A framework for performance-based assessment in post-earthquake fire: Methodology and case study

Post-earthquake fire (PEF) is a threatening hazard triggered immediately after an earthquake, resulting in extensive destruction and casualties. It is important to evaluate structural performance in this typical cascading hazard to develop mitigation strategies and improve multi-hazard resilience. However, existing research mainly focuses on the structural response in PEF scenarios, while there is still a lack of knowledge on other critical parts of performance evaluation. In contrast, there has been a well-established methodology for performance-based assessment in earthquake engineering (PBEE), which can be regarded as the basis for extension to PEF sce-narios. Based on that, a comprehensive framework has been proposed in this study for performance-based assessment in post-earthquake fire engineering (PB-PEF-E). To demonstrate the feasibility of the proposed methodology, an illustrative example of a realistic multi-storey steel frame is presented with specific details. The overall procedure considering the hazard, structure, damage, and loss domains is utilised for step-by-step PEF performance evaluation. Firstly, a dual-cause PEF ignition model is used to capture the probabilistic causation among the earthquake-fire sequence, considering ignition related to utility system damage and ignitable contents overturning. Then, structural demands with respect to both earthquake and fire intensities are obtained by a series of nonlinear analyses via numerical modelling, and uncertainties that significantly influence the responses are included. Finally, the structural capacity in different performance levels is estimated with PEF fragility development, and the consequences are measured using quantitative indicators for decision-making. The pro-posed methodology provides important benefits in evaluating the performance of alternative solutions thus facilitating robust decision-making in PEF scenarios, and it can be further extended to performance-based assessment in other multi-hazard scenarios with cascading effects.