GB1283924A - Improvements in or relating to rapid bridge construction - Google Patents

Abstract

1283924 Prefabricated portable bridge DEFENCE SECRETARY OF STATE FOR 18 Sept 1969 [20 Sept 1968] 44732/68 Heading E1G A bridge span 1 assembled from two or more prefabricated sections is installed across an obstacle, e.g. a river, by projecting the span completely or partially over the obstacle, operating jacks 21 to lower supporting piers through tubular hip members 12 which are connected to the span 1 at one or more positions therealong, the jacks 21 being mounted on the hip members 12 and having means for operatively engaging the piers, and finally securing the piers to the hip members to take the load of the span. The piers may each comprise a plurality of end-connected leg units 10, and are constructed downwardly from the span 1 by successively manhandling each leg unit 10 into its respective hip member 12, temporarily suspending it there by pins 24 engaging slots 14 in the hip member and holes 11 in the leg unit, pinning on the next leg unit above, extending the jack rod 26 carrying a support bracket 18b to engage further pins 24 in the leg unit, removing the temporary pins, and retracting the jack rod to lower the leg unit. When the pier is complete, the jack is extended, the bracket 18b is pivoted through 180‹ to engage pins 24, and the jack is retracted to lift the span 1 to remove sag. The hip member is then attached to the pier by a further bracket 18a. Whilst the first leg unit 10 is still in the hip member, a foot 16 may be connected thereto by a frangible link 28. In a modification, the completed pier is pinned directly to the hip member in a manner to allow limited angular displacement (Fig. 11, not shown). In the case of a wide obstacle, after partial projection of the span and construction of piers, fastenings 27 attaching the span 1 to a cross-beam 13 carrying the hip members 12 are released, and the span is slid further across. The span sections may be joined together by a device allowing angular adjustment thereof (Fig. 6, not shown).