094.7 6 7 .1167 1186.4 3873-4 1227.8 3946.7 1270.1 4020.8 1313.5 4096.0 7 8 .1333 1187.1 3874^6 1228. 5 3947.9 1270.8 4022.1 1314.2 4097.2 4098.S 8 9 .1500 1187.8 3875.8 1229.2 3949.2 1271.5 4023.4 1315.0 9 10 .1667 1188.5 3877-0 1229.9 3950.4 1272.2 4024.6 1315.7 4099.8 10 II .1833 1189.2 3878.2 1230.6 3951.6 1272.9 4025.8 1316.5 4101.1 " 12 .2000 1189.8 3879-S 1231.3 3952.9 1273.6 4027.1 1317.2 4102.3 12 13 .2167 1190.5 3880.7 1232.0 3954.1 1274.4 4028.4 1317.9 4103.6 4104.8 13 14 .2333 1191.2 3881.9 1232.7 3955.3 1275.1 4029.6 1318.6 14 15 .2500 1191.9 3883.1 1233.4 3956.6 1275.8 4030.8 1319.4 4106.1 15 16 .2667 1192.6 3884.3 1234.1 3957-8 1276.5 4032.1 1320.1 4107.3 4108.6 4109.8 16 17 .2833 ii93^3 3885.6 1234.8 3959.0 1277.3 4033.4 1320.8 H 18 .3000 ii93^9 3886.8 1235.5 3960.2 1278.0 4034.6 1321.5 18 19 .3167 1 1194.6 3888.0 1236.2 3961.5 1278.7 4035.9 1322.3 4111.1 19 20 •3333 ' ii9S^3 3889.2 1236.9 3962.7 1279.4 4037.1 1323.0 4112.4. 20 21 •3500 1196.0 3890.4 1237.6 3964-0 1280.1 4038.4 1323.7 4113.7 21 22 .3667 ! 1196.7 3891.6 1238.3 3965-2 1280.8 4039.6 1324.4 41 14.9 4116.2 22 23 .3833 1 1197.4 3892.9 1239.0 3966.4 1281.6 4040.9 1325.2 23 24 .4000 : II 98.0 3894.1 1239.7 3967-6 1282.3 4042.1 1325.9 4117.4 24 25 .4167 1 1198.7 3895.3 1240.4 3968.9 1283.0 4043.4 1326.7 4118.7 'I 26 •4333 1199.4 3896.5 1241. 1 3970.1 1283.7 4044.6 1327.4 4119.9 26 27 •4500 1 200.1 3897.7 1241.8 3971.3 1284.5 4045.9 1328.2 4121.2 ^l 28 .4667 ; 1200.8 3898.9 1242.5 3972.5 1285.2 4047.1 1228.9 4122.4 28 29 .4833 1201.S 3900.2 1243.2 3973.8 1285.9 4048.4 1329.7 4123.7 29 30 .5000 1202. 1 3901.4 1243.9 3975.0 1286.6 4049.6 1330.4 4125.0 4126.3 30 31 .5167 1 1202.8 3902.6 1244.6 3976.3 1287.3 4050.9 1331.1 1331.8 31 32 .5333 1203.S 3903.8 1245.3 3977.5 1288.0 4052.1 4127.S 4128.7 32 33 •5500 1204.2 3905.0 1246.0 3978.8 1288.8 4053.4 1332.6 33 34 .5667 1204.9 3906.3 1246.7 3980.0 1289.5 4054.6 1333-3 4x30.0 34 35 .5833 1205.6 3907.5 1247.4 3981.2 1290.2 4055.9 1334-1 1334.8 4131.5 4132.6 ^1 36 .6000 1206.2 3908.7 1248. 1 3982.4 1290.9 4057-1 36 37 .6167 1206.9 3909.9 1248.8 3983.7 1291.7 4058.4 1335.6 4133.9 H 38 •6333 1207.6 3911.2 1249.5 3984.9 1292.4 4059.6 1336.3 4135. 1 4136.4 38 39 .6500 1208.3 3912.4 1250.2 3986.1 1293.1 4060.9 1337.1 39 40 .6667 1209.0 3913.6 1250.9 3987.4 1293.8 4062.1 1337.8 4137.7 40 41 .6833 1209.7 3914.9 1251.6 3988.7 1294.6 4063.4 1338.5 4139.0 41 42 .7000 1210.3 3916.1 1252.3 3989.9 1295.3 4064.6 1339.2 4140.2 42 43 .7167 1211.0 3917.3 1253.0 3991. 1 1296.0 4065.9 1340.0 4141.S 43 44 .7333 1211.7 3918.5 1253.7 3992.3 1296.7 4067.1 1340.7 4142.7 44 45 .7500 1212.4 3919.8 1254.4 3993.6 1297.5 4068.4 1341.5 4144.0 ti 46 .7667 1213.1 3921.0 1255.1 3994.8 1298.2 4069.6 1342.2 4145.3 4146.6 4147.8 47 •7833 1213.8 3922.2 1255.8 3996.0 1298.9 4070.9 1343.0 :i 48 .8000 1214.S 3923.4 1256.5 3997.3 1299.6 4072.1 1343.7 49 .8167 1215.2 3924.7 I257«2 3998.6 1300.4 4073.4 1344-S 4149.1 49 SO .8333 I2I5^9 3925.9 1257.9 3999.8 1301.1 4074.6 1345-2 1346.0 4150.4 50 SI .8500 1216.6 2927.1 1258.6 4001.0 1301.9 4075.9 4151.7 SI 52 .8667 1217.3 3928.3 1259.3 4002.2 1302.6 4077.1 1346.7 4152.9 S2 S3 .8833 1218.0 3929.6 1260.0 4003.4 1303.3 4078.4 1347.5 4154.2 53 54 .9000 1218.7 3930.8 1260.7 4004.7 1304.0 4079-6 1348.2 4155.4 54 55 56 57 .9167 .9333 c^oo 1219.4 1220.1 3932.0 3933.2 I26I.4 1262. 1 4006.0 4007.2 1304.8 1305.5 4080.9 4082.1 1349.0 1349.7 4156.7 4158.0 55 56 1220.8 3934.4 1262.8 4008.5 1306.2 4083.4 1350.S 4159.3 4160.5 4161.8 11 59 58 S9 .9667 .9833 1221.5 1222.2 3935.7 3936.9 1263.5 1264.3 4009.7 4010.9 1306.9 1307.7 4084.6 4085.9 1351.2 I3S2.0 FUNCTIONS OF ONE-DEGREE CURVE 367 Use 100' Chords up to 8° Curves Use so' Chords up to 16° Curves Use 25' Chords up to 32" Curves Use 10' Chords above 32° Curves s a 72° 73° 74° 75° Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 1352.7 4163-1 1398.1 4240.0 1444.7 4317-8 1492.5 4396.7 I .0167 1353-5 4164.4 1398.9 4241.3 1445.5 4319-2 1493-3 4398.1 I 2 •0333 1354-2 4165-6 1399.6 4242.6 1446.2 4320.5 1494-1 4399-4 2 3 .0500 1355-0 4166.9 1400.4 4243.9 1447-0 '4321.8 1494-9 4400.8 3 4 .0667 1355-7 4168.2 1401.2 4245.1 1447.8 4323-1 1495-7 4402.1 4 S .0833 1356.S 4169.5 1402.0 4246.4 1448.6 4324-4 1496.5 4403.4 5 6 .1000 1357-2 4170.7 1402.7 4247.7 1449.4 4325-7 1497-3 4404-7 6 7 .1167 1358.0 4172.0 1403-5 4249-0 1450.2 4327-0 1498.2 4406.1 7 8 .1333 1358.7 4173-3 1404.2 4250.3 1451.0 4328.3 1499.0 4407-4 8 9 .1500 1359^5 4174.5 1405.0 4251.6 1451.8 4329-6 1499-8 4408.7 9 10 .1667 1360.2 4175-8 1405.8 4252.9 1452.6 4330.9 1500.6 4410.0 10 II •1833 1361.0 4177.1 1406.6 4254-2 1453.4 4332.3 1501.4 4411-4 II 12 .2000 1361.7 4178.4 1407.3 4255.5 1454.1 4333-6 1502.2 4412.7 12 13 .2167 1362.S 4179.7 1408.1 4256.8 1454.9 4334-9 1503.0 4414.0 !i3 14 .2333 1363-2 4181.0 1408.8 4258.1 1455.7 4336.2 1503-8 4415-3 14 15 .2500 1364-0 4182.3 1409.6 4259.4 1456.5 4337-5 1504-6 4416.6 15 16 .2667 1364.7 4183.5 1410.4 4260.7 1457.3 4338.8 1505-4 4418.0 16 17 .2833 1365.5 4184.8 1411.2 4262.0 1458.1 4340.1 1506.2 4419.4 17 18 .3000 1366.2 4186.1 1411.9 4263.2 1458.9 4341-4 1507-0 4420.7 '18 19 .3167 1367.0 4187.4 1412.7 4264.5 1459.7 4342.7 1507.9 4422.0 J19 20 .3333 1367-7 4188.6 1413-5 4265.8 1460.5 4344-0 1508.7 4423-3 I20 21 .3500 1368.S 4189.9 1414-3 4267.1 1461.3 4345-4 1509-5 4424-6 21 22 .3667 1369-2 4191.2 1415-1 4268.4 1462.0 4346.7 1510.3 4426.0 22 23 .3833 1370.0 4192.5 1415-9 4269.7 1462.8 4348.0 1511.2 4427.3 23 24 .4000 1370.7 4193-7 1416.6 4271.0 1463-6 4349-3 1512.0 4428.6 24 25 .4167 1371.5 4195-0 14174 4272.3 1464.4 4350.6 1512.8 4430.0 25 26 •4333 1372.2 4196.3 1418.2 4273.6 1465.2 4351-9 1513-6 4431-3 26 27 .4500 1373-0 4197.6 1419.0 4274.9 1466.0 4353-2 1514.S 4432.7 27 28 .4667 1373-7 4198.8 1419.7 4276.2 1466.8 4354-5 1515-3 4434.0 28 29 .4833 1374.5 4200.1 1420.5 4277.5 1467.6 4355-8 1516.1 4435-3 29 30 .5000 1375.2 4201.4 1421.3 4278.8 1468.4 4357-1 1516.9 4436.6 30 31 •5167 1376.0 4202.7 1422. 1 4280.1 1469.2 4358.5 1517.7 4438.0 31 32 •5333 1376.7 4204.0 1422.9 4281.4 1469.9 4359-8 1518.5 4439.3 32 33 .5500 1377.5 4205.3 1423-7 4282.7 1470.7 4361.1 1519-4 4440.7 33 34 .5667 1378.2 4206.5 1424.4 4284.0 1471-5 4362.4 1520.2 4442.0 34 35 •5833 1379-0 4207.8 1425.2 4285.3 1472.3 4363-8 1521.0 4443.3 35 36 .6000 1379.7 4209.1 1426.0 4286.6 1473-1 4365-1 1521.8 4444.6 36 37 .6167 1380.S 4210.4 1426.8 4287.9 1473-9 4366.4 1522.7 4446.0 37 38 .6333 1381.2 4211.7 1427-5 4289.2 1474-7 4367-7 1523-5 4447.3 38 39 .6500 1382.0 4213.0 1428.3 4290.5 1475-6 4369-0 1524-3 4448.7 39 40 .6667 1382.8 4214.3 1429.1 4291.8 1476.4 4370.3 1525-1 4450.0 40 41 •6833 1383-6 4215.6 1429.9 4293-1 1477.2 4371-7 1525-9 4451.4 41 42 .7000 1384-3 4216.8 1430.7 4294.4 1478.0 4373-0 1526.7 4452.7 42 43 .7167 1385-I 4218.1 1431.5 4295.7 1478.8 4374-3 1527-6 4454.0 43 44 .7333 1385-8 4219.4 1432.2 4297.0 1479-6 4375-6 1528.4 4455-3 44 45 •7500 1386.6 4220.7 1433.0 4298.3 1480.4 4377-0 1529-2 4456.7 45 46 .7667 1387.4 4222.0 1433.8 4299.6 1481.2 4378.3 1530.0 4458.0 46 47 •7833 1388.2 4223.3 1434-6 4300.9 1482.0 4379-6 1530.9 4459-4 47 48 .8000 1388.9 4224.5 1435-3 4302.2 1482.8 4380.9 1531.7 4460.7 48 49 .8167 1389-7 4225.8 1436.1 4303.5 1483-6 4382.2 1532.5 4462.1 49 SO .8333 1390.4 4227.1 1436.9 4304.8 1484-4 4383-5 1533-3 4463.4 50 SI .8500 1391-2 4228.4 1437.7 4306.1 1485-2 4384-9 1534-1 4464-7 51 52 .8667 1392.0 4229.7 1438.5 4307-4 1486.0 4386.2 1534-9 4466.0 52 S3 .8833 1392.8 4231.0 1439.3 4308.7 1486.9 4387.5 1535-8 4467-4 53 54 .9000 1393-5 4232.3 1440.0 4310.0 1487-7 4388.8 1536.6 4468.7 54 55 .9167 1394-3 4233.6 1440.8 4311-3 1488.5 4390.2 1537.4 4470.1 55 56 .9333 1395.0 4234.8 1441.6 4312.6 1489-3 4391-5 1538.2 4471.4 56 57 .9500 1395-8 4236.1 1442.4 4313-9 1490.1 4392.8 1539-1 4472.7 57 S8 .9667 1396.6 4237.4 1443.1 4315-2 1490.9 4394-1 1539-9 4474-1 58 59 .9833 1397.4 4238.7 1443.9 4316.5 1491-7 4395.4 1540.7 4475-4 59 368 THE SURVEY Use 100' Chords up to 8 ° Curves Use 25' Chords up to 32° Curves Use 50 Chords up to 16 ° Curves Use 10' Chords above 32" Curves 1 76" 77° 78° 79° i Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 IS4I.S 4476.7 1591.7 4557.8 1643.1 4640.0 1696.0 4723.4 I .0167 1542.4 4478.1 1592.6 4559.2 1644.0 4641.4 1696.9 4724-8 I 2 •0333 1543.2 4479.4 1593.4 4560.5 1644.8 4642.8 1697.7 4726.2 2 3 .0500 1544.1 4480.8 1594.3 4561.9 1645.7 4644.2 1698.6 4727.6 3 4 .0667 1544.9 4482.1 1595.1 4563.3 1646.6 4645.6 1699.5 4729.0 "4 5 .0833 1545.7 4483.S 1596.0 4564-7 1647.5 4647.0 1700.4 4730.4 5 6 .1000 1546.5 4484.8 1596.8 4566.0 1648.3 4648.3 1701.3 4731.8 6 7 .1167 1547-4 4486.2 1597.7 4567.4 1649.2 4649-7 1702.2 4733-3 7 8 • 1333 1548.2 4487.5 1598.5 4568.7 1650.1 4651. 1 1703.1 4734-7 8 9 .1500 1549.1 4488.9 1599-4 4570.1 1651.0 4652.5 1704.0 4736.1 9 10 .1667 1549.9 4490.2 1600.2 4571.S 1651.8 4653.9 1704.9 4737.5 10 II .1833 1550.7 4491.6 1601.1 4572.9 1652.7 4655-3 170S-8 4738.9 II 12 .2000 1551.5 4492.9 1601.9 4574-2 1653-6 4656.7 1706.6 4740.3 12 13 .2167 1552.4 4494.3 1602.8 4575-6 1654-S 4658.1 1707.S 4741.7 13 14 .2333 1553.2 4495.6 1603.6 4576.9 1655-3 4659.4 1708.4 4743.1 14 IS .2500 1554.1 4497.0 1604.5 4578.3 1656.2 4660.8 1709.3 4744-5 IS 16 .2667 1554-9 4498.3 1605.3 4579.7 1657.1 4662.2 1710.2 4745.9 16 17 .2833 1555-7 4499.7 1606.2 4581.1 1658.0 4663.6 1711.1 4747.3 17 18 .3000 1556.5 4501.0 1607.0 4582.4 1658.8 4665.0 1712.0 4748.7 18 19 .3167 1557.4 4502.4 1607.9 4583.8 1659.7 4666.4 1712.9 4750.1 19 20 .3333 1558.2 4503.7 1608.7 4585.1 1660.6 4667.7 1713-8 4751.S 20 21 .3500 1559.1 4505.0 1609.6 4586.5 1661.5 4669.1 1714.7 4752.9 21 22 .3667 1559-9 4506.3 1610.4 4587.9 1662.3 4670.5 1715-6 4754-3 22 23 .3833 1560.7 4507.7 1611.3 4589.3 1663.2 4671.9 1716.5 4755-7 23 24 .4000 1561.5 4509.0 1612.1 4590.6 1 664. 1 4673.3 1717.4 4757.1 24 25 .4167 1562.4 4510.4 1613.0 4592.0 1665.0 4674.7 1718.3 4758.6 25 26 .4333 1563.2 4511.7 1613.8 4593.3 1665.8 4676.0 1719-2 4760.0 26 27 .4500 1564.I 4513.1 1614.7 4594.7 1666.7 4677-4 1720.1 4761.4 27 28 .4667 1564.9 4514.4 1615.5 4596.0 1667.6 4678.8 1721.0 4762.8 28 29 .4833 1565.7 4515.8 1616.4 4597.4 1668.5 4680.2 1721.9 4764.2 29 30 .5000 1566.5 4517.1 1617.3 4598.8 1669.3 4681.6 1722.8 4765.6 30 31 .S167 1567.4 4518.5 1618.2 4600.2 1670.2 4683.0 1723-7 4767.0 31 32 .S333 1568.2 4519.8 1619.0 4601.5 1671.1 4684.4 1724.6 4768.4 32 33 •SSOO 1569.1 4521. 1 1619.9 4602.9 1672.0 4685.8 1725-S 4769.8 33 34 .5667 1569.9 4522.5 1620.7 4604.3 1672.8 4687.2 1726.4 4771.2 34 35 .S833 1570.7 4523.9 1621.6 4605.7 1673-7 4688.6 1727.3 4772.7 35 36 .6000 1571.5 4525.3 1622.4 4607.0 1674.6 4689.9 1728.2 4774.1 36 37 .6167 1572.4 4526.7 1623.3 4608.4 1675-S 4691.3 1729.1 4775-5 37 38 .6333 1573.2 4528.0 1624.1 4609.8 1676.3 4692.7 1730.0 4776.9 38 39 .6500 1574.0 4529.4 1625.0 4611.2 1677.3 4694.1 1731.0 4778.3 39 40 .6667 .1574.8 4530.7 1625.9 4612.5 1678.2 4695.5 1731.9 4779.7 40 41 .6833 1575.6 4532.1 1626.8 4613.9 1679.1 4696.9 1732.8 4781.1 41 42 .7000 1576.4 4533.4 1627.6 4615.3 1679-9 4698.3 1733.7 4782.6 42 43 .7167 1577.3 4534.8 1628.5 4616.7 1680.8 4699.7 1734-6 4784.0 43 44 .7333 1578.I 4536.1 1629.3 4618.0 1681.7 4701.1 1735-S 4785.4 44 4| .7500 1579.0 4537.5 1630.2 4619.4 1682.6 4702.5 1736.4 4786.8 45 46 .7667 1579-8 4538.8 1631.0 4620.8 1683.S 4703.9 1737.3 4788.2 46 47 .7833 1580.7 4540.2 1631.9 4622.2 1684.4 4705.3 1738.2 4789.6 47 48 .8000 1581.5 4541.5 1632.7 4623.5 1685.3 4706.7 1739.1 4791.0 48 49 .8167 1582.4 4542.9 1633.6 4624.9 1686.2 4708.1 1740.0 4792.S 49 SO .8333 1583.2 4544.2 1634.5 4626.3 1687.1 4709.5 1740.9 4793.9 SO SI .8500 1584.1 4545.6 1635.4 4627.7 1688.0 4710.9 1741-8 4795.3 SI S2 .8667 1584.9 4S47.0 1636.2 4629.0 1688.8 4712.2 1742.7 4796.7 52 S3 .8833 1585.8 4548.4 1637.1 4630.4 1689.7 4713-6 1743-6 4798.1 53 S4 .9000 1586.6 4549.7 1637.9 4631-8 1690.6 471S-0 1744.S 4799.S S4 H .9167 1587.S 4551.1 1638.8 4633.2 1691.5 4716.4 1745.4 4801.0 55 56 .9333 1588.3 4552.4 1639.6 4634.5 1692.4 4717.8 1746.3 4802.4 56 H .9500 1589.2 4553.8 1640.5 4635.9 1693.3 4719.2 1747.2 4803.8 57 S8 .9667 1590.0 4555. 1 1641.3 4637.3 1694.2 4720.6 1 748.1 4805.2 58 59 .9833 1590.9 4556.5 1642.2 4638.7 1695.1 4722.0 1749.1 4806.6 59 ITTNCTIONS OF ONE-DEGREE CURVE Use loo' Chords up to 8° Curves Use 25' Chords up to 32° Curves Use 50' Chords up to 16° Curves Use 10' Chords above 32° Curves 369 1 d 3 80" 81° 82° 83- 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 1750.0 4808.0 1805.5 4893.9 1862.3 4981.0 1920.6 5069.4 I .0167 1750.9 4809.5 1806.4 4895.4 1863.3 4982.5 1921.6 5070.9 I 2 •0333 1751.8 4810.9 1807.3 4896.8 1864.2 ,4983.9 1922.6 5072.4 2 3 .0500 1752.8 4812.3 1808.3 4898.3 1865.2 4985.4 1923.6 5073.9 3 4 .0667 1753-7 4813.7 1809.2 4899.7 I866.I 4986.8 1924.6 5075.4 4 5 •0833 1754.6 4815.2 1810.2 4901.2 I867.I 4988.3 1925.6 5076.9 5 6 .1000 1755.5 4816.6 1811.1 4902.6 I868.I 4989.8 1926.5 5078.4 6 7 .1167 1756.5 4818.0 1812.1 4904.0 I869.I 4991.3 1927.5 5079.9 7 8 •1333 1757.4 4819.4 1813.0 4905.4 1870.0 4992.7 1928.S 5081.4 8 9 .1500 1758.3 4820.9 1814.0 4906.9 I87I.O 4994.2 1929.S 5082.9 9 10 .1667 1759.2 4822.3 1814.9 4908.3 I87I.9 4995.7 1930.5 5084.4 10 II .1833 1760.1 4823.7 1815.9 4909.8 1872.9 4997.2 1931.5 5085.9 II 12 .2000 1761.0 4825.1 1816.8 4911.2 1873.9 4998.6 1932.4 5087.3 12 13 .2167 1762.0 4826.6 1817.7 4912.7 1874.9 5000.1 1933.4 5088.8 13 14 .2333 1762.9 4828.0 1818.6 4914.1 1875.8 5001.5 1934.4 5090.3 14 15 .2500 1763.8 4829.4 1819.6 4915.5 1876.8 5003.0 1935.4 509 1. 8 15 16 .2667 1764.7 4830.8 1820.5 4917.0 1877.7 5004.5 1936.4 5093.3 16 17 .2833 1765.7 4832.3 1821.5 4918.5 1878.7 5006.0 1937.4 5094.8 17 18 .3000 1766.6 4833.7 1822.4 4919.9 1879.7 5007.4 1938.4 5096.3 18 19 .3167 1767^5 4835.1 1823.3 4921.4 1880.7 5008.9 1939.4 S097.8 19 20 •3333 1768.4 4836.5 1824.2 4922.8 I88I.6 5010.3 1940.4 5099-3 20 21 •3500 1769.3 4838.0 1825.2 4924.3 1882.6 5011.8 1941.4 5100.8 21 22 .3667 1770.2 4839.4 1826.1 4925.7 1883.5 5013.3 : 1942.4 5102.3 22 23 .3833 i77i^2 4840.8 1827.1 4927.2 1884.5 5014.8 1943.4 5103.8 23 24 .4000 1772.1 4842.2 1828.0 4928.6 1885.5 5016.2 1944-4 5105.2 24 25 .4167 1773.0 4843.7 1829.0 4930.1 1886.5 5017.7 1945.4 5106.7 25 26 .4333 1773.9 4845.1 1829.9 4931.5 1887.4 5019.2 1946.4 5108.2 26 27 .4500 1774-9 4846.5 1830.9 4933 -o 1888.4 5020.7 1947.4 5109-7 27 28 .4667 1775.8 48479 1831.8 4934.4 1889.3 5022.1 1948.4 5111.2 28 29 .4833 1776.7 4849.4 1832.8 4935-8 1890.3 5023.6 1949.4 5112.7 29 30 .5000 1777.6 4850.8 1833.7 4937.2 I89I.3 5025.0 1950.4 5114-2 30 31 .5167 1778.5 4852.3 1834.7 4938.7 1892.3 5026.5 1951.4 5115.7 31 32 .5333 1779-4 4853-7 1835.6 4940.2 1893.2 5028.0 1952.4 5117.2 32 33 .5500 1780.4 4855.1 1836.6 4941.7 1894.2 5029.5 1953.4 5118.7 33 34 .5667 1781.3 4856.S 1837.5 4943-1 I895.I 5031.0 1954.4 5120.2 34 35 .5833 1782.2 4858.0 1838.5 4944.6 I896.I 5032.S 1955.4 5121.7 35 36 .6000 1783.1 4859.4 1839.4 4946.0 I897.I 5033.9 1956.4 5123.2 36 37 .6167 1 784.1 4860.9 1840.4 4947.5 I898.I 5035.4 1957-4 5124.7 37 38 .6333 1785.0 4862.3 1841.3 4948.9 1899.0 5036.9 1958.4 5126.2 38 39 .6500 1785.9 4863.7 1842.3 4950.4 1900.0 5038.4 1959.4 S127.7 39 40 .6667 1786.8 4865.1 1843.2 4951.8 1 901.0 S039.8 1960.4 5129-2 40 41 .6833 '7?7-7 4866.6 1844.2 4953.3 1902.0 5041.3 1961.4 5130.7 41 42 .7000 1788.6 4868.0 1845-1 4954.7 1902.9 5042.8 1962.4 5132.2 42 43 .7167 1789.6 4869.5 1846.1 4956.2 1903.9 5044.3 1963.4 5133.7 43 44 .7333 1790.5 4870.9 1847.0 4957.6 1904.9 S045.8 1964-4 5135.2 44 45 .7500 1791.5 4872.4 1848.0 4959.1 1905.9 S047.3 1965.4 S136.7 45 46 .7667 1792.4 4873.8 1848.9 4960.6 1906.9 5048.7 1966.4 5138.2 46 47 .7833 1793-4 4875.2 1849.9 4962.1 1907.9 5050.2 1967.4 5139.7 47 48 .8000 1794-3 4876.6 1850.8 4963.5 1908.8 5051.7 1968.4 5141.2 48 49 .8167 1795.3 4878.1 1851.8 4965.0 1909.8 5053-2 1969.4 5142.8 49 50 .8333 1796.2 4879.5 1852.7 4966.4 I9I0.8 5054-6 1970.4 5144.3 50 51 .8500 1797.1 4880.9 1853.7 4967.9 I9II.8 5056.1 1971.4 5145.8 SI 52 .8667 1798.0 4882.4 1854.6 4969.3 I9I2.8 5057.6 1972.4 5147-3 52 53 .8833 1799.0 4883.9 1855.6 4970.8 1913 8 5059.1 1973-4 5148.8 53 54 .9000 1709.9 4885.3 1856.5 4972.2 1914.7 5060.6 1974^4 5150.3 54 55 .9167 1800.9 4886.7 1857.S 4973.7 1915.7 5062.1 1975.4 S151.8 55 S6 •9333 1801.8 4888.1 1858.4 4975-1 1916.7 5063.5 1976.4 5153.3 56 57 .9500 1802.8 4889.6 1859.4 4976.6 1917-7 5065.0 1977.4 5154.8 57 S8 .9667 1803.7 4891.0 1860.3 4978.0 1918.7 5066.5 1978.4 5156.3 58 59 •9833 1804.6 4892.5 1861.3 4979.5 1919.7 5068.0 1979.4 5157.8 59 370 THE SURVEY Use loo' Chords up to 8" Curves Use so' Chords up to i6° Curves Use 25' Chords up to 32" Curves Use 10' Chords above 32" Curves s d 3 84'* 85° 86*' 87° Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 1980.5 5159.3 2041.8 5250.6 2104.8 5343.3 2169.S 5437.5 I .0167 1981.5 5160.8 2042.9 5252.1 2105.9 5344.9 2170.6 5439.1 I 2 •0333 1982.5 5162.3 2043.9 5253.6 2106.9 5346.4 2171.6 5440.7 2 3 .0500 1983-5 5163.8 2045.0 5255.2 2108.0 5348.0 2172.7 5442.3 3 4 .0667 1984-5 5165.3 2046.0 5256.7 2109.1 5349.5 2173.8 5443.9 4 5 .0833 1985-6 5166.9 2047.0 5258.3 2110.1 5351.1 2174.9 5445.5 5 6 .1000 1986.6 5168.4 ii 2048.0 5259.8 1 2111.2 5352.7 2176.0 5447.1 6 7 .1167 1987.6 5169.9 ij 2049.1 5261.4 1 2112.3 5354.3 2177.1 5448.7 7 8 •1333 1 1988.6 5171.4I! 2050.1 5262.9 2113.4 5355.8 2178.2 5450.3 8 9 .1500 1989.6 5172.911 2051.2 5264.5 11 2114.5 5357.4 2179.3 5451.9 9 10 .1667 1990.6 5174.4! 