JP2012145196A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation device in which a damping property by a damping member can be improved by enhancing constraint force for the damping member.SOLUTION: In the base isolation device 1 in which a laminated body 4 composed by alternately laminating a rigid plate 41 having rigidity and an elastic plate 40 having elasticity is disposed between a pair of flange plates 2, 3, a bore part 10 penetrating the laminated body 4 in the lamination direction is formed, and the damping member 5 for damping vibration is housed inside the bore part 10, a high elastic part 40B is provided which is annularly disposed on the radial outer side of the damping member 5, disposed on the inner circumferential side of a body part 40A of the elastic plate 40, and has a higher shearing elasticity than an elastic material of the body part 40A, in an inner circumferential portion of the elastic plate 40.

Description

  The present invention relates to a seismic isolation device in which a damping material is provided in a laminated body.

  As this type of seismic isolation device, there has been conventionally known a seismic isolation device in which a lead plug (attenuating material) is provided through a central portion of a laminated body as shown in Patent Document 1, for example. More specifically, the laminated body described above has a configuration in which an elastic plate made of rubber or the like and a rigid plate made of steel plate or the like are alternately laminated, and is interposed between a pair of flange plates respectively arranged on both sides in the lamination direction. Has been. Further, the seismic isolation device is formed with a hole penetrating in the stacking direction of the laminate, and a lead plug is accommodated inside the hole. The lead plug is a damper member that attenuates vibration, and is press-fitted inside the hole, for example. Further, caps (plug bodies) are respectively fitted to both end portions in the axial direction of the hole portions, and both end surfaces of the lead plug are pressed by the caps.

  The seismic isolation device having the above-described structure has a lower structure by fixing the lower flange plate of the pair of flange plates to the lower structure such as the foundation and fixing the upper flange plate to the upper structure of the building or the like. And the upper structure. According to this seismic isolation device, vibration energy can be absorbed by the damping material being plastically deformed at the time of shear deformation of the laminate, and vibration transmitted to the superstructure can be attenuated.

  Conventionally, as described in, for example, Patent Document 2 below, in a seismic isolation device of a type that does not have a damping material, a configuration in which the elastic plate is made of a plurality of elastic materials having different elastic moduli is known. Yes. More specifically, this seismic isolation device is made of an elastic material having a lower shear elastic modulus than the elastic material of the main body portion (high elastic modulus rubber portion) of the elastic plate on the outer peripheral portion of the elastic plate, or the outer peripheral portion and the inner peripheral portion. The low elastic part (the outer peripheral side low elastic part, the inner peripheral side low elastic part) is provided.

JP 2009-115176 A JP 2000-74141 A

  By the way, in the above-described seismic isolation device, a vertical load acts on the laminated body through the upper flange plate due to the weight of the upper structure, etc., but in the above-described conventional seismic isolation device having a damping material, the elastic plate is entirely formed. Since it consists of the same elastic material over the whole, the vertical load share rate of an elastic board becomes equal over the whole. When a vertical load acts on the laminated body in this way, pressure (hydrostatic pressure) acts on the damping material from the elastic plate due to the incompressibility of the elastic plate made of an elastic material, thereby restraining the damping material. The restraining force with respect to the damping material increases as the pressure increases, and the damping property with the damping material improves as the restraining force with respect to the damping material increases.

  Then, an object of this invention is to provide the seismic isolation apparatus which can raise the restraining force with respect to a damping material and can improve the damping property by a damping material.

  The seismic isolation device according to the present invention includes a laminate formed by alternately laminating a rigid plate having rigidity and an elastic plate having elasticity between a pair of flange plates, and penetrates the laminate in the laminating direction. In the seismic isolation device in which a hole is formed, and a damping material for damping vibration is accommodated inside the hole, the elastic plate is annularly provided on the inner peripheral portion of the elastic plate and radially outward of the damping material. And a high elastic portion made of an elastic material having a shear modulus higher than that of the elastic material of the main body portion and provided on the inner peripheral side of the main body portion of the elastic plate.

  With such a feature, since a high elastic portion made of a high elastic material is provided on the inner peripheral portion of the elastic plate, a region having high vertical rigidity is formed on the inner peripheral portion of the elastic plate. In the region where the vertical rigidity is high, the load factor of the vertical load is higher than that in a region where the vertical rigidity is lower than that. As a result, when a vertical load is applied to the laminate via the flange plate, the pressure acting on the damping material increases, and the restraining force on the damping material is increased.

