Seismic fragility and resilience assessment of large-span cable-stayed bridges under multi-support ground motions with non-Gaussian characteristics

Seismic fragility analysis and resilience assessment of large-span cable-stayed bridge structures are critical for evaluating their seismic performance. However, there is a scarcity of research on the effects of multi-support ground motions and their non-Gaussian characteristics on seismic fragility and resilience. This paper aims to addresses this issue. Initially, random ground motions with spatial variability and non-Gaussian characteristics are simulated using the Spectral Representation Method (SRM) and the Unified Hermite Polynomial Model (UHPM). Subsequently, the Fractional Exponential Moments-based Maximum Entropy Method (FEM-MEM) and the Adaptive Gaussian Mixture Model (AGMM) are employed for seismic reliability-based fragility analysis, overcoming the shortcomings of conventional lognormal assumption. Component- and system-level fragility analyses are conducted sequentially, followed by seismic resilience assessment of bridge structures based on the results of system-level fragility analysis. A numerical example is presented to validate the proposed method. Computational results indicate that: (1) The proposed method offers higher accuracy and broader applicability for seismic fragility analysis of large-span cable-stayed bridge structures compared to traditional assumptions. (2) The non-Gaussian characteristics of ground motions may significantly impact the seismic fragility analysis and resilience assessment of large-span bridge structures.