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<p>Prefabricated concrete frame structures (PCFSs) have been promoted and widely used in the construction industry due to the advantages of efficient construction, energy saving and environmental protection, etc. PCFSs may be exposed to the combined effects of multiple hazards, including earthquakes and blasts during their service life. In this paper, the damage evolution law and failure mechanism of the PCFS under the coupled effects of earthquake and blast are studied. The investigation focuses on a reference three-story, single-span PCFS (plan dimension 6&#xa0;m × 3&#xa0;m, total height 9&#xa0;m) with specified member sizes, a simplified exterior cladding representation, and an equivalent cast-in-place joint idealization. A fragility analysis framework is proposed to evaluate the vulnerability of the PCFS under multiple loads. Firstly, the fragility of PCFS was analyzed under the action of an earthquake or blast using the single-hazard fragility analysis method. Secondly, the dynamic response under multi-hazard action was analyzed by randomly combining the hazard intensities of peak ground acceleration (<i>PGA</i>) and scaled distance (<i>Z</i>). Finally, the combined fragility analysis method considers the sequential impacts of earthquake and blast to efficiently assess the failure probability of the ultimate damage state under various combinations of hazard intensities. The results show that the failure probability of the single-span PCFS increases with the increase of earthquake and blast intensities under single-hazard action. The cumulative damage of the structure caused by earthquake action significantly exacerbates the damage effect of the secondary hazards (blast) compared with the single-hazard and multi-hazard fragility curves. In addition, the elevated earthquake intensity significantly amplifies the damage effects of the secondary blast hazard on the frame structure. For a fixed scaled distance of <i>Z</i> = 0.24&#xa0;m/kg<sup>1/3</sup>, the sequential earthquake-blast scenario with <i>PGA</i> = 0.4&#xa0;g increases the exceedance probabilities of the I-II, II-III, and III-IV limit states by approximately 6.98, 46.72, and 9.35% points, respectively, compared with the blast-only scenario with no preceding earthquake, this exacerbation effect is particularly evident in the moderate to severe damage interval. Within the scope of this reference configuration, the study provides a transferable fragility analysis workflow and quantitative references for the multi-hazard assessment and design of similar prefabricated concrete frame structures.</p>

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Multi-hazard fragility analysis of a single-span prefabricated concrete frame structure under sequential earthquake and blast loading

  • 期刊论文

  • 发表日期：

    2026年5月13日

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  • Chunfeng Zhao,
  • Yingquan Liu,
  • Yingjie Chen,
  • Zunwang Zhu

摘要

Prefabricated concrete frame structures (PCFSs) have been promoted and widely used in the construction industry due to the advantages of efficient construction, energy saving and environmental protection, etc. PCFSs may be exposed to the combined effects of multiple hazards, including earthquakes and blasts during their service life. In this paper, the damage evolution law and failure mechanism of the PCFS under the coupled effects of earthquake and blast are studied. The investigation focuses on a reference three-story, single-span PCFS (plan dimension 6 m × 3 m, total height 9 m) with specified member sizes, a simplified exterior cladding representation, and an equivalent cast-in-place joint idealization. A fragility analysis framework is proposed to evaluate the vulnerability of the PCFS under multiple loads. Firstly, the fragility of PCFS was analyzed under the action of an earthquake or blast using the single-hazard fragility analysis method. Secondly, the dynamic response under multi-hazard action was analyzed by randomly combining the hazard intensities of peak ground acceleration (PGA) and scaled distance (Z). Finally, the combined fragility analysis method considers the sequential impacts of earthquake and blast to efficiently assess the failure probability of the ultimate damage state under various combinations of hazard intensities. The results show that the failure probability of the single-span PCFS increases with the increase of earthquake and blast intensities under single-hazard action. The cumulative damage of the structure caused by earthquake action significantly exacerbates the damage effect of the secondary hazards (blast) compared with the single-hazard and multi-hazard fragility curves. In addition, the elevated earthquake intensity significantly amplifies the damage effects of the secondary blast hazard on the frame structure. For a fixed scaled distance of Z = 0.24 m/kg1/3, the sequential earthquake-blast scenario with PGA = 0.4 g increases the exceedance probabilities of the I-II, II-III, and III-IV limit states by approximately 6.98, 46.72, and 9.35% points, respectively, compared with the blast-only scenario with no preceding earthquake, this exacerbation effect is particularly evident in the moderate to severe damage interval. Within the scope of this reference configuration, the study provides a transferable fragility analysis workflow and quantitative references for the multi-hazard assessment and design of similar prefabricated concrete frame structures.