2052.2 5266.0 '! 2115.5 5358.9 2180.4 5453-4 10 II •1833 1991-7 5175.9 2053.2 5267.5 J! 2116.6 5360.5 2181.5 5455.0 II 12 .2000 1992.7 5177.5 ! 2054.2 5269.0 ll 2II7.6 5362.0 2182.5 5456.6 12 13 .2167 I 1993-7 5179.0 i 2055.3 5270.6 J 2118.7 5363.6 2183.6 5458.2 13 14 .2333 1994-7 .2500 , 1995-7 5180.5 : 2056.3 5272.1 2119.8 5365.2 2184.7 5459-8 14 IS 5182.0 2057.4 5273.7 2120.9 5366.8 2185.8 5461.4 15 16 .2667 : 1996.7 5183.5 2058.4 5275.2 2121.9 5368.3 2186.9 5463-0 16 17 .2833 ' 1997-8 5185.0 : 2059.5 5276.8 •': 2123.0 5369.9 2188.0 5464-6 17 18 .3000 1 1998.8 5186.6 2060.5 5278.3 1 2124.I 5371.4 2189. 1 5466.2 18 19 .3167 1999.8 5188.0 2061.6 5279.9 1 2125.2 5373.0 2190.2 5467.8 19 20 .3333 2000.8 5189.6 i 2062.6 5281.4 2126.2 5374.6 2191.3 5469.4 20 21 .3500 ' 2001.8 5191.0 2063.7 5282.9 2127.3 5376.2 2192.4 5471.0 21 22 •3667 1 2002.8 5192.6 , 2064.7 5284.4 2128.3 5377.7 2193.5 5472.5 22 23 .3833 2003.9 5194.0 j 2065.8 5286.0 2129.4 5379.3 2194.6 5474.1 23 24 .4000 2004.9 5195.6 i 2066.8 5287.5 2130.5 5380.8 2195.7 5475.7 24 25 .4167 2005.9 5197.2 2067.9 5289.1 2131.6 5382.4 2196.8 5477.3 25 26 .4333 2006.9 5198.7 1 2068.9 5290.6 2132.6 5383.9 2197.9 5478.9 26 27 .4500 : 2007.9 5200.2 j 2070.0 5292.2 2133.7 5385.5 2199.0 5480.5 ^1 28 .4667 2008.9 5201.7 2071.0 5293.7 2134.8 5387.1 2200.1 5482.1 28 29 .4833 2010.0 5203.2 2072.1 5295.2 2135.9 5388.7 2201.2 5483.7 29 30 .5000 2011.0 5204.7 2073.1 5296.7 .2136.9 5390.2 2202.3 5485.3 30 31 •5167 2012.0 5206.3 2074.2 5298.3 2138.0 5391.8 2203.4 5486.9 31 32 •5333 2013.0 5207.8 2075-2 5299-8 2139.0 5393.4 2204.5 5488.5 32 33 .5500 2014.0 5209.3 2076.3 5301.4 2146.1 5395.0 2205.6 5490.1 33 34 .5667 20x5.0 5210.8 2077.3 5302.9 2141.2 5396.5 2206.8 5491.7 34 35 .5833 2016.0 5212.4 2078.4 5304.5 2142.3 5398.1 2207.9 5493.3 35 36 .6000 2017.0 5213.9 2079-4 5306.1 2143.3 5399.7 2209.0 5494.9 36 37 .6167 2018.0 5215-4 2080.5 5307.7 2144.4 5401.3 2210.1 5496.5 37 38 •6333 2019.1 5216.9 2081.5 5309.2 2145.5 5402.8 2211.2 5498.1 38 39 .6500 2020.1 5218.4 2082.6 5310.8 2146.6 5404.4 2212.3 5499.7 39 40 .6667 2021.2 5220.0 2083.7 5312.3 2147.7 5406.0 2213.4 5501.3 40 41 .6833 2022.2 5221.6 2084.8 5313.9 2148.8 5407.6 2214.5 5502.9 41 42 .7000 2023.2 5223.1 2085.8 5315.4 2149.8 5409.1 2215.6 55<^4.5 42 43 .7167 2024.3 5224.6 2086.9 5317.0 2150.9 5410.7 2216.7 5506.1 43 44 .7333 2025.3 5226.1 2087.9 5318.5 2152.0 5412.3 2217.8 5507.7 44 45 .7500 2026.4 5227.7 2089.0 5320.1 2153.1 5413.9 2218.9 5509.3 45 46 .7667 2027.4 5229.2 2090.0 S32I.6 2154.2 5415.4 2220.0 5510.9 46 47 •7833 2028.4 5230.7 2091. 1 5323.2 2155.3 5417.0 2221.2 5512.5 47 48 .8000 2029.4 5232.2 2092.1 5324.7 2156.4 5418.6 2222.3 5514.1 48 49 .8167 2030.5 5233.8 2093.2 5326.3 2157.5 5420.2 2223.4 5515.7 49 50 .8333 2031.5 5235.3 2094.2 5327.8 2158.6 5421.8 2224.5 5517.3 50 SI .8500 2032.6 5236.8 2095-3 5329.4 2159.7 5423.4 2225.6 5518.9 51 52 .8667 2033.6 5238.3 2096.3 5330.9 2160.7 5424-9 2226.7 5520.5 52 53 .8833 2034.6 5239.9 2097.4 5332.5 2161.8 5426.5 2227.9 5522.1 53 54 .9000 2035.6 5241.4 2098.4 5334.0 2I62.-9 5428.1 2228.9 5523.7 54 55 .9167 2036.7 5243-0 2099. 5 5335.6 2164.0 5429.7 2230.0 5525.3 55 56 .9333 2037-7 5244.5 2100.6 5337.1 2I65.I 5431.2 2231. 1 5526.9 56 57 .9500 2038.7 5246.0 2101.7 5338.7 2166.2 5432.8 2232.2 5528.S 57 58 .9667 2039.8 5247.5 2102.7 5340.2 2167.3 5434-4 2233.3 5530.1 58 59 .9833 2040.8 5249.1 2103.8 5341.8 2168.4 5436.0 2234.5 5531.7 50 FUNCTIONS OF ONE-DEGREE CURVE Use loo' Chords up to 8" Curves Use 25' Chords up to 32° Curves Use 50' Chords up to 16° Curves Use 10' Chords above 32° Curves 371 i 3 c s Co; SS** Sg** 90*' 91° Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 2235.6 5533.3 2303.6 5630.8 2373.4 S730.0 2445.1 5830.9 I .0167 2236.7 5535.0 2304.7 5632.5 2374-6 5731.7 2446.3 5832.6 I 2 .0333 2237.8 5536.6 2305.6 5634-1 2375.8 5733.3 2447-5 5834.3 2 3 .0500 2238.9 5538.2 2307.2 5635.8 2377.0 5735.0 2448.8 5836.0 3 4 .0667 2240.1 5539.8 2308.1 5637.4 2378.2 5736.7 2450.0 5837.7 4 5 ■0833 2241.2 5541.5 2309.4 5639.1 2379.4 5738.4 2451.2 5839.4 I 6 .1000 2242.3 5543.1 2310.5 5640.7 2380.5 5740.0 2452.4 5841. 1 7 .1167 2243.5 5544.7 2311.6 5642.4 2381.7 5741.7 2453.6 5842.8 7 8 8 .1333 2244.6 5546.3 2312.8 5644.0 2382.9 5743.4 2454-8 5844.5 9 .1500 2245.7 5547.9 2314.0 5645.7 2384.1 5745.1 2456.0 5846.2 9 10 .1667 2246.8 5549.5 2315.1 5647.3 2385.3 5746.7 2457.2 5847.9 10 II .1833 2248.0 5551.2 2316.3 5649.0 2386.4 5748.4 2458.5 5849.6 II 12 .2000 2249.1 5552.8 2317.4 5650.6 2387.6 5750.0 2459.7 5851.3 |l2 13 .2167 2250.2 5554.4 2318.6 5652.3 2388.8 5751.7 2460.9 5853.0 13 14 •2333 2251.3 5556.0 2319.7 5653.9 2390.0 5753-4 2462.1 5854.7 14 15 .2500 2252.5 5557.6 2320.9 5655.5 2391.2 5755.1 2463.3 5856.4 15 16 .2667 1 2253.6 5559.2 2322.0 5657-1 2392.4 5756.7 2464-5 5858.1 16 17 .2833, 2254.7 5560.9 2323.2 5658.8 2393.5 5758.4 2465.8 5859.8 I17 18 .3000 2255.8 5562.5 2324.3 5660.4 2394-7 5760.1 2467.0 5861.5 18 19 .3167 2257.0 5564.1 2325.6 5662.1 2395.9 5761.8 2468.2 5863.2 19 20 •3333 '2258.1 5565.7 2326.7 5663.7 2397.1 5763.4 2469.4 5864.9 20 21 .3500 ; 2259.3 5567.3 2327.9 5665.4 2398.3 5765.1 2470.6 5866.6 21 22 .3667 2260.4 5568.9 2329.0 5667.0 1 2399.5 5766.8 2471.9 5868.3 22 23 .3833 2261.5 5570.6 2330.1 5668.7 2400.7 5768.5 2473.1 ^0^°-^ 23 24 .4000 2262.7 5572.2 2331.3 5670.3 2401.9 5770.1 2474.3 5871.8 24 2S .4167 2263.8 5573.8 2332.5 5672.0 2403.1 5771.8 2475.5 5873.5 25 26 .4333 \ 2264.9 5575.4 2333.7 5673.6 2404.3 5773-5 2476.7 5875.2 26 27 .4500 2266.0 5577.0 2334.8 5675.3 2405.5 5775.2 2478.0 5876.9 27 28 .4667 li 2267.2 5578.6 2336.0 -5676.9 2406.6 5776.9 2479.2 5878.6 28 29 .4833 11 2268.4 5580.3 2337.1 5678.6 2407.8 5778.6 2480.4 5880.3 29 30 .5000 !i 2269.5 5581.9 2338.3 5680.2 2409.0 5780.2 2481.6 5??"-° 30 31 .5167 : 2270.6 5583.5 2339.5 5681.9 2410.2 5781.9 2482.9 5883.7 31 32 .5333 2271.7 5585.1 2340.7 5683.5 241 1.4 5783.6 2484.1 5885.4 32 33 .5500^ 2272.8 5586.8 2341.9 5685.2 2412.6 5785.3 2485.3 5887.2 33 34 .5667 2273.9 5588.4 2343.0 5686.8 2413.8 5787-0 2486.5 5888.9 34 35 .5833 "2275.1 5590.1 2344.1 5688.5 2415.0 5788.7 2487.8 5890.6 35 36 .6000 ! 2276.2 5591.7 2345.3 5690.2 2416.2 5790.3 2489.0 5892.3 36 37 .6167; 2277.3 5593.3 2346.5 5691.9 2417.4 5792.0 2490.3 5894-0 37 38 .6333 1 2278.5 5594.9 2347.7 5693.5 2418.6 5793.7 2491.5 5895-7 38 39 .6500 i 2279.7 5596.6 2348.9 5695.2 2419.8 5795.4 2492.7 5897.5 39 40 .6667 2280.8 5598.2 2350.0 5696.8 2421.0 5797.1 2493.9 5899.2 40 41 .6833 j 2281.9 5599.8 i 2351.2 5698.5 2422.2 5798.8 2495.2 5900.9 41 42 .7000 2283.0 5601.4 2352.3 5700.1 2423.4 5800.4 2496.4 5902.6 42 43 .7167 ' 2284.1 5603.1 2353.5 5701.8 2424.6 5802.1 2497.7 5904.3 43 44 .7333 2285.3 5604.7 . 2354.7 5703.4 2425.8 5803.8 2498.9 5906.0 44 45 .7500 2286.5 5606.4 ll 2355.8 5705.1 2427.0 5805.5 2500.1 5907.7 45 46 .7667 2287.6 5608.0 ; 2357.0 5706.8 2428.2 5807.2 2501.3 5909.4 46 47 .7833' 2288.7 1 5609.6 i 2358.1 5708.5 2429.4 5808.9 2502.6 5911.2 ; 47 48 .8000 2289.9 5611.2 i 2359.3 5710.1 2430.6 5810.6 2503.8 5912.9 48 49 .8167 2291. 1 5612.9 2360.5 5711.8 2431.8 5812.3 2505.1 5914.6 49 50 .8333 2292.2 5614.5 2361.7 5713.4 2433.0 5814.0 2506.3 5916.3 50 51 .8500 2293.3 5616.2 ; 2362.9 5715. 1 2434.2 5815.7 2507.5 5918.1 51 52 .8667 2294.4 5617.8 2364.0 5716.7 2435.4 5817.3 2508.7 5919.8 52 53 .8833 2295.6 5619.4 \\ 2365.1 5718.4 2436.6 5819.0 2510.0 5921.5 53 54 .9000 2296.7 5621.0 2366.3 5720.0 2437.9 5820.7 2511.2 5923.2 54 55 .9167 2297.9 5622.7 ! 2367.5 5721.7 2439.1 5822.4 2512.5 5925.0 55 56 •9333 2299.0 5624.3 || 2368.7 5723.4 2440.3 5824.1 2513.7 5926.7 56 57 .9500 2300.2 5625.9 2369.9 5725.1 2441.5 5825.8 2515-0 5928.4 57 58 .9667 2301.3 5627.5112371.0 5726.7 2442.7 5827.5 2516.2 5930.1 58 59 •9833 2302.4 5629.2 II 2372.2 5728.4 2443.9 5829.2 2517.5 5931.9 59 372 THE SURVEY Use 100' Chord* , UD to 8 ' Curves Use 2s' Chords up to 32" Curves Use so' Chords up' to i6° Curves Use lo' Chords above 32° Curves ^g 92° 93° 94° 95° a Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 2518.7 5933.6 2594.2 6038.2 2671.8 6144.7 2751.5 6253.2 I .0167 2520.0 5935-3 2595-5 6040.0 2673.1 6146.5 2752.9 6255.1 I 2 •0333 2521.2 5937.0 2596-8 6041.7 2674.4 6148.3 2754.2 6256.9 2 3 .0500 2522.4 5938.8 2598.1 6043.5 2675.7 6150.1 2755-6 6258.7 3 4 .0667 2523.6 5940.5 2599.3 6045.2 2677.0 6151.9 2756.9 6260.5 4 5 .0833 2524.9 5942.3 2600.6 6047.0 2678.4 6153.7 2758.3 6262.4 s 6 .1000 2526.1 5944.0 2601.9 6048.7 2679.7 6155.4 2759-6 6264.2 6 7 .1167 2527-4 5945-7 2603.2 6050.5 2681.0 6157.2 2761.0 6266.0 7 8 •1333 2528.6 5947.4 2604.4 6052.2 2682.3 6159.0 2762.3 6267.8 8 9 .1500 2529.9 5949.2 2605.7 6054.0 2683.6 6160.8 2763.7 6269.7 9 10 .1667 2531-1 5950.9 2607.0 6055.8 2684.9 6162.6 2765.0 6271.5 10 II .1833 2532.4 5952.7 2608.3 6057.5 2686.3 6164.4 2766.4 6273.4 II 12 .2000 2533-6 5954-4 2609.6 6059.3 2687.6 6166.2 2767.7 6275.2 12 13 .2167 2534-9 5956.1 2610.9 6061. 1 2688.9 6168.0 2769.1 6277.0 13 14 .2333 2536.1 5957-8 2612. 1 6062.8 2690.2 6169.8 2770.4 6278.8 14 IS .2500 2537.4 5959.6 2613.4 6064.6 2691.5 6171.6 2771.8 6280.7 IS 16 .2667 2538.6 5961.3 2614.7 6066.4 2692.8 6173.4 2773-1 6282.5 16 17 .2833 2539-9 S963.1 2616.0 6068.2 2694.2 6175.2 2774-5 6284.4 17 18 .3000 2541-1 5964.8 2617.3 6069.9 2695.6 6177.0 2775-8 6286.2 18 19 .3167 2542.4 5966.5 2618.6 6071.7 2696.9 6178.8 2777.2 6288.0 19 20 .3333 2543-6 5968.2 2619.8 6073.4 2698.1 6180.6 2778.S 6289.8 20 21 .3500 2544.9 5970.0 2621. 1 6075.2 2699-5 6182.4 2779-9 6291.7 21 22 .3667 2546-1 5971.7 2622.4 6077.0 2700.8 6184.2 2781.2 6293.5 22 23 .3833 2547.4 5973.5 2623.7 6078.8 2702.1 6186.0 2782.6 6295.4 23 24 .4000 2548.6 5975.2 2625.0 6080.5 2703.4 6187.8 2784.0 6297.2 24 25 .4167 2549-9 5977.0 2626.3 6082.3 2704-8 6189.7 2785.4 6299.1 ^1 26 .4333 2551-2 5978.7 2627.6 6084.1 2706.1 6191.5 2786.7 6300.9 26 27 .4500 2552.5 5980.5 2628.9 6085.9 2707.4 6193-3 2788.1 6302.7 ^l 28 .4667 2553.7 5982.2 2630.2 6087.6 2708.7 6195-1 2789.4 6304.6 28 29 .4833 2555.0 5983.9 2631.5 6089.4 2710.1 6196.9 2790.8 6306.4 29 30 .5000 2556.2 5985.6 2632.7 6091.2 2711.4 6198.7 2792.1 6308.2 30 31 .5167 2557-5 5987.4 2634.0 6093.0 2712.7 6200.5 2793.5 6310.1 31 32 •5333 2558.7 5989.1 2635.3 6094.7 2714.0 6202.3 2794-9 6311.9 32 33 .5500 2560.0 5990.9 2636.6 6096.5 2715-4 6204.1 2796.3 6313.8 33 34 .5667 2561.2 5992.6 2637.9 6098.3 2716.7 6205.9 2797.6 6315.6 34 35 .5833 2562.5 5994.4 2639.2 6100.1 2718.0 6207.7 2799-0 6317.S 35 36 .6000 2563.8 5996.1 2 640. 5 6101.8 2719-3 6209.5 2800.3 6319.3 36 37 .6167 2565-1 5997.9 2641.8 6103.6 2720.7 6211.4 2801.7 6321.2 37 38 .6333 2566.3 5999.6 2643.1 6105.4 2722.0 6213.2 2803.1 6323.0 38 39 .6500 2567.6 6001.4 2644.4 6107.2 2723.4 6215.0 2804.S 6324.9 39 40 .6667 2568.8 6003.1 2645.7 6109.0 2724-7 6216.8 2805.8 6326.7 40 41 .6833 2570.1 6004.9 2647.0 6110.8 2726.0 6218.6 2807.2 6328.6 41 42 .7000 257.1.3 6006.6 2648.3 6112.5 2727.3 6220.4 2808.6 6330.4 42 43 .7167 2572.6 6008.4 2649.6 6114-3 2728.7 6222.3 2810.0 6332.3 43 44 .7333 2573.9^ 6010.1 2650.9 6116.1 2730.0 6224.1 2811.3 6334.1 44 45 .7500 2575.2 6011.9 2652.2 6117.9 2731.4 6225.9 2812.7 6336.0 45 46 .7667 2576.4 6013.6 2653.5 6119.7 2732.7 6227.7 2814.1 6337.8 46 47 .7833 2577.7 6015.4 2654.8 6121.5 2734-1 6229.S 2815.5 6339.7 47 48 .8000 2578.9 6017.1 2656.1 6123.2 2735-4 6231.3 2816.8 6341.5 48 49 .8167 2580.2 6018.9 2657.4 6125.0 2736.7 6233.2 2818.2 6343.4 49 SO .8333 2581.5 6020.6 2658.7 6126.8 2738.0 6235.0 2819.6 6345.2 SO SI .8500 2582.8 6022.4 2660.0 6128.6 2739.4 6236.8 2821.0 6347.1 51 52 .8667 2584.0 6024.1 2661.3 6130.4 2740.7 6238.6 2822.3 6349.0 52 S3 .8833 2585.3 6025.9 2662.6 6132.2 2742.1 6240.5 2823.7 6350.9 53 54 .9000 2586.6 6027.6 2663.9 6133.9 2743.4 6242.3 2825.1 6352.7 54 55 .9167 2587.9 6029.4 2665.3 6135.7 2744.8 6244.2 2826.5 6354.6 55 56 .9333 2589.1 603 1. 1 2666.6 6137.5 2746.1 6246.0 2827.8 6356.4 S6 57 .9500 2590.4 6032.9 2667.9 6139.3 2747. S 6247.8 2829.2 6358.3 57 58 .9667 2591.7 6034.6 2669.2 6141.1 2748.8 6249.6 2830.6 6860.1 S8 59 .9833 2593.0 6036.4 2670.S 6142.9 2750.2 6251.4 2832.0 6362.0 S9 FUNCTIONS OF ONE-DEGREE CURVE 373 Use loo' Chords up to 8" Curves Use 50' Chords up to 16° Curves Use 25' Chords up to 32** Curves Use 10' Chords above 32" Curves 09 a 96^ 97" 98^ 99° 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. .0000 2833-4 6363.8 2917.5 6476.6 3004.0 6591.6 3092.9 6709.0 I .0167 2834.8 6365.7 2918.9 6478.5 3005. s 6593.6 3094.4 6711.0 I 2 .0333 2836.1 6367.5 2920.3 6480.4 3006.9, 6595.5 3095.9 6712.9 2 3 .0500 2837.5 6369.4 2921.8 6482.3 3008.4 6597.S 3097.4 6714-9 3 4 .0667 2838.9 6371.3 2923.2 6484.2 3009.8 6599.4 3098.9 6716.9 4 s .0833 2840.3 6373.2 2924.6 6486.1 3011.3 6601.3 3100.4 6718.9 5 6 .1000 2841.7 6375.0 2926.0 6488.0 3012.8 6603.2 3101.9 6720.8 6 7 .1167 2843.1 6376.9 2927.5 6489.9 3014.3 6605.2 3103.4 6722.8 7 8 .1333 2844.5 6378.7 2928.9 6491.8 3015.7 6607.1 3104.9 6724.8 8 Q .1500 2845.9 6380.6 2930.3 6493.7 3017.2 6609.1 3106.4 6726.8 9 10 .1667 2847.2 6382.S 2931.7 6495.6 3018.6 6611.0 3107.9 6728.8 10 II .1833 2848.6 6384.4 2933.2 6497.5 3020.1 6613.0 3109.5 6730.8 II 12 .2000 2850.0 6386.2 2934.6 6499.4 3021.6 6614.9 3III.O 6732*7 12 13 .2167 2851.4 6388.1 2936.1 6501.3 3023.1 6616.9 3112.5 6734.7 13 14 .2333 2852.8 6389.9 2937.S 6503.2 3024.5 6618.8 3114.0 6736.7 14 IS .2500 2854.2 6391.8 2938.9 6505.2 3026.0 6620.8 3115.S 6738.7 IS 16 .2667 2855.6 6393.7 2940.3 6507.1 3027.5 6622.7 3117.0 6740.7 16 17 .2833 2857.0 6395.6 2941.8 6509.0 3029.0 6624.7 3118.5 6742.7 17 18 .3000 2858.4 6397.4 2943.2 6510.9 3030.4 6626.6 3120.0 6744.6 18 19 .3167 2859.8 6399.3 2944.7 6512.8 3031.9 6628.6 3121.S 6746.6 19 20 •3333 2861.2 6401.2 2946.1 6514.7 3033.3 6630.5 3123.1 6748.6 20 21 .3500 2862.6 6403.1 2947.5 6516.6 3034.8 6632.5 3124.6 6750.6 21 22 .3667 2864.0 6404.9 2948.9 6518.5 3036.3 6634.4 3126.1 6752.6 22 23 .3833 2865.4 6406.8 2950.4 6520.4 3037.8 6636.4 3127.6 6754.6 23 24 .4000 2866.7 6408.V 2951.8 6522.3 3039.3 6638.3 3129.I 6756.6 24 25 .4167 2868.1 6410.6 2953.3 6524.3 3040.8 6640.3 3130.7 6758.6 ^1 26 .4333 2869.5 6412.4 2954.7 6526.2 3042.2 6642.2 3132.2 6760.6 26 27 .4500 2870.9 6414.3 2956.2 6528.1 3043.7 6644.2 3133.7 6762.6 27 28 .4667 2872.3 6416.2 2957.6 6530.0 3045.2 6646.1 3135.2 6764.6 28 29 .4833 2873.7 6418.1 2959.0 6531.9 3046.7 6648.1 3136.7 6766.6 29 30 .5000 2875.1 6419.9 2960.4 6533.8 3048.1 6650.0 3138.3 6768.6 30 31 .5167 2876.5 6421.8 2961.9 6535.8 3049.6 6652.0 3139.8 6770.6 31 32 .5333 2877.9 6423.7 2963.3 6537.7 3051.1 6653.9 3141.3 6772.6 32 33 .5500 2879.4 6425.6 2964.8 6539.6 3052.6 6655.9 3142.9 6774.6 33 34 .5667 2880.8 6427.5 2966.2 6541.S 3054.1 6657.8 3144.4 6776.6 34 35 .5833 2882.2 6429.4 2967.7 6543.4 3055.6 6659.8 3145.9 6778.6 35 36 .6000 2883.6 6431.2 2969.1 6545.3 3057.0 6661.7 3147.4 6780.6 36 37 .6167 2885.0 6433.1 2970.6 6547.3 3058.5 6663.7 3149.0 6782.6 H 38 •6333 2886.4 6435.0 2972.0 6549.2 3060.0 6665.7 3150.5 6784.6 38 39 .6500 2887.8 6436.9 2973.5 6551.1 3061.S 6667.7 3152.0 6786.6 39 40 .6667 2889.2 6438.8 2974.9 6553.0 3063.0 6669.6 3153.5 6788.6 40 41 .6833 2890.6 6440.7 2976.4 6555.0 3064.5 6671.6 3155.1 6790.6 41 42 .7000 2892.0 6442.5 2977.8 6556.9 3066.0 6673.5 3156.6 6792.6 42 43 .7167 2893.4 6444.4 2979.3 6558.8 3067.5 6675.5 3158.2 6794.6 43 44 .7333 2894.8 6446.3 2980.7 6560.7 3068.9 6677.4 3159.7 6796.6 44 45 .7500 2896.3 6448.2 2982.2 6562.7 3070.4 6679.4 3161.2 6798.6 45 46 .7667 2897.7 6450.1 2983.6 6564.6 3071.9 6681.4 3162.7 6800.6 46 47 .7833 2899.1 6452.0 2985.1 6566.5 3073.4 6683.4 3164.3 6802.6 4^ 48 .8000 2900.5 6453.9 2986.5 6568.4 3074.9 6685.3 3165.8 6804.6 48 49 .8167 2901.9 6455.8 2988.0 6570.4 3076.4 6687.3 3167.4 6806.6 49 SO .8333 2903.3 6457.6 2989.4 6572.3 3077.9 6689.2 3168.9 6808.6 50 SI .8500 2904.7 6459.5 2990.9 6574.3 3079.4 6691.2 3170.5 6810.6 51 52 .8667 2906.1 6461.4 2992.3 6576.2 3080.9 6693.2 3172.0 6812.6 52 S3 .8833 2907.6 6463.3 2993.8 6578.1 3082.4 6695.2 3173.6 6814.7 S3 S4 .9000 2909.0 6465.2 2995.2 6580.0 3083.9 6697.1 3175.I 6816.7 54 55 .9167 2910.4 6467.1 2996.7 6582.0 3085.4 6699.1 3176.6 6818.7 55 56 .9333 2911.8 6469.0 2998.1 6583.9 3086.9 6701.1 3178.1 6820.7 56 57 .9500 2913.3 6470.9 2999.6 6585.8 3088.4 6703.2 3179.7 6822.7 57 S8 .9667 , 2914.7 6472.8 3001.1 6587.7 3089.9 6705.2 3181.2 6824.7 58 59 .9833 2916.1 6474.7 3002.6 6589.7 3091.4 6707.1 3182.8 6826.8 59 374 THE SURVEY Use loo' Chords up to 8° Curves Use 50' Chords up to 16° Curves Use 25' Chords up to 32" Curves Use 10' Chords above 32° Curves s *o g 100° \S g ^ & ; "3 I fl s OQ Ext. Tan. s .0000 3184-3 6828.8 I .0167 3185.9 6830.8 I 2 •0333 3187.4 6832.8 2 3 .0500 3189.0 6834.8 3 4 .0667 3190.5 6836.8 4 5 .0833 3192. 