Tower-Beam-Pier Stress Analysis Of Single-Tower Cable-Stayed Bridge With U-Shaped Section

With the further development of China’s high-speed railway, both high-speed railway lines and other communication lines were criss-cross. In order to cross the mountains and river valleys and the existing line, more and more cable-stayed bridges were applied in high-speed railway. To improve the flexural rigidity of the cable-stayed bridge, limit the longitudinal displacement and reduce the CWR longitudinal force on the bridge, the tower-beam-pier rigid frame system was often used in the cable-stayed bridge. The working condition of tower-beam-pier node directly affected the overall stiffness and stability of the cable-stayed bridge. The node failure would result in failure of the overall structure of the cable-stayed bridge with devastating consequences. Under the role of the dead load, live load and temperature, the node stress was very complex. Therefore, it was necessary that the stress distribution for the tower-beam-pier consolidation node on high-speed railway cable-stayed bridge was analyzed by the finite element, and in view of the weak link, the improvement measures were put forward.In this paper, the (32+80+112) m single-tower cable-stayed bridge with U-shaped section on contact line of Shanghai-Kunming passenger line was taken as an engineering background. The bridge had the following two main features:①In order to reduce the impact of the construction process on high-speed railway under the bridge, the rotating construction was used. After completing the rotation, the tower-beam rigid connection increased the longitudinal stiffness of the bridge.②In order to increase the torsional stiffness of cable-stayed bridge, save clearance and avoid high-voltage cables, and at the same time, in order to prevent the ballast fall into the high-speed railway under the bridge, the U-shaped section of prestressed concrete was used for the main beam.The main works in this paper included: (1) Taking the design process for single tower cable-stayed bridge with U-shaped section as the main line, it was investigated that the cable-stayed bridge section forms, the selection process for beam width and beam height, different structural systems and quality of cable material, and the lateral force characteristics of U-shaped section of cable-stayed bridge and the configuration of the transverse prestressing were analyzed.(2) The region stress analysis methods were reviewed. The model of single tower cable-stayed bridge with U-shape section was established for the force and deformation boundary conditions.(3) For the tower-beam-pier node three-dimensional finite element model for single tower cable-stayed bridge with U-shaped section on high-speed railway, the sub-model method was used to simulate the boundary conditions of the stress and deformation, and the prestressed effect was simulated by equivalent load.(4) By modifying the boundary conditions of the stress, the consolidation area stress distribution was analyzed during the maximum cantilever stage of the construction process and under the most adverse load combinations of the operation process, and the stress concentration position was looked for. The structural optimization measures were investigated.