PURPOSE: To mildly suppress three-dimensional vibrations by installing tensile springs and dampers radially in a horizontal plane and also installing compres sive air spring and damper in the vertical direction centering on a leg part bearing a base isolation floor with mobility in all horizontal directions and in the vertical direction.
CONSTITUTION: The bearing part 1 of a steel framing 2 for a base isolation floor is borne by a steel plate 18 having steel ball 17 laid on a floor slab 3 while mobility is reserved in all horizontal directions. Radially in a horizontal plane, tensile springs 12 in pairs are arranged and fixed to the slab 3 with the aid of a chain 15 etc., and also a viscousity damper 4 in gutter form is installed. Further, compressive air spring 40 and viscosity damper 14 are installed in the vertical direction. Therein a comparatively small vibration is absorbed by the springs, while a larger vibration is damped by the dampers. Thereby three-dimensional vibrations can be suppressed gently.
YAMAMOTO MASAYUKI
HARA MAKOTO
YAMAGUCHI NOBUO
KAWAGUCHI SUMIO
OILES INDUSTRY CO LTD