Large Span Concrete Filled Steel Tube For High-speed Rail Continuous Girder Arch Bridge Seismic Performance

Liu Yong Shuidao Bridge(LYSB) is a continuous beam-arch bridge in the dedicated passenger line of Guang Zhou to Hong Kong, and span of the bridge is (76+160+76)m. The structure of main span is Prestressed concrete continuous box beam and concrete-filled steel tube arch. Site soil of LYSB is soft soil; site classification is III; seismic fortification intensity is 7 degree. So the earthquake resistance design should be pay more attention. However, the earthquake resistance design of Long-span arch bridge of CFST is not clearly regulated in the current code. So the study of aseismatic performance for Long-Span arch bridge of CFST has practical significance.Based on LYSB, main work of this paper is as follows:1. According to the structure characteristics of LYSD, simulation of transversal girder, boom and the effect of pile-soil interaction were studied. The finite element model of the bridge was made using midas. Structural dynamic characteristics were studied.2. Using the standard seismic response spectrum, the responses of LYSB to response spectrum analysis were studied. The internal forces, stresses and displacements of structural crucial sections under frequently-occurred earthquake, design earthquake and rare earthquake were analyzed. Beside, the results of earthquake were compared with the results of static analysis under double-track railway live load. It shows that the bridge meets the demand of the code under three kinds of earthquake, and bridge earthquake resistance design does not control the design of LYSB.3. Using Taft-69°seismic wave, the responses of LYSB to time history analysis were studied. The internal forces , stresses and displacements of the structural crucial sections under common occurred earthquake, design earthquake and rare earthquakes were analyzed. The safety of the bridge was checked. Beside, the results of response spectrum analysis were compared with the results of time-history analysis. Some beneficial conclusions are gained.4. The influence that the structure of transversal girder, boom and the effect of pile-soil interaction to dynamic characteristics and dynamic responses of long span concrete filled steel tubular arch bridge was discussed. Some beneficial conclusions are gained, which could provide some references for the dynamic analysis and optimization design of other similar bridges.The research results of this paper can service design of LYSB and provide references for other similar structures.