JPH09177370A - Vibration isolation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure having an effect on an eathquake and excellent vibration-isolation performance not subject to an effect by a wind shaking, etc., at the normal time and superior durability. SOLUTION: This vibration isolation structure has a composite laminate, in which a plurality of hard plates 16 having rigidity and soft plates 18 having viscoelastic properties are alternately laminated respectively, between an upper face plate 12 and an underside plate 14. The structure has at least two piston- shaped viscous dampers 24, which are placed outside the composite laminate and in which both ends of each damper 24 are connected to the upper and lower face plates 12, 14 by connecting means capable of following the deformation at 360 of ball joints 22, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device, which can be suitably used not only for a large building but also for a light load of a detached house which is particularly susceptible to wind sway or the like. It relates to the seismic isolation structure used for.

[0002]

2. Description of the Related Art Conventionally, seismic isolation structures in which a plurality of rigid hard plates such as steel plates and soft plates such as rubber having viscoelastic properties are alternately laminated are used for middle and low-rise buildings. It is widely used as a rubber support piece for seismic isolation devices such as bridges and bridges. An elastic body such as rubber constituting a soft plate of such a seismic isolation structure is generally designed to have the following spring characteristics. That is, the lateral spring constant KH of an elastic body such as rubber
, And the mounted mass is M, the horizontal natural frequency fH is designed to satisfy the following conditions.

[0003]

[Equation 1]

Since the natural frequency fH is determined by the ratio of the weight of a building or bridge to the lateral spring constant KH of an elastic body such as rubber, the seismic isolation device is flexible even if the building or bridge has a large loading weight M. As the elastic body forming the plate, a material having a high spring rigidity or a highly elastic material is generally used. In addition, a structure in which a plastic material such as lead is used together in the laminated portion of the base isolation structure is generally used.

[0005] Such a seismic isolation structure using lead in combination, for example, has both high elasticity at low strain and low elasticity at high strain, and high damping properties.
It can be effective against wind sway. However, in the case of a large earthquake with a shear strain of up to 200%, the effect of seismic isolation can be exhibited, but due to the high shear strain and strain stress, the plastic material such as lead used inside is greatly plastically deformed or cut and fractured. Since it is not possible to replace only the seismic isolation structure when it is used in buildings, it has higher durability that can be used continuously even after it is subjected to vibration such as a large earthquake. A seismic isolation structure was requested.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional techniques, and the seismic isolation device is not only used for heavy objects such as buildings and bridges but also lightweight for detached houses. An object of the present invention is to provide a seismic isolation structure that has high performance even when applied to an object and has excellent durability without plastic deformation or cutting fracture.

[0007]

The seismic isolation structure of the present invention comprises:
A composite laminate in which a hard plate having rigidity and a soft plate having viscoelastic properties are alternately laminated between the upper and lower face plates, respectively, and a composite laminate located outside the composite laminate, At least two dampers, both ends of which are connected to the face plate, are provided.

This damper is a piston-like viscous damper having air or a viscous fluid in a cylinder, and is further characterized in that the damper and the upper and lower face plates are connected by a ball joint.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The material used for the soft plate having the viscoelasticity of the seismic isolation structure of the present invention is a material having a 50% modulus of 1.5 to 10 kgf / cm ² and a dynamic shear at 25 ° C. An elastic modulus G indicates a property of 1.5 to 10 kgf / cm ² , and a 50% modulus is 2 to 8 kgf.
/ Cm ² , dynamic shear modulus G is ^{2 to} 8 kgf / cm ²
Are preferred.

The 50% modulus and the dynamic shear modulus G of various materials are, for example, JIS K6301, K6394.
It can be measured according to.

Here, examples of the material having viscoelastic properties include organic materials such as thermoplastic rubber, urethane rubber, various vulcanized rubbers, unvulcanized rubbers, slightly crosslinked rubbers and plastics, foams thereof, Various materials such as inorganic materials such as asphalt and clay, and mixed materials thereof having the above viscoelastic properties can be used.

These materials are molded into a flat plate and used as a soft plate. The shape and size of the soft plate are not particularly limited, and are appropriately selected so as to meet the desired seismic isolation performance. Usually, a so-called columnar one is used, and each soft plate has a disc shape. The thickness of the soft plate is generally 5 to 10 mm when it is used for heavy objects, and about 1 to 4 mm when it is used for lightweight objects.

