Seismic energy dissipation and system fragility analysis of continuous reinforced concrete highway bridges

Abstract

The seismic resilience of bridge infrastructure is critical to ensuring the continued functionality of transportation networks during earthquakes. Traditional force- and displacement-based design approaches assess structural performance based on peak response measures. In contrast, energy-based seismic assessment offers a unified approach that inherently aptures both force and deformation demands. This study examines component-level seismic energy dissipation and its impact on the global system fragility of multi-span reinforced concrete (RC) bridges. A high-fidelity finite element model was developed, and extensive nonlinear time-history analyses were conducted using a suite of real ground motion records. The distribution of hysteretic and damping energy across critical components, including columns, bearings, abutments, and shear keys, was quantified. The results indicate that hysteretic energy dissipation in bearings predominantly governs the seismic response, while damping energy remains relatively stable, governed by the structural mass and bearing properties. Component and system fragility curves reveal that components exhibiting higher energy dissipation drive system fragility. These findings advance the understanding of energy dissipation mechanisms and aid into retrofit prioritization strategies to enhance bridge resilience.