Chain Reaction Failure Analysis for Cable-Stayed Bridge Considering Cable Corrosion

Cable corrosion has become a critical concern for long-span bridge structures, particularly in cable-supported systems such as suspension, cable-stayed, and tied arch bridges. Many of these bridges, constructed in the 1980s and 1990s, face increasing risks due to progressive cable deterioration. The collapse of the Nanfang'ao tied arch bridge in Taiwan (2019), attributed to corroded cables, underscores the urgent need for a deeper understanding of failure mechanisms. This study develops a numerical bridge model inspired by the Taiwan bridge collapse to examine the dynamic chain reaction failure triggered by cable corrosion. Corrosion is simulated by reducing the yield stress and fracture strain of the cables, while the initial cable rupture is modeled as an instantaneous loss of tensile force. Unlike prior studies that assume ideal cable conditions, this study considers degraded cables to simulate realistic failure propagation. The analysis reveals that in corroded conditions, a single cable rupture can propagate through sequential failures, leading to progressive collapse. This corresponds to the initial dynamic phase of progressive collapse, which we refer to as a “chain reaction failure” in this study to highlight the rapid sequential rupture of adjacent cables immediately after the first failure. Results show that the Dynamic Amplification Factor (DAF) can exceed 5.6 in corroded cables, amplifying impact forces, while the Load Redistribution Ratio (LRR) is highly sensitive to the initial rupture location. These findings highlight how corrosion-induced strength degradation in cables significantly increases structural vulnerability and emphasize the importance of proactive inspection and maintenance strategies to mitigate failure risks in aging cable-stayed bridges.