JP4600144B2 - Complex seismic isolation bearing - Google Patents

Description

  The present invention relates to a composite seismic isolation bearing, and more particularly to a composite seismic isolation bearing that accelerates the recovery of distortion after deformation and improves the damping effect in accordance with the speed of vibration.

  The center of a rubber laminate in which multiple rubber layers and steel plates are alternately laminated in the vertical direction as a seismic isolation bearing to minimize damage caused by shaking or collapse of structures such as buildings during an earthquake. 2. Description of the Related Art An elastic bearing body is known in which a lead rod is inserted into a hole provided in a metal plate to provide a damping function by plastic deformation. However, the elastic bearing body having such a configuration has a drawback that the steel plate in the rubber laminate damages the lead bar during a large earthquake and is easily broken by repeated deformation.

From such a viewpoint, there are some proposals in which a viscous body is filled in a hole provided in the center of the rubber laminate to provide a damping function against horizontal vibration (for example, Patent Documents 1 and 2). reference). However, in any proposal, the strain recovery function after deformation cannot be obtained sufficiently and the speed dependence of the damping characteristics is low, so that it can still be satisfied as a seismic isolation bearing for a large earthquake. It was not a thing.
JP-A-4-337130 JP-A-5-202636

  An object of the present invention is to solve the above-mentioned problems, and to provide a composite seismic isolation support body that accelerates recovery of distortion after deformation and improves the damping effect according to the speed of vibration. is there.

In order to achieve the above object, the composite seismic isolation bearing of the present invention comprises a rubber laminate in which a plurality of rubber layers and steel plates are alternately laminated in the vertical direction and a viscoelastic rubber arranged in parallel on the same plane. In addition, in the composite seismic isolation bearing body in which the upper and lower surfaces of the rubber laminate and the viscoelastic rubber are sandwiched by a bearing plate, the equivalent viscous damping constant of the rubber layer constituting the rubber laminate is 0.03 to 0. 05 , rubber having an equivalent viscosity damping constant of 0.3 to 0.5 is used for the viscoelastic rubber, and the total volume of the viscoelastic rubber occupies the total volume of the rubber laminate. The gist is that the ratio is 120% or more and 200% or less .

According to this invention, since the seismic isolation bearing body has the rubber laminate and the viscoelastic rubber arranged in parallel on the same plane, a high spring constant is provided in the vertical direction and a low spring constant is provided in the horizontal direction. Therefore, the vibration of the building due to the earthquake can be efficiently absorbed. Further, the equivalent viscous damping constant of the rubber constituting the rubber laminate is 0.03 to 0.05 , the equivalent viscous damping constant of the viscoelastic rubber is 0.3 to 0.5 , and the total volume of the viscoelastic rubber is Occupies 120% or more and 200% or less of the total volume of the rubber laminate, thereby speeding up the recovery of distortion after deformation and increasing the speed dependency of the damping characteristics, depending on the vibration speed. The attenuation effect can be improved.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a cross-sectional view showing an example of a composite seismic isolation bearing according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line XX of FIG.

1 and 2, the composite seismic isolation bearing body 1 includes a rubber laminate 4 and a viscoelastic rubber 5 in which a plurality of rubber layers 2 and steel plates 3 are alternately laminated in the vertical direction arranged in parallel on the same plane. At the same time, the upper and lower surfaces of the rubber laminate 4 and the viscoelastic rubber 5 are sandwiched between support plates 6a and 6b. In the figure, reference numeral 7 denotes a cover rubber layer covering the periphery of the viscoelastic rubber 5. The rubber layer 2 constituting the rubber laminate 4 uses a rubber having an equivalent viscous damping constant of 0.03 to 0.05 , and the viscoelastic rubber 5 has an equivalent viscous damping constant of 0.3 to 0.5. Of rubber is used.

Thus, since the rubber laminate 4 and the viscoelastic rubber 5 are arranged in parallel on the same plane, a high spring constant is provided in the longitudinal direction of the composite seismic isolation bearing 1 by the rubber laminate 4, and in the lateral direction. Is provided with a low spring constant by the viscoelastic rubber 5, and can efficiently absorb the vibration of the building due to the earthquake. Furthermore, since the equivalent viscous damping constant of the rubber constituting the rubber laminate 4 is 0.03 to 0.05 and the equivalent viscous damping constant of the viscoelastic rubber 5 is 0.3 to 0.5 , In addition to speeding up the recovery, the speed dependency of the damping characteristic can be increased, and the damping effect can be improved according to the speed of vibration.

