LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 ClMS 
 

 GENERAL SPECIFICATIONS 
 
 FOUNDATIONS AND SDBSTRDCTDRES 
 
 HIGHWAY AND ELECTRIC RAILWAY BRIDGES, 
 
 ILLUSTRATED. 
 19O2. 
 
 By THEODORE COOPER, 
 
 Consulting Engineer. 
 
By THEODORE COOPER, M. Am. Soc. 0. E. 
 
 Specifications for Foundations and Substructures 01 
 
 Highway and Electric Railway Bridges, 1902, . $1,00 
 
 Specifications for Steel Highway and Electric Railway 
 
 Bridges, 1901, . 0,50 
 
 Specifications for Steel Railroad Bridges, 1901, . . 0,50 
 
 SENT BY MAIL, POSTPAID, ON RECEIPT OP PRICE. 
 
 FOR SALE BY 
 
 THE ENGINEERING NEWS PUBLISHING COMPANY. 
 
 22O Broad-way, Ne-w York: 
 

 PREFACE. 
 
 Standard specifications for the superstructures of high- 
 way bridges, giving the proper loadings, methods of pro- 
 portioning and character of workmanship are readily 
 obtainable. But for the foundations and substructures of 
 such bridges, there is no standard practice or set of rules. 
 
 The author has herewith endeavored to illustrate the 
 more common forms of substructures and foundations suit- 
 able for highway bridges and give the required proportions 
 for all ordinary cases, with instructions and specifications 
 for their construction. 
 
 Standard proportions and specifications for the sub- 
 structures of highway bridges will not only broaden the 
 competition for their construction, but will result in obtain- 
 ing a better class of substructures than has generally been 
 the case heretofore. They will also enable in many cases 
 the local artisans to proportion and build the same. 
 
 The author excludes from consideration, difficult founda- 
 tions in deep water or those requiring pneumatic or other 
 special appliances or works of such expense as would 
 demand especial study of the conditions to determine the 
 best or most economical solution ; also city bridges and 
 long span bridges, where a higher and more elaborate class 
 of substructure may be demanded and justified. 
 
 117945 
 
Copyright by THEODORE COOPER, Consulting Engineer, 
 35 Broadway, New York. 
 
 General Specifications for Foundations 
 and Substructures 
 
 OF 
 
 Highway and Electric Railway Bridges. 
 
 X. 
 PRELIMINARY FACTS. 
 
 The proper determination of the character and location 
 ol the piers and abutments for a bridge at any particular 
 locality requires a careful judgment, based upon a knowl- 
 edge of the conditions of the stream during its varying 
 stages of low and flood water ; the action of the ice and 
 flood trash ; the liability of the banks and bottom to scour ; 
 the character of the bottom as to its bearing capacity and 
 the possible presence of poorer material below that which 
 is visible or can be reached by ordinary means of examina- 
 tion. 
 
 In cases, therefore, where the local knowledge of the 
 river and the material of its banks and bottom is not com- 
 plete and certain, a special examination should be made by 
 an experienced engineer. 
 
 The author therefore assumes that either from local 
 knowledge or by a special examination, the character of the 
 bottom upon which the piers and abutments are to rest and 
 the action of the stream at its various stages are known. 
 
 For any particular crossing, the best arrangement of 
 spans for economy in first cost and for future maintenance 
 will depend upon the proper placing of the piers and abut- 
 ments and the selection of the kind of piers best suited to 
 the conditions. 
 
 In many cases the location of the piers and the length of 
 the spans are determined by the natural conditions of the 
 
banks and bottom or by the necessities of the waterway, for 
 the navigation of boats or rafts or on account of flood trash 
 or ice floes. 
 
 In cases where there is liberty to select such spans as 
 may be most economical for the situation, Appendix A will 
 give the method by which the economical arrangement of 
 spans may be determined. 
 
 CHARACTER OF THE BOTTOM. 
 
 1. The material of the bottom upon which piers and 
 abutments must be founded may, for the purpose of these 
 specifications, be divided into the following general classes: 
 
 Rock. 
 
 Hard ground, as hard-pan, gravel, compact sand or hard 
 dry clay. 
 
 Soft ground, as soft or wet clay, silt or mud, whose 
 sustaining power must largely depend upon the frictional 
 resistance of long piles or piles driven through the soft 
 material to an underlying material of a harder character. 
 
 PREPARATION OF FOUNDATIONS. 
 
 First. Where they are above the water or where the 
 water can be excluded or diverted by earth or timber dams 
 (Plate I, Fig. i). 
 
 2. Rock. The site of the pier should be cleared of all 
 the over-lying soil and other material, all the loose and dis- 
 integrated portions of the rock removed and where the 
 surface of the rock is inclined, it should be leveled in steps to 
 prevent any tendency of the piers to slip ; all irregularities 
 of the surface should be leveled up for starting the masonry, 
 by filling them with concrete. 
 
 3. Hard Ground. The material should be excavated to 
 a depth below the action of frost or scour by surface cur- 
 rents, with a minimum depth of 3 feet, if above the 
 water. And for foundations in the water, to a depth suffi- 
 cient to be below any possible scour by the river currents 
 (usually increased by the placing of piers in the stream) and 
 to give the piers sufficient foothold to resist displacement 
 by the shoving action of floods, ice or floating material. 
 
 4. Where the foundations are on or near the banks of 
 
streams or on sloping strata they should be carried deep 
 enough to ensure them from slipping by the sliding of this 
 underlying material. 
 
 5. Where the material is liable to be softened, scoured 
 or undermined by water action or where under water 
 the foundations cannot be carried deep enough to be be- 
 yond any possibility of being affected by scour the bottom 
 should be piled. 
 