1 6838.9 5 6 .1000 3193.6 6840.9 6 7 .1167 3195.2 6842.9 7 8 .1333 3196.7 6844.9 8 9 .1500 3198.3 6847.0 9 10 .1667 3199.8 6849.0 10 II .1833 3201.4 6851.0 II 12 .^000 3202.9 6853.0 12 13 .2167 3204.5 6855-1 13 14 .2333 3206.0 6857.1 14 15 .2500 3207.6 6859-1 15 16 .2667 3209.1 6861.1 16 17 .2833 3210.7 6863.2 17 18 .3000 3212.2 6865.2 18 19 .3167 3213.8 6867.2 19 20 •3333 3215.4 6869.2 20 21 .3500 3217.0 6871.3 21 22 .3667 3218.5 6873.3 22 23 .3833 3220.1 6875-4 23 24 .4000 3221.6 6877.4 24 25 .4167 3223.2 6879.4 25 26 .4333 3224.7 6881.4 26 27 .4500 3226.3 6883-5 27 28 .4667 3227.9 6885.5 28 29 .4833 3229.5 6887.6 29 30 .5000 3231.0 6889.6 30 31 •5167 3232.6 6891.7 31 32 .5333 3234.1 6893.7 32 33 .5500 3235.7 6895.7 33 34 .5667 3237.3 6897.8 34 35 .5833 3238.9 6899.8 35 36 .6000 3240.4 6901.8 36 37 .6167 3242.0 6903.9 37 38 •6333 3243.5 6905.9 38 39 .6500 3245-1 6908.0 39 40 .6667 3246.7 6910.0 40 41 .6833 3248.3 6912. 1 41 42 .7000 3249.8 6914.1 42 43 .7167 3251-4 6916.2 43 44 .7333 3253-0 6918.2 44 45 .7500 3254-6 6920.3 45 46 .7667 3256.2 6922.3 46 47 .7833 3257-8 6924.4 47 48 .8000 3259-3 6926.4 48 49 .8167 3260.9 6928.5 49 SO .8333 3262.5 6930.5 50 SI .8500 3264.1 6932.6 51 52 .8667 3265.7 6934.6 52 S3 .8833 3267.3 6936.7 53 S4 .9000 3268.8 6938.7 54 5S .9167 3270.4 6940.8 55 S6 .9333 3272.0 6942.8 S6 S7 .9500 3273-6 6944.9 57 S8 .9667 3275.2 6946.9 S8 59 .9833 3276.8 6949.0 59 FUNCTIONS OF ONE-DEGREE CURVE 375 Use loo' Chords up to 8° Curves Use 25' Chords up to 32° Curves Use 50' Chords up to 16° Curves Use 10' Chords above 32° Curves 1 101° 102° 103° 104° 105° 1 Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. 3278.3 6951.0 3375.1 7076.0 3474.6 7203.6 3577-1 7334-1 3682.6 7467.5 10 3294'-3 6971.7 3391.5 7097.1 3491.5 7225.1 3594-4 7356.1 3700.4 7490.0 10 20 3310.3 6992.4 3407.9 7118.2 3508.4 7246.8 3611.9 7378.2 3718.4 7512.6 20 30 3326.4 7013.2 !3424.5 7139.4 3525.5 7268.5 3629.4 7400.4 3736.5 7535-3 30 40 3342.5 7034.03441.1 7160.7 3542.6 7290.3 3647-1 7422.7 3754-6 7558.1 40 so 3358.8 7055.0 J3457.8 7182. 1 3559.8 7312.1 3664.8 7445-0 3772.9 7581.0 50 60 3375.1 7076.0 3474.6:7203.6 3577.1 7334-1 3682.6 7467-5 3791-2 7604.0 60 106° 107° 108'' 109° no" S 3 c ^ Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. ^ 3791.2 7604.0 3903.1 7743.7 4018.5 7886.7 4137.4 8033.2 4260.0 8183.3 10 3809.6 7627.0 3922.1 7767.3 4038.0 7910.8 4157-5 8057.9 4280.8 8208.7 10 20 3828.1 7650.2 3941.2 7791.0 4057.7 7935.1 4177-8 8082.8 4301.7 8234.2 20 30 3846.7 7673.4 3960.4 7814.7 4077.5 7959.5 4198.2 8107.8 4322.7 8259.8 30 40 3865.4 7696.7 3979.6 7838.6 4097.3 7983.9 4218.7 8132.8 4343-8 8285.5 40 50 3884.2 7720.1 3999.0 7862.6 4117.3 8008.5 4239-3 8158.0 4365.1 8311-3 50 60 3903-1 7743.7 4018.5 7886.7 4137.4 8033.2 4260.0 8183.3 4386.4 8337.2 60 Cfl III*' 112° 113'' 114'' 115° ^ :3 d ^ Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. ^ 4386.4 ^2>S1-2 4516.9 8495.1 4651.6 8657.1 4790.7 8823.4 4934-4 8994.3 10 4407.9 8363.2 4539.1 8521.8 4674.5 8684.5 4814.4 8851.6 4958.9 9023.2 10 20 4429.5 8389.4 4561.3 8548.6 4697.5 8712.0 4838.1 '8879-9 4983-4 9052.3 20 30 4451.2 8415.6 4583.7 8575.6 4720.6 8739.7 4862.o'89o8.3l 5008.1 9081.5 30 40 4473.0 8442.0 4606.2 8602.6 4743.9 8767.5 4885.08936.8 5032.9 9110.8 40 50 4494.9 8468.5 4628.9 8629.8 4767.2 8795.4 4910.2 8965.5 5057-9 9140.3 50 60 4516.9 8495.1 4651.6 8657.1 4790.7 8823.4 4934-48994-3 5083.C 9169.9 60 116° 117° 118° 119° 120° 1 1^ Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. Ext. Tan. 5083.0 9169.9 5236.6 9350.5 5395.4 9536.3 5559.7 9727.6 5730.0 J 9,924.6- 10 •5108.2 9199.7 5262.6I9381.1 5422.4 9567-8 5587.7 9760.0 5758.9 9,958.1! 10 20 5133.6 9229.6 5288.9 9411.9 5449.5 9599-5 5015.8 9792.6 I5788.0 9,990.6' 20 30 5159.1 9259.6 5315.319442.8 5476.819631.3 5644.1 9825-4 I5817.3 10,025.61 30 40 5184.8 9289.8 5341.8 9473.8 5504.3 9663.2 5672.6 9858.3 5846.8 10,059.7 40 50 5210.6 9320.1 5368.5 9505.0 5532.0 9695.3 5701.2 9891.4 5876.4 10,093.7 50 60 5236.6 9350.5 5395.4 9536.3 5559.7 9727.6 5730.0 9924.6 5906.1 10,127.7 60 376 THE SURVEY L = loo X -7; = Central angle X 100. D Degree of curvature For the convenience of the field engineer column i, Table 32, gives the central angle (A) in degrees and minutes (as read by the transit); column 2 gives the same angle expressed in degrees and decimals for figuring curve lengths. Tangent Length and Externals. — Sketch No. 71 shows a general curve problem. The deflection angle between the tangents at the point of intersection (P. 1.) = the central angle of the curve that will fit these tangents; it is referred to as A. The tangent distances equal the distance from the P. C (be- ginning of curve) to the P, I, or P. I. to P, T. (end of curve) and is expressed by the formula T = Radius X tangent of — (4) Externa!; PC. \ Bl. -.■^^ ^^ '(Center of Curve J Pig. 71. Therefore, for a given central angle A, the tangent length is di- rectly proportional to the radius. If the tangent lengths of a 1° curve for different A's are tabulated, the tangent length for any desired degree of curve equals tangent length for 1° curve for the specified A divided by the degree of the desired curve ex- pressed in degrees and decimals of a degree. Expressed as a formula this reads: Tangent for desired curve = __ Tangent 1° curve for specified A D (5) D (6) and reversing the formula we can determine the desired degree of curve for a specified tangent length by the formula Tangent 1° curve for specified A Specified tangent length desired The external is the distance from the P. /. to the curve arc on the line between the P, I. and the center of the curve. It is deter- mined by the formula : Ext. =f : — E.adius = Radius/ Gosine- \ Cosine- ■) (7) CURVE FORMULAE 377 iand is directly proportional to the radius in the satne manner as the tangent length; therefore, the external of any desired curve for a specified A equals the external of a i° curve for that A divided by the degree of curvature. 'Pointof Tang en cy ;S Angle=^CenlTalAngkA ^Center of Curve Pig. 72. Fig. 73. Expressed as a formula this reads: Ext. 1° curve for specified A External for desired curve = D (8) 378 THK SURVEY and reversing; as for tangents, the desired degree of curvature is obtained that gives a specified external distance, by the formula, _ Ext. 1° curve for specified A ^ , . Specified Ext. distance desired Methods of Running Curves. — Curves are run in the field by tangent offsets, middle ordinates or deflection angles. Deflec- tion angles is the simplest method and is almost universally used. It is based on the principle that the angle S between the tangent and arc chord, one end of which is at the point of tangency, is equal to 3^ the central angle subtended by that chord. Sup- pose the angle A is 4° and the arc length ST = 100 feet. This curve would then be a 4° curve. From the previous definitions locate the point T (Fig. 72) by turning the deflection angle S = 2° from the tangent and measuring 100 feet of arc in such a position that the end of the arc would be on the line of the chord ST. It is impossible to conveniently measure the arc distance and for all practical purposes a chord length of 100' will answer for a 4° curve (see discussion, page 379). Suppose we wish to locate the points 2, 3, 4, 5, and 6 on the 4° curve from point i or the P.C. of a curve (Fig. 73). Set the transit at the P.C: if we turn a deflection — = 2° from 2 the tangent xy the line of sight will pass through the point 2; if we turn — = 4° the line of sight will pass through point 3; 6°, 2 point 4, etc.; it only remains to measure to these points to locate them definitely. This can be done in two ways,^ by measuring the distances 1-2, 1-3, 1-4, 1-5, etc., or by measuring 1-2, 2-3, 3-4, 4-5, etc. In the first case the difference between the length of arc and the chord length becomes so great that, unless a correction is made, the points are not exactly located; that is, the length of arc between points i, 2, 3, 4, 5, 6, = 500' while the chord length 1-6 = 497.5'; also, it takes longer to measure the distances 1-2, 1-3, 1-4, 1-5, 1-6, etc., than it would 1-2, 2-3, 3-4, 4-5, etc. In the second method we can use chords of 100' from 1-2, 2-3, etc., with no appreciable error, as the distance measured by chords I, 2, 3, 4, 5, 6, = 499-94'- Therefore, the method usually adopted is to turn the deflection A angle — and measure the chord 1-2, which locates the point 2; 2 then turn the deflection angle — and measure the chord distance 2 2-3, locating point 3, etc. The fact has been mentioned that the use of the chord distance as equal to the arc introduces an error but that this error is of no importance for a 4° curve: As the degree of curvature in- creases, the difference between an arc length of 100' and the chord SIMPLE CURVE PROBLEM 379 length becomes greater, and it is necessary to determine the limit of curvature that will allow the use of 100' chords in locating curve points. On page 324 the statement is made that center line chain- ing should be correct to within o.i' per 100' of length, which allows a difference in arc and chord of o.i. This occurs when the degree of curvature reaches 9° per 100'. The difference can then be reduced by the simple expedient of using 50' chords, which re- duces the error for this degree of curvature from o.io' per 100' of length using 100' chords to 0.02' using 50' chords; 50' chords can be used up to 18° curves and beyond that point 25' chords. It is better not to use the full limit of allowable error, and a good working rule is 100' chords up to 8° curves, 50' chords up to 16° curves, 25' chords to 32° and beyond that 10' chords. For any given curve the deflection angle and central angle are directly proportional to the length of the arc, and if the de- flection angle for 100' arc of 10° curve equals 5° the deflection angle for one foot of arc of 10° curve equals = = 3 minutes. 100 100 An example of a typical simple curve problem can now be given : j^^ K 'Ten. Length— -^_pj_^^f^^23t4?.6 B Fig. 74. To determine the degree of curvature desired from a fixed external distance At station 23 -|- 42.6 we have a deflection angle of 25° 10' be- tween tangents AB and B'C\ suppose upon exaraining the ground it is decided that to fit the old roadbed and give good alignment the curve should be located somewhere between 13.5' and 14.5' to the right of the transit point at station 23 + 42.6. Proceed as follows: from table 32 pick out the external for a 1° curve for A = 25° 10', this equals 141.0'. The problem is to determine the degree of curvature that will give an external of between 13.5' and 14.5'. Use formula (9). ^ Ext. T° curve for 25° 10' 141. o' o D = -. = > = 10.44 curve. 13.5 13.5^ ^ Ext. 1° curve for 2K° 10' ,141.0' o D = -. ^ = = 9.72 curve. 14.5 14-5 380 THE SURVEY To fit the conditions some curve must be selected between a 10.44° and a 9.72°. A 10° curve would be naturally selected as being the simplest to figure. To determine the required degree of curvature for a fixed tangent length Take the same problem as above except there must be a tangent length of between 127' and 129'. Use formula (6). ^ Tangent 1° curve for 25° 10' 12 79.1' D — ; = ;— = 10.07° curve. 127' 127' ^ Tangent 1° curve for 25° 10' 12 79.1' o D = -. = ~- = 9.91° curve. 129 129 Table 32 gives tangent for 25° 10' = 12 79.1'. These limiting values would result in the selection of a 10° curve. The degree of the desired curve is usually selected in one of these two ways; ordinarily it is determined by the external distance. £>« WR'^ 573.0 r--IZ7.9L^ 251.7 RC.-^Sta.2ZH4.7 P.T.^Sta.24t66.4 Fig. 75. Simple Curve Problem. Case i. — To compute the notes for a 10° curve for a deflection angle of 25° 10' between tangents at station 23 + 42.6. Central angle = 25° 10'. Table 32 gives the tangent 1° curve for 25° 10' = 1 279.1. rr 4. o 1279. 1 Tangent 10 curve = ^— = 127.91. 10 The station of the P.C. then equals station 23 + 42.6 P./. minus 127.9' == station 22 + 14.7. The length of curve = -7: = ^^'^ o ^ X 100' = 251.7 feet. JJ 10 The station of the P.T. (Tangent point, or end of the curve) as measured around the arc is then station (22 + 14.7 P.C.) + 251.7' = station 24 + 66.4. The rule for running curves requires the use of 50' chords for SIMPLE CURVE PROBLEM 381 a 10° curve. We must, therefore, figure the deflections for the even stations and the 50' stations as follows: Station 22 + 50, 23 + 00, 23 + 50? 24 + 00, 24 + 50, and to check the curve station 24 + 66.4. For a 10° curve, Table 31. The deflection for 100' of arc = 5° " " " 50' '' ". = 2° 30' u u u jr u u ^ qO ^y The distance from the P,C, station 22 + 14.7 to station 22 + 50 is 35.3'; the deflection per foot = 0° 03', for 35.3' = 35.3 X 0° 03' = 105.9 minutes = 1° 46'. The distance P.C. to station 23 + 00 equals 85.3', or 50' farther than for station 22 + 50; the deflection per 50' of arc equals 2° 30'; therefore, the deflection for station 23 + 00 equals the deflections for station 22 + 50 (1° 46') plus 2° 30', the deflection for 50' of arc or 4° 16'; in a like manner the deflection for station 23 -|- 50 is 6° 46'; for 24 + 00, 9° 16'; for 24 + 50, 11° 46'; the distance from station 24 + 50 to the P.T, station 24 + 66.4 is 16.4'; the deflection for 16.4' equals 16.4 X 0° 03' = 49.2'; the deflection for station 24 + 66.4 is, therefore (11° 46' + 49') = 12° 35'; if the deflection notes have been properly figured this last deflection to the P.T. should always be J^ the central angle of the curve; in this case J^ of 25° 10', which equals 12° 35', checking the notes. To run the curve. Set up the transit at the P./.; sight along the tangent {B.A.)y measure off the distance 12 7. 9" (tangent length) along this line and set the P.C. exactly on the line. In a like manner set the P.T. on the forward tangent {B'.C.) 127.9' from the P.I, Then set up the transit on the P.C. and with the vernier at 0° 00' sight on the P./., using the lower plate motion. Loosen the upper motion and deflect i°l46'; measure along this line 2tS'3\ which locates station 22 + 50 on the curve arc; then loosen the upper motion and set the vernier to read 4° 16'; measure 50' from the just located station 22 + 50, so that the forward end of the tape is in line with the transit deflection of 4° 16'; this locates station 23+00 on the curve arc. In a like manner deflect 6° 46' and measure forward 50' from station 23 + 00 to station 23 + 50, etc., until the \P.T. is reached. If the curve has been correctly run the last deflection of 12° 2>S' will strike the previously located P.T. and the distance from station 24 + 50 to this P.T. will be 16.4'; if the distance checks within 0.2' it is sufficiently close. The above problem and method of laying out a curve is the simplest form encountered; in it we assume that the P./., P.T, and all intermediate points on the curve are visible from the P.C, and that the P.I. is accessible. In nine cases out of ten this method is applicable to road curves, but where the P.I. occurs outside of the road fences it sometimes is located in a stream, pond, building, etc., and cannot be occupied. This is known as the problem of the inaccessible P.I. More often it is impossible to see the P.P., or some intermediate point on the curve from the P,C.i which necessitates intermediate 382 THE SURVEY transit points on the curve. The problem of inaccessible P.C.s or P.T.s is so rare it will not be illustrated. Problem of the Inaccessible P. I. Case 2. — The point H (P.L) can not be occupied. Locate any two convenient points, 5 and t on the tangents A.B, and B'.C. and measure the distance st equals, say, 1 10.5'. Set the transit at ^ and measure the angle between the line A.s. produced and st, say, 5° 10'; in a similar manner measure the angle at t between st produced and the forward tangent /C, say, 20° 00'. The total deflection then between the tangent AsB and B'tC or the central angle of the curve to be run is the sum of these two deflections, angles (5° 10') + (20° 00') = 25° 10'. Assuming a 10° curve is desired we must locate the P,C. from the point s and the P.T, from the point /. k- /2Z9-- -• -y [EC. \S=5fa.2Z+53X, Hj ^l- inaccessible Pig. 76. In the preceding simple curve problem the tangent length of a 10° curve with a central angle of 25° 10' was figured to be 127.9'; it, therefore, remains to compute the distance sE which subtracted from 127.9' will give the distance from s along the tangent sA to the P,C., of the curve.