System Reliability–Based Disaster Resilience Analysis of Cable-Stayed Bridge under Tank Truck Fire Hazards

The concept of disaster resilience has emerged to describe the holistic ability of civil infrastructure systems to withstand various hazards by preventing initial disruptions, progressive failures, and critical long-term consequences. However, existing approaches often lack an integrated systems view and thus can lead to suboptimal design or policy decisions. The reliability-redundancy (β-π) analysis method has recently been proposed to promote the system reliability–based assessment of disaster resilience. This paper demonstrates the practical applicability of the β-π analysis to complex structural systems under human-made hazards, with an example of a cable-stayed bridge in South Korea, the Seohae Grand Bridge, exposed to tank truck fire hazards. First, a detailed probabilistic model of tank truck fire was developed, accounting for heat transfer mechanisms and their effects on the cables, while considering uncertainties in fire size, location, and the heat transfer model. The limit-state functions of component- and system-level failures were evaluated using a sophisticated finite-element model of the target structure, considering thermal effects on structural response and material degradation. Component and system reliability analyses required in the β-π analysis were performed efficiently through active learning of surrogate models. The causal effects of initial disruption scenarios on progressive system failures were studied in detail. The β-π analysis results identify the initial disruption scenarios for which the bridge does not have sufficient resilience for the hazard occurrence rates estimated from public information sources. The application example clearly illustrates how the β-π analysis can effectively help maintain the resilience of complex structural systems against various human-made hazards.