Further, in the seismic isolation device according to the present invention, a radial width dimension of the highly elastic portion is not less than a radial dimension of the damping material and not more than ½ of a radial width dimension of the elastic plate. Preferably there is.
Thereby, the vertical load burden rate of the inner peripheral part around a damping material becomes high remarkably, As a result, the pressure with respect to a damping material increases more and the restraint force with respect to a damping material is raised.

  According to the seismic isolation device of the present invention, as described above, the pressure on the damping material increases and the restraining force on the damping material is increased, so that the damping performance by the damping material can be improved.

It is a longitudinal cross-sectional view of the seismic isolation apparatus for demonstrating embodiment of this invention. It is a cross-sectional view between AA shown in FIG.

  Hereinafter, embodiments of the seismic isolation device according to the present invention will be described with reference to the drawings.

The seismic isolation device 1 shown in FIG. 1 is interposed between a lower structure (not shown) such as a foundation and an upper structure (not shown) such as a building body, and the upper structure can be moved horizontally relative to the lower structure. It is a device to support. As shown in FIG. 1, as a schematic configuration of the seismic isolation device 1, a pair of flange plates (a lower flange plate 2 and an upper flange plate 3) that are disposed facing each other vertically, and a pair of flange plates 2 and 3. And a plug 5 (attenuating material according to the present invention) penetrating through the laminate 4.
1 is a central axis line of the stacked body 4 extending in the stacking direction of the stacked body 4, and is hereinafter referred to as an “axis O”. A direction along the axis O is referred to as an “axial direction”, a direction orthogonal to the axis O is referred to as a “radial direction”, and a direction around the axis O is referred to as a “circumferential direction”.

  The lower flange plate 2 is a fixing member fixed to the lower structure, and the upper flange plate 3 is a fixing member fixed to the upper structure. The lower flange plate 2 and the upper flange plate 3 are rigid hard plates having a circular shape in plan view, and are made of, for example, a steel plate. The lower flange plate 2 and the upper flange plate 3 are each formed to have a larger diameter than the cross-sectional shape of the laminate 4, and the outer peripheral portions of the lower flange plate 2 and the upper flange plate 3 extend over the entire circumference. The laminated body 4 protrudes outward in the radial direction. Further, a plurality of bolt holes (not shown) are formed in the outer peripheral portions of the lower flange plate 2 and the upper flange plate 3 at intervals in the circumferential direction. Fixed to each.

  The laminated body 4 is a columnar body in which elastic plates 40 having elasticity and rigid plates 41 having rigidity are alternately laminated, and is a shear deformable portion capable of shear deformation in the horizontal direction. The plurality of elastic plates 40 and the rigid plates 41 are each formed in a circular shape in plan view, and the laminate 4 is formed in a substantially cylindrical shape extending in the axial direction. In addition, a covering portion 42 that covers the outer periphery of the elastic plate 40 and the rigid plate 41 over the entire periphery is provided on the outer peripheral surface portion of the laminate 4.

The plurality of rigid plates 41 are, for example, hard plates made of steel plates, and are disposed in parallel with the lower flange plate 2 and the upper flange plate 3.
Note that the rigid plate 41, the lower flange plate 2, and the upper flange plate 3 described above may be other than a steel plate, for example, a plate material made of hard resin.

The elastic plate 40 is a soft plate made of an elastic material that can be elastically deformed, and is interposed between the rigid plates 41 and 41 and between the rigid plate 41 and the flange plates 2 and 3.
The covering portion 42 is made of an elastic material that can be elastically deformed, and is formed integrally with the elastic plate 40. More specifically, the elastic plate 40 and the covering portion 42 are each made of vulcanized rubber, and the unvulcanized elastic plate 40 and the covering portion 42 are vulcanized together with the plurality of rigid plates 41 and the flange plates 2 and 3 described above. Thus, the elastic plate 40 and the covering portion 42 are bonded to the plurality of rigid plates 41 and the flange plates 2 and 3 by vulcanization.
The elastic plate 40 and the covering portion 42 described above may be other than rubber, and may be formed of, for example, a soft resin.

