JPH11153190A - Laminated rubber bearing and seismic isolation building using the same - Google Patents

Abstract

(57) [Summary] [Problem] Compared to an adhesive type seismic isolation bearing that hardens and breaks for large horizontal deformation exceeding a predetermined limit and hardens for large deformation. The breaking limit is extremely large, but the repeated spring deformation exceeding the predetermined limit eliminates the disadvantages of the non-adhesive type laminated rubber bearing in which the horizontal spring constant becomes unstable, and the advantages of both can be secured. A laminated rubber bearing is provided. SOLUTION: In a laminated rubber support 1 formed by laminating a rubber-like elastic plate 2 and a rigid plate 3, a part of the joint between the rubber-like elastic plate and the rigid plate is made non-adhesive, and the other is adhered.

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 and the like and a seismic isolated building using the same.

[0002]

2. Description of the Related Art As a basic material for protecting heavy objects such as buildings from earthquakes, use of a laminated rubber bearing 1 as shown in FIGS. 3A and 3B is spreading. This is obtained by alternately laminating rubber-like elastic plates 2 such as natural rubber or synthetic rubber and rigid plates 3 such as a steel plate. The structure shown in FIG. 3a, the laminate 4 is connected to upper and lower flange plates 5, 5 for mounting. Reference numeral 6 denotes a through hole provided at the center of the laminate 4 for facilitating vulcanization bonding and the like, and 7 denotes a mounting hole provided in the flange plate 5.
As shown in FIG. 4, the laminated rubber bearing 1 is used as a cushioning material for mounting and supporting a heavy object (upper structure) 8 such as a building on a foundation (lower structure) 9 thereof.

[0003] Seismic isolation is possible with the above structure because the hardness, thickness t, diameter D, total lamination height H (= t x number of laminations), primary shape factor D / t, and secondary shape of the rubbery elastic plate 2 By setting the coefficient D / H to an appropriate value, the ratio of the vertical spring stiffness / horizontal spring stiffness of the laminated rubber support 1 can be made very large.
This is due to the ability to secure stability against large horizontal deformation due to a large earthquake.

That is, due to the large vertical spring stiffness,
It stably supports heavy objects 8 such as buildings without moving them up and down,
Moreover, the heavy object 8 such as a building can be vibrated in the horizontal direction by a small horizontal spring stiffness (constant). Since the horizontal spring constant is small, the natural oscillation period in the horizontal direction is longer than that of the maximum amplitude component of the shear wave of the ground motion that causes the destruction,
Slow translation is performed on the ground when an earthquake occurs.
Thereby, the input acceleration of the earthquake is reduced, and the heavy object 8 such as a building is protected.

The rubber-like elastic plate 2 and the rigid plate 3 of the laminated rubber support 1 are generally bonded by vulcanization or the like. A non-adhesive laminated rubber bearing body is proposed in which the rubber-like elastic plate 2 and the rigid plate 3 are fixed to each other with a large frictional force generated by a heavy object 8 such as a building to be laminated without being bonded ( JP-A-2-153137).

[0006]

The behavior of the adhesive type laminated rubber bearing and the non-adhesive type laminated rubber bearing at the time of seismic isolation will be described.

FIG. 5 shows the change characteristics of the horizontal spring constant K with respect to the shear deformation in the vulcanized adhesive type laminated rubber bearing. The horizontal axis represents the amount of shear deformation δ, the vertical axis represents the elastic force Q, The spring constant K (= shear force Q / shear deformation δ) is expressed as the slope of the characteristic curve. The performance of this vulcanized adhesion type laminated rubber bearing is evaluated by a value of a horizontal spring constant K with respect to a deformation rate γ [= shear deformation δ (cm) / total rubber thickness H (cm)]. As can be seen from FIG.
Elastic deformation occurs at a constant horizontal spring constant K up to a deformation rate γ of about 250%, but when the horizontal spring constant K exceeds this, hardening occurs in which the rubber solidifies, and fracture occurs at a deformation rate of 400%.

As described above, the hardening occurs because the rubber-like elastic plate 2 sandwiched between the rigid plates 3 swells to the side while the heavy object 8 such as a building is loaded, and Since the peripheral edge of the elastic plate is held in a stretched state, if there is a large horizontal displacement, the amount of extension of the peripheral edge drawn by the rigid plate 3 further increases, and eventually, the maximum This is because, when a tensile load is applied, the peripheral portion of the rubber-like elastic plate 2 becomes in a high tension state, reaches the yield region, and is hardened. The rupture further progresses at once from the hardened peripheral portion when the amount of stretching increases.

