Multi-Parameter Seismic Fragility Analysis of High-Speed Railway Track-Bridges: Embracing Structural and Earthquake Uncertainties

This study introduces a novel multi-parameter seismic fragility assessment approach based on blending ensemble learning, designed specifically for seismic fragility assessment of high-speed railway track-bridge (HSRTB) systems. This approach addresses the urgent need for efficient post-earthquake infrastructure evaluation and mitigation of economic impacts in quake-affected regions. By incorporating an extensive range of earthquake intensity measure parameters, the study enhances the understanding of HSRTB systems’ seismic resilience. It provides a comprehensive analysis that integrates the complexities and uncertainties of seismic motions and structural variables. A key innovation lies in utilizing the earthquake intensity measure Sa([Formula: see text]) as a primary indicator for establishing mean seismic fragility curves, demonstrating unprecedented precision with a root mean square error of approximately 0.15 compared to traditional Monte Carlo simulations. The research further reveals the critical role of HSRTB system parameter uncertainties, illustrating that neglecting these factors can lead to significant fragility misestimations, potentially causing overestimation or underestimation by as much as 0.5. The study highlights yielding displacement, span length, and pier height as critical factors impacting the seismic vulnerability of HSRTB systems, underscoring their importance in the design and assessment of resilient infrastructure.