Probabilistic seismic fragility analysis of high pier of steel tube-reinforced concrete column
HUANG Zhitang;CUI Shengai;School of Civil Engineering,Southwest Jiaotong University;
In order to assess the seismic performance of high pier of steel tube-reinforced concrete column,according to the theory of structure reliability,resolution function of probabilistic seismic fragility was deduced. A continuous rigid frame bridge with high pier of steel tube-reinforced concrete column was taken as the research object,reasonable performance index of high pier of steel tube-reinforced concrete column was analysed and quantified,the probabilistic seismic capacity model for the section of steel tube-reinforced concrete column with axial force as the variable was built. Considering the uncertainty of steel tube-reinforced concrete column material strength and the ground motion,seismic demand of structure-seismic samples was analysed using IDA method,and the probabilistic seismic demand model for control sections with PGA as the variable was built. And probabilistic seismic fragility of of high pier control sections is obtained. The results show that the logarithmic mean value of curvature index and logarithmic axial force consistented with the three polynomial regression relationships,and seismic capacity of curvature decreased with the axial force increased. Curvature demand and PGA still meet the logarithm linear relationships under the longitudinal seismic. The bottom region of pier is most easily damaged,and the shorter pier of structure system is more easily damaged than higer pier. The high pier of steel tube-reinforced concrete column is hardly collapsed under design seimic.