VIBRATION RESTRAINT APPARATUS FOR DOUBLE FLOOR

PURPOSE:To develop excellent vibration-proofing effect for a floor slab and a double floor by simple structure that can be constructed easily, requiring less space for installation and less sophisticated means for changing spring constant. CONSTITUTION:A vibration restraint apparatus 1 is equipped with a support 3 erected over a floor slab 5 for supporting a double floor 2, a spring member 11 arranged to surround the support 3 and made capable of expanding and contracting in the axial direction of the support 3, an upper holder 8 mounted to the support 3 for holding the upper end of the spring member 11, a lower holder 18 mounted slidably on the support 3 and connected to the lower end of the spring member 11 and an additional weight 19 mounted on the lower holder 18. As vertical vibration is transmitted to the support 3, the spring member 11 moves in expansion and contraction by inertial force of the additional weight 19, and the vibration restraint apparatus 1 produces, in accordance with spring constant of the spring member 11, the vibration that acts in the direction of restraining vertical vibration of a building.