Research On Calculation Method And Characteristics Of Steel-concrete Composite Girder Bridge By Incremental Launching Construction

The internal forces and displacements of the Zhadian Bridge,which is made of steelconcrete composites,are analyzed for evaluating the incremental launching construction stages in this thesis.Suggestions advantage of the structural safety are proposed based on the investigated influencing factors of local forces.In addition,the differences in the characteristics of the forces of composite girder bridges are also compared via finite element analysis,both in the construction phase and the operation phase,which provides important references the engineering design.The main research works are as follow:(1)Change laws of structural internal forces,displacements,stresses,and reaction forces in different incremental launching construction schemes were compared,whereby the most reasonable construction plan(MECP)is determined.Further,the most unfavorable working condition(MUWC)and position of the girder during the MECP were revealed.(2)The characteristics of local stress responses under the MUWC were comparatively analyzed both by the local-model and the hybrid finite element model.Moreover,the influence of the stiffness and thickness of the rubber block,as well as the out-sync of incremental launching and jacking-up during construction on the local stress responses of the girder were investigated.Some suggestions for ameliorating the local stress responses were further proposed.(3)The performance of composite girder double element model and composite crosssection model in the finite element analysis of composite bridges were first studied,and the simulation method of the interface in the composite bridge was discussed.Moreover,the characteristics of four kinds of finite element modeling method of the composite girder(i.e.,double element,composite cross-section,plate-girdle hybrid and detailed model)were presented,and responses of the Zhadian bridge under the construction and operation phase were studied based on the four methods.Lastly,several simulation models of the shrinking and the creep of the concrete were compared.