Seismic Response Analysis Of Long Span Bridge In The Liquefiable Ground

In several large earthquakes in recent years, a large number of bridge was damaged. Seismic safety problems of bridge structure has attracted more and more attention. The earthquake disaster investigation showed that:in addition to the earthquake,site conditions is one of the important factors affecting the safety of the bridge structure. That the seismic analysis of bridge in liquefiable site has become an important engineering problem.Based on a high-speed railway three span continuous beam-arch bridge in the liquefiable ground, the influence of pile-soil interaction on seismic response of the bridge in liquefiable ground was discussed. Based on the m value method and P-Y curve method, with the ANSYS (finite element analysis software), the whole-pile model Ⅱ、model Ⅲ and the bottom of the pier consolidation model Ⅰ were established. The dynamic characteristics, seismic response spectrum and time history was calculated by using the finite element software ANSYS.Through the comparison of model Ⅰ and model Ⅱ, pile-soil interaction influence on the dynamic characteristics and the seismic response of the structure was analyzed. At the same time, through the comparison of model Ⅱ and model Ⅲ, soil liquefaction and nonlinear effect on seismic response of the structure was analyzed. After the analysis and summary of the seismic response of the structure, the weak link of the bridge seismic was given.The calculation results show that:the basic mode of the 3 finite element model was the same, and lateral bending was the basic mode of this bridge. The whole pile model of Ⅱ and Ⅲ have the same front 5 modes, which shows that the model analysis of contrast method and application of P-Y curve method was reasonable. The first order frequency model of Ⅰ,Ⅱ and Ⅲ was 0.83669,0.51895,0.50278. The frequency of this structure was reduced while considering the pile-liquefied soil interaction, The transverse displacement response spectrum values was 0.00518m、0.0211m and 0.0216m,and the dynamic characteristics calculation values was 0.00513m、0.0203m and 0.0221m. The displacement response value of key locations of this structure was increased while considering the pile-liquefied soil interaction and liquefied soil nonlinear.