. Détails des ponts de treillis ferroviaire rivetés . ensemble par des barres de treillis, le lateralis est habituellement fait aussi profond que la corde supérieure et attaché à elle par le biais d'une plaque à la fois sur son haut et le bas. JTL -46- UN problème plus difficile se trouve dans les détails du système latéral inférieur. Le système de plancher est habituellement fait soque le fond de la hauteur de plancher vient sur un niveau avec le fond de la corde inférieure. Dans ce cas, une grande plaque de jonction |rivetée au fond de chacun fournit un lieu pour la connexion ;( des latrines inférieures. Le côté inférieur se compose généralement des angles seulement, plutôt
2152 x 1161 px | 36,4 x 19,7 cm | 14,3 x 7,7 inches | 150dpi
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. Details of riveted railroad truss bridges . together by lattice bars, the lateralis usually made as deep as the upper chord and fastened to it bymeans of a plate on both its top and bottom. JTl -46- A no more difficult problem is found in the details ofthe lower lateral system. The floor system usually is made sothat the bottom of the floor-heam comes on a level with the bottomof the lower chord. When this is the case a large gusset plate |riveted to the bottom of each affords a place for the connection ;( of the bottom laterals. The bottom lateral usually consists ofthe angles only, rather than the lattice laterals, UThere it ispossible for the bottom of the stringers to be placed as low ornearly as lovi as the plain of the bottom laterals the lateralsare riveted to the stringers. the panels are short is to run the laterals as shown in Pig.81.The laterals themselves being single angles. The details of theintersection of the laterals is the same as used for the diagon-als. An additional detail is shown by Fig.82. This detail is. Pig.81. A method sometimes used in double track bridges where -47- used for both angles and plates^ but no advantage can be claimedover that in which, one of the angles or plates is unbroken. Art, 10. Bearings. The last problem which confronts a bridge designer isthat of the pedestal and bearings. There have been many solu-tions offered but none seem to be just what is wanted. Forbridges of spans up to 75 or 80 feet a base plate is fastened totne end of the bridge and bolted to the abutment. One end isbolted solid and the other is allowed to slide on a smooth plane.This plate is held in line however by a stone bolt passedthrough the slot in the plate. These slots allow for any move-ment due to the contraction or expansion of the truss, Por bridges of over 85-foot span the bearing platerests on rollers. These rollers are made of hardened steel andare held in place by a frame. The diameters of the rollers varyfrom 3 to 5 inches. The larger th
