Study On Torsional Performance Of Prestressed Concrete Cable-stayed Bridge With Wide Box Girder And Single Cable Plane

Cable-stayed bridge with wide box girder and single cable plane have quite competitiveamong the moderate span bridges due to its multi-lanes and wide vision. Because the singlecable plane does not work on the main beam torsion, the torsional stiffness of structure istherefore small, which leads to larger torsional deformation and uneven distribution of sectionstress of the main girder under the sevice load. For the cable-stayed bridge with wide boxgirder and single cable plane under construction, the final structural system has not yetcompleted, structural stiffness, especially torsional stiffness is lower, the torsional effect ofstructure will be more apparent. In this thesis, taking the Lushan Bridge in Fu yang asexample, the torsional performance of whole construction process has been numericallyinvestigated.Based on the structural analysis software MIDAS/CIVIL, a plane structural finiteelement model is firstly establish, and the reasonable state of cable-stayed bridge incompletion is determined by using the unkNown load factor method. On the computed finalstate of the bridge, the reasonable state of the bridge under construction is determined byusing the reverse-forward iteration method. Secondly, a refine finite element model of thebridge is established by using3D plat, solid and beam elements, and the torsionalperformance of the bridge in comletion is investigated by applying eccentric loads. Finally,the torsional performance of the bridge under the biggest double, single cantilever, and theclosure construction stages is analyzed under the wind load and construction load.The results show that:1) the reasonable cable forces of the bridge in completion can beefficiently determined by the MIDAS/CIVIL unkNown load factor method, but for the initialcable forces under construction, it requires the reverse-forward iteration analysis.2) For thebridge under completion and construction stages, the torsional deformation is relatively small,the stress distribution is relatively symmetrical, torsional angles of the top and bot plates are basically identical, which indicates that such a long span cable-stayed bridge with wide boxgirder and single cable plane has good torsional performance and safety.