When the above-mentioned hardening occurs, the horizontal spring constant K becomes large and hinders the horizontal movement of the heavy object 8 such as a loaded building, so that the seismic isolation performance against a large earthquake is reduced. In addition, if it breaks, the laminated rubber bearing 1 loses its seismic isolation supporting ability. Therefore, the design of the laminated rubber bearing body 1 is such that the deformation rate γ for the expected maximum-scale earthquake has a predetermined safety factor with respect to the above-mentioned rupture limit of 400%, and at the hardening start point. Some 250%
It is necessary to take this into consideration as much as possible. For this reason, design restrictions such as an increase in the size of the laminated rubber support 1 have arisen.

The behavior of the non-adhesive laminated rubber bearing at the time of seismic isolation will be described for the case of the single-layer type shown in FIG. 6 and the case of the multilayer type shown in FIG. 6 and 7 are the same as those in FIG. In FIG. 6 showing the characteristics of the single-layer type, the rubber-like elastic plate 2 is elastically deformed to a deformation ratio γ = about 300%, and when it exceeds this, it does not lose its load-bearing capacity and undergoes complete plastic deformation until γ = 1000% deformation. . In this completely plastic deformation region, the rubber-like elastic plate 2 absorbs vibration energy and exhibits a vibration damping effect. As described above, the non-adhesive type exhibits ideal bilinear type deformation, and the breaking limit is dramatically increased.

The reason why the non-adhesive type does not cause hardening is that the upper and lower rigid plates 3 sandwiching the rubber-like elastic plate 2 sandwich it during large deformation because the peripheral edge of the rubber-like elastic plate 2 is not bonded and is not restrained by the rigid plate 3. For this slide, this peripheral portion causes a rolling motion to substantially expand the free surface exposed to the external space, to reduce stress concentration and eliminate hardening.

However, in order to reduce the horizontal spring constant K of the non-adhesive type laminated rubber bearing to a small value required for seismic isolation, the laminated rubber bearing having the same size and shape as the laminated rubber bearing having the characteristics shown in FIG. Then, the behavior is as shown by a solid line and a dotted line in FIG.

In FIG. 7, the laminated rubber bearing member 2 is elastically deformed up to a deformation rate γ = 300%, and enters a completely plastic deformation area when the deformation rate exceeds γ = 300%. An instability phenomenon occurs in which the horizontal spring coefficient K fluctuates as shown by the dotted line with the repetition of. This gradually departs from the theoretical characteristics (indicated by the dashed line) estimated from the characteristics of the single layer shown in FIG. As described above, when the non-adhesive laminated rubber bearing is formed into a multilayer, a large plastic deformation region obtained by a single layer cannot be expected.

The above-mentioned instability phenomenon occurs because the rubber-like elastic plate 2 approaches a hardening region (hardened region) at the time of large deformation, and the viscous resistance and frictional resistance of the rubber are reduced. This is because a minute slip occurs between the rigid plates 3 and the deformation between the rigid plates becomes non-uniform due to partial accumulation when repeated large deformations occur. This unstable phenomenon can be alleviated to some extent by limiting the secondary shape factor D / H or increasing the thickness of the intermediate steel sheet 3, and the complete plastic deformation region can be enlarged. However, no significant effect can be expected, and this measure reduces the degree of freedom in design.

Accordingly, the present invention prevents hardening and breakage, which are the drawbacks of the adhesive type, and eliminates the instability of the horizontal spring constant at the time of large deformation, which is the drawback of the non-adhesive type. It is an object of the present invention to provide a laminated rubber bearing body capable of securing advantages.

[0016]

(1) A laminated rubber support provided by the present invention is constituted by alternately laminating a rubber-like elastic plate and a rigid plate, and mounts a heavy object so as to be capable of swinging in a horizontal direction. When the horizontal spring constant does not become unstable against large deformation in the horizontal direction at the time of a large earthquake, the hardening of the rubber-like elastic plate is suppressed and the fracture is prevented. The bonding surface of the rubber-like elastic plate and the rigid plate is not bonded as many as necessary, and the other bonding surfaces are bonded.