 6. Soft Ground. The material should be excavated to a 
 stratum of harder material or else it must be excavated to 
 a depth where the soil is permanently wet, if on land, and 
 below possible scour, if in the water. Piles spaced not 
 over 2-J feet centers should then be driven over the whole 
 area to a "good refusal." The piles should be cut off or 
 driven to one level and then covered with a timber plat- 
 form or a layer of well- rammed concrete 2 feet thick, upon 
 which to start the masonry. (See Plate i, Fig. i.) 
 
 7. In all cases as the masonry is built up, the remaining 
 openings of the excavation should be refilled with good 
 material well rammed in place. 
 
 8. Second. Where the foundations are under water which 
 cannot be readily excluded or diverted by dams, some of 
 the special methods of founding hereinafter described 
 should be adopted. 
 
 GENERAL REQUIREMENTS. 
 
 9. No piles, timber or wood shall be used as an essential 
 part of any foundation, above the water-line or in ground 
 which is not permanently wet. 
 
 10. No iron or steel cylinders, beams, columns or other 
 forms shall be used in direct contact with any kind of earth 
 or soil, except where the use of piers with metal shells in 
 deep water, and the use of disk or screw piles may be justi- 
 fied. 
 
 11. Wherever possible, all concrete and masonry must 
 be laid in the open and not deposited through the water. 
 
 12. Preference will be given to such forms and methods 
 of founding piers as do not require the concrete to be de- 
 posited through the water or the use of metal shells per- 
 
6 
 
 manently exposed to oxydation by direct contact with the 
 water and mud. 
 
 13. The tops of trestle or viaduct piers on land must be 
 at least 18 inches above the surface of the ground. 
 
 14. Pedestal stones and bridge seats must be single stones 
 or concrete blocks, and should have a superficial area 
 double of that of the metal bearings resting upon them, 
 with a minimum size of 18 inches square. 
 
 15. Where required, all anchor bolts and anchors shall 
 be properly placed and built in by the masonry contractor, 
 the material for the same being furnished in suitable time 
 by the contractor for the metal work. 
 
 TIMBER AND PILES. 
 
 16. The timber and piles may be sound pine, spruce,, 
 hemlock or other woods equally good. They shall be free 
 from wind shakes, large or loose knots, decay, worm holes, 
 or other defects impairing their strength or durability. 
 
 17. The piles shall be at least 6 inches in diameter at the 
 small end and not less than 10 inches in diameter at the butt 
 for even the shortest lengths. They shall be of sufficient 
 lengths to allow being driven to a "good refusal " under a 
 hammer weighing 1,500 pounds falling freely 12 to 15 feet 
 or its equivalent. 
 
 18. The minimum penetration accepted for the piles 
 should be about 8 to 12 feet in wet gravel, sand or stiff clay, 
 and 20 to 40 feet in soft clay or silt. 
 
 19. All piles in each foundation must be driven or else 
 cut off to such a level, that no wood, including the plat- 
 forms or grillages, will be above the permanent water line. 
 
 SPIKES. 
 
 20. Spikes for underwater platforms, grillages or cribs 
 need not be headed, but may be cut from round or square 
 bars to the required lengths and sufficiently pointed or 
 sharpened at one end to allow their being driven readily ; 
 when the timber is dry or hard enough to require boring 
 for the spikes, the holes must be bored % inch less than the 
 size of the spikes. The length of the spikes must be suffi- 
 cient to pass through the first timber or timbers and enter 
 
the last one at least 6 inches or its full thickness. The 
 spikes should be -^ square or ^ round for timbers up to 8 
 inches in thickness and jj square or round for timbers 12 
 inches and over. 
 
 NOTCHING AND DOVETAILING. 
 
 21. The lateral resistance of cribs and wooden box piers 
 { 56, 86), against spreading must not depend solely upon 
 spiking or nailing, but shall be secured by proper notching 
 or dovetailing of the sticks together. 
 
 CEMENT. 
 
 22. The cement used for all mortar, concrete or masonry 
 shall be an accepted and established brand of either Natural 
 or Portland cement. It must be in good condition, per- 
 fectly dry and free from lumpiness and must be protected 
 from moisture till used. Small pats made from either pure 
 cement or from a mixture of cement and sand in equal pro- 
 portions must set under water, hard and strong within 24 
 hours, be of a uniform color and show no signs of cracking 
 or swelling. 
 
 SAND. 
 
 23. The sand used for all mortar and concrete shall be 
 hard, clean, coarse and sharp ; it must be free from parti- 
 cles of soft stone, earthy or alluvial matter. When used for 
 mortar, unless free from pebbles or gravel, it must be 
 screened. When used for concrete a moderate amount of 
 small gravel or pebbles may be permitted. 
 
 CEMENT MORTAR. 
 
 24. Cement mortar will be made by thoroughly incorpo- 
 rating the cement and sand in the following proportions, 
 viz., one barrel of 300 pounds of Natural cement and 12 
 cubic feet of sand, or one barrel of 375 pounds of Portland 
 cement and 16 cubic feet of sand, with sufficient water to 
 obtain the proper consistency. 
 
 GRAVEL AND BROKEN STONE. 
 
 25. The broken stone used for concrete must be hard, 
 tough and sound stone, free from all dirt and earthy matter 
 
8 
 
 and must not contain any stone exceeding 2^- inches in any 
 dimension. Clean or washed gravel, free from all earthy 
 matter, may be used instead of broken stone for concrete 
 without screening. But an allowance must be made in the 
 proportions of sand to be added, for the quantity of sand 
 contained in the unscreened gravel. 
 
 CONCRETE. 
 