- In a similar manner compute tH, which subtracted from 127.9' gives the distance along the forward tangent tC to the P,T. of the curve. Knowing the station of the point s as measured along the tangent A.B. the station of the P.C is determined; then figure the de- flections in the usual manner and run the curve. For the values given the computations are as follows: To determine sU and Ut. Use the law of sines (see Trigono- metric formulae, page 843). sH :st : sin 20° 00' : sin 25° 10' ^ff = ^^ sin 20° 00' ^ 1 10.5 X 0.34202 ^ gg , sin 25° 10' 0.42525 5/ sin 5® 10' 1 10.5 X 0.09005 , Ht = "o — J- = = 23.4 sm 25 10 0.42525 Therefore, the distance from s to the P,C. is 127.9' — 88.9' = 39.0'. The distance from / to the P,T. is 127.9 "" 23.4 = 104.5. Having these distances the P.O. and P.T, are located. As- CURVE PROBLEMS 383 sume that station of 5 was measured along the tangent AB and found to be station 22 -f 53-7- The station of the P.C, then equals 22 + 14.7 " " P.L " '' 23 + 42.6 '' " P.T. " " 24 -f 66.4, using the length of curve figured in Case i. The deflections are figured and the curve run as in Case i, assuming that all the curve points are visible from the P.C. Case 3. — Where the P.T, or intermediate points on the curve are not visible from the P.C. (a) Where an intermediate set-up is required. Use the same curve as in Case i. The deflections for the different curve points were figured as follows: Deflections. — Instrument at P.C, foresight on P.I. P.C, Station 22 -f 14.7 22 + 50 23 + 00 23 + 50 24 + GO 24 + 50 • • '24 + 66.4 eC. 22f/4.7 PI. Deflection 0° 00' 1° 46 4° 16' 6° 46' 9° 16' 11° 46' " 12° 35' ,,.,0 -B~~^ ^"""^^^-^ Z4+50 JRT. 24 -h 66.4- Fig. 77. Set up the instrument at the P.C, and locate the points 22 + 50, 23 + 00 and 23 + 50; suppose 24 + 00 is not visible, set up at station 23 + 50, set the vernier at 0° 00' and back sight on the P.C; transit the telescope and finish the curve, using the same deflections as figured for the instrument set up at the P.C] that is, turn the deflection of 9° 16' for station 24 + 00, 11° 46' for 24 + 50, and 12° 35' for the P.T, In general it can be said that when- ever the P.C is used as a backsight from the intermediate set-up, set the vernier at 0° 00' when sighting on the P.C; transit the 'telescope and use original notes for the balance of the curve. (b) Where two or more intermediate set-ups are required. For the first set-up, say, at 23 + 50, proceed as above and set station 24 + 00; suppose 24 -f- 50 is not visible from station 23 + 50; set up at station 24 -f- 00 and with the vernier reading 6° 46' back sight on station 23 + 50; transit the telescope, set the vernier to read 11° 46' for station 24 + 50, and proceed, using the same deflections as originally figured. In general, where the P.C, is not visible from the intermediate set-up, set the vernier to read the deflection figured for the point used as a backsight; transit the telescope and proceed with the curve, 384 THE SURVEY using"3the notes originally figured. That is, if the instrument is set up at station 24 + 00 and 22 + 50 used as a backsight, the vernier is set at 1° 46', and using the lower motion the wire is set on station 22 + 50; then transiting the telescope the curve is run by setting the vernier at 11° 46' for station 24 + 50, etc. If station 23 + 00 is used as a backsight, set the vernier at 4° 16' when sighting the machine; then transit and proceed as above. These three cases cover any ordinary road curve problems. (b) NEW LOCATION SURVEYS General. — The details of survey work depend entirely on the character of the improvement and range from simple alignment determination on Mesa Wagon trails to the complete surveys required for difficult mountain locations which are to be constructed by contract on unit price bids. The following data are for complete first-class surveys. The same methods are used for more incom- plete surveys but parts of the procedure can often be omitted if the work is to be done by force account or convict labor. Organization and Equipment. — Eight to ten men parties are a convenient and efficient force. Locating engineer Transitman Levelman 3 Chainmen, rodmen, etc. 1 to 3 Axemen. Cook If drafting is to be done in the field add a draftsman and computer to the party, but this is not advised as field drafting is rarely satisfactory. Organization. (First stage of work.) T . . • f Picking out line and general Locating engineer | supervision. Transitman 1 2 Chainmen I Running base line. Necessary axemen [ ° . I Stakeman J Le elman 1 Running bench levels and check ^\ \ profile levels. Keeps all this ^^ J work close up to base line party. Organization. (Second stage of work.) Locating Engineer 1 Drainage areas. Classification 1 Assistant J of materials and topography. I'nSl } cross-sections. Levelman 2 Assistants > Cross-sections. SURVEY ORGANIZATIONS 385 Extra men moving camp, odd jobs, etc. The first stage of the work varies in speed from J^ mile to 3 miles per day depending on the character of the county. Three-fourths mile per day is a fair average for ordinary mountain work. The second stage should make a speed of from i mile to 2 miles per day. A fair average is about i J^ miles per day. Allowing for unavoidable loss of time, rnoving camp, etc., 10 miles a month for an eight man party is a fair average when they are doing first class work. Cost of Survey. — The cost of first class complete mountain road location surveys runs from $75 to $150 per mile exclusive of rail- road transportation to the job, allowing $150 per month for the locating engineer, $120 per month for transitman; $100 per month for leveler and $70 to $90 for laborers, etc. Meals are furnished free to the men at an average cost of $0.75 per man per day ex- clusive of labor or about $1.00 to $1.30 per day including cooks salary. The average speed for a party of 8 men is approximately 10 miles per month of completed survey, at an average cost of $100 to $120 per mile exclusive of railroad transportation. In easy flat country this speed can be easily doubled and the cost halved. Depreciation on Engineering Equipment per Mile of Survey Assumed 50 miles of survey per season Quan- tity Item ~ Value Years Annual Deprecia- tion and Repairs Rental Charge per Mile Survey I I I 2 3 4 2 2 3 6 I 4 2 I I Transit (mountain) tripod . Level (dumpy or Y) Locke level I300.00 150.00 7.00 33 00 36.00 9.00 30.00 20.00 7.00 6.00 10.00 4.00 4.00 24.00 10.00 10 10 3 5 2 2 I 5 I I 10 2 3 4 I $40 . 00 25 .00 2.50 6.00 18.00 5 00 30.00 4.00 7.00 6.00 1 .00 2.00 1.50 6.00 10.00 Abney levels @ 1 16.50 100' chains @ $12.00 Range poles (8' wooden) @ $2.25 Level rods, Philadelphia 13' extension Chain repair kits Metallic tape boxes, $2.45. Metallic fillers Set sounding bars (i3'i"-i'' and ^i" tool steel) Plumb bobs Pocket compasses Kodak 3-A Engineer's trunk Totals $650.00 S164.00 $3.30 (Say $3.00) * Marking crayon. * Use a crayon having a large amount of oil as it will last longer. On- AH" is a good brand. "Stay- 386 THE SURVEY Camp Drafting Equipment (if desired). — Camp equipment is listed in Chapter XII. Methods. — The chief of party should precede the men to the work and go over the entire line as outlined in the preliminary investigation report picking out his camp sites and making all necessary arrangements for transportation of camp equipment and supplies. He should also mark the base line location for two or three miles so that when the party arrives there will be no delay in making camp and starting the line work. First Stage of Survey. — (a) Tracing the location. (b) Running base line. (c) Running bench levels and base line profile. (a) Locating Line. — This work is done by the locating engineer who considers all the principles of grade, alignment, etc., discussed in Part I. In high altitudes he pays particular attention to avoid- ing bad snow conditions which in general means avoiding north exposure as much as possible. Very often he can be helped in this part of the problem by making a snow map the spring preceding ^^^^^^^^^^^^^^^^^^X%ss^ ■ ^^^^^^^^ ^^^^^^^^^^^^^^^^ /^^^^x^^^^Jvv^^^$$$$$$$VvSS$$*oC^ LE6BND. Area of Snow April /— Area of Snow Maij 1^ Area of Snow June l^ Note. — This map shows that it is advisable to keep on the north side of Buck Creek and the west side of Wind River from the standpoint of avoiding snow. It also shows that the Pass was open by June ist. Fig. 79. BASE LINE ' 387 the survey. This is done by sketching in the areas where snow lies at different dates, say April ist, May ist, June ist. When furnished with a map of this kind he avoids the areas of late snow where possible. Lacking a definite investigation for snow conditions the best available local data should be obtained from hunters, etc. The different trial lines are traced with an Abney level in open country and a combination of Abney level and aneroid in timbered country. The line that he decides to adopt is marked at sufficiently close intervals either by blazing trees or tall stakes with flags on them so that the base line party will have no difficulty in following the correct location. This work must be kept far enough ahead of the base line party so that there is no danger of the work of the main party becoming worthless by the line getting into a loca- tion which has to be abandoned and relocated. When working on a ruling grade the line should be traced down hill from the highest point on the route. When working on a rul- ing grade the line in the field should always be traced at a less rate of grade than the maximum allowed. That is if the maximum grade is set at 7% the locator should trace his line on a 63^ or 6% grade in order to give the designer a little leeway for economical variations from the field grade and yet keep within the maximum rate. When w^orking on portions of the route requiring less than the ruling grade it makes no difference in which direction the line is traced so long as the base line is run in one direction with con- tinuous stationing. (b) Base Line. — The base line follows the marked route of the location. It is a chained, transit line marked on the ground by stakes at least every 100 feet well driven and marked with crayon (Stay on All) with the stationor plus of each stake. Stakes are placed at each point on the line where a profile shot or cross-section will be required and should be well made and well driven so that they will remain in place at least three years. The transit points (angle points) are marked with well driven hubs with tack center- ing; every third or fourth transit point should be permanently and carefully referenced by both azimuth and distance (see sample notes). The angles in the line are determined by transit readings and the bearings of the courses are recorded by azimuth using true north as the zero azimuth. The use of true north as the reference line in these surveys is desirable on account of permitting a check on the accuracy of the transit work at any time; on account of retracing a lost line and on account of right-of-way descriptions in localities laid out on the U. S. Land system. The methods of determining true meridian by polaris and solar observations are explained, pages 395 to 415. In fairly flat or rolling topography the base line should follow the center line of the proposed improve- ment exactly and all curves at tangent intersections should be run in the field. It has been found from experience that for the topo- graphic conditions mentioned that the field men can pick the best location in easy country and also that where the center line is actu- ally run and staked that it simplifies the work of cross-sectioning, the office design and the staking for construction. 388 THE SURVEY However, on sidehill locations or any kind of difficult work experience has shown that the field men can not pick an exact center line which will be economical in design and that under these conditions it is a waste of time and money to run in curves. Under these conditions the base line is run as a series of tangents keeping as close to the probable center line as possible and using short tangents iii going around any natural features that will re- quire a sharp curve in the finished road. Later when the cross- sections are taken they must be extended far enough from the line to allow the designer to shift the center line from the base line as Skrfion Back Sight Transm Notes . Fore, Sighf I5-I-73.1 Back Ay. Fore Check '■ Angles £2fiL Wm stake- Stake -0--Q StZM. I2+3I.3 19005 3^05 lOyiaiidOak None 5-I-23.0 TheAyrnuthbta. 0. to 5+23 was cfeter^ TheAy ^-^ mined Claris Observation. SeptdOf^ 1918 Time 10-25 P.M. Pig. 8o. far as he desires as well as varying his vertical grade from the field grade. This requires considerable extra work in cross-sectioning as will be taken up later but is well worth while, as in difficult country a paper location is always more economical to construct than a field location. Bench Levels. — Ordinary engineers spirit level work reading turning points to nearest o.oi of a foot. Benches figured to nearest o.oi ft. in elevation (see sample notes. Figure 8i). Permanent benches should be established at least every J^ mile and preferably at J-^ mile intervals. The datum for the levels should be referred to U. S. Geological Survey datum if possible or lacking this reference a datum can be assumed but in any case the method of arriving at the elevation of the initial bench mark {(Continued page 390) TANGENT OFFSET METHOD 389 Staking Curves by Tangent Offset n 11^' Mh i ! I ilni / 1 ' mil ' 1 1 / o.n tlwMt-^-^ t t 1^ ^0 Illy m J t 1 1 Mr^hn'- 1 ^ • l%Uim-i4^t-. t ^ +-• mktuttl-i Z ^-.^1 ^ op; tttUtttu r ti ^ I ^^ ^Auuttj.4 ^7 J. ^2 - MuMUtttl t tfj^^ \' ^mUutu^t4 <^j t ^ % mt%iuTi4 t m ^ 7. t on .^mUulttttj. jM^TjZ^ 6 ^^ kmttt-U4 t uv.j' 1 1 MtutT-tti^ 7 '_,^ J. t ZMt%7-t4^ tj^thLv S MUmTttj- TZj-^v^^Z ^ ,R mmu4^-/4%w^ 2^v. t%%tTttJ fl^l/^ /.'T ^ 4%%%lti4jl//JX^J^ y tm%7-ttiJ7:^'^7^^^s.^'^ iS2z5 //_,/' y 7.y ' k ,0 JMZZCv Z/Z^^^ ^^ ^ , '^ M2Z7ZZ/^Z^ .^^^^^^0.^^ ^m%zi/.'^ziz^^ 7- #"■ it J»24^$iz^^^/ ^"^ ^• tm^ttt/^' zz.^' y ^^^Tuw- iMMyyy^^yyy .^ ^^ ---^ jTcop-" ^^g^>^/;<^< X •'^^^ -''■ ^-^" qq' - " J^^^^yf^'^'^^l^'^,.' ^ _ ^ -^ "^ ^0,2-- y '^^^^ ^ ^^ r'^'C--^"^" --■'"' ^ ^^' —i^^^^j^ --- — 50 100 150 200 250 Distance in feet measured along the curve from the P.C. orP.T. Pig. 81. The following instructions accompany the chart: In measuring up to the P. L, leave temporary markers at enough points so that the line of the tangent can be readily lo- cated by eye. From the newly located P. I. turn off the desired deflection angle. Determine the degree of curve necessary to fit the conditions from the external and tangent length and take from table the tangent and length of curve, and record the station of the P.C. and P.T. Make the curve correction for difference in length of the sum of the tangents and distance on the curve at the P.I., and start measurements along next tangent, leaving temporary markers up to the P.T. of the curve. To lay out curve, start at the station or plus station near the P.C. and measure along the curve, using standard chord lengths, and using the offsets from tangent as read from chart, which increases as the distance from the P.C. or P.T. increases. To be useful a chart of this kind should be drawn to a larger scale than we can reproduce in a handbook of this size and this has been inserted more to show a convenient method than for actual use. In the same manner a chart can be prepared for short radii curves from 40' radius to 150' radius that is very useful in mountain road location. 390 THE SURVEY should be fully explained in the notes. The computations of level notes should be made in the field and checked each night. Profile Levels. — These levels also act as a check on the bench levels and therefore require an independent line preferably run in the opposite direction. The turns are read to the nearest o.oi foot and the profile ground elevations of the base line to the nearest O.I foot. In case there is no radical difference in the two lines of levels (Bench and Profile) the profile levels are corrected to agree with the bench levels at each bench and carried ahead on the bench elevations. This is done so that there will be no cumulative differ- ence in the levels. An error of o.i foot in running between* benches Sfa. Sample Bench Levels \ r^ 11 1 1 1 1 1 1 Aua I. IcilR iiljl 1 MM' '"N Cate\ Level i- H.l. - Elev. 1 Remarks Thoma5 Rod r^ A IIIIIIIM IMIII " " d.M.O. 52^.?l \j Y-5-65-5enchcTtHet ^er. Bron^i ' ■A^ 10.43 5258.64 Tab let in School House. T.R 2.14 5256.50 7^ 6.91 5265.41 T.R 1.22 5255.19 7^' 9.33 5267.52 B.MNo.l. 5. 16 5262.36 Spike in Blazed Pi neTree lOO'Rtof n IA7 5263.83 Srh. 10-^20 T.R 8. 