Research On Effect Of Structure Parameters On High-Speed Railway Continous Beam Bridge Seismic Fragility

China, as earthquake-prone country, has encounter many earthquake situations in recent years that caused great casualties and economic losses. Bridges represent a highly ratio of Chinese high-speed railway lines. PC continuous beam bridge is normally used when the span is relatively long. The earthquakes in history resulted in a lot of destruction of railway bridges. Obviously, Chinese high-speed railway bridges have not experienced the test of earthquake.As an important part of seismic risk assessment, seismic vulnerability analysis presents the iea of performance-based seismic design. Seismic vulnerability analysis of bridge structure can obtain damage probability of bridge under different intensity earthquake. Thus, it can evaluate the seismic performance of the bridge rationally. Analyzing the seismic vulnerability of high-speed railway continuous beam bridge can not only evaluate its seismic performance, but also evaluate the seismic risk and provide the basis for seismic disaster prevention policy formulation.Engineering background of this paper is a high-speed railway continuous beam bridge with a span of (32+48+32) m. OpenSees software was used to establish the finite element models, and natural ground motion records were selected for the nonlinear time history analysis. According to the seismic damage feature, this paper analyzed the seismic fragility of a high-speed railway continuous beam bridge, assess its seismic performance. To study the effects of structure parameters on high-speed railway continuous beam bridge seismic fragility, this paper changed material parameters and damper parameters which are relatively easy to be modified in design. It is expected that this paper will benefit the aseismatic design of high-speed railway bridge. The main contents of this paper includes:(1) The basic theory of bridge seismic fragility analysis;(2) The analysis on seismic fragility of high-speed railway continuous beam bridge based on IDA method;(3) The effect of material parameters on seismic fragility by adjusting the material parameters of bridge structure;(4) The effect of damper parameters on seismic fragility by installing dampers with different parameters on original bridge structure;(5) Global seismic fragility analysis of bridge structure.The results show that concrete strength is the material parameter which has the greatest influence on the seismic vulnerability of high-speed railway continuous beam bridge. Installation of dampers makes the internal force of each pier more balanced, and decrease the curvature of the fixed pier and displacement of sliding supports. Therefore, it has a significant influence on seismic vulnerability of bridge.