JPH06158910A - Laminated rubber bearing body - Google Patents

Abstract

PURPOSE:To make assurance of performance against a large-scale deformation practically possible for a nonadhesive type laminated rubber bearing body that is prepared for improvement of base isolation against the large-scale deformation and lengthening of service life and is made up by laminating, in nonadhesive manner, rubber-like elastic plates and intermediate plates made of rigid material. CONSTITUTION:Assurance of performance against a large-scale deformation is made by the following means: A laminated rubber bearing body 1' is covered, being brought in contact with the circumferential edges of intermediate plates 3, in a cylindrical shape with its upper and under beds fixed to base plates 4, and a protection rubber 7 is provided to arrange the intermediate plates 3 so that the amount of displacement becomes equal to each of the intermediate plates 3 when deformation is made to the laminated rubber bearing body 1' in the horizontal direction. Thin rigid layers are formed on the surface and the undersurface of each of rubber-like elastic plates 2, and thereby contact between the rubber-like elastic plate 2 and the intermediate plate 3 becomes friction contact made by each of rigid bodies. Thereby, Coulomb's law regarding friction can be applied to calculation of the amount of slippage at the time of large-scale deformation, and the calculation of the amount of slippage in the large-scale deformation can be facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated rubber bearing used for seismic isolation of buildings.

[0002]

2. Description of the Related Art A laminated rubber bearing 1 has a structure as shown in FIGS.

This is one in which a rubber-like elastic plate 2 such as natural rubber or synthetic rubber and an intermediate plate 3 made of a rigid material such as a steel plate are alternately laminated, and the upper and lower surfaces thereof are sandwiched by a base plate 4 for mounting. , The building 5 which is a superstructure as shown in FIG.
And as a cushioning material between the foundation 6 which is the substructure thereof.

The seismic isolation is possible with the above structure because the laminated rubber support 1 has a very high vertical spring rigidity / horizontal spring rigidity ratio. That is, due to the large vertical spring rigidity,
Stable support without moving the heavy building 5 up and down,
In addition, the small horizontal spring rigidity allows the building 5 to vibrate in the horizontal direction. Since the horizontal spring stiffness is small, the horizontal natural vibration period can be made longer than that of the maximum amplitude component of the shear wave of the seismic motion that causes destruction, and a low-speed translational motion is performed on the ground when an earthquake occurs. . This reduces the input acceleration of the earthquake and protects the building 5.

The applicant of the present invention has proposed, as an improvement plan of the laminated rubber bearing 1, a laminate in which the rubber-like elastic plate 2 and the intermediate plate 3 are laminated in a non-adhesive state (Japanese Patent Laid-Open No. 2-153137). .

This proposal has a drawback in the case where the rubber-like elastic plate 2 and the intermediate plate 3 are adhered and fixed, that is, the peripheral portion of the rubber-like elastic plate is hardened against a large deformation, which causes characteristic deterioration and life shortening. It is a solution to the problem.

This hardening phenomenon is a seismic isolation operation against a large earthquake, and when the amount of deformation of the rubber-like elastic plate 2 adhered to the intermediate plate 3 becomes large, the internal rubber-like elastic plate due to the compressive load of a heavy object This occurs because the amount of stretching of the peripheral portion of the rubber-like elastic plate that suppresses outward bulging in a stretched state becomes particularly large and becomes a high tension state, and reaches the yield region.

When such hardening occurs, the horizontal spring rigidity of the laminated rubber bearing 1 increases and the seismic isolation performance deteriorates. At the same time, a crack is formed in this hardened portion, which triggers the rupture and promotes the rupture at once. And shortens the service life.

However, in the above-mentioned improvement plan, the peripheral edge of the rubber-like elastic plate 2 is not adhered to the intermediate plate 3 made of a rigid material. Causes a rolling motion to substantially enlarge the free surface exposed to the external space, relieving stress concentration and eliminating hardening. As a result, the horizontal spring rigidity is kept substantially constant even during large deformation, cracks in the rubber-like elastic plate 2 are prevented from occurring during large deformation, and seismic isolation performance and durability of the laminated rubber support 1 are improved. be able to.

Further, in this improved structure, when a large deformation due to a large earthquake occurs, the outermost edge of the peripheral portion is greatly distorted and rubbed by the upper and lower intermediate plates 3 to cause elasto-plastic deformation, resulting in an earthquake. It also has the effect of absorbing a large amount of energy and producing a large damping effect. Since this plasticized peripheral part is hardly subjected to vertical load, the supporting capacity does not change, and it behaves like an adhesive type bearing as an elastic spring when it is slightly deformed by a small earthquake. .

Furthermore, since this improved structure is non-adhesive, its assembly only requires positioning and stacking, which reduces manufacturing costs.

[0012]

The above-mentioned improved laminated rubber bearing 1 has a rubber-like elastic plate 2 and an intermediate plate due to the frictional force due to the weight of the structure 5 to be placed against a small-scale earthquake. Three
Can be maintained in a fixed state, and there is no problem in practical use.