72 525511 r\ -r\ - - _/\ o- -\J- -- ,__,., j ^ . -r- -p is allowable (see Figure 82 for sample profile level notes). Level computations should be figured and checked each night and a pencil profile plotted for the convenience of the locator. Second Stage of Work (a) Cross-sections. {h) Topography. {c) Drainage. (d) Classification of materials. {e) Field drafting. {a) Cross-sections. — Cross-sections are the most important part of the detail work on survey. The tendency is to slight this part of the work as it is tedious and uninteresting. The author has seen so much trouble experienced in the office design due to inadequate cross-section field work that he wishes to emphasize the CROSS-SECTIONING 391 importance of taking wide enough sections particularly wjiere a paper location is contemplated. In level country where center line is exactly run 30 feet each side of the center line is enough. In hilly countr}^ on side slopes averaging 25° where the center line is exactly located 60 feet each side of the line is enough. Where the center line is not exactly located the engineer must use his judgment but as a rule it is not safe to use less than 100 feet each side of the line. For switchback turns or where a large variation from the survey base line is probable a careful stadia survey is desirable. C " Profile Level ^ ( yoq'4.)3]8\\ M~6uire LeveP" Turninq Poinfs Remarks: 1 Thomas Rod 9^af/on + ^ H.I. "^W Elev. r-) B.M.O 524821 U.S.eS. School House , He her 7R 10.20 5258fH llllllllllll Mil 1 MM 11.2 47.2 Sfa. OfoS No Clean r qorOrubbinct- 1 10.7 477 " * 2 9.5 46. e 2f25 8.2 50.2 3 5.1 53.3 4 2.7 55.7 Putin l2"Cor.Iron 1 ''ipe. 5 2.4 56.0 T.F 2.33 5256.06r\ _r\ ^ 8.10 5264.18 :2:::::::::::::::; e 8.0 56.2 Clean nq Sfa. 5 to 10 . Scrub Oak e-t2F 6.5 573 " 7 e.o 58.2 8 53 583 .9 4.1 eo.h 10 3.1 61.1 B.M-No.l. 1.65 5262.33 Be rich Levels 5262.3 ^ Use this 7^ 5.27 526763 Correc ied. Elevation Forward Qr — ^ Pig. Z2, In flat country cross-sections are taken with the engineers level, rod and metallic tape in a similar way to the methods described in the first of this chapter for high class improvements. In rough country they are generally taken with a hand level, rod and tape and each section is referred to the profile ground elevation of the base line (see sample notes, Figure 83). The abso- lute elevation of each point is figured from the base line ground elevation. This is important as while it entails more field com- putation they can be done at night, and by the use of the ab- solute elevations the office and design work is made simpler, cheaper and more accurate. Experience has demonstrated that the method of absolute elevations for cross-sections is much superior and cheaper in the end than relative elevations. 392 THE SURVEY Cross-sections are taken at all breaks in the profile and in uniform topography at least every loo feet and preferably at shorter intervals. Special cross-sections are taken for all drainage crossings and show the skew angle of the proposed structure (see Figure 83). Cross-section notes should be computed and checked each night. (&) Topography. — Taken in the same manner as previously described (see sample notes, Figure 84) . (c) Drainage. — Field drainage notes on new locations must be detailed and specific as the recommendations determine the ofiice design absolutely; there is no possibility of the designer checking the conclusions. Such notes should be made personally by the chief ot party and should indicate exactly where he wants' the culverts or bridges placed and the size of opening of the structure. He uses the principles discussed in the chapter on drainage, and determines the size of waterway either from the physical evidence of high water or from the area of the drainage basin. Areas can be run out by paced, hand compass traverses, determining the divide lines with a hand level or can be plotted directly in the field on a small 9" or 15" plane table. The type of structure as log, corrugated pipe, concrete box, etc., should be stipulated for each structure, as the field man is the only one who can decide on the best type, considering the local materials that are available. SAMPLE NOTES 393 stall IS" \ \ \ 5fa.l0 Fig. 83. SM-ion Topo graph q Nofes rW/5// M\m\ ^ Remarks: r^5ufri, Ta;)l _C SH^e-hztf --- -- , . , „ . . . (j 12+31 Q .12 f^ n i \....JMLll^imJjf - ninr *" - » ^'hiai ■ 10 ' \\ T^^f^ W r t^rt"" ■ * :::::::::|/z!|^r?:::::;:::: :" 6 §..._. ..I D _r ^j..l l-r--~. - . - \J ^ Ml!r>^c:J 6 -'''''" 1 i . t^+i". 1 m 4 '^'^^7'<3?^:-«-5{?> ^^?: J_ I4!'|v,t tin 2 :::::::::;s^^:;1l?:::::": :: School ^ ^f^)^ ^^ C T^(f ^ Hoii^fi ^hl^n' . . -A, . . . 0-f-O ^N '^ V . I ^: ::;;;::::: :::::;:;:; = ^;:;:;:;:: ;^ Fig. 84. 394 THE SURVEY {d) Classification of Material. — The classification of material has a marked effect on office design and should be handled by the chief. The expenditure of considerable time and money is justified in determining the sub-surface conditions within the probable limits of proposed excavation where there is reason to believe that solid rock will be encountered. This is done by bar soundings and test pits. Where the soil contains a large percentage of boulders bar soundings are of little value. As a rule it is impracticable to determine more than a general classification for the largest part of the distance unless rock outcrops show on the surface. (e) Field Drafting. — The field drafting should be confined to special problems desired by the chief and should only be done where there is doubt as to whether sufficient field data has been obtained for the office design. Complete design in the field is costly and is rarely as satisfactory as office design. Camp is no place for careful design. Location Survey Reports. — A report should be worked up as the survey progresses. The object of this part of the record is to make it possible for a man not personally familiar with the ground to make a reasonable design. It should include all information of a general or special nature not shown in the survey notes such as: 1. A description of the general topography. 2. A description of alternate locations and the reasons in detail for the selection of the route surveyed. 3. A statement of the portions of the line where the survey alignment should be rigidly adhered to and an undulating grade used. 4. A statement of the portions of the line where the alignment can be shifted to fit a grade contour and a ruling grade adhered to. 5. The portions of the line where both line and grade can be varied in the final design. 6. Snow conditions and how bad exposure is avoided or why it can not be avoided. 7. Special designs to fit unusual conditions. 8. Special designs utilizing supplies of nearby local materials. 9. Photographs to illustrate special features or to give a general idea of conditions. Determination of True North. — The simplest method of deter- mining the true meridian is by observation on Polaris at elongation. For all practical purposes fairly close results can be obtained by observation on Polaris or the Sun at any time. The following tables and explanation of simple methods are quoted or briefed from the Manual of the United States Geodetic Survey on Mag- netism and the determination of the true meridian, and the Metro Manual of the Bausch & Lomb Optical Co. Meridian by Polaris at Elongation. — For all practical road survey purposes a determination of the meridian to the nearest minute of angle is sufficiently close. For one-half hour before elongation to a half hour after elongation the azimuth of Polaris does not vary over 30 seconds of angle which gives plenty of time for check determinations and the element of exact standard time is of little importance. POLARIS MERIDIAN 395 The following instructions for determining meridian at elongation by transit observation and by plumb line and peep sight are quoted from the U. S. Geodetic Manual. SIMPLE METHODS FOR DETERMINING THE TRUE MERIDIAN BY OBSERVATIONS ON POLARIS^ (U. S. Geodetic Manual) I. To Determine the True Meridian by Observation on Polaris at Elongation with a Surveyor's Transit (Be sure transit is in good adjustment) ^' I. Set a stone, or drive a wooden plug, firmly in the ground and upon the top thereof make a small distinct mark. *' 2. About thirty minutes before the time of the eastern or western elongation of Polaris, as given by the tables of elongation. No. 33, set up the transit firmly, with its vertical axis exactly over the mark, and carefully level the instrument. ''3. Illuminate the cross hairs by the light from a bull's-eye lantern or other source, the rays being directed into the object end of the telescope by an assistant. Great care should be taken to see that the line of coUimation describes a truly vertical plane. *' 4. Place the vertical hair upon the star, which, if it has not reached its elongation, will move to the right for eastern and to the left for western elongation. *' 5. As the star moves toward elongation, keep it continually covered by the vertical hair by means of the tangent screw of the vernier plate, until a point is reached where it will appear to remain on the hair for some time and then leave it in a direction contrary to its former motion, thus indicating the point of elongation. " 6. At the instant the star appears to thread the vertical hair, depress the telescope to a horizontal position; about 100 yards north of the place of observation drive a wooden plug, upon which by a strongly illuminated pencil or other slender object, exactly coincident with the vertical hair, mark a point in the line of sight thus determined; then quickly revolve the vernier plate 180°, again place the vertical hair upon the star, and, as before, mark a point in the new direction; then the middle point between the two marks, with the point under the instrument, will define on the ground the trace of the vertical plane through Polaris at its eastern or western elongation, as the case may be. *' 7. By daylight lay off to the east or west, as the case may re- quire, the proper azimuth taken from the Table 34; the instrument will then define the true meridian, which may be permanently marked by monuments for future reference." 1 In the preparation of this article use has been made of the United States Land Office Manual of Instructions, Washington, 1896, 396 THE SURVEY Table 33. — ^Local Mean (Astronomical) Time or the Culmi- nations AND Elongations of Polaris in the Year 191 5 (Computed for latitude 40° north and longitude 90** or 6^ west of Greenwich) Date East Elongation Upper Cul- mination West Elongation Lower Cul- mination 191S Hr. Min. Hr. Min. Hr. Min. Hr. Min. January i January 15. . . February i . . . February 15. . March i March 15. • • April I April 15 May I May IS June I June 15 July I July IS August I August 15. . . . September i . September 15 October i . . . . October is.. • November i . , November 15 December i . . December 15. 46.9 SI. 6 44 S 49-2 S4 o 58.8 iL3. 52.9 50.0 55.1 48.5 S3 -7 SI. I S6.3 49-7 SSO 48.4 S3S SO. 7 SS.8 48.9 S3. 8 SO. 8 S5.6 42.1 46.8 39-7 44-4 49.2 S4 o 47.1 S2.0 49.2 54-2 47.6 52.8 ^jO.2 51.5 44.9 50.2 43-6 48.7 45. 9 510 44 I 49.0 46.0 50.8 44.9 49.6 42. 5 47.2 52.0 56.8 49 9 54-8 52.0 57 o 50.4 55-6 53.0 58.2 51.7 56.9 SO. 3 55.4 ,g2J^ 53.8 46.9 51.8 48.8 53.6 A. To refer the above tabular qtmntities to years other than 191 5. For year 1919 add /add 1921 add 1922 add 1923 add TOO. /add ^924 1 add 1925 add 1926 add 1927 add 'add add 1928 1 ; 2 . 5 minutes 4 . o up to March i o . I on and after March i 1.6 31 4-5 5 . 9 up to March i 2 . o on and after March i 3-3 4.6 5-9 7 . 2 up to March i 3 . 3 on and after March i B. To refer to any calender day other than the first and fifteenth of each month subtract the quantities below from the tabular quantity for the PRECEDING DATE. Pases .106 and 397.') POLARIS MERIDIAN 397 Day of Month Minutes No. of Days Elapsed 2 or i6 3-9 I 3 17 7.8 2 4 i8 II. 8 3 5 19 15.7 4 6 20 19.6 5 7 21 23.5 6 8 22 27.4 7 9 23 31.4 8 lo 24 35-3 9 II 25 39.2 10 12 26 43.1 II 13 27 47.0 12 14 28 5I-0 13 29 54.9 14 30 58.8 15 31 62.7 6 C To refer the table to Standard time and to the civil or common method of reckoning: (**) Add to the tabular quantities four minutes for every degree of longitude the place is west of the Standard meridian and Sub- tract when the place is east of the Standard meridian. (^) The astronomical day begins twelve hours after the civil day, i.e., begins at noon on the civil day of the same date, and is reckoned from o to 24 hours. Consequently an astronomical time less than twelve hours refers to the same civil day, whereas an astronomical time greater than twelve hours refers to the morning of the next civil day. It will be noticed that for the tabular year two eastern elongations occur on January 14 and two western elongations on July 13. There are also two upper culminations on April 14 and two lower culminations on October 14. The lower culmination either follows or precedes the upper culmination by ii'' 58"*.o. D. To refer to any other than the tabular latitude between the limits of 10® and 50° north: Add to the time of west elongation o"*.io for every degree south of 40° and subtract from the time of west elongation 0*^.16 for every degree north of 40°. Reverse these operations for correcting times of east elongation. £. To refer to any other than the tabular longitude: Add o"*.i6 for each 15° east of the ninetieth meridian and subtract 0^.16 for each 15** west of the ninetieth meridian. Standard Times in United States (Mean solar for the following meridians) Eastern time 75 th meridian standard Central '' 90th Mountain " 105th " " Pacific " i2oth '' '' (See plate No. 39.) 398 THE SURVEY 00 0\ O o w ^o a N lO Ov NvO M lo O »0 O vO N 00 lO w On t^»0 rfro uDvOOOvO O O O O O l> t^ t^OO 00 o o o o o On OnO O m O O H M M i-i (N .oO M - o o o o t^ o o o o o t-.t^oooo a o oo o o On On O O M O O M M M M M M M M »ONOvO.b-00 M M H M M M o lO l^ O C^ lO 00 (N »r> 0\ fO t^ N O M t^ ro On VO N On NO "^M w O vOvO t-t- t- o o o o o r-oooo 00 On O O O O O OnO O M M O M M M M N cs ro -^ -^ »onO t-00 On o 00 O roOoo M IDOO (N vO O lO o »o o nO o vOO t^oo On M M M H M o f^ rfOoo (N lOOO N to 0\ rfoo rooo rf O nO N OnvO Tl-N ooooo o o o o o 00 00 On Ov 0\ O O O O O O O M w (N fO fO rf Tj-io vO t^oO 00 On M Tt t^ 0\ :> 00 M lOOO (N t^ M\0 N t^ (T) OnvO N O t^lO fO N M t^ t-r-oo 00 o o o o o 00 On O O O O O O O M O M i-i ri oj fO ro Tl-iOvO H4 M M M M vO t^oo On O M M H M M 0\ o 00 O M rt- t^ M Tfl^ (N i> fs vo cs r^ roONvO re O OOO "tfO N 00 00 00 a a o o o o o M OnO O O M O M M W M M cj M ro fO M M 1-1 M M TfTt lOvO t^ t^OO On O w M M M N CS M O H o b-a <^» "^t- O Tl-OO mnO O »00 liO H t-roONvO "^ M onoo r^NO CO 00 Ov 0\ 0\ o o o o o M O O O M M N CN ro ro ^ Tfin lovO t^ 00 00 OnO M M M M CS N 00 M 0\ M o O M »O00 O rht^M ioOn rooc r^oo rt OnO POO t> lOCO w O O 0^ OOsOO O O O O M H O O M M M M N ro ro ■^ H M M H H 00 On O w (N M M (N N (N 1 o O M N PO Tt M M M M M too t^OO o> M M M M M O M M ro ■^ N Cl CS CS M lOvO t^OO O M M 00 ^ N O On O M 0\ O "-" N ro t-i N W (N CS Tj-vO t^OO o M c^ (S M ro M ro v> t^oo rororororo vOOvOOO O M Tj-00 MO -Ov O N « cs N fO M roiO t^ On fOrororo ro O O O O NO O lO M 00 vo •rfro O M (N CO Tt M M CS CS «S »o 1^00 O w cs N M O 00 00 O M (N roio N CS IN N CS O t^a O M N PJ M ro ro rou^ t-oo O ro roro ro "I- M H .0 -^00 Tl- GO '^fO ro ro M CI r*5 '^ lo N N W CS CN OOO 0\0 -0\ M ro fO ro ro rf 00 On O M fO lOOO C» 00 oo O w ro M c^ ro ro ro •^Ooo O c^ fO ro ro ^ ^ M OnmO mo ro Ooo t^ t^ 00 5 N (N CS M M t^ O O c^ ro < ro ro ro vo i> 0\ M ro ro ro ro^t Tf O O M o »oO\ir> MOO t^OO M (N N 0 t-oo On o lO 400 THE SURVEY Table No. 34 was computed with the mean declination of Polaris for each year. A more accurate result will be had by applying to the tabular values the following correction, which depend on the difference of the mean and the apparent place of the star. The deduced azimuth will, in general, be correct within o'.3. For Middle of Correction For Middle of Correction January February March April May June -05 -0.4 -0.3 0.0 +0.1 +0. 