 26. The concrete must not be made faster than it can be 
 properly placed in position. It shall be made on a close 
 board platform. The materials for each batch must be 
 carefully measured to ensure the correct proportions. The 
 sand and cement shall be evenly spread and then thoroughly 
 mixed by turning them over with shovels or hoes, before 
 wetting ; they should then be wetted and worked to a soft 
 mortar ; then the proper amount of broken stone or gravel, 
 previously well drenched with water, should be spread 
 over the mortar and well incorporated with the same by 
 turning the whole over at least twice with shovels or hoes. 
 The resulting mixture should be of such consistency as to 
 quake slightly when rammed, but not before ramming. 
 All concrete as soon as made should be placed in position 
 in layers about 6 to 8 inches deep and thoroughly rammed 
 till all the spaces are flushed with mortar. 
 
 27. If the mortar does not flush to the top under the 
 ramming, the proportion of the stone must be reduced till 
 this result is obtained. On the contrary if the material 
 will not admit of proper ramming, being too quaky, more 
 stone should be used in the mixture. 
 
 NATURAL CEMENT CONCRETE. 
 
 28. For foundations below the surface of the ground 
 where the concrete will not be exposed to the action of 
 running water or to the weather, the concrete shall be 
 made of the following proportions: For each barrel of 
 Natural cement, 12 cubic feet of sand and 24 cubic feet of 
 broken stone or coarse gravel. 
 
 PORTLAND CEMENT CONCRETE. 
 
 29. For monolithic piers and abutments, for cylindrical 
 and wooden box piers and for foundations where there is a 
 
liability to the action of running water or where the bottom 
 is soft or of unequal firmness, the concrete shall be made of 
 the following- proportions : One barrel of Portland cement, 
 10 cubic feet of sand and 20 cubic feet of broken stone or 
 coarse gravel. 
 
 30. Pedestals and bridge seats may be made of con- 
 crete containing i barrel of Portland cement to 8 feet of 
 sand and 16 cubic feet of broken stone or coarse gravel 
 not exceeding three-quarters of an inch in their largest 
 dimensions. 
 
 ROCK-FACED BROKEN-RANGE MASONRY. 
 
 31. All stone must be sound, durable, and suitable in form 
 for good bonding. All stone shall be laid on their natural 
 beds and be rough squared on the joints, beds and faces, 
 breaking joints at least 6 inches and with at least one header 
 to every three stretchers. Headers shall be at least 3 feet 
 long or extend entirely through the wall and be at least 15 
 inches in width. No stone shall be less than 6 inches in 
 thickness or less than 12 inches on the least horizontal 
 dimension. The work need not be laid up in regular 
 courses, but shall be well bonded by the use of headers 
 and stretchers. The stone shall be cleaned and damp- 
 ened before setting and shall be laid in Natural or Port- 
 land cement mortar, as per 24. The joints of each course 
 must be completely filled with cement mortar before the 
 succeeding course is laid. The joints must not exceed 
 three-quarters of an inch in thickness. 
 
 32. No stone less than 12 inches in thickness or of a less 
 superficial area than 12 square feet will be allowed in 
 foundation footings, cutwater faces or the coping. 
 
 33. The bridge seats or that part of the coping which 
 may be used for bridge seats shall be single stones not less 
 than 12 inches thick and must be dressed level and true 
 on the upper bearing surface. 
 
 ROCK-FACED COURSED MASONRY. 
 
 34. The stone shall be sound, durable and of an accept- 
 able character for the locality. All stones shall be laid on 
 their natural beds in regular courses. The face stones shall 
 
10 
 
 be squared, jointed and bedded and laid in regular hori- 
 zontal courses of not less than 10 inches in thickness, de- 
 creasing in thickness from the bottom to the top of the 
 work. They shall consist of headers and stretchers not 
 less than 3 feet long and i feet wide, and shall have a 
 breadth at least one and a quarter and a length twice the 
 depth of the course. There shall be one header to every 
 two stretchers and these shall be so distributed through- 
 out each course and in alternate courses as to bond the 
 work in the best manner. Each stone must bond with the 
 stones of the underlying course; no bond of less than 9 
 inches will be allowed. All corners and batter lines must 
 be run with a neat chisel-draft of i^ inches on each face 
 and the projection of the rock face must not exceed 3 
 inches. 
 
 35. The backing shall be either of cement concrete or of 
 good-sized, well-shaped stones laid so as to break joints 
 and bond the work in all directions. 
 
 36. The whole of the masonry shall be laid in Natural 
 or Portland cement mortar, as per 24. The joints of each 
 course must be completely filled with cement mortar before 
 the succeeding course is laid. The mortar joints must 
 not exceed three-quarters of an inch in thickness. 
 
 37. The footing courses shall be large selected stone not 
 less than 15 inches in thickness, nor of less superficial area 
 than 15 square feet. 
 
 38. The coping shall be large selected stone, not less than 
 15 inches thick, nor of less thickness than the thickness of 
 the average course in the body of the work. The tops and 
 faces of the coping shall be bush-hammered and the 
 mortar joints throughout must not exceed 3/8 inch. 
 
 39. Wing walls of abutments shall be capped with stone 
 covering the full width and not less than 6 inches thick. 
 
 40. When directed, the wing walls shall be stepped and 
 the cap stones dressed on the top surface and faces. 
 
 MONOLITHIC CONCRETE MASONRY. 
 
 41. These should be built within suitable molds, to the 
 same sizes, forms and dimensions as for other classes of 
 masonry, except all edges and corners to be chamfered and 
 filleted at least one inch. 
 
11 
 
 The molds should be built of plank and made sufficiently 
 rigid to be practically unyielding under the ramming and 
 tamping of the concrete. The sides in contact with the 
 concrete should be smooth to give a good finishing surface 
 to the concrete. The concrete must be of unquestioned 
 good and selected materials and carefully and thoroughly 
 mixed. (As the strength and homogeneity of monolithic 
 masonry depends upon the cement, the strength and 
 uniformity of all the cement used should be carefully 
 tested and inspected by a competent person to see that it 
 fully comes up to the standard requirements of the best 
 Portland cement.) The concrete should be deposited in 
 layers of 6 to 8 inches in thickness and be well ram- 
 med and consolidated before adding the next layer. The 
 portion next the mold must be well cut in by spades, tamped 
 and flushed to secure a full and smooth external surface. 
 Special care is to be taken to insure the perfect adhesion of 
 any new work, after the previous work may have taken a 
 set, by roughening the old work by picks and giving 
 it a thorough wetting before placing additional concrete. 
 
