Probabilistic Seismic Assessment for Reinforced Concrete Bridges

Abstract

Seismic assessments of reinforced concrete (RC) bridges play an important role in the sustainable development of societies and the determination of the critical values of demand measures for various damage limit states is a key issue in seismic assessments. The results of a seismic assessment largely depend on which kind of demand measure is used, but few studies have investigated the nature of the relationships between damage measures in order to avoid inconsistency between seismic assessments. In this study, a finite element model of an RC bridge was constructed to act as a benchmark example. Three parameters, system-equivalent displacement, rotation angle of a plastic hinge, and material strain, were used as the engineering demand parameters (EDPs) to assess the seismic performance of different earthquake levels. Numerical examples demonstrated that the exceedance probabilities significantly depended on the selected EDP and the critical values of the EDPs for the three damage states. To obtain a consistent seismic assessment of the representative bridge for the different EDPs, an iterative probabilistic seismic assessment method was adopted. The EDP critical values could then be determined using the performance-based exceedance probabilities. It was suggested to the exceedance probabilities within 50 years for the three damage limit states (performance-based) at half of the exceedance probability within 50 years for three seismic levels of earthquakes (hazard-based), respectively.