Research On Key Process And Control Technology Of Large Span Hybrid Composite Beam Cable-stayed Bridge Construction

Cable-stayed bridge has long span capacity,beautiful shape,and it can be used in cantilever construction.Hybrid combination girder cable-stayed bridge has characteristics of mixed girder cable-stayed bridges and composite beam cable stayed bridge characteristics.The anchoring ability of side span and the span capacity of mid span are improved by using concrete girder in side span.Composite beam can make full use of the properties of concrete and steel to enhance the mechanical properties of the structure and reduce construction cost by composite beam.However,the hybrid composite beam cable-stayed bridge structure is complicated and the construction process is various.Internal force state and bridge line of the completed bridge structuresis closely related to construction process.At present,domestic and foreign scholars study mainly focus on the design theory of cable-stayed bridge,there have been few study on the key process of construction.In the engineering background of Wujiang bridge,The following research is carried out on the hybrid composite beam cable stayed bridge:(1)The survey of actual engineering,construction process and the key technology of construction are introduced,the technology difficulties of construction are discussed.(2)The theory of bridge construction control is systematic introduced.The space finite element model of cable-stayed bridge is established for considering the whole construction process.(3)The improved difference method is used for the forward iteration calculation of initial cable force,and the tensioning force of stay cable is calculated for construction process.The tangent initialdisplacement method and zeroinitial displacement are used for the fabrication geometry and rib alignment of steel beam that based on the overall construction control mind.It is proved that accuracy of simulation of finite element model and the correctness of calculation of the initial cable force,the fabrication geometry and rib alignment of steel beam.(4)Aiming at the effects of sensitivity factor of the girder linear,it is analyzed that the influence to the girder linear include deadweight and stiffness of steel bean and the error of stay cable stretching.In view of the key process of construction,it is studied that the process of pouring wet-joint of bridge deck,it is analyzed that the influence to main span linear include the order of remove stents and the location of hoister of deck derrick crane.Finally,aiming at analysis of the closure problems of cable-stayed bridge,analyze the influence of temperature rising,lowering and gradient on the girder alignment,and analyze the influence of temperature change to the girder alignment,it is analyzed that influence of loads change to the elevation of cantilever beam in the process of closure construction.