2 July August September October November December / +0.2 +0.1 — 0. I -0.4 -0.6 -0.8 II. — To Determine the True Meridian by Observation on Polaris at Elongation with a Plumb Line and Peep Sight " I. Attach the plumb line to a support situated as far above the ground as practicable, such as the limb of a tree, a piece of board nailed or otherwise fastened to a telegraph pole, a house, barn, or other building affording a clear view in a north and south direction. " The plumb bob may consist of any weighty material, such as a brick, or a piece of iron or stone, weighing 4 to 5 pounds, which will hold the plumb line straight and vertical fully as well as one of turned and finished metal. " Strongly illuminate the plumb line just below its support by a lamp or candle, care being taken to obscure the source of light from the view of the observer by an opaque screen. *' For a peep sight, cut a slot about one-sixteenth of an inch wide in a thin piece of board, or nail two strips of tin, with straight edges, to a square block of wood, so arranged that they will stand vertical when the block is placed flat on its base upon a smooth horizontal rest, which will be placed at a convenient height south of the plumb line and firmly secured in an east and west direction, in such a position that when viewed through the peep sight Polaris will appear about a foot below the support of the plumb line. " The position may be determined by trial the night preceding that set for the observation. " About thirty minutes before the time of elongation, as given in the tables of elongation, bring the peep sight into the same line of sight with the plumb line and Polaris. " To reach elongation the star will move off the plumb line to the east for eastern elongation, or to the west for western elongation; therefore by moving the peep sight in the proper direction, east or west, as the case may be, keep the star on the plumb line until it appears to remain stationary, thus indicating that it has reached its point of elongationc POLARIS MERIDIAN 40I " The peep sight will now be secured in place by a clamp or weight, and all further operations will be deferred until the next morning. " By daylight place a slender rod at a distance of 200 or 300 feet from the peep sight and exactly in range with it and the plumb line; carefully measure this distance. ",Take from the Table 34 the azimuth of Polaris corresponding to the latitude of the station and year of observation; find the natural tangent of said azimuth and multiply it by the distance from the peep sight to the rod; the product will express the distance to be laid off from the rod exactly at right angles to the direction already determined (to the west for eastern elongation or to the east for western elongation) to a point which with the peep sight will define the direction of the true meridian with a fair degree of accuracy," To Determine the True Meridian by Means of an Obser- vation OF Polaris at Any Hour when the Star is Visible, THE Correct Local Mean Time Being Known^ " This method requires a knowledge of the local mean time within one or two minutes, as in the extreme case when Polaris is at culmination its azimuth changes i' (arc) in 23^ minutes (time). The Standard time can usually be obtained at a telegraph office from the signals which are sent out from observatories. From this the local mean time may be derived by subtracting four minutes of time for every degree of longitude west of the Standard meridian or adding four minutes for every degree east of the Standard me- ridian. The local mean time may be obtained also by observa- tions of the sum, one method being ^explained later. * * The following table, 35, is intended to be used in connection with the American Ephemeris and Nautical Almanac. The surveyor should read carefully the chapter in that publication in which the formation and use of the Ephemeris are explained, especially the portion defining the different kinds of time. ''•'The following example explains the use of the table and the derivation of the hour angle of Polaris:" Position,- latitude 36° 20' N., longitude . 80° oy'.s or s^ 20'" 30* W. of Greenwich. h. m. s. Time of observation, July 10, 1908, standard (75th mer.) mean time 8 52 40 p. m. Reduction to local time (5° 07' west of 75th mer.) — 20 30 Local mean time 8 32 10 Reduction to sidereal time (Table III, Amer. Ephem.) . . + 01 24 Sidereal time mean noon, Greenwich, July 10, 1902. ... 7 12 02 Correction for longitude s^ 20"* 30s (Table III, Amer. Ephem.) + 00 53 Local sidereal time 15 46 29 Apparent right ascension of Polaris, July 10, 1908 i 26 05 Hour angle before upper culmination 9 39 36 1 cf. Appendix No. 10, Coast and Geodetic Survey Report for 1895. 402 THE SURVEY Declination for which Table 35 applies 88 51 Apparent declination, July 10, 1908 88 48.7 Decrease in declination — 2.3 Azimuth from Table 35 (interpolated) ... 48 39 Correction for 2'. 3 decrease in declination. + i 37 Computed azimuth 50 16 East of north. "It is to be remembered that Polaris is east of the meridian for twelve hours before, and west of the meridian for twelve hours after, upper culmination. "Without the American Ephemeris the table' may be conveniently used for obtaining the true meridian, in connection with Table 2>2> giving the approximate mean times of culminations of Polaris, and the additional knowledge of the fact that the mean declination of Polaris is 88° 51'.! in 1915 and increasing at the rate of about o'.3 per year. Without the use of the Ephemeris the computation would be as follows: h. m. s. Time of observation, July 10, 1908 standard (75th mer.) mean time 8 52 40 p. m. Reduction to local mean time — 20 30 Local mean time 8 32 10 Local mean time of upper culmination of Polaris (Table 33 and A) 18 10 12 Mean time of observation before upper culmination 9 38 02 Reduction to sidereal time -f- 01 35 Hour angle before upper culmination 9 39 37 o / Declination for which Table 35 applies ... 88 51.0 Mean declination, 1908 88 49 - o Decrease in declination — 2.0 o / /r Azimuth from Table 35 o 48 40 Correctionfor 2'. o decrease in declination. + i 24 Computed azimuth o 50 04 East of north. Tables are generally given in books on surveying for reducing mean solar to sidereal time, but for this computation it is near enough to consider the correction 10* an hour, as the stars gain very nearly four minutes on the Sun each day."^ Solar Meridian by Direct Observation with an Ordinary Transit. — Where the method of Polaris at elongation is not used, Direct Solar Observation is the most convenient method of meridian determination as while it involves more computation and introduces more chances of error the work can be done during daylight hours and the accuracy that can be attained (within 01' of arc) with the usual facilities is close enough for all practical purposes of ordinary surveys. 1 The sidereal correction always increases the hour angle. SOLAR MERIDIAN 403 There are a number of different forms of the fundamental formulae governing the determination; the following form has found considerable favor: sin [5 -(90°- alt.)] sin [5—(90° - lat.)] sm sm [o — (90 — dec.) J In the formula A is the angle of the sun from the true north measured to the right in the morning and to the left in the afternoon. S is one-half the sum of (90° — the observed altitude of the sun corrected for refraction) plus (90° — the latitude of the point of observation) plus (90° — the declination of the sun at the time of observation). Note. — Notice carefully the sign of the declination. A south declination is a — declination which would make the expression (90° — ( — south declination)) = 90° + south declination. A solar ephemeris from which the sun's declination is found is necessary for the computations. All instrument makers publish small pocket editions each year which can be obtained from them for ten cents. An ordinary well regulated watch set for standard time at the nearest telegraph office serves for the time determination on which the sun's declination depends and any good transit with vertical circle can be used for observing the horizontal angle and altitude of the sun 'but observers are cautioned that it must be in good adjustment and the observer must work with reasonable care. If standard time is not available mean local time can be determined by observation as explained la4er on page 413. The latitude of the point of observation can generally be deter- mined closely enough from U. S. Geological Survey Maps or Land Office Maps and if these are not available can be determined by observation as explained on page 413. Longitude for standard time correction can be taken from any good map. If these are not available determine local mean time by observation. Considering all the different sources of error, time, latitude and observed altitude the best time of day to make the observation is between 9.00 and 10.00 A. M. and between 2.00 and 3.00 P, M. {Continued page 412.) 404 THE SURVEY Correction for I' In- crease in De- clination of Polaris jfs 5 "too po 1 1 T M (N « OwOOC (N t^ rooo M i t^ On to too o to lO OnnO to c< fO ro iH i-x O to M PO "^M >0 - ??? 0\ fOOO N M cs (N ro O O rfoo M lOOO O to to too ro to t^Ov O O O O O w N c^ M M M M o o o o O O O O O O O O O O O M W H M M H M M M • 0) V rj-ooo i> CS CO cs o ro t^l> fO N to (N H (N (N fO \0 O -^00 to to too r*5 to t>.00 O O O O O M M CI H M M H 00 C! .2 o o o o o o o o o o o o O O O M M M M M ' M M H M :: uo On O NO 00 OnOO H M O "^ troooo M M roONOO Tf-lOvTl-N 00 M lO M TtioroO "^ O O M 00 ro t> N M cs CN ro NO O Tj-t^ M rj-t>.0 toioioo N Tj-vOOO O O O O OnO h c< O H H M 73 o O O O O O O O o o o o DOOM M M M M M M M M ■m V re »o »o •^ M CO lO O O lO ro 00 M On ro to M o »o M rroo NO (N ro c^ O nO On PO On C^ 01 M CO . Q V O O M 00 ro r^ M M (N CS r<5 nO O ro t-^ O rj-1-.a lOlOlO »o (N TJ-vOOO O O O O OnO M M O M H M o O o o o O O O O COCO o o o o M M M M M M M M ii= - lO lo 0\ to coo M M N N ro TO On ro 1-* fO rO '^ ^f O roO On to to to to O O O O OnO O M O M M M 6 o O o O O O O O O O O O O O o o o.o M M M H M H H M 11= :: M o t- O 00 MvO ro lO (N fO ro M 00 -^ •rf Tt (N O 00 On NO 00 M ro fO i-i rj-io O t^ rt to to (N t^ On PO On "Tf Tt ro to V O O M 00 N t^ H M (N (N fO lO 0\ fO » O fONO On lO to to to w fO to t^ O O O O 00 OnO O O O H M O O O O o o o o O O O O o o o o H M M M M M W H • (U V roo t^ o i COM ^ H roio O On ro t- On O O "^M O 00 rr (N r-vO On to '^to '^(N ttnO OnO rf^P0»O «|2 - O O M 00 c^ vO w M M (N M VO CM CM ro MvO VOM CO -^ CM -^ M M M M 0\ l^io M ro 000 -^ 10 10 MOO TfO 10 •^ •^ -^ 00 ^0\rJ• M M CO M S^ M M M M M M M W W M 0000 0000 0000 M ^ VO 00 t- l> 0\ CM J> 10 10 CM VO M M On t^Ol^ »o CM CO fO M CM M OV CM 10 M M <0 VO VOOO M '^M -^?^? 00 VO ^ CM M M C^ M 00 t^ 10 M N I> -^ 10 VO VO rf -^ -^ \0 C^ t> ro CO CO CM CM 00 rhO\ "^ M M CM jgOO S VO v-l M M M M M W M M M 0000 0000 0000 M ^ VO COM u^ 00 fO ^ M t^fOO VO '^Ti•':}• M I>fO ro ro CM 01 CO rJ-0\Tt M M CM jgOO S VO M H M M M M M M M M 0000 0000 M -Si VO OvOO 0\ M 10 CS Tf 10 M N 00 t>.^ t^rOOi VO '^t^ro VO M t^ CM ro 00 M M 00 coo* <* M M M M S VO 1-1 M M M M l-l M >-l M 0000 0000 0000 M ^ VO \0 VOO 0\ ■^ N 6» ON ?S VO -Si VO O 4o6 THE SURVEY Correction for i^ In- crease in De- clination of Polaris If" - 1 1 T 00 ro t^ w M N (N ro 1 1 1 1 Vi On pOnO PO PO "t -* 1 1 1 1 © POO 00 1 1 1 1 M rorl-O OOOO 1 1 1 1 00 On On On OOOO MM its - Tfoo ro 1 1 T I^ M in On H C>« N . On M ro ©©MM M M M M ©O PO o> © © m M M M M M M M M M j1" o o o o ^ O u- ©MM o o o © lO PO »-• © ^OntJ- CJ CS N PO © © © o PO CO © '^© © © 00 PO t^ M rO ^"^lO O © © © ©OO M Tf© M M TtOO M Tt- \r)\r) o O ©©MM On On M m Tj-o M m O On M M ©©MM ©O PO On M M M ro M M M M o CS N O o o o ©MM o o o POM rf-00 lOTj-M in o Tj-apo M M •«t f^ © rf 0\ rfOiPO M e^ c^ ro O O O © Tj- t- On 00 ©MM© 00 MO © PO •^ ^«o © © © © moo m t^ rt© M © PO t-© PO inm o O ©©MM M M M rt "^© © -"^ moo © M © © M M t^ MOO m © M m M POrtrtm M M M M M M M M - © © M o o o ^j-oo in in fo M m M On "^00 PO M pvj (N PO © © © O v© l^ I>«0 »M in On PO '^'^ '^ O O O O © M l> t>- M TtTj-PO POO On M O O © M M OnOn© M M M M mt*ON M O © © H M M M M TtOO Tt© PO PO M m M PO ^rf M M M M M M M M o looo 00 lOTtro © O M O O O in i^ m M M © MO On M O © © M PO OnOO On rt mm PO rtO 00 © © © © M MO WOO © © m M M PO PO -^ M M M M M W M M 11= o (N ro N © © M O O O \0\© o> lO M m 1 1 1 1 >>^ -^ POPO P^ «N Mil 00 PO On Tt TT M 1 «o Ci OOOvO 1 1 1 1 M 000 VO vOO tovo MM ir> PO 000 \r> xTi \r> -rt MM li^ P^ 00 to ^T^POrO MM MOO Tl-O PO P^ P4 (N MM vO P« 00 Tt M M Mil Tt SO 1 to P< + ?2^^ PO -^ -^ c^ POlO '+M li-) IT) l> PO (N 10 M P» TtPl t-0\ N N M ^ -^ O\00 l^ M M M M 10 POM M M M M 00 »0 M 0\ »o lO PI 00 PO 0\ TtO vr> PO fO POCN »o TO PI M M On 5^ M M M M M M M M M MM 0000 0000 0000 M .< to COOO Of 00 \r> Tt t^c^ PO 10 W M »0 11 10 t^O N PO PO C^ TtTtPOO POi^O N Tt M vO M M M Tt to ■^- 00 00 00 t^ M M M M li-> rt C< t^lT) (N 00 10 10 M t^PO 0000 OV Tt 0»10 PO PO N C^ 0000 »i^ 10 C< M M 0000 00 M -Si to W5 CI W OvnOO m •-• PO PO N 100 M PO Tt l> P» Tt M P0»O M 10\0 PO 0000 ? "S 00 t^ t->0 M M M t-TfMOO 10 T}- M t^ PO 0000 00 TfOv Tt PO PO P^ 00 P4 ^'^^ PO t^ PJ On M UO PI PO M 00 M 1/510 PJ -S t^t^o VJ rtPO M On M M l-l '*'-' t^ »o ■rJ-OvO M io»o -^ Tt 0000 00 PO Oi Tt PO PO n p« 0000 On TtO 10 M M M 0000 l> M -« to (r> M a 00 00 PO 10 Ci TfPO 0\ PO M On 10 M N M TtO t-t- Tt N M 0000 Tt 10 10 to -^ "^ M M M M PON 000 M M M sO PO l^ »o PO 00 w 0000 00 POOV Tt PO PO N c>« 0000 ONTj-ONTt M M 0000 M M JS to 00 »o ro « »o W CO 00 O'^t'sf POiO 10 0> M MOO M 10 10 vO Tt POvO Tt P» \0 M N PO M vO PO Tt lOlO 00 '^^ VJlOTf M M M M PC M 000 M M M 10 P^ 00 10 pOOnvO m 10 ';J•TJ■Tt t>PO00 Tt PO PO N PJ 0000 ONTfONTt M M 0000 SO s 10 ^ to C» O^OO t>- f*5 M Tt»0 t>-0 POOO "^t M fO CNJ P< M O^ t^ M M t^OvOOO PO PO M •^00 c^ -^PO OiOO V5 M TtO t^POOO Tt POPO PI N 0000 19 23 14 37 09 46 04 54 PJ PO 10 -«; to «0 Wi rt ro li^iO POO V5 M »iO '*'0 10 M PO "^tTl- OVO M Tt CI Tto l^M-O Tt ir» TtM Tt l^rtOO N PO to 10 PJ -? M M M M M 000 vO M M Tj-MOO TO 10 10 P^OO lr>M VO TtTt^ \C N 00 PO PO PO N P< ONTtONTt M M Tt 8% M M 0000 0000 0000 M -Si to Tf p*5 CI ro 10 -^ M N Tj-O »0 0\ l^PO Tl-O p< PO OnvO in t^ P> M 10 P< PJ PO MVO 10 M PO Tt «o2^ M M M H Ot^vi H M M M M POOOO rt lOVO M M MOO -to lOTt Tt^ 0000 \0 PI r^ PO PO PO C^ o »J^ M PO Tl- w^O v: M PO Tt li^ 10 M PO ""t 100 V) M POTt »0 V5 M PO Tt too to M PO-^. U ^ vOvOvOO t^l^ t>» b- 00 00 00 00 OOvOnOn 0000 M M M M MM M M W)S a 4o8 THE SURVEY Correction for I' Increase in Declination of Polaris Lati- tude 40° - lO OO 1 "{^ MVO HVO P« M roco 1 1 1 1 tn 0\ ro Tt'-t ^10 1 1 1 1 t^O fOO toooo 1 1 1 1 0\ N "^to l^ l^ t^ i 1 1 1 r^oooo 1 1 1 1 j5" - lOOvrl- 1 1 T 00 CO t^ H M c< M ro 1 i 1 1 to 0\ roO roro rl■»t l 1 1 1 roOOO 10 10 to to 1 1 1 1 M CO TfO 0000 1 1 1 1 MM So 00 c .2 a a a s 1 a e o U «) •n *o :2 a < o O t- o O M t^ OHM o o o NO H »» rtCS O C^ roaioo N N ro -^ O O O O N to 10 On '^'^roO too too rj-io to M 00 0\ csO c< cs M ro rl-oo J W N t^M PI M N H Tf t^oooo N N W PI j5" o 0\ r^ M lO M t^ O M M o o o H TtO t^ O roo H rooo rtO\ cs N ro fO O O O O rooo 0>iO N M 10 N rtO> rooo Tl" TflO to 0000 r- MOO t- CO roO N c^O ro H M to roO W N N 0\ H ro M M N Ci 1000 0\ t» to to PI TtOO t- N PI p^ PI j-2 " - TtN O to M t^ O M M o o o N H N Tt -"tM rOTf MOO rooo o« cl rofO O O O O TtrOH ro rooo ro t^ -. roo N V) MvO O M M OOO OvO lOO U^ O M M M t^ N t^ N c« ro fO O O O O t^O ro t^ ^H Ci ClO H to Tj-TttOtO 0000 1000 to ■'t N ro -"t rtOOO 0\ rOO H N tOt^ON M M M M t- ^tO TfO H PI ro P« PI PI PI o t^roO Ci I/) M li^OO O M M OOO fO rj-io Tf M O HvO N N ro ro O O O O t^ ro t^ t^ ro H CO "^ *-t^ '^ rtTttOtO 0000 CO TfOO Tt •^N rflO 00 N 1000 too M M M rororo't -"tH N M M TfOOO M M M M M M M M Ttrl-Pi Tt to TtH OnO h pi H PI PI PI M H M M j5" o ro»r! Tt w Tt O w^OO O M M OOO 21 19 26 28 31 30 36 24 00 M CI "^O w M too Tf Tj-Tj-lOlO 0000 C^ M COOO rl-O 00 H 1000 too Tt ro N M toM ro N rotot^ M M M M M OnOO to 1010 rfM 00 OnO H M M PI PI j5" o OOO rj- w roto irsO »o O M M OOO in M On H MO y^^ N w ro ro 0000 M M a^i- TfM C« CO toaro T|-'^' c« ct roro 0000 to c< t-O M TtlOO 0^00 ro ■^TftlO 0000 00 C* H N rJ-iOTt 0\M coto H M M M On t^-^ M M ro 1^00 On On M M M M w"5 8 t/50 1/5 • ^ M r«5 Tt JS O O O. to to w ro "^ M H MM too to M ro Tt « « N N too to H roTj- rorororo too to M rOTt 10101010 POLARIS MERIDIAN 409 00 00 l^O t^ t^ t^ r^ 1 1 1 1 II 1 1 rtMOO vOOO »o MM -too (^ lOiO -^-^ MM 00 Tj-Os -^ fO PO P^ P^ MM too to <^M \0 10 to to MM 00 »o PS 00 ^'^'^ro MM PO PO 0« M MM 00 POOv^ ^^ 1 1 ?■: ^0 t>. M M fO»0 rJ-H w N Tl-Os N M Tj-iO t^Ovt^ M to po c^ -"ttOt^O N M lOPO tOM fO-t to J. 00 '^ O.O\O>00 ro N w ->o » C« M vO POOvO M M CJ t^ POOO to to -^ MOOO POOO POOO rt-POPOP< 0000 PS t^M to PS M M 0000 M^ to fO M CO.PO -"^O too M ro cs to TtM OvO M M ^M rtn-a M M fOO P^ N C» Tt M M "«t tooo PS to M fO PO^ N (N (N • •st-rOPO PO PO ""tPOPS PO t- t^*"* POO PO M '^ fO \00 lOrJ- N (N (M (M M M M M row ao «N + 0000 M\0 MvO "tPOPO P^ 0000 mnO to es M M 0000 PO eo p< S: to M.