Study Of Dynamic Characteristics Of Long-Span Cable-stayed Concrete Filled Steel Tubular Arch Bridge And Vibration Of Stay Cables

Because unified the cable-stayed bridge and the arched bridge merit, the long-span cable- stayed concrete filled steel tubular (CFST) arch bridge which is a new-type composite bridge has already utilized in the actual project. But its fundamental research only then just started. As the same as the cable-stayed bridge and the long-span arched bridge, the cable-stayed CFST arch bridge is a flexibility structure. Accordingly, the problem of dynamical, such as seismic response, wind induced vibration, coupled dynamical vibration between bridge and vehicle should not be ignored. Especially, stay cable, which is one of the main components in cable-stayed CFST arch bridge, is susceptible to environment and traffic excitations because of its flexible, low damping small weight, then the significant vibration is induced. The accurate analysis of the dynamic characteristics of cable-stayed CFST arch bridge is very important for the design of this type bridge. In this thesis, taking the example of some cable-stayed CFST arch bridge (the Fourth bridge over Xiangjiang River in Xiangtan city), with the help of ANSYS, one universal FEM software, author analyze its dynamic behaviors and abstract it as follows:1. Establish 3-D finite element model of this whole bridge, calculate its dynamic characteristics, besides, compare and study dynamic characteristic of CFST arch bridge and cable-stayed CFST basket-handling arch bridge. Modify above model along with altering structural form or the constitution of the bridge, such as different standard, steel ratio, steel pipe diameter, concrete module, brace allocation, the length of concrete of the main ribs, suspending pole mode and cable local vibrations, calculate the variety of dynamic character, analyze this factors which will affect.2. The seismic responses behavior of cable-stayed CFST arch bridge under one dimension seismic excitation and two-dimension seismic excitation is studied by time history method. The influence of vertical seismic excitation to cable-stayed CFST arch bridge is discussed. Finally the thesis appraises the anti-seismic reliability of cable-stayed CFST arch bridge.3. According to the finite element method result, the parametric vibration of cables in cable-stayed arch bridge becomes prone to be exhibited. Then a model of non-linear parametric excitation vibration coupling the stayed cable and the girder, namely, the mode of cable-stayed beam, is proposed in the thesis. And the nonlinear dynamical...