PERFORMANCE-BASED PROBABILISTIC SEISMIC DEMAND ANALYSIS OF BRIDGE STRUCTURES

Based on probabilistic seismic demand analysis, this paper established the dynamic non-linear models of the bridge structure with and without dashpots. The maximum relative displacement of the activity bearings was obtained by incremental dynamic analysis and two performance levels were defined. The fragility curves of the two structures were presented and compared. Combining the fragility curve with seismic hazard curve, the 50 years demand hazard curves of the structure were obtained. The results show that, during fifty years, the exceeding probability of collision of the bridge without dashpots was close to the limit probability; nevertheless, it was decreased significantly with dashpots installed, such that the requirement of performance levels can be satisfied. During weak earthquakes, the effect of dashpots to improve structural seismic performance was not as evident as during strong earthquakes.