Seismic motion incoherency effects on SSSI responses of nuclear buildings

Abstract

The spatial variation of ground motion may significantly aggravate the seismic damage of large‐scale structures such as nuclear buildings. Establishing the seismic wave field with spatial features is the basis and key to seismic analysis of large‐scale complex structures. For the nuclear island buildings, which are arranged close to each other, the influence of structure–soil–structure interaction (SSSI) and incoherent motion on the structural seismic response should be considered. Taking a domestic nuclear power project as an example, the seismic response analyses under incoherent seismic motion and coherent seismic motion are carried out respectively. The seismic motion incoherency effects on the nuclear island buildings on the common raft and the adjacent seismic category I structure are explored by comparing the results of the in‐structure response spectrum (ISRS) at key elevations. The results indicate that the seismic motion incoherency does not change the trend of the response spectrum curve and the dominant frequency. Both the peak acceleration and zero‐period acceleration of ISRS are changed to some extent. Overall, seismic motion incoherency has a more significant impact on the ISRS of nuclear buildings with smaller volumes.