PROBABILISTIC PERFORMANCE ASSESSMENT OF EXISTING RC BRIDGE IN A MODERATE SEISMIC ZONE

Observations from previous earthquakes indicated that substandard bridges in different parts of the world could be severely damaged or even suffer a collapse under strong earthquakes. Potential damage to substandard and pre-seismic code bridges can be identified using detailed inelastic assessment procedures, which supports the selection of suitable seismic mitigated approaches. In this study, a five-span simply supported typical bridge located in the UAE, which is selected as a case study representing moderate seismic zones, is investigated numerically for seismic vulnerability. The fiber-based modeling approach adopted in this study is verified using a bridge bent tested in another study using quasi-static cyclic loading experiments. A three-dimensional (3D) model is developed to consider the bridge components' geometric non-linearities and material inelasticity, including multi-column piers, superstructure, gaps, and bearings. A set of diverse input ground motions are selected, scaled, and applied to the bridge model with increasing intensities to develop fragility curves. Lower strength and higher deformation demands are observed in the longitudinal direction of the bridge compared to its transverse counterpart. The fragility analysis also confirmes the higher vulnerability in the longitudinal direction. The study highlights the pressing need for seismic retrofit to ensure the post-earthquake functionality of substandard bridges in the study region.