Incremental dynamic analysis of SRC frame-bent structures in CAP1400 NPP

Abstract

Under the earthquake, the collapse or damage of buildings would result in significant casualties and economic losses. Especially when essential lifeline projects such as nuclear power plants and thermal power plants were affected by earthquakes, they also resulted in severe consequences, such as the paralysis of urban functions, delays in post-earthquake disaster relief, and social chaos. In this paper, the conventional island steam turbine main building of the CAP1400 nuclear power plant (NPP) in Shidaowan, Shandong Province was taken as the research object, and the seismic performance of the main building structure of the SRC frame-bent was studied by using the incremental dynamic analysis (IDA) method. Firstly, the dynamic characteristics of the substructure of the steel reinforced concrete (SRC) frame-bent main building structure were obtained by experiments. Then, the prototype structure model of the main building was established and verified with the experimental results. Finally, 15 natural ground motions were selected and the corresponding torsional components were calculated. With peak ground acceleration (PGA) and Sa (T1, ξ) as IM indicators, top displacement of structure (Dt) and maximum inter-story drift ratio (θmax) as engineering demand parameters (EDP) parameters, the IDA of the structure were carried out, and the IDA curve cluster and percentile curve of the structure under multidimensional ground motion were obtained. The results show that the discreteness of the IDA curve cluster with Dt-Sa index was relatively small compared with the other three groups; the discreteness of the IDA curve cluster with Dt-PGA as the index was large. In addition, the results of the IDA conducted on the SRC frame-bent main building structure with PGA as an intensity measure (IM) parameter were deemed more conservative.