. American engineer and railroad journal . five The bridge has a main roadway ft. in width, andtwo sidewalks, each ft., making the total width be-tween the railings ft. For the roadway the floor-beams carry a system of troughs of iron, shown in sectionin fig. 4 ; these support a bed of gravel on which the pav-ing blocks are laid. The sidewalks are of asphalt, laidon a bed of gravel resting on sheet-iron plates with largecorrugations, as also shown in section in fig. 4. Iropergutters are provided at the edge of the roadway for carry-ing off rain-water. ^ At the left end of ihe bri
. American engineer and railroad journal . five The bridge has a main roadway ft. in width, andtwo sidewalks, each ft., making the total width be-tween the railings ft. For the roadway the floor-beams carry a system of troughs of iron, shown in sectionin fig. 4 ; these support a bed of gravel on which the pav-ing blocks are laid. The sidewalks are of asphalt, laidon a bed of gravel resting on sheet-iron plates with largecorrugations, as also shown in section in fig. 4. Iropergutters are provided at the edge of the roadway for carry-ing off rain-water. ^ At the left end of ihe bridge a staircase is formed in theabutment, by which foot-passengers can descend to a land-ing stage, also formed in the abutment, just above iheusual water level. In designing this bridge regard had to be taken of theworks in progress for regulating the Tiber ; this deter-mined to some extent the location of the piers. The gen-eral location was so made as to continue the Via Lunga-retta across the river in a straight line, doing away with. THE PALATINE BRIDGE OVER THE TIBER. spans, the lengths of which, measured on the center, are ft.; ft.; ft-; > ft.; 98 ft. The piers and abutments are of Maddalena granite,and are foundeil on caissons sunk through the mud andsilt of the river bottom to a solid foundation. The cais-sons are rectangular in form and are made of iron ; theywere sunk by the pneumatic process and filled in withconcrete. The depth to the bed-rock varied, and the dis-tances to which the several caissons were sunk, measuringfrom the ordinary water level, was : Right abutment, ft.; first pier, ft.; second pier, ft.; thirdpier, ft.; fourth pier, ft.; left abutment, 368 depths below the riverbed varied from to 36 6 general elevation and plan of the bridge are shown infigs. 2 and 3. ;_ The caissons for the abutments are both ft. inwidth ; those for the four piers are all 18 ft. in width, butvary in l
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
