Abstract
In order to prevent a resonance on the small base isolation system using friction bearings, a bearing ball of this device is changed to a marble plate type and to a bearing ball with rubber ring. As the results by excitation experiment using seismic wave, the damping ratios of this system were increased. The natural frequency in case of the marble plate was increased. It was depending on the radius of the marble plate. However, in case of the bearing ball with rubber ring, the natural frequency was little changed. In the case that the thickness of rubber that makes contact with the spherical concaves plate is 1.0mm, the peak acceleration amplitude on the base isolation system has decreased to 40% compared to the input wave. The bearing ball with rubber ring is better than other bearings on this system.
