Seismic response of RC bridges under near-fault ground motions: A parametric investigation

Natural disasters such as earthquakes can potentially harm bridges and incur significant socioeconomic losses. This study examines the effect of near-fault ground motions on reinforced concrete bridges, specifically the variation in the seismic performance with the height, aspect ratio, and longitudinal reinforcement. A suite of 332 near-fault ground motions is used to evaluate the performance of 60 bridge models in OpenSees, and the seismic responses are measured in terms of pier curvature ductility, maximum bearing deformation, and deck displacement. Linear regression analysis is used to generate probabilistic seismic demand models and fragility curves corresponding to different damage states. Expected behaviors are displayed within the models grouped with respect to height classes. Since the column diameters are based on aspect ratios, the effect of taller columns reduces the exceedance probabilities. This brought forward a need to define the damage states for tall columns in a manner different from short or medium columns. Moreover, this study underscores the need to update HAZUS fragility median values for near-field seismic response of RC bridges.