Seismic Fragility Assessment of Isolated Structures Based on Stochastic Response Database

Abstract

The seismic isolation system makes structures isolated from ground motions to protect the structures from seismic events. Base isolation techniques have been implemented to full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. However, the seismic performance evaluation of the isolated structure should be re-evaluated considering the effect of the seismic isolation system. It is well known that the most uncertain aspects are the earthquake and the structure itself. Therefore, the probabilistic seismic performance of isolated structures should be evaluated. This thesis proposes an alternative approach for seismic fragility assessment of isolated structures by using the stochastic response database (SRD). The concept of the SRD is defined to obtain the seismic response distributions of the isolated structure instantaneously which can reduce the computational efforts tremendously. The methodology of the seismic fragility assessment for isolated structures using the SRD is proposed, which is a highly effective technique. Also, the proposed methodology is applied to the isolated nuclear power plant. The seismic fragility assessment of the isolated nuclear power plant is successfully evaluated by taking into account of the uncertainty of the isolation system. Finally, the Seismic Probabilistic Risk Assessment (SPRA) of the isolated nuclear power plant is evaluated by combining the fragility curve and the hazard curve. Computational efforts are significantly reduced via the use of the SRD.