  Further, the lower flange plate 2, the upper flange plate 3, and the laminated body 4 are formed with a hole 10 extending in the axial direction. The hole 10 is a circular hole in plan view that accommodates the plug 5, is disposed at the center position of the stacked body 4, and is formed coaxially with the stacked body 4 with the axis O as a common axis. The hole 10 is a through hole penetrating in the axial direction. That is, a circular hole communicating with each other is formed in each central portion of the lower flange plate 2, the upper flange plate 3, the elastic plate 40, and the rigid plate 41, and the hole portion 10 is formed by these circular holes. Has been. In addition, the opening edge part of the axial direction both sides of the hole part 10 is expanded in the substantially T shape in the longitudinal cross-sectional view.

  Moreover, the above-mentioned elastic board 40 consists of two types of elastic materials from which a shear elastic modulus differs, as shown in FIG. More specifically, a high elastic portion 40B made of an elastic material having a higher shear elastic modulus than the elastic material of the main body portion 40A of the elastic plate 40 is provided on the inner peripheral portion of the elastic plate 40. In other words, the elastic plate 40 includes a main body portion 40A having an annular shape in plan view, and a highly elastic portion 40B disposed on the inner peripheral side (radially inner side) of the main body portion 40A.

  The main body portion 40A is a portion constituting the outer peripheral portion and the radial intermediate portion of the elastic plate 40. The main body portion 40A is formed in an annular shape in plan view with the axis O as the central axis, and the outer edge and inner edge of the main body portion 40A are each formed in a circular shape in plan view. The shear modulus of the main body 40A is, for example, about 0.4 to 0.6 MPa. The “shear elastic modulus” referred to here is the elasticity when shear deformation of 100% is applied, that is, when the laminate 4 is shear-deformed by the total thickness dimension of the plurality of elastic plates 40. Rate.

  The highly elastic portion 40 </ b> B is a portion constituting the inner peripheral portion of the elastic plate 40. This highly elastic portion 40B is formed in an annular shape in plan view with the axis O as the central axis, and is formed over the entire circumference along the inner edge of the main body portion 40A and at the outer peripheral side (radial direction) of the plug 5 The outer circumference is provided around the entire circumference. Further, the high elastic portion 40B is integrated with the main body portion 40A by vulcanizing together with the main body portion 40A, and the outer edge of the high elastic portion 40B is integrated over the entire circumference with respect to the inner edge of the main body portion 40A. It is joined to.

  The above-described high elastic portion 40B preferably has a shear elastic modulus of 1.5 to 2.0 times that of the main body portion 40A. This is because the high elastic portion 40B has a shear elastic modulus of 1.5 or more of the shear elastic modulus of the main body portion 40A, thereby effectively increasing the vertical load share of the high elastic portion 40B. By making the shear modulus of the elastic portion 40B 2.0 times or less than the shear modulus of the main body portion 40A, stress does not become discontinuous at the boundary between the high elastic portion 40B and the main body portion 40A, and stress concentration is prevented. This is because it is possible to prevent bending deformation of the flange plates 2 and 3 due to an excessively high vertical load ratio.

  Further, the radial width dimension w1 of the high elastic portion 40B is equal to or larger than the radial dimension r of the plug 5, and is equal to or smaller than ½ of the radial width dimension W of the entire elastic plate 40. That is, the radial width w1 of the highly elastic portion 40B is smaller than the radial width w2 of the main body portion 40A, and the outer edge of the highly elastic portion 40B is the radial center line of the entire elastic plate 40. It is located radially inward from L (a position that is half the width dimension W).

  As shown in FIG. 1, a plug 5 is accommodated inside the hole 10 described above. The end surfaces on both sides in the axial direction of the plug 5 are respectively held by cap bodies 7 and 7 fitted to the opening ends on the both sides in the axial direction of the hole portion 10, whereby the axial position of the plug 5 is maintained. Has been.

The plug 5 is a damper member that absorbs vibration energy by plastic deformation at the time of shear deformation of the laminate 4, and is made of, for example, a cylindrical lead plug. More specifically, the plug 5 is formed to have the same diameter as the hole 10 or a slightly larger diameter than the hole 10, and is press-fitted from either one end of the hole 10 so that a gap is formed inside the hole 10. It is completely filled. The length dimension (axial dimension) of the plug 5 is larger than the height dimension (axial dimension) of the stacked body 4, and the upper end surface of the plug 5 is located above the upper end surface of the stacked body 4. The lower end surface of 5 is located below the lower end surface of the laminate 4. That is, the plug 5 is filled over the entire length of the laminated body 4 and both ends are inserted into the holes of the lower flange plate 2 and the upper flange plate 3, respectively.
Note that the plug 5 described above may be other than a lead plug, and may be a member made of another metal such as tin or an alloy. Further, the plug 5 described above may be a member other than a metal member, for example, an elastomer member obtained by mixing iron powder or the like with rubber.

