Research on the seismic performance of bridge with high piers and long spans using Incremental Dynamic Analysis

The seismic responses of bridge with high piers,for which the seismic design criteria are unavailable,are quite different from the regular bridge.In order to assess the seismic performance of the irregular bridges with high piers and long spans,a continuous rigid frame bridge is taken as an example.Using OpenSees,a dynamic elastic-plastic finite element model is built,and then the Incremental Dynamic Analysis is carried out with 15 seismic ground motions selected from the PEER database.With the Ramberg-Osgood equation,a statistical analysis of the controlling parameters is performed,and then by ascertaining the 10%,50%,90% IDA responses and combining with the defined damage to the structure,the seismic performance is accessed.According to the distribution for maximum curvature along the piers,the length of the plastic zone and the formulas for estimating the beam displacement based on the curvature are proposed.The results show that IDA fractile curves can well measure the seismic performance,and can evaluate the reliability at the corresponding performance level;besides,under the strong ground motion,the length of the plastic zone is consistent with the criteria at home and abroad and the formulas for estimating the beam displacement meet the IDA analysis results well.