STEEL TUBULAR PIERS FOR HIGHWAY BRIDGES. 



257 



ami data on piers, pier beams and pier bracing are given in Fig. 16. In calculating the weight of a 

 pin- add one foot to the length of each tube. The weight of the concrete in two tubes is given 

 in Fig. 1 6. The concrete is assumed to fill the tube, and the space occupied by piles should be de- 

 durti-d. The number of piles required for different diameters of tubes is given. The number of 

 pilrs m|iiiied for large tubes agrees quite closely with Cooper's Specifications, but the number 

 for small tubes is very much less. 



Pier Beams. The sizes of pier beams required for different panel lengths and clear distance 

 between tubes in feet are given in Fig. 16. The pier beam should be assumed as one foot longer 

 than the clear distance between the tubes, in calculating the weight of the beams. 



PLAN 



Up stream end to At 

 same as down stream 

 except wnere starkwttr 

 is necessary. 



Fer square crossings*- 



V/hert sp/icingr ofrai/s in 

 Piers over 30-0 "hig>/> to Foundation to suit /oca/ conditions^ foundation is necessary thest 



but must be not /ess than 4-0 dey>, to be ful/y boJ ted with two 

 un/ess pood roc* is found. any/ebars, breahnfjowts. 



foundation to be c/ass S concrete 

 /'3 : 6 without rubb/e, un/ess /oca/ 

 conditions maJce stone cheaper. 



Number of pi/es, if reyu/red, 

 to be determined by character 

 ef under/yiny maferia/. 



FIG. 8. MASONRY PIERS, N. Y. C. & H. R. R. R. 



. urse. 



fl/so corM course to be 

 wed w/rtn the c/vtanct 

 from top of starkwater 



for skew crossings 

 incsuse ft if necessary 



Pier Bracing. The piet bracing for piers supporting the ends of two spans are given in 

 Fig. 16. If the spans are unequal in length, enter the table with one-half of the algebraic sum 

 of the spans. For example, for a pier carrying a 75 ft. and a 125 ft. span, enter the diagram with a 

 span of loo ft. Steel tubular piers should never be used for end abutments carrying a fill. 



In calculating the weight of the diagonal bars the length of the bar should be multiplied by 

 the weight per foot as obtained from a handbook, and the details for one bar added to the product. 

 In calculating the weight of the struts add one foot to the clear length. 



Pier Caps. Tubular piers may be capped with steel plate caps, may be finished with con- 

 crete, or may have a stone pedestal block. The weights given in Fig. 16 do not include the 

 weights of steel caps. 



Specifications for Steel Tubular Piers for Highway and Electric Railway Bridges. The 

 plates for the tubes shall be not less than 1 in. thick for tubes up to 30 in. \n diameter, not loss 

 than ^ in. for tubes from 30 to 48 in. in diameter, and not less than | in. for tubes from 48 to 

 72 in. in diameter. Where the plates are in contact with the soil the thickness shall be increased 

 at least ^ in. For A in- plate and less use { in. rivets; for | in. plate and over use I in. rivets. 



The horizontal seams shall be single lap joints riveted with a pitch of 4 diameters of rivet, 

 while the vertical seams shall preferably be butt riveted with single riveting spaced 4 diameters 

 of rivet, up to 48 in. diameter of tubes, and double riveting with 3 in. spacing for tubes of larger 

 diameter. 



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