 42. Small stones, not exceeding one-man stone, well 
 cleaned and thoroughly wetted, may be incorporated into 
 these piers in the following manner : On any well-rammed 
 layer such stone may be bedded in mortar composed of 
 i part of Portland cement and 2\ of sand (i barrel of 
 cement to 10 cubic feet of sand), but no stones are to be 
 closer together or to the molds than 6 inches or f the 
 depth of the adjacent stones ; the spaces are then to be 
 filled with well-rammed concrete ; before laying another 
 layer of stone, the previous layer of stone must be covered 
 by a layer of concrete of sufficient thickness to keep the 
 stones in adjacent layers at least 6 inches apart. 
 
 43. The molds must not be removed in freezing weather 
 or until the concrete has had forty-eight hours with the 
 temperature above 40 Fahr. in which to set. The masonry 
 should be thoroughly wetted every day and protected from 
 the sun until at least one week after its completion. 
 
 44. After removing the molds the external surfaces, if not 
 perfectly full and smooth, must be made so by troweling 
 with cement mortar ; the top surfaces must also be brought 
 to a level in the same manner. 
 
12 
 
 STEEL SHELLS FOR CYLINDRICAL OR 
 OBLONG PIERS. 
 
 45. The plates for these shells shall be of soft or medium 
 steel. For all parts below low- water the plates shall have 
 a minimum thickness of f of an inch, except where the out-- 
 side is protected by concrete (Plate 7) it may be T 5 g-. For 
 parts between low and high water the minimum thickness 
 shall be ^ of an inch. For parts above high water, of 
 an inch. 
 
 46. All circumferential seams should be single riveted, 
 and all longitudinal seams double riveted. The pitch of 
 the rivets shall be four diameters of the rivets for single 
 riveting, and six diameters for each row of the double 
 riveting. The rivets shall be or f inch. 
 
 47. The shells shall be thoroughly painted, both inside 
 and out, with two good coats of red lead and linseed oil 
 paint, or some accepted waterproof preparation of acknowl- 
 edged merit. 
 
 48. The oblong shells shall be properly and effectively 
 braced against distortion by either the water pressure or 
 the ramming of the concrete filling. 
 
 49. The bracing between a pair of cylindrical shells shall 
 be sufficient to meet all the wind forces at the ends of the 
 spans resting upon them. Where such braces will be sub- 
 jected to the blows or entangling of floating materials, they 
 must be protected by plank bulkheads or fenders. 
 
 50. The material, workmanship and proportions of such 
 bracing shall be in accordance with Cooper's Highway 
 Bridge specifications of 1901. 
 
13 
 
 GENERAL DESCRIPTION 
 
 OF 
 
 SUBSTRUCTURES 
 
 AND 
 
 METHODS OF FOUNDING. 
 
 TIMBER PLATFORMS, GRILLAGES, CAISSONS 
 AND CRIBS. 
 
 51. To spread the loads and weight of the masonry over 
 soft or unequal soil or to facilitate the founding of piers 
 under water, it is often expedient to use timber platforms, 
 grillages, caissons or cribs* 
 
 52. Timber platforms consist of two or more layers of 
 closely-laid timbers alternately crossing each other and 
 thoroughly spiked together to act as a solid platform. The 
 thickness and size of each platform must be such as to 
 distribute in a proper manner the full load over the piles, 
 where used, or over the underlying material, without 
 exceeding the carrying capacity of such material. 
 
 53. Timber grillages are similar layers of alternately 
 crossing timbers laid with open spaces about the width of 
 the timbers, so they can be weighted with gravel, stone or 
 concrete, to facilitate the sinking and placing into position. 
 They are generally floored top and bottom with plank. 
 
 54. Open caissons, the only kind of caissons here con- 
 sidered, are timber platforms or grillages with water-tight 
 wooden sides attached thereto (usually so as to be remov- 
 able after the work is complete), so as to form a water- 
 tight box in which the masonry can be built in the dry; 
 and which can be floated into place and sunk in proper 
 position, either upon the pile heads or on the prepared 
 bottom (Plate I, Fig. 2). 
 
 55. Timber cribs are formed of alternate longitudinal 
 and transverse timbers, notched, dovetailed and spiked 
 together at their crossings, so as to form a rigid structure 
 
14 
 
 divided into a series of pockets several feet square. The 
 open spaces of the ends and sides may be filled in with 
 timber, so as to make them close and solid. A portion 
 of the pockets are floored over so they can be filled and 
 loaded with broken stone or concrete to sink the cribs into 
 position upon the bottom or into the mud to a depth 
 sufficient to get the desired stability. After the crib 
 is in proper position the floored pockets should be loaded 
 and the open pockets dredged until the desired depth 
 is obtained. For hard bottom, where it is not possible 
 to obtain a level surface by dredging, the ground should be 
 carefully cross-sectioned and the bottom of the crib built 
 to the correct shape to get a proper bearing. 
 
 56. No part of the cribs, grillages or platforms must ex- 
 tepd above the permanent water-line. 
 
 57. Care must be taken that the upper parts of the cribs 
 or grillages do not lift free from the loaded bottoms by 
 buoyancy of the water, through faulty or deficient spiking. 
 
 58. After the cribs are sunk into position, if the crib is to 
 be the only foundation for the masonry above, the open 
 pockets are also to be filled with stone or concrete. 
 