These materials may be used alone or as a mixture of two or more kinds, and may be formed of a uniform material as a whole, but a high damping material is used for the inner part and creep performance is used for the outer part. You may use it in combination of 2 or more types with a good and soft material.

As the material of the soft plate of the present invention, various vulcanized rubbers, thermoplastic rubbers, urethane rubbers and the like having the above-mentioned preferable properties can be used. Further, as the inner portion of the soft plate, various vulcanized rubbers, unvulcanized rubbers, slightly cross-linked rubbers, organic materials such as plastics, foams thereof, inorganic materials such as asphalt and clay, mixed materials thereof, etc. Various things can be used.

Further, as the hard plate in the seismic isolation structure of the present invention, metal, ceramics, plastics, FR
Various materials having required rigidity, such as P, polyurethane, wood, paper board, slate board, decorative board, etc., can be used. Here, the required rigidity means a rigidity of a patent with shear deformation or a buckling phenomenon, although it varies greatly depending on design conditions.

There is no particular limitation on the thickness and shape of the hard plate,
It can be selected depending on the material used and the desired seismic isolation performance, but its thickness is generally
2 to 4 mm, 0.5 to 2 mm when used for lightweight items
It is of a moderate thickness. The shape is arbitrary, like the laminated soft plates, but usually the same shape as the soft plate used together is used, and a disk-shaped one is common.

A plurality of layers of the soft plate and the hard plate are alternately laminated to form a composite laminate. Although the shape, area and thickness of each of the soft plate and the hard plate differ depending on the seismic isolation performance required as described above, the composite laminate usually has a columnar shape as described above, and both the soft plate and the hard plate have a cylindrical shape. A disk having the same shape and the same surface area is commonly used.

In order to impart weather resistance to the seismic isolation structure of the present invention, the outside of the laminated composite may be coated with a material having excellent weather resistance. Examples of the coating material include butyl rubber, acrylic rubber, polyurethane, silicone rubber, fluororubber, polysulfide rubber, ethylene propylene rubber (ERP
And EPDM), chlorosulfonated polyethylene, chlorinated polyethylene, ethylene vinyl acetate rubber, chloroprene rubber and the like can be used. These materials may be used alone or as a blend of two or more. Further, it may be blended with natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber and the like.

In the seismic isolation structure of the present invention, a damper which is located outside the laminated composite body and which is arranged by connecting both ends of the upper and lower face plates to each other is known as long as it exhibits effective damping performance. Any of the dampers can be used. As a damper that can be used, a viscous damper having a simple structure and excellent damping characteristics is generally used. Specifically, for example, a piston flow hole type damper, a piston-side clearance type damper, a dash pot, etc. may be mentioned, and the fluid sealed therein may be gas such as air or liquid such as silicone oil. May be.

Both ends of these dampers are respectively connected to the upper and lower face plates of the seismic isolation structure. As a connecting means, a damping effect can be exerted against vibration from any direction, 360 ° for ball joints, etc.
It is preferable to use a means capable of following the modification of From the same viewpoint, the dampers are preferably arranged at at least two positions outside the laminated composite, and more preferably at four positions.

By arranging this damper, a resistance force against the stress of the damper works and a damping property can be imparted to the seismic isolation structure. Therefore, in addition to the seismic isolation performance of the laminated composite that uses a low damping rubber material with excellent creep properties, by placing dampers at multiple locations outside the laminated composite, it is effective for large deformation such as earthquakes. High damping property can be achieved.

The seismic isolation structure of the present invention can be selected from heavy objects such as bridges and buildings, to detached houses such as detached houses, by selecting the sizes of soft and hard plates, the number of laminated layers, and the types and arrangements of dampers. It is possible to obtain a seismic isolation structure that exhibits excellent seismic isolation performance even for relatively lightweight (lightly loaded) objects. Here, the light load means a surface pressure of less than 50 kgf / cm ² , and further a surface pressure of 3
0 kgf / cm ² or less, more preferably a surface pressure of 20 kgf
/ Cm ² or less.

The structure of the present invention is a composite laminate in which a plurality of rigid hard plates and soft plates having viscoelastic properties are alternately laminated between the upper and lower face plates of the seismic isolation structure. And at least two dampers, which are located outside the composite laminate and whose both ends are connected to the upper and lower face plates, respectively.

