Dynamic characteristics of base-isolated reactor building subjected to various types of travelling waves

In the isolation systems, laminated elastomer bearing pads (LEBPs) are widely used to decrease the responses of structure by lengthening the natural period. Most of the devices having LEBPs are effectively operated only for the horizontal motion, but they are ineffective for the vertical or rocking motions. There have been few studies on the responses of the structure with the base isolation systems subjected to the motion with phase difference. This paper describes the earthquake response analysis of a typical BWR MARK-II type reactor building supported by the laminated elastomer pads, which is subjected to obliquely incident SH and SV waves. Dynamic characteristics of the base-isolated reactor building and base isolation device are investigated. In order to solve this problem, the frequency domain analyses are carried out for a linear system using the substructure technique where the soil system is analyzed by boundary element method and the structure is modeled by a spring-mass system. Since the sliding characteristics are greatly influenced by variation of axial forces when the structure is subjected to SV wave, nonlinear analyses are further conducted for a reactor building supported by sliding laminated elastomer bearing pads (SLEBPs)