 59. Such cribs are not recommended for bridge founda- 
 tions, where other methods can be employed. But where 
 other expedients prove too difficult or expensive, or where 
 the bottom is of such a character that cribs may be placed 
 without possibility of their future settlement or displace- 
 ment by scour, they may be justified. 
 
 60. The difficulties attending their use for bridge piers, 
 unless on hard bottoms, even when well and substantially 
 made, are (i) their further settlement, either evenly or un- 
 evenly, after being loaded, thus throwing the work out of 
 line and level ; (2) their greater obstruction to the river 
 currents and hence the greater liability to scour, owing to 
 their increased size, over piers of more solid construction. 
 
 61. Cribs for bridge piers and abutments should prefer- 
 ably be made of square timber. Round timbers do not 
 give as good bearings and fastenings ; round timber cribs, 
 as usually constructed, are more liable to distort and settle 
 unequally, and also offer more resistance to the river 
 currents. 
 
15 
 
 62. Cribs may sometimes be used to protect and hold the 
 footings of cylindrical piers on hard bottoms as will be 
 hereafter described, Plate 7 ; or to give lateral stiffness 
 to pile foundations in soft mud or deep water, Plate 9. 
 
 ABUTMENTS. 
 
 63. Abutments, in addition to supporting the bridge and 
 its loads, must also hold back and protect the river banks 
 and road filling. Generally to sustain the slopes of the 
 banks and road filling and protect them from the scouring 
 action of the currents, wing walls will be needed at both 
 the upper and lower sides ; their most favorable inclination 
 to the direction of the stream must be determined by the 
 local conditions. In some cases the abutments may be 
 placed far enough back into the banks or the banks may be 
 of such a character, that no wing walls will be needed. In 
 other cases it may be sufficiently satisfactory to protect the 
 banks by rip-rap, paving or piles sheathed with plank. 
 
 64. As the tendency of the material behind an abutment 
 is to push it outward or to overthrow it on its footing, 
 which would be greatly increased by any scour along or 
 under the footing, the foundation should go well below any 
 possible scour and be of a width sufficient to render it 
 stable against such a tendency. 
 
 65. Generally abutments should be of stone or concrete 
 masonry. The thickness of the masonry at any depth below 
 the grade of the roadway should be four-tenths of such 
 depth, down to the footing courses. 
 
 66. The footing courses, at least 2 feet thick, either of 
 concrete or good large selected stone should project in 
 front two-thirds of their thickness. 
 
 67. The thickness on top should be sufficient for the 
 bridge seats and a back wall to sustain the roadway em- 
 bankment. The coping should project at least 3 inches, 
 but not more than one-third of its thickness. 
 
 68. The front batter should be i in 12. 
 
 69. Provision should be made, especially where wing 
 walls are used, for drainage of the water in the banks behind 
 the walls, by weep holes or other means. 
 
16 
 
 70. As the masonry progresses the back filling must be 
 replaced and consolidated by being well rammed in layers. 
 
 71. Plate 2 shows an abutment without wing walls, with 
 the governing dimensions for bridges of different spans and 
 widths. Plate 3 shows an abutment with wing walls. (See 
 110). 
 
 72. Abutments may be built of rock-faced broken-range 
 masonry, rock-faced coursed masonry or monolithic con- 
 crete masonry as previously described. 
 
 73. Where the foundation cannot be carried to good hard 
 bottom below possible scour, the bottom should be piled 
 with piles spaced not over 2|- feet centres, cut to a level; 
 the spaces filled in with broken stone and the whole covered 
 with a timber platform upon which to start the masonry; 
 all the timber being kept below low water. (See 6.) 
 
 MASONRY PIERS. 
 
 74. These will be built of either rock-faced broken- 
 range masonry, rock faced coursed masonry or mono- 
 lithic concrete masonry as previously described. The 
 body of the pier shall have a batter of i in 24 at the ends 
 and at the sides. The coping should extend at least 
 3 inches all around, but not more than one-third of its 
 thickness. The footing courses at least 2 feet thick, either 
 of concrete or good large selected stone, should extend 
 two-thirds of their thickness all around. The cut-water 
 should extend 3 feet above high water line. 
 
 75. Plate 4 gives the dimensions for such a pier for spans 
 of different lengths and widths. (See no.) 
 
 76. These piers should be founded below any possible 
 scour by some of the usual expedients, viz., excavating 
 inside of earth or timber coffer-dams, or sheet piling, or by 
 some method of dredging. Or else piles, spaced not over 
 2\ feet centers, should be driven over the bottom and cut 
 off to one level close to the bottom by an underwater saw 
 and an open caisson whose bottom is a properly propor- 
 tioned timber platform sunk thereon, and the masonry laid 
 up therein in the open air. 
 
17 
 
 DIAGONAL PIERS. 
 
 77. In quiet waters or where the piers will not be sub- 
 jected to shocks of heavy ice or floating materials, two iso- 
 lated piers placed diagonally to the stream may sometimes 
 be substituted with advantage for a single pier. 
 
 78. Plate 5 shows the form and dimensions of such piers. 
 
 CONCRETE PIERS WITH METAL SHELLS. 
 
 Plates 6, 7 and 8. 
 
 79. For such piers either one oblong shell or two cylin- 
 drical shells braced together, can be used. 
 
 80. For soft bottom or where piles can readily be driven 
 into the material of the bottom, the shells should be sunkinto 
 the ground well below any possible scour, by weighting the 
 shells and excavating the material from the inside. The in- 
 closed space should then be filled with piles of such lengths 
 as will permit driving to a " good refusal," with their tops 
 at low water level. The piles should be kept free from the 
 metal shell 4 to 6 inches, and the spaces between the piles 
 must be less than the size of the smallest pile used. For the 
 oblong shells this close spacing need only apply to the end 
 portions, symmetrical with the center of the bearings of the 
 trusses. The spaces between and about the piles must then 
 be well filled and rammed with Portland cement concrete. 
 The shells above low water shall .then be pumped dry and 
 filled with Portland cement concrete, in well-ramrned 
 layers, to the top, where it must be finished off in proper 
 shape for the bridge seats and drainage. 
 