« 10 M N N (^ »O00 c< M CO ro N t^tovO 0\P0iO PO PO'SfPOM MOO t-.00 ^too N MvO 0\ tOPO M M "^ M P» M CS .POO\tO 10 to •*"«* 0000 tOMNO "^POPON 0000 H too to es M M 0000 CS ^ to M^ to Tl-CTi- M M TtO M ^ CS 0^ PO rj- Tf tOlO t- M M fO-^to Ov M C> to rJ-rJ-N M CS ,-00 w '^ M M OV C< N N H 000 "^N H M H M t^<*o MOOO t^ro O^'-t lOtO"^-^ 0000 too 10 ■tPOPoes 0000 too to CS M M 0000 M g t^ CS ?: to M-« 10 «0 M-O rotoO ^ 00 0\ -^PO M OJ o to PS 00 ro lOlO '^'^ a^+o to PO PO PO P< to to CS M M 0OvO>0 t^t^t-t» 00 00 00 00 0^0^0^0^ 0000 M H M M' §1 s 4IO THE SURVEY Correction for i' Increase in Declination of Polaris Lati- tude SO" i NO fc a lO NOO CO CM ro CO '^ 1 1 1 1 On ^Ov rj- 1 1 1 1 00 NnO NO t^ t^OO 1 1 1 1 POOOO 00 00 00 On MM H N POTj- ONa On On i M 1 - M M 1 1 1 HvO wnO CM CM PO PO Mil tA OnCO 1 1 1 1 txO coo IOvOnOO MM On cm rfiO NO t^ t^ t^ MM NO t»oooo t^ t^ t^ t^ MM M % 00 g a o p 1 3 ! "o 1 < o W M t^ M CS M CM cs » mno M CM CM CO tOt^ TtlO M CM Tft^ CM PO rO'-t "^ On to Tj-O M Ttrj-M Tj-iovO t^ "^ nroo o o o t-Tt-M O l-l (N o o o M TfOO 10 ro rO t^ tJ-m i> CM fO"^"^ 0000 ID CO "«t rj-co M CO C0 0>»00 10 100 M M M vOOO l> 10 PO M CO CO to TtOO M CM CM CM M M M M 00 t^ M On M M c^ tooo PO PO PO >* M M M M M rf to M POPO M PO rtiO rt-rt rj-rt M M M M o vO rOO O M cs O O O r- MOO CO M 10 M ro l>roOO 0000 10 CM -St On CO M 10 M 00 ro On icuoo M M 10 M vO On rtto Tt TtOO CM M M (N CM M M M M 00 TJ-VO M N cq pOnOoo CO PO PO CO M M M M rt M CM M POPO M CM PO rJ-Tj-Ttrt M M M M o O O O •"tfOM O M CM o o o »0 CM 000 TfM (VJ PO vO fOCMD POrOfO -^ 0000 CO •^O 00 COM TtTt M t^ CM t^ 10 100 M M On 000 COM CM CM t^ M to M M CM CM M M M M "^PO rl-OQ PO PO M CM 00 M n-NO C^ PO PO PO M M M M 000 TflO M PO PO 00 On M CO PO rt"^ M M M M o 00 Tj-t^ fO M Tf o o o M ro '■t'^ vO NOO -* CM rorO-"^ 0000 10 On 0> CM CO C^ fO CO MvO li^iOO M M t^ PO On PO M Tt TJ-PO M to On PO M M M CM M M M M Tj-Tj-O M 10 to PO '^ vO 0>CM rh CM CJ POCO M M M M t^OO ''t -^ P< rt^M nO t^oO On CO PO PO PO M M M M iP o M O »0 roO CM o o o ii-> On ro i^ T^io »0 10 MOO 00 CM ro CO rf 0000 Onoo cm ro c^ CM On »0 »^ rtlOO M M ro CM CM rJ-00 CM M M M C>J M t^ On CM M to to tooo CM CS pq popo rt TtON On rt to M Td-sOO t- PO PO PO PO m o CM Tl-O o o o 00 lO fO M M CM C^ M 10 M t^ CO (^ rOfO -"t 0000 t- 000 M Tf M M H 00 TfON "^ TtlO »0 M vO POO t^ "^0.0 CO 00 PO t- M M M pOnOnO PO 10 -^M M POnO On m C^ CM CM PO NO to M M to PO rtto to POPOPO PO m o o o o CNl fO »0 t^ lOiO-^CM CM CO ro^ 0000 t^ 1000 \0 lOM M t^ rooo CO Tj-ioio M vO OvCOO CO '^'^M t^ M 10 0\ M M M 00 On t>- M CM M rtio CM to t^ On CM M CM CM Tt CM to 10 PO to rl-M M M CO "^ PO PO POPO o M M t^ M CM CM o o o 00 C^ 00 »o CM CM ■^ rtOO M CM fO rO "^ 0000 CM M Tt M CM CM TfiO 10 M On On On POPO N to vO "tt^ M M M M M M M OOvO CMvO to CM P< M POnOOO CM N CM CM NO pOnO to CM M rt M CM e« CO POPOPO M M M M o u^ 0\ 0\ o o o vO CMOO O M M o o o 24 04 29 53 35 34 41 05 \ri POO XT) CM ro CM \0 MVO M -^ 10 100 M 00 CM OnvO CM PO M Tt 10 On poo M M CM 00 50 to M port POCOPOCO to »o M PO Tf too to M PO rt to to to to POLARIS MERIDIAN 411 fOfO N M 0\ l^ 10 N 0\0 N 00 -^CMO VOO TfO\ rooo NO MM 00 00 00 00 MM 1 M 1 10 10 ir> MM MM N M M Mil oooot^O i/^P0NO\ O'+i-ioO ^OON OOTfOsrf OtOOiO r^ i> t^ t^ t^t^t^O OOOio loio-^-^ rr> fO N N n m m I I I I I I I I I I I I I I I I I I I I I I I I > <>o ^0 M 10 '^ N mO »0 liO M M M 100 t^ 10 10 N 00 NOO CO ro N 10 N 10 p<5 N M rf 000 PO M N -"tiO M N -Si t^OO '^ CO 00 10 M 00 fO 0\ ro N N M rto 'too M 10 NO PO 10 Tt rt r<5 0000 l^O POO N N M 0000 ^ 10 OiO t^ "^lOTj- 00 '-OO N 10 10 M p, N l> ro N M 10 ro M M 10 N POPO N 00 'tio Ti- ro N t M -^ 10 "stPO N 000 fO 00 N J> ro N N M rooo N t^ M »0 M lOO fO 10 't PO PO 0000 POO N-N M 0000 ♦= 10 rfO M rj-io Tf mO l> rt to N fO a M ro 't M Ttrj-N l> N M 10 Tf 10 n-M 10 00 00 PO '* t N 00 N 00 TtM ro 00 '•K fO N H 00 "TfM fO fO fO fO 00 -^oo N N N M mO MO M »iO 'too N li-; Tt ro fO 00 POO N M M 0000 PO rj- H 000 M 00 ^0 ^ 00 N N H Tj-io M t-TtO -stO M 00 ■^PO N PO PO M "^00 PO rt 10 10 10 0000 PO N W^ N M M -? M 000 l>»0 N 0\ ro fO fO N N N M M »r»o »o M 10 POt^ M 't -^POPO 0000 10 NO N M M 0000 ""t M e to OSOO N M M 10 M li^lO NO N N w 00 aOO ro^^ PC 10 M N N M t^oo 00 rfO M M N N N M Tl-N N ■* M 00000 t^ ro fO fO fO 10 ro MOO ro ro PO N 10 M I>fO N N M M 1010 00 PO t>. M -"t-^POPO 0000 to NO N M M 0000 PO M -Si to r 10 N 't't t^ 0»r> TtrfN M 10 PO "^ t^ t^O 10 ro M o^'^ fOfO N N fO 00 N N N M M 00 POOO PO 1010 t- NO -"t 'tPOPO 0000 rfoo NO N M M 0000 PO M ^ to mOOO I> M M 1/5 M "^N N M 10 M M 10 M t^ lO N PO N N 'tt^ M ^0 M N N t^ N N M 10 Co f*> '^ PO corOfOfO N t^lO roro N N N 00 »i^ M N M M M ej t^ N voio t-MO ""trl-rOPO 0000 ■"too NO N M M 0000 10 PO M s 1/5 MOO M N M M M 00 N 10 t-00 ""t ir>poo MO t^ IT) N POPO 10 POOOO N PO 't OiOO 't 100 N -5 rfrffo N 0000 PO ro N N N l> 'to N M M M 10 mO M 1010 M XO 't 'tPO N POOO NO N M M 't PO s;;^ M M M l-l M M M M M M M M M M 0000 0000 M -Si to N Tj- 10 roio Tl- 10 rtMO M N M ro MONO TtN lOlO -^^o 10 N f=t (VJ VO t^ M "^N 10 N t^oo -"too fO TflOlO »0 -u N N M fj PO fO fO CM^iD N N N N N 00 NOO M M M 10 vo 1/5 'to ■^'t PO N 0000 rO t- M 10 N M M 0000 N fO M SK5 ^ to 10 t^o N N N •rfio Tt N lO »0 N t^O t^ N M TflTi N ^"^ ioPO»o N 00 ^ •^ N 10 N Tf N M fO 'tiO N "§ M M ro fO PO N t^O fO M N N N N 00 tC M t^ M M M ro "to 10 lo 10 b-O^oO 'tPOPO N fO t^ M 10 N M M PO go ^ 10 W M M M M M M M M M M M MOOO M ■"too ro ""to l>0 M W M N rl-O N M vtin l> 0M> M \C PO ©"N Tj-int^ N M 10 PO 10 M ro 1^ 10 00 ^0 Ov aoo ro N N N TtN N N N N MM 2"^ N 00 ^J-O ic »o 't 'to POOO tPOPO N N t^ M 10 N M M PO go MOOO 0000 0000 M ^ to t^ t^ i> t>. 00 00 00 00 0000 0000 O to O to •• . O M ro ""t C • O^ o 412 THE SURVEY The following table gives the correction for observed altitude due to atmospheric refraction. This correction is always minus as the sun always appears to be higher than it actually is. A Table of Mean Refractions Due to Altitude Bar. 30 in., Ther. 5o°F. App. Alt. Ref. App. Alt. Ref. App. Alt. Ref. "SI. Ref. 7° 8° 9° 9' 46" 8' 23" 7' 20" 6' 30" 5' 49" 10° 12° 14° 16° 18° 5' 16" 4' 25" 3' 47" 3; < 2' 56" 20° 2' 37" 2' 03" i' 40" i' 22" 1' 09" 5°: 60° 70° 80° 90" 0' 48" 0' 21" 0' 0" A Table of Semi-diameters of the Sun Jan. I, i6'i8" Apr. i, i6'o2" July i, i5'46'' Oct. i, i6'oi" Feb. I, i6'i6" May i, is'sV' Aug. i, i5'48" Nov. i, i6'o9'' Mar. I, i6'io" June i, i5'48" Sept. i, i5'53" Dec. i, i6'i5" Effect of Errors in Latitude and Declination on Meridian Determination. — It is well to bear in mind the effect of wrong latitude, or time (which affects the declination), on your meridian computations. The following table prepared by Professor J. B. Johnson of Wash- ington University, St. Louis, Mo., reprinted in the Metro Manual of the Bausch & Lomb Optical Co. shows the effect of error in lati- tude and declination for different latitudes and dift'erent hours in the day. Errors in Azimuth (by Solar Observation) for i Minute Errors in Declination and Latitude TT/^ r J/////M//////)////////w//w^^^^ in first-class shape and must use a rod with a fairly broad face with clear distinctive markings; this rod must be held steady and vertical which can be accomplished by the use of a small universal circular level attached to the rod, and steadiness can be secured by a short hand rod (about 4' long) that the rodman uses as a shifting brace. The transit must be steady, must have a first-class lense and must be equipped with fixed stadia wires. Adjustable stadia STADIA MEASUREMENTS 417 wires are worthless if good work is required. Distances between hubs should as a rule not exceed 500 to 600 feet for close line meas- urements but side slots can be taken up to 1500 feet. The essential elements of the theory of stadia measurement are briefly as follows : The measurement depends on the optical angle of the stadia wires. This angle is governed by the distance apart of the stadia wires. The rod intervals A and A' subtended between the stadia wires are directly proportional to the distances b and b^ from the apex of the optical angle. The apex of this optical angle is always a certain fixed distance in front of the instrument and is different for different makes of transit. Call this distance C which can be determined as later explained by test or is generally noted in instructions furnished by the instrument maker. The actual rod interval as read by the observer is therefore proportional to the distance from a point ahead of the instrument and not from the center of the transit. For close work this distance C must be known and also the rod interval per 100 feet of distance beyond the apex of the optical angle. The rod interval per 100' of distance ' I I is desirably i.o' but unless unusual care is exercised in setting the vires it is rarely exactly this value. To determine the actual value of this interval proceed as follows: Case I. — Where the value of C is known. (Note. — C generally ranges between 0.75' and 1.25'.) Pick out a level line about 800 to 1000' long. Drive a transit hub; place a foresight picket. Measure from the transit hub toward the foresight the distance C which we will assume in this case to be 1.25' and drive a hub. This hub represents on the ground the apex of the optical angle. From this hub measure carefully with a steel chain 100' and set a hub on line with the foresight and continue to set points at intervals of exactly 100 feet until you have a test line 800. to 1000 feet long. Now level the telescope and read the rod intervals when the rod is held on each of the stakes and record this interval to the nearest fraction of a foot that you are sure you can actually see. As the length of sight increases it becomes less and less possible to determine exactly the interval and when you are not certain of the reading to a o.oi' stop attempting to lengthen the sight and you have practically determined the safe length of sight for actual line work that the instrument is capable of handling. To deter- mine the rod interval record your readings and take the average value. Assume your rod intervals to be as follows: 4i8 THE SURVEY 997 feet -^ •995 '' -7 •99 ~ •99 " -T .985 " -7 97 " -T •95 '' -f .02 '' -i = 0.997 = 0.9975 = 0.9967 = 0.9975 = 0.997 = 0.995 = 0.993 = I . 002 This indicates that beyond 500' the readings become uncertain and that about 600' is the limit of practical line sight for close work. Good stadia work requires that the instrumentman is perfectly honest with himself and recognizes his limitation when it is reached. The rod interval per 100' is therefore 0.997 in this case and every foot on the rod when the line of sight is level means an actual distance from the apex of the optical angle of ~ = 0.997 100.3 feet. To get the actual distance then for a level line of sight rod reading of 2.45 feet multiply 2.45 X 100.3 = 245.73 feet. Say 245.7 feet from the apex of the optical angle and the distance from the center of the instrument will be 245.7 feet plus the constant C (1.25) equals 246.95 feet from the center of the instrument. The efifect of the inclined line of sight will be discussed later. —too ->4< -100" W//////////A Case 2. — Where the constant C is not known. To determine the constant C and the rod interval per 100' of distance beyond the apex of the optical angle. Measure a base line 800 to 1000' long as previously stated placing hubs every 100'. Set the transit up over the first hub and with a level line of sight read the stadia wire rod interval at each of the stakes on the line which are at actually measured known distances from the center of the instrument of 100', 200', 300', etc. The problem is to determine two unknown quantities, C the constant and X (the rod interval per 100 feet of distance beyond the apex of the optical angle). According to Case i, -^—:^ — ■* = STADIA MEASUREMENTS 419 the actual distance beyond the apex represented by a rod interval of one foot. Therefore we can determine the constant C from two equations using the actual rod intervals a^ and a^ at the stakes which are 100' and 200' from the center of the instrument thus. T on' 100' — C = observed rod interval a^ X X 1. 00 / - C = " " , " ""'^ X Suppose the rod interval a^ = 0.0845 " " " a^ = 1.9815 lOO.O — C = 0.9845 —y- 200.0 — C = 1. 9815 -^ W) call ( -^ I the symbol F. loo.o — C = 0.9845 F Equation i, 200.0 - C = 1.9815F " 2. loo.o = 0.997 F Subtract Equation I from 2. _ 100.00 0.997 F = 100.3 feet. That is, a one foot rod interval equals 100.3' of distance beyond the apex of the optical angle. To determine C substitute this value of F in Equation i . loo.o — C = 0.9845 X 100.3 - C = - 100 + 98.75 C = 100 — 98.75 C — 1.25 feet. Apply this principle to three or four sets of readings and take the mean values. You now have the basic constants of the instruments for close work. Effect of Inclined Sight on Stadia Readings. — The previous discussion is based on a level line of sight. It should be borne in mind that the stadia distance as previously discussed refers to the distance along the line of sight when the rod is perpendicular to the line of sight. In case the line of sight is inclined the rod reading must be corrected to a true rod reading perpendicular to the inclined 420 THE SURVEY line of sight and the distance along the inclined line of sight must be corrected to the true horizontal distance. Rod interval X cos A (angle of inclination) = corrected rod interval. (Corrected rod interval in feet X actual distance value per foot as determined by test X cos angle A) + (the constant C X cos angle A) = corrected horizontal distance. CorrecHd ->| Horijonfal i ProJecHonof /\ , ^,^ 'r ! L" I Correc-hed ^ I "Horhotifal ^ ^ ^ I Distance, ^^-<\0^3 Corrected Rodlnfgrval Perpendicular fo ^Line Qf^ighf. 1 Acfual Rod Interval. 'Rod held Vert/calftf. All standard stadia reduction tables and diagrams similar to Table 30, page 335, are based on (100 feet of distance for i.o of rod interval) plus the constant of the instrument. If much stadia work is to be done all instrument makers will set fixed stadia wires guaranteed to measure 100' distance per i.o of rod interval for the distance from the apex of the optical angle and such wires are generally sufficiently close to this standard so that for all practical survey work on which stadia methods are desirable no correction for rod interval need be applied. The following example of reduction of stadia reading for careful line work will show the method. fie igh-h of Instrument above Hub 5.3' ;^;>^. ■hub Elevation Top^2^S.26 ^^ub zievafjp.n df top $210.Z Case I. — Where the stadia wires are guaranteed to read 100' distance per foot of rod interval and the constant C = 1.25 feet. Procedure. — Measure the height of the center of the telescope axis at the standards above the top of the transit hub; this is called the Height of instrument. Assume this for example to be 5.3 feet. To get the vertical angle to the next hub sight on the rod with the middle horizontal wire set on 5.3 feet on the rod held on the foresight hub and read the vertical angle say + 10° 13': level the telescope by the large telescope bubble and record the index error say -f- o*' 01': the correct vertical angle is then + 10° 12'. To get the rod interval reading corresponding to the vertical STADIA MEASUREMENTS 421 angle of +10° 12' sight on the rod with the middle horizontal wire on 5.3': then shift the vertical line of sight so that the lower stadia wire is exactly on one of the main rod divisions and read the rod interval between the two stadia wires. Say in this case 3.37 feet or ^t,^ feet distance. Look in Table 30, page 337, which gives for a vertical angle of 10° 12' the correct horizontal and vertical distance per 100' of stadia reading as horizontal distance 96.86'; vertical difference in elevation 1 7.43'. The total horizontal distance for the stadia reading of 337 feet is therefore (337 X 96.86 = 326.42) + (constant C X cos 10° 12') given at bottom of page in table as 1.23) = 327.65 total horizontal distance. The Vertical difference in elevation is (337 X 17.43' = 58.74') + ((constant C X sin 10^12') given at bottom of page in Table 30 as 0.22) = 58.96' total difference in elevation. The elevation of the new hub is therefore 5230.3 + 58.96 = 5289.26. Case 2. — Where a stadia interval must be corrected for poor wire interval. Suppose the instrument used measures 100.3' f^i" ^^-ch foot on the rod and the rod reading for a vertical angle of 10° 12' is 3.36 feet. The correct stadia distance is found by multiplying 3.36 feet X 100.3 — 2>^7 fe^t in distance. Then proceed as in Case i. Stadia Rods. — Stadia rods can be divided in innumerable ways and it makes little difference what symbols are used so long as they are clear and distinct. The principle of bisection for the smallest readings is a good system. The face of the rods should be wider than the ordinary level rod; a width of 23^ to 3" is about right. They should have a very brilliant white background and jet black face markings with large numbers for the even feet marks the tenths should not he numbered. The practice of special graduations to fit the wire interval of the instrument is not desirable particularly in rough country where rods are often broken. A standard i.o ft. division is safer, as any standard rod can then be used. The following system of face markings has been used by the author and is given merely as an example in case the reader has no preference of his own. The rods should be as light as possible with a back brace to prevent warping and provide hand holes and a length of 10' is ample for all practical purposes. 