Abstract
On March 11^<th>, 2011, the Pacific coast of Tohoku Earthquake caused damages to Industrial facilities with a seismically isolated structure. For that reason, in order to improve the safety evaluation methods on the current isolation systems, a new estimation using higher earthquake standards inputs are required. This paper deals with the earthquake response analysis of the seismic isolation equipment for nuclear power plants using laminated rubber bearings. The high amplitude of this new input shows a hardening property of the rubber bearing in the horizontal direction and a softening property in the vertical direction. So far, the horizontal and vertical directions analyses are considered independently, but in reality, there is a mutual influence between the horizontal and vertical behavior. Consequently, in this paper, the analysis of the coupling between those two directions will be carried out. Then, after comparing these two approaches, the utility of considering this dependency will be estimated.
