Seismic Performance Enhancement of RC Bridge Bents Using Advanced Retrofit Techniques

Recent seismic events have revealed an increased vulnerability of substandard reinforced concrete (RC) bridges to various damage modes, underscoring the essential need for seismic retrofitting. This study thus investigates the effectiveness of modern retrofit approaches to upgrade the seismic performance of RC bridge bents, mainly focusing on high-performance concrete jackets and buckling restrained braces. The chosen retrofit measures are intended to mitigate the curvature ductility demands of substandard RC bridge piers. The adopted retrofit approaches are verified against previous experimental results through detailed three-dimensional fiber-based modeling and implemented in a representative multi-span RC bridge in a medium seismicity region. The inelastic dynamic response of the case study bridge bents before and after retrofitting with the adopted seismic mitigation measures is assessed under different seismic scenarios. The relative effectiveness of the retrofit measures in minimizing the curvature ductility of the bridge columns is evaluated through fragility analyses. The seismic assessment results indicate that both the adopted mitigation measures are comparable in reducing the probability of damage related to bridge bents. However, the adopted measure that integrates seismic performance and cost for the buckling restrained braces is almost 40% to 80% higher than that of the other alternative under the effect of different seismic scenarios, confirming its preference among the two retrofit alternatives. This study thus offers insight into selecting effective and economical retrofit solutions for upgrading RC bridge bents, thus ensuring the bridge’s continuous functionality.