Damage performance based seismic capacity and fragility analysis of existing concrete containment structure subjected to near fault ground motions

Abstract

Containment structures fill the critical role of providing the final barrier against release of radioactive materials. Near fault earthquake pose great threaten to the function of existing containment structure. There is a growing necessity of performing a detailed seismic capacity and fragility analysis of existing containment structure. This paper presents seismic capacity and fragility analysis of existing containment structure subjected to near fault ground motions from damage performance based perspective. To capture uncertainties associated with the ground motions, incremental dynamic analysis technique is conducted, and three damage levels are proposed based on tensile damage factor provided in concrete damaged plasticity (CDP) model. Fragility curves of containment structure under minor damage, moderate damage and severe damage is obtained with MATLAB optimization program. Results of this study reveal that tensile damage of containment structure within 8 m of the bottom of the containment is most vulnerable locations in containment structure. The bottom location of the containment structure is dominant by bending cracks, and the lower location of the containment structure (except the bottom location) is governed by diagonal shear cracks. With the increase of ground motion intensity, shear behavior of the containment structure becomes more obvious.The HCLPF seismic capacity of this containment structure under minor damage, moderate damage and severe damage is 0.452 g, 0.631 g and 0.790 g, respectively.