Seismic fragility analysis of steel reinforced concrete frame‐bent structures in CAP1400 nuclear power plant

SummaryThis paper evaluates the seismic performance of the frame‐bent structure of a conventional island main building in a nuclear power plant (NPP) using the CAP1400 NPP project of Rongcheng Shidaowan in Shandong Province as a case study. A 12‐pin 3‐span prototype structural model of a steel reinforced concrete (SRC) frame‐bent main building is established in ABAQUS, and its seismic fragility is analyzed. The results show that under the conditions of an 8‐degree frequent earthquake and an 8‐degree fortification earthquake, the transcendental probability under the four limit states of the structural seismic fragility matrix with Sa as intensity measure (IM) is higher than that with peak ground acceleration (PGA) as IM. Moreover, under an 8‐degree rare earthquake, the structure has completely exceeded the normal service performance level and has reached the service performance level of temporary use and repair. The seismic damage index of the structure demonstrates that the structure's seismic damage does not exceed the medium damage state under a small earthquake. However, under the action of a moderate earthquake, the seismic damage of the structure ranges from moderate to serious damage. When subjected to large earthquakes, the seismic damage of the structure is basically in a state of serious damage.