Title: Internal force adjustment of three main trusses and the parameters that influence it in steel truss bridge with three main trusses and double decks
Abstract: Aiming at that internal forces of middle truss were larger than those of side truss in multi-truss steel bridges after construction,based on a steel bridge with three main trusses stiffened with rigid cables—Dongjiang Bridge,a new technique which could balance internal forces of three trusses by setting camber of lateral direction was introduced and the principle of internal force adjustment was analyzed in detail.In order to prove the validity of this method,a 3D finite element model of Dongjiang Bridge was established by FEM software,axial forces and unbalance factors for main chords and stiffened rigid cables of middle truss and side truss before and after internal force adjustment were compared,and the influences of the vertical flexible stiffness(EI) of floor beam and connection stiffness(K) between floor beam and primary truss on internal force distribution of middle truss and side truss and efficiency of internal force adjustment were studied.The results show that the method distributes the redundant internal forces from middle trusses to side trusses through floor beams by forcing supports of middle truss to settle down 37 mm,and the unbalance factor ηi between middle truss and side truss is controlled within the range of ±5%.The flexible stiffness(EI) of floor beam has great influence on internal force adjustment of three trusses,and ηi becomes smaller with the increase of EI.The connection stiffness(K) between floor beam and main truss has significant influence on internal force adjustment of three trusses and is the key to determine internal force adjustment effect.Being aware that connection between floor beam and primary truss is not completely rigid in practice,both displacement and reaction monitoring of supports is suggested in construction.
Publication Year: 2011
Publication Date: 2011-01-01
Language: en
Type: article
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