. The elements of railroad engineering . THE MASONRY 75 on p?^? ® <9 O to 0*0 O W MS s < . ~ . r f- J » § 5. - J ^- c -r o - g. g<n4 76 CULVERTS, BRIDGES, AND MINOR STRUCTURES bracing of plates or angles. Such piers may be used where thereis considerable depth of firm bottom to hold the pier againstflood and ice, and when the necessary bottom is wanting thecylinders may be bedded in a cribwork filled with stone orconcrete. For temporary wooden bridges in new country, pile abutmentsand piers may be used. Superstructure. — For short spans, or where more than onespan is required, a deck
. The elements of railroad engineering . THE MASONRY 75 on p?^? ® <9 O to 0*0 O W MS s < . ~ . r f- J » § 5. - J ^- c -r o - g. g<n4 76 CULVERTS, BRIDGES, AND MINOR STRUCTURES bracing of plates or angles. Such piers may be used where thereis considerable depth of firm bottom to hold the pier againstflood and ice, and when the necessary bottom is wanting thecylinders may be bedded in a cribwork filled with stone orconcrete. For temporary wooden bridges in new country, pile abutmentsand piers may be used. Superstructure. — For short spans, or where more than onespan is required, a deck bridge is economy if there is head roomfor the necessary water way. The depth of the truss or girderwill be from j\ to i of the span. For spans under 20 feetrolled I beams may be used ; between 20 and 100 feet, plate gird-ers ; between 100 and 250 feet, riveted lattice girders; over 250feet, pin connected trusses. These figures represent about aver-age present practice, but there is a strong tendency to make allbut very long trusses of the riveted type, which, while more costly,are stiff. For very long spans, 500 to over 600
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