During an earthquake or the like, a large deformation is applied to the base-isolated structure, but the damper absorbs the shear deformation, the vibration is effectively damped, and the laminated structure is damaged to cause so-called plastic deformation. Never happens. Therefore, the seismic isolation effect is not lost in one earthquake, and has a durable seismic isolation effect. Moreover, since the laminated composite body using the low-damping rubber material excellent in creep property is used, the durability performance is improved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. Table 1 collectively shows the conditions and test results of Examples and Comparative Examples.

(Embodiment 1) FIG. 1 is a sectional view of a seismic isolation structure 10 according to Embodiment 1 of the present invention. In the seismic isolation structure 10 shown in FIG. 1, a top plate 12 (iron plate) and a bottom plate 1
Between 4 (iron plates), 30 hard plates 16 having an outer diameter of 250 mm and a thickness of 1.6 mm, and a soft plate 18 of 50%
Modulus 2.3 kgf / cm ² , tensile strength 90
A rubber material having a kgf / cm ² and an elongation at break of 760% was used, and 31 layers of the soft plate 18 (one sheet having a thickness of 2.5 mm) were used. The shear rigidity (G) at a shear strain of 200% of this rubber material was 2.0 kgf / cm ² , and tan δ was 0.1. Further, the outer periphery of this laminated composite was covered with the outer rubber 20 made of a natural rubber type rubber material. Piston type (side clearance type, silicone oil filled) 24, which is connected to the upper plate 12 and the lower plate 14 at both ends by ball joints 22, is arranged at four locations on the outer side of the laminated composite. The seismic isolation structure 10 was obtained and set as Example 1.

With this seismic isolation structure, a load of 10 t and a frequency f
The shear rigidity (G) and tan δ when a vibration was applied with a sine wave of = 0.2 Hz and a shear strain of 100% were measured. The results are shown in Table 1 below.

Further, the damper 2 is provided outside the laminated composite.
In the same manner as in Example 1 except that 4 was not arranged,
A seismic isolation structure was produced and used as Comparative Example 1. The seismic isolation structure of Comparative Example 1 was evaluated in the same manner as in Example 1, and the results are shown in Table 1 below.

[0029]

[Table 1]

As is apparent from Table 1, Example 1 which is the seismic isolation structure of the present invention is compared with the seismic isolation structure of Comparative Example 1 in which the damper for vibration damping is not arranged on the outer side of the laminated composite body. The damping effect was significantly improved.

Further, looking at this result, the shear rigidity (G)
It was confirmed that the numerical values of 2.5 kgf / cm ² and tan δ of 0.3 are, for example, sufficient levels for a seismic isolation structure for a detached house.

FIG. 2 shows a sectional view in the case where a large deformation is applied to the seismic isolation structure 10. As shown in FIG. 2, since the dampers provided at four places outside the laminated composite can impart the vibration damping property to the base isolation structure 10, high damping property is exhibited even in the case of an earthquake or the like. I know you can get it.

[0033]

As is apparent from the above description, the seismic isolation structure of the present invention has high performance when applied to not only heavy objects such as buildings and bridges but also light objects such as detached houses. In addition, it was possible to obtain a seismic isolation structure having excellent durability without plastic deformation or cutting fracture.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a seismic isolation structure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view when a large deformation is applied to the seismic isolation structure according to the first embodiment.

[Explanation of symbols]

 10: Seismic isolation structure 12: Top plate (iron plate) 14: Bottom plate (iron plate) 16: Hard plate 18: Soft plate 20: Outer rubber 22: Ball joint 24: Damper

Claims (3)

[Claims] 1. A plurality of hard plates having rigidity and a plurality of soft plates having viscoelastic properties are provided between the upper and lower face plates, respectively.
A seismic isolation structure comprising: a composite laminate that is alternately laminated; and at least two dampers that are located outside the composite laminate and that are connected to upper and lower face plates at both ends thereof. 2. The seismic isolation structure according to claim 1, wherein the damper is a piston-like viscous damper having air or viscous fluid in a cylinder. 3. The seismic isolation structure according to claim 2, wherein the damper and the upper and lower face plates are connected by a ball joint.