Life-Cycle Performance Assessment of Aging Bridges Subjected to Tsunami Hazards

Coastal reinforced concrete (RC) bridges have the potential to be subjected to tsunami hazards within their service life. On the other hand, the time-dependent chloride-induced corrosion will degrade the performance of the bridges. Few efforts have been made to investigate the life-cycle performance of deteriorating RC bridges subjected to tsunami hazards. In this paper, the time-dependent collapse fragility analysis is conducted to investigate the life-cycle performance of deteriorating RC bridges subjected to tsunami hazards. With corrosion modeling, the time-dependent deterioration of material properties as well as shear capacity deterioration of the columns are considered. Uncertainties from materials are accounted for in developing numerical bridge models. Nonlinear tsunami pushover analysis is used to investigate the bridge damage under tsunami loading. Tsunami collapse failure curves are constructed assuming a lognormal distribution, and the time-dependent tsunami collapse fragility curves can be efficiently calculated with the quadratic model for the median and standard deviation of tsunami intensity, that is, flow velocity. Time-dependent collapse fragility analysis is conducted for a three-span, two-column bent RC bridge. Results indicate that the bridge columns can fail in shear for low inundation depth flow and high corrosion levels. Collapse failure probability of the bridge increases with the flow depth and a clear jump of collapse failure probability for inundation depth from below to above the deck can be observed. The collapse failure probability also increases over time due to corrosion effects.