GB548439A - Improvements relating to triangulated frameworks and their application to the construction of bridges and the like - Google Patents

Abstract

548,439. Bridges. INGLIS, C. E., and KRYN & LAHY (1928), Ltd. July 14, 1941, No. 8889. [Class 20 (i)] The lateral stability of a bridge or triangulated framework of the kind such as described in Specification 540,945, wherein the girder members are formed of tubes interconnected by upper and lower junction boxes, is increased by providing supplementary members, outwardly sloping from the top member to which they are connected and which form with the main. girders, pyramids, the bases of which are formed by outward extensions of the transoms of the main framework, and lorigitudinals between the ends of adjacent transoms. The transoms 3 are provided with triangular extensions 2 which carry at their outer ends pinned seatings 12 for the apertured ends 4 of supplementary tubular members 1a, which are connected at their upper ends to bearings 19 carried by forked plates 15 disposed between the upper ends of adjacent lattice tubes 14 of the main girders. The forked ends of these plates embrace the lattice tubes 4 and closure plates 22 secured by bolts 21 retain them on the tubes. The outer ends of the extensions are interconnected by further tubular members 1b. The supplementary tubular members 1 are screwed at their ends to receive sleeves 7 welded to rings 8 through the central apertures of which the pins of the flattened ends 4 loosely project so that the sleeves may be rotated to adjust the length of the members. The transoms may be stiffened by a truss member 25, Fig. 1, secured at its ends to lugs 24 on the extensions and carried at its centre by adjustable ties to plates 36 clamped to the lower portions of the transoms, which may also be interconnected by longitudinal links in alignment. To relieve the end transoms 37, Fig. 10, from the longitudinal horizontal forces produced by the sudden starting and stopping of heavy vehicles, these transoms are supported on roller bearings 38 connected by inclined tubes 39 to the junction boxes on the adjacent transoms 41, the bridge as a whole being anchored against bodily movement in a longitudinal direction.