Seismic fragility assessment of a multi-span RC bridge in Bangladesh considering near-fault, far-field and long duration ground motions

Seismic vulnerability of a three-span continuous highway bridge located in Kishoreganj, Bangladesh is assessed numerically in this study. Fragility curves have been derived from the nonlinear incremental dynamic analysis results of the bridge subjected to medium to strong near-fault, far-field and long duration ground motions. This study aims to investigate the damage probability of bridge components (piers and isolation bearings) and the bridge system under different types of ground motions. A total of 48 near-fault, far-field, and long duration ground motion records with peak ground acceleration values ranging from 0.08 g to 2.31 g are used in the nonlinear dynamic analysis of the bridge. A 3-D finite element model scheme is used in this study considering nonlinearity in the bridge piers and the elastomeric isolation bearings. The fragility curves are constructed for two bridge components (i.e., piers and isolation bearings), and the system as well. The numerical results show that both component levels and bridge system failure probabilities are dominated by long duration ground motions than those of near-fault and far-field ground motions.