Reinforcement structure of truss bridge or arch bridge

Abstract

Through co-action between auxiliary triangular structural frames, which are each constructed at opposite ends of a truss girder or arch girder, and a cable stretched between the auxiliary triangular structural frames, an upwardly directed force is exerted to the truss girder or arch girder, thereby effectively inducing a load resisting force. A reinforcement structure of a truss bridge or arch bridge is comprised of a truss girder or arch girder, a first and a second end of which are each provided with a main triangular structural frame. The main triangular structural frame is provided at an inner side thereof with an auxiliary triangular structural frame. The auxiliary triangular structural frame is joined at vertexes thereof with frame structural elements at respective sides of the main triangular structural frame. A cable extends in a longitudinal direction of the truss bridge, being stretched between a nearby part of a joined part at one of the vertexes of the auxiliary triangular structural frame on a side of the first end of the truss girder or arch girder and a nearby part of a joined part at a corresponding one of the vertexes of the auxiliary triangular structural frame on a side of the second end of the truss girder or arch girder. Deflecting structure, adapted to exert a downwardly directed force to the cable, is inserted between the cable and a lower chord of the truss girder or arch girder so as to tension the cable, and an upwardly directed force is exerted to the lower chord by a reaction force attributable to tension of the cable via the deflecting structure.