GB1020094A - Improvements in or relating to suspension bridges and methods of constructing them - Google Patents

Abstract

1,020,094. Suspension bridges. E. LUBBERT, U. FINSTERWALDER, R. JECHT, E. RUF, E. LUBERT, E. LOFFLER and G. LUCKING. Nov. 29, 1962 [Nov. 29, 1961], No. 45225/62. Heading E1G. The, or each, span of a suspension bridge is formed by suspending longitudinal tension members between supports, surrounding them with concrete to form a load-bearing structure so that the tension members form at least 20 per cent of the cross-sectional area of the structure which takes up the form of a catenary without longitudinal pre-stressing apart from that imparted by its own weight. The tension members 10 are suspended from supports such as a rock-founded trestle 21, Fig. 2, anchored by means of stressed members 6 and 8. Alternative forms of end support for use where the subsoil is poor are shown in Fig. 3 in which the members 10 are connected to tension members 15 anchored in a block 12 and in Fig. 5 in which the support 16 is anchored by its own weight optionally augmented by a gantry 17, the part 18 in which the members 10 are anchored being connected to the support 16 by tension members 19. When the supports have been constructed, two cables 10 are suspended between adjacent supports and are used to carry a walkway from which suspension of the rest of the cables may be carried out. The cables 10 are then anchored to the supports and tightened to achieve the desired sag. Starting at the centre of each span and using shuttering concrete is introduced around the cables so that they form at least 20, preferably 25 per cent of the cross-sectional area of the slab 1 thus produced. Each end support includes a cantilever arm 2 with an upper surface curved to follow the slab 1 has a resilient end portion 9 and the intermediate supports (not shown) include such an arm at each side.