 8 1. For material which can be excavated from the inside 
 of shells to a sufficient depth below possible scour, but 
 which does not need piling ; the shells should be sunk to 
 the proper depth, the bottom sealed against the admis- 
 sion of water by depositing concrete through pipes or in 
 bags, then pumped dry and the interior properly filled with 
 Portland cement concrete. Or, the bottom may be dredged 
 beforehand to a proper level and the shells bolted rigidly 
 to timber platforms or grillages and then sunk as open 
 caissons. 
 
 82. For rock bottom, where it is possible to fit the plat- 
 forms to the rock surface, this form may be used, but where 
 
18 
 
 the weight of the piers is not sufficient to give abundant 
 security against the shoving action of floods, ice or floating 
 material the platforms should be anchored securely to the 
 rock by anchor bolts. 
 
 83. For rock or hard bottom cylinder piers may be 
 steadied and also protected from scour by a surrounding 
 crib, as shown on Plate 7. After the crib is placed and 
 sunk by filling the floored pockets with broken stone or 
 concrete, the cylinders should be lowered into place, through 
 the open pockets provided for them ; then the open spaces 
 outside of the cylinders should be well filled and rammed 
 with Portland cement concrete to the full depth of the 
 crib. Then the interior of the cylinders should be 
 pumped dry and filled in the usual way with concrete. 
 Where the crib cannot be sunk to the rock, owing to the 
 overlying mud, sheet piles or sheeting can be driven 
 around the periphery of the open pockets to the rock and 
 the mud removed, before placing the cylinders or 
 depositing the concrete. 
 
 84. The permanency of the wooden crib in fresh water 
 and the protection of the metal shell, both outside and inside, 
 by cement concrete give this style a superiority over those 
 where the outside of the shell is in direct contact with the 
 water and hence subject to continuous oxydation. 
 
 85. Little or no faith should be put in the claim that when 
 the metal shells do finally rust away, the concrete core will 
 be able to serve the full purpose of a pier, even for the best 
 concrete work; and when the concrete is deposited through 
 the water as has been the usual custom heretofore it will 
 probably be found to be no better than loose stone. 
 
 WOODEN BOX PIERS. 
 
 86. In many localities wooden boxes, as shown on Plate 
 10, can be advantageously substituted for the metal shells. 
 
 87. On account of their square form, they should be 
 placed diagonally to the current. The timbers being entirely 
 under water, will be permanent in fresh water, or where the 
 waters are free from the teredo and limnoria. 
 
 88. The horizontal sticks should be notched over each 
 other, and be spiked together at each crossing and to the 
 
19 
 
 vertical corner sticks. Horizontal washboards at or near 
 the level of the ground will reduce the undercutting ac- 
 tion of the currents, and will also serve for loading with 
 stone or concrete for sinking the boxes to place. It may 
 be best in some cases to make the exterior flush by a series 
 of vertical timbers spiked to the horizontal sticks. 
 
 89. For soft bottom these boxes may be placed in position, 
 weighted and then sunk by excavating the interior till the 
 proper depth is obtained. The inner space should then be 
 piled and filled with concrete up to low water level 
 above that stone or concrete masonry must be carried up 
 to receive the superstructure. In some cases it may be 
 best to drive the piles or at least a few of them first and 
 build the box in place around them. 
 
 90. For hard bottom where piles cannot be driven, a simi- 
 lar form of box or crib can be secured to a timber platform 
 or grillage and sunk as an open caisson upon the prepared 
 bottom, Fig. 2, Plate 10. 
 
 91. The upstream corners of these wooden boxes can, 
 where considered desirable, be protected with an angle iron 
 nose. 
 
 TRESTLE OR VIADUCT PIERS. 
 
 PIERS ON LAND. 
 
 92. These shall be built of stone or concrete masonry 
 and capped with suitable pedestal stones (14). 
 
 93. For gravel, sand or good hard bottom the base 
 area of the piers should not be less than 3^ feet square for 
 spans up to 50 feet. This area should be increased 50 per 
 cent, for moderately good ground and the bottom piled, if 
 it is soft. 
 
 94. For double-track electric railway viaducts these 
 areas should be doubled. 
 
 95. The tops of such piers are assumed to be only a mod- 
 erate height above the ground ; if it is found desirable to 
 raise them considerably above the ground, the sizes must 
 be increased accordingly, for a proportional strength. 
 
 PIERS IN THE WATER. 
 
 96. Any of the previously described forms and kinds of 
 piers for use in water may be used for trestle piers. 
 
20 
 
 97- In addition disk or screw piles, with shafts or 
 columns of solid or hollow metal, wrought or cast, or of 
 wood, may be used for this purpose. Below the mud 
 line the shafts should preferably be of cast iron or timber. 
 
 98. The disks or screws must be of sufficient bearing 
 area to support the loads properly, and the shafts must be 
 considered as columns for their unsupported lengths and 
 be proportioned as such. And in case of screw piles, the 
 shafts and the fastenings to the screw must be propor- 
 tioned to resist the torsion needed to force the screws into 
 the ground. 
 
 99. Disk Piles. Plate 11. These are used where the 
 materials of the bottom can be penetrated by means of the 
 water-jet. The disks must be sunk sufficiently below any 
 possible scour, so as to have at all times a depth in the 
 sand of 6 to 10 feet. For silt or soft material, the disks 
 should penetrate to a good stiff bottom or else to a depth 
 such as would be required for good piling in the same 
 material. 
 
