Seismic Response Analysis Of Long-span Multi Tower Highway And Railway Cable Stayed Bridge

The design and the seismic performance of cable-stayed bridge have been widely concerned by engineers.On the basis of the layout of the bridge span,the size of the main beam section and the structure system of the Jinhai bridge,this thesis designs a scheme different from the original whole steel towers.It has done some work on the material and layout of bridge towers,seismic response under uniform excitation and asynchronous excitation and bridge seismic isolation.The research of the thesis mainly includes the following aspects.(1)Four types of schemes were designed,which are bridge with steel towers,reinforced concrete towers and combined steels towers and reinforced concrete towers.The finite element model of five spans and four towers highway-railway cable-stayed bridge has been established and the dynamic characteristics war analyzed.(2)According to the four schemes,the effect of the material and layout of the bridge tower on the seismic dynamic response of the long-span multi towers cable-stayed bridge is studied.The four schemes are evaluated,which can be used for reference for the material and layout of the long span multi-towers cable-stayed bridge.(3)The scheme of bridge with reinforced concrete at middle towers and steel for side towers which is a competitive mode is selected.The dynamic time history analysis of uniform excitation is carried out.The results are compared with the results of the corresponding response spectrum analysis,and the difference between the two is analyzed.Furthermore,the asynchronous excitation dynamic time history analysis considering traveling wave effect is carried out,and the influence rule of apparent wave speed on long-span multi towers cable-stayed bridge is discussed.(4)According to the force characteristics of the bridge under earthquake,the damper is designed by setting up viscous dampers.Further,the sensitivity analysis of viscous dampers is carried out,and the seismic effect is analyzed,which provides reference for the design of long-span multi-towers cable-stayed bridges.