| 摘要 |
PURPOSE: To facilitate the prevention of traffic vibration and wind lateral swinging and the display of base isolation effect in the case of an earthquake by designing the natural frequency of a base isolation device to be less than a specified value. CONSTITUTION: As a base isolation device whose strain quantity at the time of horizontal 100% shearing strain exceeds 50mm, plural layers of elastic bodies 1, 2, 5, 6 having viscous elastic property are laminated between upper and lower face plates 7,. In this case, when the lateral spring constant of the base isolation device is designated by KH, and loading mass onto a base device is designated by M, horizontal natural frequency fH computed by fH=(1/2π) (KH/M)<1/2> is set up so as to be O.7Hz<=fH<=1.5Hz at the time of inputting of vibration being 2mm in horizontal amplitude and 1.4Hz<=fH<=2.2Hz at the time of inputting of vibration being 10mm in horizontal amplitude. In addition, the horizontal natural frequency is designed so as to be 0.1Hz<=fH<=0.8Hz at the time of inputting of vibration having horizontal amplitude equal to the 100%. strain of the elastic bodies 1, 2,5, 6 having viscous elastic property. The effects of base isolation and earthquake prevention can be displayed by setting up the natural frequency in this way. |