However, this improved laminated rubber bearing 1
Since they are not bonded, the rubber-like elastic plate 2 approaches the hardening area (hardening area) when the amount of horizontal deformation becomes considerably large due to a large-scale earthquake, and the viscous resistance and frictional resistance of the rubber increase. As a result, the rubber-like elastic plate 2 and the intermediate plate 3 made of a rigid material are slightly slipped. This slippage is a very preferable behavior from the viewpoint of prevention of hardening of the peripheral portion, but the intermediate plate 3 does not undergo repeated large deformation.
The residual displacement of is accumulated and the seismic isolation performance deviates from the design expected value.

This slip is caused by the rubber-like elastic plate 2 and the intermediate plate 3.
The friction phenomenon should be analyzed not by Coulomb friction (dry friction) but by grasping the property change of the rubber-like elastic plate at the molecular level. At present, it is difficult to obtain it by calculation. It is necessary to conduct a measurement experiment for each rubber bearing.

The occurrence of the above slip does not immediately impair the practicality. However, since the laminated rubber bearing 1 is used as a safety device, the structure is such that slip does not easily occur, or the degree of slip is within a safe range against a large earthquake that may actually occur. It is necessary to guarantee the performance by showing that it is a number.

Therefore, an object of the present invention is to provide a structure capable of easily performing the above performance guarantee in a non-adhesive type laminated rubber bearing.

[0017]

SUMMARY OF THE INVENTION The present invention is configured by sandwiching the upper and lower surfaces of a laminated body in which a rubber-like elastic plate and an intermediate plate made of a rigid material are alternately stacked in a non-bonded state with a mounting base plate. The following is provided as the structure of the laminated rubber support for supporting the placed heavy object so as to be swingable in the horizontal direction.

The upper and lower ends are fixed to the base plate,
The laminated body is covered in a cylindrical shape in a state of being in contact with the peripheral edge of the intermediate plate,
A laminated rubber bearing provided with a protective rubber which is arranged so that the displacement amounts of the respective intermediate plates are aligned evenly with respect to the horizontal deformation of the laminated body.

A laminated rubber bearing body in which thin rigid layers are formed on the upper and lower surfaces of the rubber elastic plate, and the contact between the rubber elastic plate and the intermediate plate is frictional contact between rigid bodies.

[0020]

The above two configurations ensure the seismic isolation performance against a large earthquake by the following actions.

In the above construction, the upper and lower ends of the protective rubber 7 are fixed to the base plate 4 and are inclined and deformed following the relative displacement in the horizontal direction. This deformation has a shape that follows the edge of the intermediate plate 3 when there is no slip. Since this protective rubber 7 contacts the peripheral edge of the intermediate plate 3 and regulates the position, the intermediate plate 3 can maintain the same alignment state as if there was no slip even during large deformation. This action enables performance guarantee.

In the configuration, the intermediate plate 3 made of a rigid material and the rubber-like elastic plate 2 are in contact with each other by rigid bodies, and F = μW.
Since the Coulomb friction is represented by (F: friction force, μ: friction coefficient, W: weight of building), the slip amount can be easily calculated. Therefore, the slip amount at the time of large deformation can be shown by the calculation data, and the safety can be easily guaranteed.

[0023]

EXAMPLES Examples of the present invention will be described below.

As shown in FIG. 1, a laminated rubber bearing 1'of the first invention (having the above-mentioned structure) has a rubber-like elastic plate 2 and an intermediate plate 3 made of a rigid material laminated in a non-adhered state, In the structure in which the upper and lower surfaces are sandwiched by the mounting base plate 4, the protective rubber 7 which is in contact with the peripheral edge of the intermediate plate 3 and covers it in a cylindrical shape.
The upper and lower ends are fixedly attached to the base plate 4.

In the mounting structure of this embodiment, a steel ring 8 is vulcanized and adhered to both ends of a cylindrical protective rubber 7, and the steel ring 8 is formed in a stepped circular recess 9 provided on the inner surface of the base plate 4. It is fitted from the inside, and further, the disc-shaped pressing plate 10 is fitted into the inside of the steel ring 8 and fixed so as not to move. The steel ring 8 and the holding plate 10 are respectively
It is fixed to the base plate 8 with screws 11 and 12.

The outer shape of the intermediate plate 3 is larger than that of the rubber-like elastic plate 2 so that the protective rubber 7 can be effectively aligned. Further, the rubber-like elastic plate 2, the intermediate plate 3, the protective rubber 7, and the steel ring 8 do not necessarily have to be circular, and may be rectangular, and the protective rubber 7 may be divided to facilitate assembly. .

Here, the protective rubber 7 is one which does not affect the horizontal deformation of the laminated rubber bearing 1'and which can give the intermediate plate 3 an elastic restoring force for keeping the intermediate plate 3 in the aligned posture.
For example, it retains the properties of rubber and stretches up to 3 times,
Continue to stretch 40kg / cm ^{2 to} 100kg / c
Use a material that has the strength to break only when a force of about m ² is applied. If it stretches about 3 times, it can sufficiently cope with the horizontal deformation of the laminated rubber bearing 1'to the largest earthquake, and if the protective rubber 7 having such strength is used, the intermediate plate 3 is temporarily not aligned. Even if it becomes, it can be restored to the aligned state by repeating the vibration. Even if the protective rubber 7 having such strength is used, since the protective rubber 7 is a single layer, the rigidity of the horizontal spring of the laminated rubber bearing 1'is hardly affected.

