Among multiple deterioration mechanisms, the seismic performance of bridges is mainly influenced by chloride-induced corrosion deterioration of reinforced concrete (RC) bridge components. Out of 617,000 bridges across the United States, currently, 42% of all bridges are at least 50 years old, and 7.5% of bridges are considered structurally deficient. The vulnerability of these degraded bridges can be increased when located in areas with moderate to high seismicity. The resilience assessment for aging highway bridges subjected to multiple hazards is of great interest to bridge owners and decision-makers for restoring the functionality of the bridge or proposing a suitable retrofitting method. However, this evaluation is challenging due to the significant uncertainty that may be involved. The uncertainty in seismic resilience assessment arises from the inherent variability of material, structural, and modeling parameters, corrosion deterioration, bridge functionality loss ratio, recovery time, and recovery functions, among others. Selecting the parameters affecting the seismic resilience of bridges is often challenging. This demands the evaluation of various parameters that not only have a substantial impact on the seismic response of bridges but also affect the overall resilience of the bridges.
Addressing the drawbacks, this study presents a framework to evaluate the seismic resilience of non-seismically designed multi-span simply supported (MSSS) bridges in India, considering uncertainties related to corrosion deterioration, functionality loss, and recovery time. A detailed experimentally validated three-dimensional finite element model of the bridge is developed by considering nonlinear behavior and corrosion deterioration effects. Nonlinear time history analyses are conducted using a suite of ground motions representative of the seismic hazard of the case-study region to develop seismic fragility curves. The results obtained from the fragility analysis are used to estimate losses and combined with recovery models to obtain functionality loss and resilience. A comprehensive uncertainty analysis is conducted using random sampling and Monte Carlo simulation techniques to determine the variation in seismic resilience curves. Corrosion deterioration and increasing intensity measures lead to increased uncertainty in resilience values. The research findings indicate that it is essential to consider the different sources of uncertainty in seismic resilience assessment of deteriorating bridges in multi-hazard conditions.