Abstract
This paper describes the effect of a rocking suppression system installed in a newly developed 3-dimensional base isolation system using a velocity reduction mechanism. This base isolation system achieved very low vertical natural frequency using the velocity reduction mechanism which is composed of a worm gear system. Vertical motion is transformed into the rotational motion by a rack-pinion system. A multiple sets of these worm gear and rack-pinion systems compose a unit of a vertical base isolation system. In this system, pinion shafts are connected to each other. Therefore, rocking motion could be suppressed effectively by the tortional rigidity of the pinion shaft.
