Novel time-dependent seismic fragility assessment tool for existing RC highway bridges in a multi-hazard environment considering regular maintenance
Alaa Al Hawarneh, M. Shahria Alam
Abstract
In environments where bridges are subjected to multiple hazards over their lifetime, assessing the fragility of bridges solely under earthquake loading would not provide proper insights into the actual performance of bridges. Moreover, existing time-based fragility tools in the literature fail to accurately represent bridge behavior, as they depict corrosion as an ongoing process that continuously deteriorates the bridge until its end. This study addresses the necessity of employing realistic, time-dependent fragility tools that consider the impact of routine maintenance activities, such as concrete patching and grouting, in bolstering the future resilience of bridges. The performance-based assessment in this study is conducted on existing bridges that have already suffered from past corrosion. In this research, climate change scenarios are first investigated based on future forecast models to anticipate the temperature and relative humidity changes up to the year of 2100. Subsequently, corrosion is quantified in concrete and steel using the proposed climate change scenarios. Then, nonlinear static pushover analysis is conducted to assess the drift ratio at various limit states of the bridge. Based on the pushover curves, time-based fragility analysis is conducted to assess the performance of reinforced concrete bridge columns in various environments under different corrosion levels using multiple climate change scenarios. Accordingly, maintenance-adjusted fragility tools are developed using different maintenance strategies at various intervals. The proposed temporal fragility tools serve as a benchmark for bridge engineers to evaluate the seismic performance of existing bridges in multi-hazard environments. • Novel maintenance-adjusted fragility tools are developed for bridges in multi-hazard environments. • Time-dependent incremental dynamic analysis is performed to assess seismic performance degradation over the bridge's lifespan. • Performance-based assessment is conducted on existing bridges that have suffered from past corrosion.