Abstract
In this paper, the authors have developed a new type of horizontal seismic isolation system which has large effect of vibration isolation for ordinary earthquakes and suppresses the resonance of the isolation system due to long-period ground motions. This seismic isolation system is composed of coil spring and two slide rails. Further, an optimal frictional force is added to this system. The seismic isolation system adding the optimal frictional force is effective for suppressing the vibration of this system caused by short-period earthquakes and long-period earthquakes. Frictional force is used to suppress the resonance of the seismic isolation system. The trial seismic isolation table was made, and the effects of vibration suppression of the isolation table were discussed experimentally and numerically. In addition, we discussed the relation between optimal friction coefficient and maximum acceleration of the earthquake. We defined a parameter α as percentage of low frequency component in frequency response of earthquakes. As a result, it is shown that the optimal friction coefficient is in proportion to the corrected maximum acceleration of earthquake using parameter α.