 100. The disks shall be of cast iron and of the sizes given 
 in the tables for the particular span as proposed. The 
 thickness of the metal in the top plate and thicker parts of 
 the cone and connecting ribs should not be less than i 
 inches for disks 24. inches diameter or i|- inch for larger 
 sizes. The cone and its ribs not only strengthen the disk, 
 but are useful, when layers of clay or other tough mate- 
 rial occur, to aid in penetrating them, by turning and 
 dropping the pile. 
 
 101. The cone should have a tapered interior ending in 
 a hole large enough to pass freely the water pipe, which 
 should be at least i^ inches diameter. 
 
 102. The shafts or columns should bear squarely and 
 fully upon the tops of the disks and should be well secured 
 to the same. 
 
 103. Screw Piles. Plate 12. Although the extra cost 
 of the screws and the greater difficulties and expense of 
 founding screw piles render their use in most cases unde- 
 sirable, cases do occur where their use is justified. 
 
 104. As experience has shown that in sinking such piles, 
 it is a common thing to call into play the full torsional 
 
21 
 
 capacity of the shafts at times, the thickness of the metal of 
 the screws and all the connections should be proportioned 
 for this expectation. 
 
 10$. The best pitch for different materials is a matter of 
 experience and judgment. In general it should be from 
 one-third to one-sixth of the diameter of the screw, the 
 larger pitch being for soft material and decreased as the 
 material increases in toughness of penetration. 
 
 106. The points of the screws may be made of various 
 forms to suit the material, which is to be penetrated, viz., 
 gimlet pointed for gravel, serrated for soft rock or coral, 
 blunt for sand or fitted for the assistance of the water-jet 
 in sand or gravel. (See different forms shown on Plate 12.) 
 
 107. Experiment has shown that for driving screw piles 
 with disks of 48 inches diameter into chalk rock, gravel 
 or hard bottom, a torsional power of 125,000 Ibs. feet was 
 needed. 
 
 TABLES OF SIZES AND DIMENSIONS. 
 
 108. In order to render the plans as given herein of more 
 general usefulness the author has omitted all data as to 
 the loads allowed in different cases, and such other data as 
 would be necessary to compute and design the substructures 
 for each particular case. 
 
 He has considered that for the commoner kinds of high- 
 way and electric railway bridges it would be better to de- 
 termine the proper dimensions for the various cases and 
 present them in a tabular form. 
 
 He believes that he has not varied from what is con- 
 sidered good practice in the pressures used for good 
 masonry, or the classes of soils considered or the carrying 
 capacity of piles, screw piles or disk piles. 
 
 SIZE OF PIERS AND ABUTMENTS. 
 
 109. The dimensions and proportion of parts shown upon 
 the accompanying plans and tables for piers and abutments 
 of different kinds, for the span corresponding to that of the 
 proposed bridge, shall be considered the minimum sizes to 
 be used for such bridge. 
 
22 
 
 no. The lengths shown on Plates 2, 3 and 4 are for piers 
 and abutments of bridges without skew. For skew 
 bridges these lengths must be proportionally increased. 
 
 LOCATION AND LEVELS. 
 
 in. The contractor must locate the foundations and 
 construct the substructures at the exact distances, and to the 
 correct alignment and levels required for the proposed 
 superstructure. 
 
 PROPOSALS. 
 
 112. In making proposals for any work under these 
 specifications, bidders must clearly state the kind of sub- 
 structure, character of the masonry, depths of the founda- 
 tions, length and kind of piles, kind of cement they intend 
 to use, and such other facts as will enable a fair judgment 
 and comparison of the several bids. 
 
23 
 
 APPENDIX A. 
 
 ECONOMICAL NUMBER OF SPANS. 
 
 The total cost of a bridge at any particular crossing must 
 include both the cost of the superstructure and the cost of 
 the substructures and foundations. One additional span, 
 by decreasing the length of the spans, decreases the cost of 
 the superstructure, but by adding another pier increases the 
 cost of the substructures. Where the cost of an additional 
 pier equals the saving on the superstructure, either number 
 of spans can be used without effecting the total cost. 
 
 In order to have a ready means of determining the proper 
 number of spans for any crossing, where the local conditions 
 admit of a choice, the diagram on Plate 13 has been pre- 
 pared for different lengths of crossings and different costs 
 for one river pier. 
 
 To provide for bridges of different widths the cost of one 
 pier per foot of clear width'is used; the clear width for high- 
 way bridges being the width of roadway and sidewalks, 
 and for electric railway bridges, 14 and 26 feet for single 
 and double track bridges. 
 
 The vertical column at the left Jiand of the diagram 
 (scale of square roots) gives varying costs per foot of clear 
 width for one pier, including towers, if there be any. 
 
 The horizontal line at the bottom gives the length of the 
 crossings between centres of abutments (one scale for high- 
 way and one for electric railway bridges). 
 
 Having made an estimate of the cost of one pier (see 
 Appendix B) of the required dimensions as per the speci- 
 fications, divide it by the clear width of the proposed 
 bridge. Then follow the horizontal line through this value 
 to the vertical line through the length of the crossing and 
 the number of spans given for that point will be the required 
 number for economy. 
 
 Example: Crossing, 500 feet; width of roadway, 20 feet 
 and two sidewalks, each 5 feet. 
 Should one pier cost $900 or $30 per ft. of width, use /spans. 
 
 " $1,800" $60 " " " " " 5 " 
 " " $4,000 " $133 " " " " " 3 " 
 
APPENDIX B. 
 
 TABLE I. 
 APPKOXIMATE. CONTENTS OF ONE MASONKY PIEK. PLATE 4. 
 
 SEE 110. 
 
 Spans. 
 
 Roadways. 
 
 DEPTH OP PIERS, FEET. 
 
 10 
 
 15 
 
 20 
 
 25 
 
 30 
 
 100 ft < 
 
 12 feet... 
 