  The cap body 7 is a plug body that plugs the opening end portion of the hole 10 and is fixed to the lower flange plate 2 and the upper flange plate 3 by bolt fastening, welding, or the like.

  According to the seismic isolation device 1 having the above-described configuration, when the above-described seismic isolation device 1 is interposed between a lower structure (not shown) and an upper structure (not shown), the upper structure supported by the seismic isolation device 1 The natural period of the vibration system becomes longer, and the stress that the superstructure receives during, for example, an earthquake is relaxed. Specifically, when the lower structure vibrates due to an earthquake or the like, the laminate 4 undergoes shear deformation in the horizontal direction. Thereby, the vibration transmitted to the superstructure is reduced.

  Further, the plug 5 is plastically deformed with the shear deformation of the laminate 4 described above. Thereby, vibration energy is absorbed, and vibration transmitted to the superstructure is attenuated. This damping property increases as the restraining force of the plug 5 increases. As the restraining force of the plug 5 increases, the pressure (hydrostatic pressure) on the plug 5 increases as the vertical load ratio of the inner peripheral portion around the plug 5 increases. Become higher. Here, in the seismic isolation device 1 having the above-described configuration, the high elastic portion 40B is provided on the inner peripheral portion of the elastic plate 40, and the region having high vertical rigidity (the high elastic portion 40B) is provided on the inner peripheral portion of the elastic plate 40. Therefore, the vertical load share rate of the inner peripheral portion around the plug 5 in the elastic plate 40 is increased. As a result, the pressure (hydrostatic pressure) on the plug 5 is increased, the restraining force on the plug 5 is increased, and the damping property by the plug 5 can be improved.

  In particular, in the seismic isolation device 1 described above, the radial width w1 of the highly elastic portion 40B is equal to or larger than the radial dimension r of the plug 5, and 1/2 of the radial width W of the entire elastic plate 40. Since it is below, the vertical load burden rate of the inner peripheral part around the plug 5 becomes remarkably high. As a result, the pressure on the plug 5 is further increased, the restraining force on the plug 5 is increased, and the damping property by the plug 5 can be reliably improved.

As mentioned above, although embodiment of the seismic isolation apparatus which concerns on this invention was described, this invention is not limited to above-described embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, the present invention may be configured such that the laminated body is installed obliquely and the laminated body is subjected to shear deformation in a direction inclined with respect to the horizontal plane.

  In the above-described embodiment, the plug 5 is press-fitted inside the annular high elastic portion 40B, and the inner peripheral surface of the high elastic portion 40B and the outer peripheral surface of the plug 5 are in close contact with each other. The inner peripheral surface of the highly elastic portion 40B and the outer peripheral surface of the plug 5 may not be in direct contact with each other. For example, in order to prevent the outer peripheral surface of the plug 5 from being scraped by the rigid plate 41 or entering the elastic plate 40, the outer periphery of the plug 5 may be covered with a cylindrical body.

Further, the present invention may be configured such that an end plate is provided at an end portion in the axial direction of the laminated body 4 and the end plate abuts on the flange plates 2 and 3.
In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

1 Seismic isolation device 2 Lower flange plate (flange plate)
3 Upper flange plate (flange plate)
4 Laminate 5 Plug (damping material)
DESCRIPTION OF SYMBOLS 10 Hole 40 Elastic board 40A Main-body part 40B High elastic part 41 Rigid board

Claims (2)

Between the pair of flange plates, there is interposed a laminate formed by alternately laminating a rigid plate having rigidity and an elastic plate having elasticity,
In the seismic isolation device in which a hole penetrating the laminated body in the laminating direction is formed and a damping material that attenuates vibration is accommodated inside the hole,
The elastic plate is annularly arranged on the radially outer side of the damping material on the inner peripheral portion of the elastic plate and is disposed on the inner peripheral side of the main body portion of the elastic plate, and is more elastic than the elastic material of the main body portion. A seismic isolation device having a high elastic portion made of an elastic material having a high rate. The seismic isolation device according to claim 1,
The seismic isolation device characterized in that a radial width dimension of the highly elastic portion is not less than a radial dimension of the damping material and not more than 1/2 of a radial width dimension of the elastic plate.

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