In the above structure, when the upper and lower base plates 4 are displaced relative to each other in the horizontal direction by the seismic isolation operation, the protective rubber 7 follows the inclination and is deformed. This deformation is a shape along the edge of the intermediate plate 3 when there is no slip. Therefore, even if the laminated rubber support 1'is largely deformed by the seismic isolation operation against a large earthquake, the elastic force of the protective rubber 7 causes the intermediate plates 3 to maintain a non-slip aligned state.

The protective rubber 7 is made of rubber-like elastic plate 2.
And, the intermediate plate 3 is shielded from the outside air to prevent its deterioration, and also has an effect as a protective cover for improving the appearance. Since it is customary to attach a protective cover to the laminated rubber bearing, it is convenient that the above-mentioned effects can be obtained without substantially increasing the cost.

Next, a modified embodiment of the invention will be described with reference to FIGS.

These are intended to stabilize the seismic isolation performance by facilitating the parallel posture of each intermediate plate 3 to reduce the possibility of buckling.

The protective rubber 7a shown in FIG.
The curved ridges 13 that fit into the gaps are formed on the inner peripheral surface at predetermined intervals. The protective rubber 7b shown in FIG.
Grooves 14 are formed on the inner peripheral surface at predetermined intervals so that the peripheral edge portions of the cans can be fitted tightly. With these structures, the protection rubbers 7a and 7b can be divided into structures to facilitate assembly.

As shown in FIG. 4, the laminated rubber bearing 1 ″ according to the second invention (having the above-mentioned structure) has thin rigid layers 15 formed on the upper and lower surfaces of the rubber-like elastic plate 2. The rigid body layer 15 is formed by, for example, a method of attaching a thin steel plate by vulcanization adhesion, or a method of attaching a thin ceramic layer with an adhesive or the like. The rubber-like elastic plate and the like in this structure have an arbitrary planar shape as in the first invention.

In this structure, the intermediate plate 3 and the rubber-like elastic plate 2 are provided.
The friction between the two is caused by the contact between the rigid plates, which results in Coulomb friction that has been theoretically elucidated, and the magnitude of the slip that occurs when the horizontal force exceeds a certain amount is determined by an actual experiment. It is possible to easily perform quantitative assurance of safety by performing calculation only without performing.

[0035]

According to the present invention, in a non-adhesion type laminated rubber bearing in which a rubber-like elastic plate and an intermediate plate made of a rigid material are non-adhesively laminated, a practical safety guarantee against slippage during large deformation is obtained. Can be possible.

[Brief description of drawings]

FIG. 1 is a half sectional view of a laminated rubber bearing showing an embodiment of the first invention with a protective rubber attached.

FIG. 2 is a sectional view showing a first modification of the protective rubber of the first invention.

FIG. 3 is a sectional view showing a second modification of the protective rubber of the first invention.

FIG. 4 is a half sectional view showing an embodiment of the second invention in which thin rigid layers are formed on the upper and lower surfaces of a rubber-like elastic plate.

FIG. 5 is a side view (a) and a plan view (b) showing a general structure of a laminated rubber bearing.

FIG. 6 is a side view showing a seismic isolation structure using a laminated rubber bearing for a building.

[Explanation of symbols]

 1 ', 1' '' Laminated rubber support 2 Rubber-like elastic plate 3 Intermediate plate using rigid material 4 Base plate 5 Structure 6 Foundation 7, 7a, 7b Protective rubber 8 Steel ring 9 Stepped circular recess 10 Presser plate 11,12 Screw 13 Raised 14 Groove 15 Rigid layer

Claims (2)

[Claims] 1. A horizontal structure for placing a heavy object, which is constructed by sandwiching the upper and lower surfaces of a laminated body in which a rubber-like elastic plate and an intermediate plate made of a rigid material are alternately laminated in a non-bonded state, with a mounting base plate therebetween. In the laminated rubber bearing body that swingably supports in the direction, the upper and lower ends are fixed to the base plate, and the laminated body is cylindrically covered in a state of being in contact with the peripheral edge of the intermediate plate. A laminated rubber bearing characterized by being provided with a protective rubber which is arranged so that the displacement amounts of the plates are equal. 2. A rubber-like elastic plate and an intermediate plate made of a rigid material are alternately laminated in a non-bonded state, and the upper and lower surfaces of the laminated body are sandwiched by base plates for mounting, and a placed heavy object is placed horizontally. In a laminated rubber support that is swingably supported in any direction, thin rigid layers are formed on the upper and lower surfaces of the rubber elastic plate, and the contact between the rubber elastic plate and the intermediate plate is frictional contact between rigid bodies. And laminated rubber bearings.