  In the present invention, the equivalent viscous damping constant of rubber refers to a damping constant obtained by replacing the nonlinear restoring force characteristic of rubber with an equivalent linear restoring force and damping. This damping constant is disclosed in the applicant's disclosure. It can be obtained in the same manner as the shear characteristic value (Heq) described in JP-A-2002-20546, and the vertical load on the rubber laminate and the viscoelastic rubber is 10 MPa and 0 MPa, respectively, with a shear tester. Equivalent viscous damping constant obtained with a frequency of 0.5 Hz and 100% strain.

  If the equivalent viscosity damping constant of the rubber constituting the rubber laminate 4 is more than 0.05, it is difficult to obtain mechanical properties and temperature dependence as the rubber laminate. Further, if the equivalent viscous damping constant of the viscoelastic rubber 5 is less than 0.3, it is difficult to sufficiently secure the damping property as a composite seismic isolation bearing.

  1 and 2, the rubber laminated body 4 formed in a cylindrical shape is arranged at the center of the composite seismic isolation bearing 1, and the viscoelastic rubber 5 is arranged around the rubber laminated body 4. The configuration of the rubber laminate 4 and the arrangement relationship with the viscoelastic rubber 5 are not limited thereto, and the viscoelastic rubber 5 is arranged in the center of the composite seismic isolation bearing 1, and the rubber laminate is arranged around the viscoelastic rubber 5. 4 can be arranged.

In the composite seismic isolation bearing 1 of the present invention, the proportion of the viscoelastic rubber 5 in the composite seismic isolation bearing 1 dominates the deformation strain recovery speed of the composite seismic isolation bearing 1 and the speed dependence of the damping characteristics. Will do. Therefore, in this invention, the total volume of the viscoelastic rubber 5 is a proportion of 120% or more relative to the total volume of the rubber laminate 4 is adjusted to be 200% or less.

  In the present invention, natural rubber may be used for the rubber layer constituting the rubber laminate 4 described above, and carbon black-filled rubber based on thermoplastic rubber or diene rubber may be used for the viscoelastic rubber 5. The cover rubber layer 7 may be made of chloroprene rubber having excellent weather resistance and wear resistance.

As described above, the composite seismic isolation bearing according to the present invention includes a rubber laminate and a viscoelastic rubber arranged in parallel on the same plane, and the rubber and the viscoelastic rubber constituting the rubber laminate. By specifying the equivalent viscous damping constant of each and specifying the ratio of the total volume of the viscoelastic rubber to the total volume of the rubber laminate , the strain recovery after deformation is accelerated and the speed dependence of the damping characteristics Since the damping effect is improved according to the speed of vibration, it can be preferably applied as a seismic isolation support for a building against a large earthquake.

It is sectional drawing which shows an example of the composite seismic isolation bearing body by embodiment of this invention. It is XX arrow sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite seismic isolation bearing body 2 Rubber layer 3 Steel plate 4 Rubber laminated body 5 Viscoelastic rubber 6a, 6b Bearing plate 7 Cover rubber layer

Claims (2)

A rubber laminate in which a plurality of rubber layers and steel plates are alternately laminated in the vertical direction and a viscoelastic rubber are arranged in parallel on the same plane, and upper and lower surfaces of the rubber laminate and the viscoelastic rubber are arranged In a composite seismic isolation bearing sandwiched between bearing plates,
The rubber layer equivalent viscous damping constant constituting a rubber laminate using the rubber 0.03-0.05, equivalent viscous damping constant to the viscoelastic rubber to use rubber 0.3 to 0.5 In addition, a composite seismic isolation bearing in which the ratio of the total volume of the viscoelastic rubber to the total volume of the rubber laminate is 120% or more and 200% or less . The composite seismic isolation bearing according to claim 1, wherein the rubber layer constituting the rubber laminate is made of natural rubber, and the viscoelastic rubber is made of carbon black-filled rubber based on thermoplastic rubber or diene rubber.

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