Yasamin Rafie N azari - M.Sc. Student, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran
Khosrow Bargi - Professor, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.

Bridges are key elements of transportation systems. Previous seismically induced damages to these structures revealed the necessity of seismic vulnerability assessment of them according to performancebasedearthquake engineering philosophy. The purpose of this study is applying Incremental DynamicAnalysis for seismic assessment of a typical two span concrete bridges according to this philosophy. Incremental dynamic analysis consists of scaled time history analysis to gain structural performanceunder different levels of ground motion excitation. 20 model of the bridge structure was constructed in Open System for Earthquake Engineering Simulation. Peak Ground acceleration and column curvature ductility factor were chosen as intensity measure and seismic performance indicator, respectively. Eight time history records of past earthquakes were scaled and applied incrementally to the numerical model to evaluate seismic performance of the bridge. Damage states were defined as slight, moderate, extensive and collapse state. The resulted curves can be used to estimate mean annual frequencies of exceeding each damage state

Damage states, non-linear time history analysis, seismic peiformance evaluation, two span concrete bridge, peiformance-based earthquake engineering