Research On Construction Control And Force Analysis Of Extradosed Cable-stayed Bridge

Extradosed cable-stayed bridge is a new type composite structure which is composed of main girder,inhaul cables and cable bent tower.From the structural characteristics,the extradosed cable-stayed bridge is between rigid continuous beam bridge and flexible cable-stayed bridge.It has great potential to be applied in construction.Taking one extradosed cable-stayed bridge under construction as research background,MIDAS CIVIL is used to establish the whole bridge model for global analysis,and MIDAS FEA for local analysis.The specific research can be summarized as the follows:(1)The finite element model of the full bridge is established by MIDAS CIVIL to mainly analyze the force condition of the extradosed cable-stayed bridge under several important working conditions and provide theoretical data for future construction monitoring work.(2)The whole bridge model and simplified bridge model without substructure are established by MIDAS CIVIL to judge the feasibility and accuracy of the simplified bridge model by comparing the deflection and the stress of main girder in the state of maximum cantilever and POSTCS.(3)The sensitivity analysis of structure parameters are conducted in order to provide theoretical foundation for taking targeted measures during construction and finishing construction control.(4)Two working conditions for removing full framing of side span ahead of schedule and pier-beam temporary anchorage behind schedule are stimulated.By comparing the changes of vertical displacement of main pier,stress and cable force,the influences on stress state and line type of the whole bridge under the two working conditions are cleared to provide theoretical foundation for the construction scheme design.(5)The finite element model of bracket is established by using MIDAS FEA to calculate the dead load bearing capacity of the first layer concrete of 0# block after hardening and its load-bearing capacity of the second layer.The results can provide theoretical foundation for the bracket optimization design.(6)The benchmark model of the main tower J1 cable saddle and J9 cable saddle are established by MIDAS FEA respectively to study the stress distribution in concreteand analyze the weak area.By comparing the results of J9 simplified model and J9 benchmark model,the rationality and reliability of the simplified model is validated...