| 摘要 |
PURPOSE: To provide a base isolation structure body prevented from being influenced by wind shaking or the like at ordinary time, by specifying an external diameter of a hard plate, sectional area of lead, modulus of shearing elasticity of a soft plate, etc., in the base isolation structure body of sealing a columnar lead inside a compound layered body of laminating alternately the hard/soft plates between upper/lower surface plates. CONSTITUTION: A base isolation structure body, suited for a light load of a detached house or the like, is formed by sealing a columnar lead 5 inside a compound layered body of laminating alternately a hard plate 1 having rigidity and a soft plate 2 having a viscoelastic property between upper/lower surface plates 3, 4. Here are set an external diameter of the hard plate 1 to 23 to 30cm, sectional area of the lead 5 to 0.4 to 3.0% sectional area of the compound layered body, modulus of shearing elasticity of the soft plate 2 having viscoelasticity of 200% shearing distortion to 1.5 to 2.5kgf/cm<2> and tanδat 20cm deformation time of the base isolation structure body to 0.3 or more. In this way, when a large earthquake occurs, a deformation amount of the base isolation structure body is suppressed to 20cm or less, further to suppress a period of this shaking to a 2±0.2sec range.
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