Study On Closrue Scheme And Its Influence On Structural State For Multi-Pylon Cable-Stayed Bridges

With the development of analysis theory and construction technology of cable-stayed bridge, more and more multi-pylon cable-stayed bridges have been constructed at home and abroad. The cantilever construction method is usually applied in the construction of long span multi-pylon cable-stayed bridge. The closure scheme of multi-pylon cable-stayed bridge is quite complex as its relatively more closure gaps. Therefore, it is necessary to analyze the influence of closure scheme on bridge’s completed state and all of construction states. Taking the Jiaxing-Shaoxing Bridge as study object, the influence of closure scheme for multi-pylon cable-stayed bridge is studied, and the measures to guarantee the completed profile to meet the requirement of design is discussed.Following works are focused for carrying out above mentioned study.(1) The state of art for study and construction of multi-pylon cable-stayed bridge is introduced. The research on bridge closure sequences for cantilever construction is discussed also.(2) The geometry nonlinear analysis theory, non-stress configuration calculation and completed state determination of cable-stayed bridge are reviewed. Combination Forward Tangents-Installation Method with Zero-Displacement Method, a more effective algorithm is figured out to correct the unstressed cable length of Jiaxing-Shaoxing Bridge,and it is convenient and feasible to apply in real bridge engineering.(3) The FEM model of jiaxing-shaoxing bridge is established by plane frame nonlinear analysis software NLABS. The increments of the internal force and the displacement of the bridge’s components for different closure plans are calculated and compared, furthermore,the influence of different closure scheme is obtained.(4) The measures to guarantee the completed geometric state to meet the designing requirement is discussed from the viewpoints of different closure schemes and temperatures.