System Fragility Analysis of Bridges Based on Response Variables Dimensionality Reduction

Abstract

Earthquake resistance of bridge structures is an important part of ensuring the functionality of transportation network systems. The structural system of a bridge is composed of multiple components, and the damage of different components may affect the function of the bridge, while the system seismic fragility analysis provides an effective way to evaluate the overall seismic performance of the bridge. In the past, the failure probability of a system is often estimated by the correlation between components, but the complex correlation between components brings certain difficulties to the actual calculation. In this paper, an efficient, accurate and universal method of system fragility analysis is proposed. This method decouples the correlation between components from the perspective of relative damage, adopts the critical demand-to-capacity ratio as the response variable of the system, realizing the dimensionality reduction of the response variables and simplifying the system fragility analysis from high-dimensional fragility analysis to one-dimensional fragility analysis. This methodology offers a viable solution to the challenges posed by the wide estimation of fragility boundaries in the boundaries estimation method and the complexities involved in analyzing correlation of components in the joint probability method. Comparison with traditional methods indicates that the proposed method exhibits high efficiency and convenience, making it suitable for practical engineering applications in system fragility computation. The proposed method holds great potential for future applications in the field of complex bridge structure fragility analysis, large-scale regional seismic damage prediction, rapid assessment, and beyond.