Seismic Response Analysis Of Long Span Concrete Filled Steel Tube Arch Bridge

Recently, with the continuous perfection of concrete filled steel tube(CFST) theory, the application of CFST arch bridge has become more popular than ever. As the span of CFST arch bridge becomes more and more longer ,the anti-seismic analysis is great important as other type bridges. But there is not the regulation about anti-seismic of CFST arch bridge in code and a little of reference deal with it. In this dissertation, certain problems relating to seismic response behavior of CFST arch bridge are studied.In this dissertation, According to CHUN-AN NANPU CFST bridge of 308 span, a finite element model of long span CFST arch bridge is set up. Compared to the actual means, the truss CFST combined section is simplified as the single pure steel section based on the stiff equivalent principle, which constitute the double arch model. On the foundation of double arch model , the model add suspender and the system of bridge floor, which constitutes the whole bridge finite element model .The dynamic characteristic and seismic response of two models are analyzed in order to study the coupling behavior between arch and the system of bridge floor.Secondly, transient analysis method is applied to the dynamic analysis and computing of long span CFST arch bridge. The two models of arch bridge are computed and compared in order to achieve the response displacement and structural forces and moments under the consistent transverse seismic excitation. The research indicates that the coupling behavior between arch and the system of bridge floor has little influence on the displacement and element force of arch. But the element force has large changes in some single section.Finally, The seismic response behavior of the bridge model is studied under the asynchronous seismic excitation, primary considering the traveling wave effect. And the effect of different wave velocity to the displacement and element force is studied. The result indicates that the effect of transverse seismic excitation to the displacement of the traveling-wave direction is obvious and the effect to the element force is also negative. If the wave velocity is slower, the effect to the displacement and element force are more obvious. So it is necessary to consider the seismic traveling wave effect of long span CFST arch bridge.