Nonlinear Static Analysis for Seismic Performance Evaluation of Multi-Span Bridges Considering Effect of Lateral Load Distributions

Performance-based approaches as an alternative method of the existing force-based approach have gradually become recognized tools for the seismic design and evaluation. The nonlinear static procedure (NSP) based on pushover analysis has been developed as a practical engineering tool to estimate the inelastic response quantities in the performance-based approaches. To estimate an inelastic force-displacement relationship as capacity curve by the NSP, the monotonic increments of equivalent seismic load with constant lateral load distribution are generally used. One of important variables related to an accuracy of the NSP is the lateral load distribution. The pushover analyses for three multi-span bridge structures were performed using the six types of lateral load distributions. To evaluate an accuracy of the NSP according to the applied lateral load distributions, the maximum displacements estimated by the capacity spectrum method are compared to those by the inelastic time history analysis.