Architect and engineer . es govern, while in the designof the main girders the distributed load gave maximum stress. In the stringersthe maximum fiber stress of the concrete is 350 pounds per square inch. In thesteel a maximum fiber of 16,000 pounds per square inch was permitted and theshear is 145 pounds net section. Because of the likelihood of rusting and corro-sion, too, it was decided not to use roller bearings to carry the expansion move-ment of the girders. Instead a thin sheet of asphalt was poured at each endand 4 inches latitude allowed for expansion and contraction. The influence of
Architect and engineer . es govern, while in the designof the main girders the distributed load gave maximum stress. In the stringersthe maximum fiber stress of the concrete is 350 pounds per square inch. In thesteel a maximum fiber of 16,000 pounds per square inch was permitted and theshear is 145 pounds net section. Because of the likelihood of rusting and corro-sion, too, it was decided not to use roller bearings to carry the expansion move-ment of the girders. Instead a thin sheet of asphalt was poured at each endand 4 inches latitude allowed for expansion and contraction. The influence of concrete ship design and construction is noticeable in thelayout of the reinforcement and in placing the concrete. Steel bars, it will beseen from the sections, have to be distributed closely through the flanges of thegirders, and, as in the concrete ships, they are separated with spacers. Placingthe concrete, too, was facilitated by the use of pneimiatic hammer on the forms,as was done in the Government concrete SHOWING STRUCTURAL DESIGN OF HIGHWAY BRIDGE OVER SALT RIVERH. J. Brunnier, Engineer Reinforcement in the girders was built up to shape in the forms. An open-ing was left along the upper side of the bottom flange of the forms throughwhich to place the bars below that level, and each layer was fastened as it wasplaced. The steel used in top and bottom flanges is all l^g-inch bars, plainrounds, which were delivered on the job in lengths up to 80 feet. In order toavoid the possibility of confusion in placing the steel and to insure a location ofjoints that would give a sufficient cross-section of continuous steel at any point,there was added to the blue-print an extra sheet on which was plotted thelength and location of every longitudinal bar in top and bottom flanges. In the bottom flange there are nine layers of six and five bars each. Eachlayer was numbered and the successive runs of bars in each layer were laying off the length of these bars to sca
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