Study on Ultimate Behavior of Base-Isolated Layer in Nuclear Facility for Cliff-Edges Effect

This study evaluates the ultimate behavior of base-isolated layer in nuclear facility in condition with high surface pressure and huge shear strain of laminated type base isolation device as one of Cliff-Edge effects of safety evaluation by experimental and analytical examination. As the first step of the study, the dynamic properties of laminated base isolation devices were investigated from several loading tests, and then analytical model of the device with strong nonlinearity was examined based on the results of loading tests. Besides, the urethane elastomer was applied to the device that has been newly developed as a base isolation material instead of rubber material. This material has unique characteristics compared with rubber material such as a simple and easy molding, an excellent dynamic property in small deformation, an adjustment of mechanical characteristic by material combination design and so on. In this paper, the evaluation of ultimate behavior of urethane isolation device and the validation of analytical method using finite element method are summarized.