Abstract
This paper describes isolation performance of semi-active seismic isolation system using variable damper. Recently, the relatively long period seismic waves have been observed in the various earthquakes. These seismic waves have the predominant period that is equivalent to natural period of seismic isolation structures. Therefore technology is required that supply more safety to isolation structure. A semi-active isolation system in this paper has been proposed to satisfy the requirement. Variable damper is applied to isolation system to vary damping ratio. It was confirmed by numerical analysis that this isolation system has good performance of isolation.