422 THE SURVEY Stadia rod. CHAPTER XII PHOTOGRAPHY, CAMP EQUIPMENT AND NOTES ON CAMP MEDICINE Editor's Note. — Photographs are often as important as survey notes particularly on reconnaissance work and the failure of a negative is compar- able to the loss of field notes. The following data has been inserted to help the inexperienced photographer reduce his percentage of failures. A green- hand is puzzled chiefly by diaphram opening and time of exposure and does not understand the effect of latitude, altitude, time of year, light, etc., on the problem. The following simple notes have been prepared by a man who has taken Engineering Photographs all over the world and should be helpful. There are a number of very excellent exposure charts and mechanical sensi- tized paper exposure meters on the m^arket which consider all these points in more detail than we can give in a book of this character. NOTES ON PHOTOGRAPHY General. — The following discussion of the subject of photog- raphy in connection with engineering operations has been prepared with the idea of giving to the engineer the foundations and princi- ples upon which he may make exposures in the field under most all conditions, and secure fairly uniform results. The engineer is, in the day's work, required to make exposures under some very ad- verse conditions, and it is not rare that the exposure most needed or the most important point along the line of survey or construction is reached when weather and light conditions are at their worst. In many cases the results are failures, poor, or only fair. This fact, under the ordinary procedure of having the film developed after the point has been passed, or the survey completed, is discovered weeks or months afterward, and a return to the point would either bjB expensive — so much so as to make it prohibitive — or impossible on account of adverse weather conditions. Views on preliminary surveys are of more importance and should receive corresponding attention. Views on construction and lo- cation are important, but the opportunities for making successful exposures on location and construction are many. This is due to the fact that the engineer is located longer at one camp on location than on preliminary, while on construction he is constantly on the job. It is urged that all work be done in the field at the time of making the exposures on preliminary investigations or reconnaissance surveys in order that failures may be discovered and additional exposures made which will supply the omissions, and assure a continuity of views. By so doing the finished view may then and there be properly identified and notations made as to its value in 423 424 PHOTOGRAPHY connection with the surveyed line, and the subsequent report and estimate, as explained on page 283. With this end in view the fol- lowing equipment is suggested. Equipment. 1. Camera with good stout leather case and tripod. 2. Tank developing outfit complete. 3. Films, chemicals, and paper sufficient of photograph length of the line. This outfit has been used for a number of years by men who have had a wide experience, and it has been found to be a convenient and complete camp kit to properly care for the picture end of a survey. Roughly the films should be estimated at three exposures to the mile of line. Camera. — The best sized camera, that is, the one which produces the largest picture in proportion to the bulk of outfit and cost of operation, is the 434 X 63^ film camera — Eastman 4A. Cameras having smaller dimensions produce views so small as to be of little value from an engineering standpoint, while the outfit necessary to carry on development is practically the same in size and weight as that required for the camera above mentioned. Enlargements may be made, but this is an additional expense and delay. What is required is speed and accuracy. This sized film when properly masked will give a picture 4 3^" X6%'' exclusive of legend. If the roll is cut so as to leave the un- exposed portions between the exposures, on the bottom of vertical views, or the left hand end of horizontal views, space is left for filing number and legend. This information is put on the face of the film with india ink as soon as it is dry and is a clear but concise statement of (a) station from which the view was taken, (b) direc- tion of the camera, {c) general description of features shown, or purpose for which taken, and (d) index number by which the same may be identified. This information is obtained from the exposure record which is made and kept at the time of the exposure, and regarding which description is given on page 430. ^ Autographic backed cameras are in use but are not specially desirable unless the films are to be developed by some other person at a latter date. The writing that may be done while specific, is generally so large as to take up all the space between the exposures which should be devoted to more detail. If used it is better to merely record the roll and exposure number as R 23-2 and depend on the exposure record for detail data. Lens. — The camera should be equipped with a standard lens of known value. In the matter of lenses nothing empirical may be said. Generally, however, the regular B. & L. f 16 rectilinear lens gives excellent results. As speed is not essential the higher priced rapid lenses are not necessary, and the investment of money is such a refinement which the work in hand does not call for, is a luxury to say the least. Given a well made and flawless lens, an equally good picture may be secured, provided the proper time is given, as with the more expensive lens. As there are no moving COMPOSITION 425 objects in the class of views that the engineer will photograph, exposures may be properly timed. Shutter. — The shutter should be of the ordinary variety, operated or snapped with a bulb or cable. For rough handling the bulb release is considered the best. There are a number of standard shutters on the market, anyone of which gives entirely satisfactory results. Improvements are being continually made, and it is ad- visable to purchase the most durable pattern on the market. There is less liability of making errors with the shutter that sets and re- leases automatically with a bulb or cable. Those that have to be set by hand ofttimes produce no exposure, the photographer for- getting to set the shutter. Diaphram. — Most all cameras are now equipped with the iris diaphram, and this attachment is the best with which to control the stop. The stop is the technical term for regulating the size of opening in the diaphram. There are two systems of indicating the dif- ferent stops. The ^'Universal Standard" (U. S.) and "f " for focal speed of lens. The following list shows the usual stops for both systems that are equal to each other. U. S. 1.2 2.0 2.5 4 8 16 32 64 f 4.5 5.6 6.3 8 II 16 22 32" Ordinary kodak stops 123 Stop . U. S. 1.2 gives the largest opening. '' 64 " ''smallest '' . Manipulation.— The most important factors that enter into making an exposure are : 1. Composition. 2. Distance. 3. Aperture. 4. Time. 5. Strength and direction of light. 6. Phases of views. 7. Recording all operations in the exposure record. Taking up these operations in their order: Composition. — A photo should not be looked upon as a miscel- laneous lot of black and white spots on a piece of paper; In order that the photo should properly show the information required, it should in most instances be taken from some station along the line of work, or from some point which has been definitely located without the line of work. The most desirable position from which to make the exposure is one from which professional as well as artistic points may be seen. The selection of such a point is made after carefully studying the composition of the view as seen in the finder. If a view is required along the survey line, select if possible, that station where the light will come from behind or from the side. Carefully study the composition. If on a survey line, along a stream bank, on the edge of a mesa, 426 PHOTOGRAPHY at the shore of a lake or bay, bring the important features into the middle of the finder. No picture should be taken that does not contain some life, as only professionals can make a good picture of still life. Picket a rodman with a level rod or stadia board of known length on a station 50 or 100 feet away on line — or more particularly at the point it is intended to feature. This not only gives life to the view, but provides a medium by which distances in the view may be estimated. Have, if possible, one-third of your view composed of sky. Balance your picture. Guard against having the center view obstructed by a 6 foot tree 15 feet from the camera, while the feature you are trying to photograph is 100 feet away. Such a composition blurs the foreground, reduces the field of view, and in general spoils what might have been a successful photo. Hold or set the camera level. If it is necessary to obtain some feature that is below or above the outline as shown in the finder, manipulate the shifting front of the camera. Never tip the camera up or down, for to do so will produce distorted photos on account of the vanishing point lying outside of the horizontal plane. Distance. — Ascertain the distance from the camera to the object to be photographed. Do this with reasonable care as too many poor negatives result from carelessness in estimating distances. Set the indicator at the proper point on the scale of distance. The nearer the subject is to the camera, the more care should be exercised in ascertaining the distance. For universal focus use stop U. S. 16, 32 or 64 and set focusing indicator at 25 to 30 feet. Aperture and Time. — The aperture (stop) and time of exposure are the governing points in making an exposure.' For a given condition a number of different combinations of aperture and time will give satisfactory results. The larger the aperture the shorter the time. The smaller the aperature the better the detail of the picture becomes. In general it is desirable to use a fairly small aperture to get detail and as long a time as conditions permit. The correct combination of aperture and time is affected by the use of a tripod, movement of objects, speed of plate or films used, altitude, latitude, season of the year, intensity of light and composition of the picture.- This sounds complicated and is for the best results but fortunately considerable variation from the best timing will still produce a fairly good negative for all practical purposes. Effect of Use of Tripod. — It is advisable to use a tripod for all engineering photography as it prevents blurring by movements of the camera during exposures and makes it possible to use a small aperture, with the necessary time of exposure, to get good detail. If the camera is held in the hands the time of exposure should be J^s of a second or less and the aperture will have to be made large enough to allow this speed. Effect of Motion of Objects. — As a rule moving objects need not be photographed but if necessary the following speeds of ex- ; posure will stop motion. ' EFFECT OF ALTITUDE 427 J^5 of a second will stop wind in foliage. J^O of a second will stop pedestrians and slow moving rigs. J^OO of a second distant trains. Moo to Ho 00 of a second near trains, automobiles, etc. The aperture must be regulated to allow these speeds. That is, time governs aperture where motion is encountered. Under most conditions, however, where a tripod is used aperture governs time and a small aperture is desirable in order to obtain detail. For most landscape engineering survey work a U. S. stop 16, 32, or 64 is used and the time is varied to correspond with the stop selected. Bright sun use stop U. S. 64 or U. S. 32. Fair light use stop U. S. 32 or U. S. 16. Moderate light use stop U. S. 16 or U. S. 8. An aperture of U. S. 8 will give moderately good detail. Speed of Plate or Film. — Different makes have different speeds but there is no great variation in the speed of the ordinary roll films or speed pack films and the follomng exposure chart is based on the commercial film in ordinary use. Effect of Altitude. — Altitude has a marked effect on time of exposure. Exposure charts are worked out for sea level. Wilson topographic surveying quotes Mr. E. Deville as stating that altitude has practically no effect on timing when the sun is near the zenith in the middle of the day but that as the sun ap- proaches the horizon the effect becomes evident. He gives the following relative time of exposure at sea level and 10,000 feet altitude. - Altitude of Sun Relative Time of Exposure At 10,000 ft. Altitude At Sea Level 90 40° 25° 15° I second I second 3>^ The rule generally used for ordinary engineering photography 1 is to cut the time of exposure in half when you are working at an i elevation of 5000 to 10,000 feet. Effect of Latitude. — Exposures at the equator require the shortest timing. As the latitude increased, the time of exposure increases. i For example conditions requiring J^ 5 of a second at the equator - requires M of a second in Alaska. Effect of Season of the Year. — The summer months require less ; exposure than the winter months. 428 PHOTOGRAPHY For example conditions requiring an exposure of Mo of a second in summer will require 3^ of a second in winter, except that it must be remembered that snow on the ground changes the classification of ''phase" discussed below. The chart on page 429 is prepared for sea level at average con- ditions of latitude and season in the United States and the effect of latitude and season can be disregarded for all practical purposes except for extreme cases as they have a relatively small effect for this territory as compared to light intensity and phase of the picture. The extreme variation from the chart will be approximately as follows; for winter months along the Canadian boundary, doublet the time of exposure given in the chart. For southern Floridal in midsummer use J^ the time given in the chart. When it is borne in mind that this variation in relative exposure does not ruin a negative it can be seen that unless these extreme 1 conditions of combined location and season prevail that the chart j| time without correction should give reasonably good results. "" Altitude should however be considered. EFFECT OF LIGHT AND PHASE , Light Values. — Judgment and experience are essential if good, average negatives are to be secured. However, the following discussion of light values of different lights and phases of views may be of use. There are five distinct conditions of light that are generally taken into consideration when calculating for an exposure. (A) Bright Sunlight. — When the sun is shining brightly in a cloudless sky. (B) Light Clouds, — When a thin film of white clouds partially obscures the sun, but fairly well defined shadows are discernible. (C) Diffused Light. — An even light but no shadows. (D) Dull. — Sky covered with dull clouds with no sunlight penetrating. (E) Very Dull. — Sky overcast with very dark clouds. Gloomy. Phases of Views. — For the purpose of classifying views or sub- jects in a view — the five following phases are given: 1. Landscapes. — This view contains distant landscapes, sea- scapes, snowclad hills, or broad expanses of river scenery. Such views reflect a large percentage of actinic light, and should be short timed or stopped down accordingly. 2. Light Foreground. — This view contains open fields and woods, flocks of live stock, buildings, and small expanses of water. 3. Strong Foreground. — This view contains a large percentage of foliage, buildings close enough to make strong and distinct outlines, fences, figures, animals, well defined roadways, rock j cliffs, or well defined hill slopes not over 400 feet from the camera, urban scenes where the sky line is serrated with buildings, or full views of concrete structures. 4. Very Heavy Foreground. — This view contains close-ups of the following: landscapes having dark green foliage and shadows. TIME OF EXPOSURE 429 bridges and other structures with heavy shadows, and rock cliffs which are generally located in canyons where considerable direct light is shut out. 5. Shaded Foreground. — Under this caption comes, ravines, wooded hillsides, standing timber, under trees, and small dark box canyons where sun light is shut out by shadows. 91 Zl 8 9 / / / / e z I % H % 'A 9V. >/ c5*X ^/ / J' •>/ / f/ ^/ / / f^ / / .^y / / / ^'^ / <^ / ^V ^'4^ / ^A y / y .12T^ 7W^^^ /I 001/, "»'/, oor/, 00c/, / y 4^^X- / /A f>f^ / Sl / /.£/ / / / / / 1-4 (N roio i-t ^ 0- - - CO rl« bo+^- - ' C\ % GO « w (U~ 4J J3 •Cd^ U) r! bo J r auth ht Clo sed Li Light Dull 1 1 H 12; _sd