 29 
 38 
 31 
 50 
 
 34 
 46 
 37 
 
 58 
 
 39 
 53 
 43 
 66 
 
 44 
 61 
 48 
 73 
 
 49 
 68 
 54 
 
 80 
 
 44 
 59 
 46 
 75 
 
 51 
 70 
 54 
 
 86 
 
 58 
 80 
 63 
 99 
 
 66 
 91 
 74 
 109 
 
 73 
 101 
 80 
 120 
 
 60 
 82 
 62 
 102 
 
 70 
 95 
 7i 
 118 
 
 80 
 109 
 86 
 135 
 
 90 
 123 
 98 
 149 
 
 100 
 137 
 109 
 164 
 
 77 
 108 
 80 
 132 
 
 90 
 125 
 96 
 153 
 
 103 
 143 
 112 
 
 174 
 
 116 
 160 
 127 
 192 
 
 130 
 177 
 142 
 210 
 
 94 
 136 
 100 
 166 
 
 111 
 157 
 120 
 191 
 
 128 
 178 
 140 
 217 
 
 145 
 199 
 159 
 288 
 
 162 
 
 220 
 178 
 260 
 
 20 " 
 
 I 
 150 ft -! 
 
 E, single T 
 
 E, double T 
 
 12 feet... 
 
 20 " 
 
 00 ft -I 
 
 E, single T 
 E, double T 
 
 12 feet... 
 
 20 " 
 
 250ft { 
 
 E, single T 
 
 E, double T 
 
 12 feet... 
 
 20 " 
 
 ( 
 800 ft. . -i 
 
 E, single T 
 E, double T 
 
 12 feet. . . 
 
 20 " 
 
 
 E, single T 
 E, double T 
 
 
 Contents in cubic yards. Depth of pier from top of coping to bottom of footing. 
 
 TABLE II. 
 
 APPKOXIMATE CONTENTS OF ONE MASONKY ABUTMENT, WITHOUT 
 WING WALLS. PLATE 2. 
 
 SEE 110. 
 
 Spans. 
 
 Roadways. 
 
 DEPTH OP FOOTING BELOW GRADE, FEET. 
 
 10 
 
 15 
 
 20 
 
 25 
 
 30 
 
 100 ft -I 
 
 12 feet... 
 
 20 
 28 
 21 
 36 
 
 22 
 81 
 25 
 49 
 
 39 
 56 
 44 
 
 72 
 
 45 
 63 
 50 
 
 84 
 
 67 
 95 
 75 
 120 
 
 77 
 106 
 85 
 141 
 
 100 
 145 
 112 
 183 
 
 116 
 161 
 128 
 210 
 
 145 
 
 206 
 160 
 260 
 
 165 
 
 227 
 181 
 296 
 
 20 " 
 
 I 
 800 ft . | 
 
 E, single T 
 E, double T 
 
 12 feet... 
 
 20 " 
 
 
 E, single T 
 E, double T 
 
 
 Contents in cubic yards. 
 
 [H 9273.] 
 

 
 
! 
 
 ( \^j . x v ; ; ! f j;,., ' 
 
 I 
 
 T* ' ^>\' \\ x -. ^^ -r- ^ ; " 
 

 
 
 Jrl 
 
 SITY 
 
 or 
 
. ; " ' ;i i i' 
 
 ,Uvl ! ' ' lL> * 
 
 ! ^i^-iiliy 
 

 
 
 
Cooper on Highway 
 Bridge Foundations 
 
 Plate No.5. 
 
 DIAGONAL 
 
 MASONRYPIER. 
 
Jto I ^f 
 
 .-!> 
 
 
 

 
 
 
 
 *f 
 
 
 
 
 
Cooper on Highway 
 Bridge Foundations. 
 
 P/cf+eNo.7. 
 CYLINDER PIE.R 
 
 ON ROCK 
 
 wifhCrib Protection. 
 
 Dimensions as per 
 Plate No. 6. 
 

Cooper 
 
 on 
 
 H/qhway Bridge 
 Foundations. 
 
 Plate NaB. 
 
 OBLONG 
 
 STEEL SHELL 
 PIER. 
 

 
 
 
 
 
 3VAOA&O 
 
Low wafer. 
 
 Cooper on Highway Bridge Foundations. 
 
 Plate No.9. 
 CRIB AND PILE FOUNDATION 
 
 FOR MASONRY ORGYLINDER 
 

 .a' 
 
 -.ttS&VA* 
 
 5V 
 
I \dassesC.D 
 " \and Esaltrlc. 
 
 Glasses 
 
 Cooper on Highway 
 Bridge foundations. 
 
 PlateNoJO. 
 WOODEN Box FOUNDATION 
 
 FOR MASONRY PIER. 
 
? 
 
 
 
-1 
 
 VA 
 
 10**% 
 
 $ f.V-^-fSf 
 
 %$ % %1'f 
 
 ksl^i 
 
 2 .- ^ 
 
 *u 
 
 g 
 
 
 
 
 
 
 
 
 

 
 
 
100 ZOO JOG 400 500 600 700 800 900 10*0 
 
 Scale for Length of Crossing for Highway Bridges. (Feet) 
 
 100 200 300 400 500 600 700 800 900 10 10 
 
 Scale for Length of Grossing for Electric Ry. Bridges. 
 
 Cooper on Highway Bridge Foundations. 
 
 PlateNo.13. 
 DIAGRAM or ECONOMICAL^SPANS. 
 

 
 > 
 
 hMVS 
 
 
 
 
 -* 
 
 y_t 
 
 tt 
 
 
 
 
 
 
UNIVERSITY OF CALIFORNIA LIBRARY 
 
 THIS BOOK IS DUE ON THE LAST DATE 
 STAMPED BELOW 
 
 AUG 31 
 MAY 31 1932 
 
 30m-6,'14 
 
vn * 
 <U l 
 
 7945