A practical approach for seismic fragility analysis of building clusters based on national seismic hazard map

This is the authors' abstract. We don't add key points for this paper.

Seismic fragility analysis is well established for individual buildings, typically relying on recorded ground motions as input and refined finite-element models for structural seismic response simulation. However, its application to building clusters is constrained by the scarcity of region-specific ground motion records and the difficulty of efficiently evaluating structural seismic response for diverse building types. To address these challenges, this study proposed a practical approach that integrates the national seismic hazard map with a simplified structural model to develop recurrence period-based seismic fragility curves. Specifically, an iterative algorithm was first developed to generate stochastic ground motions at each recurrence period by matching the target response spectra specified in the national seismic hazard map. Then, a simplified structural model incorporating the Bouc-Wen-Baber-Noori (BWBN) model was developed to capture the complicated hysteretic behavior of building structures under earthquake excitations. Furthermore, the probability of the maximum inter-storey drift ratio exceeding the threshold for each damage state was calculated to characterize the structural seismic performance of each building. Moreover, the damage-state exceedance probabilities were converted into discrete probabilities of five mutually exclusive seismic performance levels, identifying the most probable seismic performance level of each building at different recurrence periods. Finally, the proposed approach was applied to three representative buildings and a building cluster including 2879 buildings in Yangjing Street, Shanghai, China. The results indicated that the proposed algorithm to generate stochastic ground motions is capable of reproducing the time-frequency nonstationary characteristics associated with different recurrence periods. The corresponding mean response spectra are in good agreement with the target response spectra specified in the national seismic hazard map. By adopting the recurrence period derived from the probabilistic seismic hazard analysis as an intermediate variable, the proposed approach eliminates the need to select a structure-specific intensity measure for seismic fragility analysis, enabling consistent seismic performance comparison of heterogeneous buildings at the regional scale.