Application of the Performance- Based Seismic Design in urban rail transit

摘要

The current seismic design codes aim to ensure people's safety￡(r)However,the cost and time expended on repair or restoration of the damaged structures according to the requirements of these codes will be unexpectedly high.The extensive damage of the recent earthquakes have led to significant advance in bridge seismic design and retrofitting. The performance-based seismic design (PBSD)will develop future seismic codes which should be based on the theory of satisfying different performance targets at different hazard levels￡?not on the purpose of ensuring people?ˉs life safety as suggested by the traditional theory.In China, urban rail transit is playing more and more important roles in modern urban transportation, Compared with those employed in railway and highway, bridges in urban rail transit have their own characteristics. This article attempts to shed some light on several critical problems for the seismic analysis of bridges in urban rail transit. It is proposed that the design of bridges of urban rail transit be dependent on the requirements of its performance and appropriate principles of multi-level defenses.