Seismic fragility analysis of nuclear shield building based on zoned structure

•Focus on the seismic fragility analysis of nuclear power plants with zoned structure.•Investigation on the IDA is analyzed for the response of each zone under the action of different seismic intensities.•Analysis of detailed seismic fragility analysis is carried out for each zone based on the IDA results. This paper focuses on the seismic fragility analysis of nuclear shield building. Combined with the characteristics of structural catastrophic damage, it is divided into 9 zones (RS-1, RS-2, RC-1 ∼ RC-7) along the height direction. An incremental dynamic analysis of 200 working conditions (PGA 0.3 g-2.1 g with an interval of 0.2 g) is carried out on the dynamic catastrophic behavior of the nuclear shield building. The seismic fragility analysis of nuclear shield building based on zoned and overall structure idea is compared and studied. The results show that the damage and failure of both the overall structure and the zoned structure are deepened as the PGA increases. In the light damage state and extended damage state (especially the latter), the overall structure has a lower failure probability of the tension and compression damage than the zoned structure (such as RC-1 ∼ RC-4 and RC-7). Based on the zoned structure, the seismic fragility analysis demonstrates that the nuclear shield building with shear failure characteristics has different damage state for each zone, which can effectively show the failure mode and provide a more accurate assessment basis for the damage state and the failure mode of such structures.