Construct the seismic response analysis model of an existing nuclear facility using 4SID

Abstract

Abstract The seismic response analysis model of a nuclear facility can be used to evaluate the integrity of the structure as well as the safety of humans and machines within in the event of an earthquake. This study accordingly proposed a methodology for constructing the seismic response analysis model of a nuclear facility based on observed strong motion records. First, to evaluate the seismic response characteristics of an example nuclear facility in Japan, the subspace state-space system identification [1] technique was applied to strong motion records from the 2011 off the Pacific coast of Tohoku Earthquake. The identified natural modes were then clustered using the hierarchical clustering technique. Second, a seismic response analysis model of the example facility was constructed for each cluster based on the sway–rocking model. The stiffness and damping factors for each model were calculated from the mean values of the corresponding mode characteristics. Third, the constructed models were employed for seismic response analysis using the strong motion record observed during the main shock of the 2011 Tohoku earthquake as input, and the root mean square errors between the response records and analytical results were evaluated to select the most accurate model. Finally, the selected model was validated by performing a seismic response analysis using the strong motion records from an aftershock of the 2011 Tohoku earthquake. The analytical responses showed good agreement with the records, indicating that the proposed method represents a valid approach for constructing seismic response analysis models of nuclear facilities.