JPS61229075A - Earthquake-proof structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a seismic isolation structure in which a plurality of hard plates and soft plates having viscoelastic properties are laminated alternately, and in particular, it is extremely durable. The present invention relates to a seismic isolation structure with excellent properties.

[Prior Art] A structure in which a hard plate such as a copper plate and a soft plate having viscoelastic properties such as rubber are laminated is widely used as a support member that is required to have vibration-proofing properties, vibration-absorbing properties, and the like.

In such a support member, excessive stress is concentrated on the rubber portion that is in contact with the edge portion of the copper plate, and damage is likely to occur in this portion. This will be explained with reference to FIG. 2. FIG. 2 is an enlarged sectional view of a main part of a conventional support member, where 1 indicates a soft plate such as rubber, and 2 indicates a hard plate such as steel plate. However, in the conventional support member shown in Fig. 2, compressive stress (force in the direction of pinching from above and below in the figure) is applied to the support member.
When this is applied, the end surface 3 of the soft plate 1 made of rubber or the like tends to bulge outward as shown by the broken line 4. Then,
Since the portion 5 of the soft plate l made of rubber or the like that is in contact with the edge portion of the hard plate 2 is restrained by the hard plate 2, a large stress is generated in this portion 5.

By the way, seismic isolation structures support the foundations of buildings and are required to last for several decades.

(i) The maximum local strain that occurs in the soft part during deformation will cause cracks to occur in the soft part, leading to damage to the structure; (11) Rust will occur in the hard part, causing adhesion between the hard part and the soft part. It is absolutely necessary to avoid damage to the structure due to a significant decrease in strength.

In order to reduce the local stress on the soft plate that comes into contact with the hard plate edge, an inclined surface is formed on the peripheral edge of the hard plate (steel plate), and a vertical cross-sectional shape is formed on the side surface of the soft plate (rubber elastic body). A rubber bearing piece is known in which a concave portion forming an open surface is formed so as to cover an inclined surface of a steel plate (Japanese Utility Model Publication No. 58-30818).

[Problems to be Solved by the Invention] In a seismic isolation structure having a structure in which a plurality of hard plates and soft plates are bonded together, providing an open surface on each soft plate may worsen the releasability from the mold. There are problems such as high mold costs and high mold costs. In particular, when the thickness of the soft plate is small, such problems become even more serious.

Furthermore, in the conventional laminated structure described above, since the end surfaces of hard plates such as steel plates are exposed to the outside, there is a problem in that corrosion tends to progress from the end surfaces. In order to prevent such corrosion, the surrounding surface of the exposed metal plate of anti-vibration rubber is sometimes coated with paint, etc. However, in the case of seismic isolation structures, the usage period is significantly longer. Considering the long term (for example, in the case of houses and buildings, durability must be satisfied for about 50 years), it is difficult to guarantee durability over a long period of time with this type of painting method.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a seismic isolation structure in which a plurality of hard plates and a plurality of soft plates are laminated together, in which the side end surfaces of the hard plates are turned outward. In addition to having a bulging arcuate cross section, the outer peripheral portion of this hard plate is also covered with a soft material, and the hard plate is embedded within the soft material.

[Function] In the present invention, since the side end portions of the hard plate are bent in an arc shape, the local stress generated in the soft plate that comes into contact with the end portions of the hard plate is extremely small. Furthermore, in the present invention, since the hard plate is completely covered with the soft material, corrosion due to contact of the hard plate with the outside air is almost completely prevented, resulting in extremely excellent durability.

Furthermore, in the present invention, there is no need to use a mold with a special structure as in Publication of Utility Model Publication No. 58-30818, so that the releasability from the mold is good and the cost of the mold is low.

[Example code] Examples will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a base isolation structure according to a first embodiment of the present invention. This seismic isolation structure is constructed by laminating a soft plate 1 made of rubber or the like having viscoelastic properties and a hard plate 2 made of a composite material such as a steel plate.

Therefore, in the present invention, as shown in FIG. 3 (an enlarged view of the part marked ■ in FIG. 1), the outer circumferential portion 6 of the steel plate 2 has a curved surface with an arcuate arm. The outer peripheral portion 6 is covered with a soft material 7 made of the same material as the soft plate l,
It is cut off from the outside air. In this way, in the present invention, since the hard plate 2 is completely covered with the soft material,
The hard plate 2 does not come in contact with the outside air and cause corrosion.

In addition, by covering the outer circumferential portion 6 of the hard plate 2 with a soft material and curving the outer circumferential portion 6 of the hard plate 2 into an arc shape, a local part of the surface of the soft material that comes into contact with the circumferential portion 6 can be formed. The stress or the maximum local stress can be respectively reduced.

In this first embodiment, the radius R of the arc shape of the outer circumferential portion 6 of the hard plate 2 is preferably different from the portion in which the upper and lower surfaces of the inside of the hard plate 2 are parallel, as shown in FIG. The embodiment shown in FIG. 4, which is preferably shaped as shown in FIG.

According to the research conducted by the present inventors, the local stress generated in the soft material that comes into contact with the outer peripheral portion of the hard plate 2 gradually decreases as the thickness of the soft plate 1 increases, but it reaches a certain level of thickness. It was found that even if the thickness was increased further, the effect of reducing local stress was extremely poor. Therefore,
In the present invention, when a rubber plate is used as the soft plate 2, the thickness t (mm) of the soft plate (rubber plate) l is 1≦t
It is preferred that ≦20, especially 2≦t≦15, especially 3≦t≦lO.

In the present invention, as the material of the hard plate 2, metal, ceramics, plastics, FRP, polyurethane, wood, paper board, slate board, decorative board, etc. can be used. In addition, as the soft plate l, various vulcanized rubbers, unvulcanized rubbers, organic materials such as plastics, foams of these materials,
Various materials such as inorganic materials such as asphalt and clay, and mixed materials thereof can be used.

In order to bond such a hard plate and a soft plate, an adhesive may be used or co-vulcanization may be used.

In addition, the present inventors conducted various studies and found that the hard plate 2
An iron plate with a thickness of 3 mm was used as the plate, and a rubber plate with a thickness of 22 mm was used as the soft plate.
In the conventional example shown in Fig. 2, when a rubber plate l is compressed by an average of 4% and a load is applied to the disc-shaped rubber plate l,
While the maximum local tensile strain reached as much as 55%, the maximum local tensile strain in FIGS. 1 and 3 was reduced to 14%.

In addition to the seismic isolation function, the seismic isolation structure of the present invention has vibration isolation (vibration isolation,
It has characteristics such as vibration damping).

[Effects] As detailed above, in the seismic isolation structure of the present invention, generation of excessive local stress in the soft material is avoided, and corrosion of the hard plate is also prevented.

Therefore, according to the structure of the present invention, an extremely excellent seismic isolation effect is exhibited, and the seismic isolation structure has durability that guarantees this seismic isolation characteristic over an extremely long period of time.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a seismic isolation structure according to an embodiment of the present invention;
FIG. 2 is a sectional view showing a conventional example, FIG. 3 is an enlarged view of the main part of FIG. 1, and FIG. 4 is an enlarged sectional view of the main part of a base isolation structure according to a different embodiment. l...soft board, 2...hard board, 6...
- Hard plate outer peripheral portion, 7... Soft material.

Claims (1)

[Claims] (1) In a seismic isolation structure in which a plurality of hard plates and soft plates with viscoelastic properties are laminated alternately, the side end surfaces of the hard plates are shaped like an arc bulging outward, and A seismic isolation structure characterized in that the outer peripheral portion of the plate is covered with a softening agent having viscoelastic properties.