. The elements of railroad engineering . plank under each post, or masonry piers sohd throughoutthe length of the sill, or separate under each post, or on masonry piers are used on solid ground, and piles wherethe ground is soft for a considerable depth. The height of thebent is from the top of the cap to the bottom of the sill. Thebatter posts have a rake or batter of 3 inches to the foot or length of the sill depends on the height of the bent. The 68 CULVERTS, BRIDGES, AND MINOR STRUCTURES posts maybe mortised into the sills and cap, and treenails used;they may be notche
. The elements of railroad engineering . plank under each post, or masonry piers sohd throughoutthe length of the sill, or separate under each post, or on masonry piers are used on solid ground, and piles wherethe ground is soft for a considerable depth. The height of thebent is from the top of the cap to the bottom of the sill. Thebatter posts have a rake or batter of 3 inches to the foot or length of the sill depends on the height of the bent. The 68 CULVERTS, BRIDGES, AND MINOR STRUCTURES posts maybe mortised into the sills and cap, and treenails used;they may be notched and drift bolted, or drift bolted alone,they may be doweled; they may be joined by splice pieces on theside, making a plaster joint; special iron-joint plates may beused, or split caps and sills. The last two methods are the mostmodern and approved. Sway bracing, one plank diagonally on each side of the bent,should be 3 by 10 inches, or 3 by 12 inches, bolted or spiked to ^ Single Deck ^ Single Deck ^®2 ^T)ouHe Deck j, Double Deck _. 119)4 LONGITUDINAL ELEVATIONS OF BENTS Fig. 26. Trestle Bents the cap, each post, and the sill. It is not absolutely necessarythat they should extend over the caps and sills, but it is betterthat they should. When the bents exceed 18 to 30 feet in height they are madein two parts, and the bridge is knovni as a double-deck the height is greater than 40 to 50 feet, special designs are used. PILE BRIDGES 69 For the ordinary double-deck bent the Hnes of the posts are keptcontinuous, the intermediate horizontal piece being sill for theupper story and cap for the lower story. Longitudinal bracingof various forms is introduced, to give longitudinal stabihty tothe bridge as a whole. The stringers may rest on the caps ^\^th filling blocks or bracketsto keep them in place, or they may be drift bolted to the use of corbels is not recommended. When trestle bridges occur on curves, the best way of provid-ing for the cant of the track is to
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