Since the laminated rubber bearing has a small number of non-bonded rubber-like elastic plates, it does not cause an unstable phenomenon in the non-bonding type seismic isolation bearing (multilayer) described with reference to FIG.
An ideal bilinear deformation shown in FIG. 6 is performed. Then, the bonded rubber-like elastic plate is deformed to a greater extent in the horizontal direction enough to cause hardening. Improve seismic isolation performance against large deformation. Further, since the non-adhesive rubber-like elastic plate has a large amount capable of being completely plastically deformed, it is possible to prevent breakage due to large deformation.

The meaning that the joining surface between the rubber-like elastic plate and the rigid plate is made non-adhesive means that one surface is made non-adhesive and the other surface is made other than the case where the front and back surfaces of the rubber-like elastic plate are made non-adhesive. If the surface is to be bonded, another thin rubber is stuck to the rubber-like elastic plate, and if the joining surface between this thin rubber and the rigid plate is not to be bonded, only the peripheral edge of the rubber-like elastic plate is to be non-bonded. Including the case. This is because they have the effect of the present invention on hardening and breaking.

(2) The arrangement of the rubber-like elastic plate bonded to the rigid plate in a non-adhesive manner may be, for example, both or one of the upper and lower ends. The vulcanization bonding of the laminate in this case can be performed in a state where the intermediate steel plate and the Flange plate are separated, so that the temperature rise of the rubber-like elastic plate in the heating furnace is accelerated and the vulcanization bonding process is completed in a short time. At the same time, heat treatment can be performed in a heating furnace that is smaller than in the past, and manufacturing costs can be reduced. Furthermore, the vulcanized and bonded laminate, the non-adhesive rubber-like elastic plate, the connected steel plate and the flange plate are separately stored to prepare for final assembly, thereby reducing the production management cost. In particular, when the rubber-like elastic plate is disposed at the end of the laminate, there is an advantage that the components to be vulcanized and bonded become one and the production and management are easy.

(3) A seismic isolation building using the laminated rubber bearing of the present invention can be constructed by using a laminated rubber bearing having the same shape and dimensions as compared with a case using a conventional laminated rubber bearing. And the safety against large deformation can be enhanced. In addition, since the design restrictions are eased, the seismic isolation design of this seismic isolation building becomes easy.

[0021]

Embodiments of the present invention will be described below. FIG.
The upper and lower surfaces of the rubbery elastic plates 2x, 2x at the upper and lower ends of the laminate 4 are not bonded to each other. This laminated rubber bearing 1
Are the upper and lower connecting steel plates 3a and 3
a and vulcanized adhesive except for the upper and lower rubber-like elastic plates 2x, 2x.
x, 2x, the connecting steel plates 3a, 3a and the flange plates 5, 5 are superposed and assembled. In this manufacturing method, the intermediate laminated body 4 placed in the vulcanizing and bonding furnace is smaller than the final shape, so that during vulcanizing and bonding, the internal temperature of the rubber-like elastic plate is vulcanized. The time required to raise the temperature to the required temperature can be shortened, and productivity can be increased and manufacturing costs can be reduced.

FIG. 2 shows a state in which the rubber-like elastic plate 2x at the intermediate position of the laminate is not bonded. The assembly in this case is
This is performed by separately assembling the upper and lower sides of the laminated rubber support, vulcanizing and bonding each, and finally sandwiching a rubber-like elastic plate at an intermediate position. Also in the case of this manufacturing method, since the vulcanization bonding is performed in a state where the number of laminations is small, the rubber-like elastic plate can be raised to a required temperature in a short time, and the manufacturing cost can be reduced.

In the first embodiment, the number of non-adhesive rubber-like elastic plates 2x is two, and in the second embodiment, the number of non-adhesive rubber-like elastic plates 2x is one. This number may be used as long as the horizontal spring constant K for repeated repetition of large deformation does not become unstable, as long as it is necessary to suppress the hardening of the bonded portion and prevent the breakage.

The concept of determining the required number will be described. For example, in the embodiment of FIGS. 1 and 2, eight rubber-like elastic plates are used.
When one sheet is used, the effect of preventing hardening and breakage can be obtained by 1/8. This seismic isolation bearing 1
Is 250% when all the rubber-like elastic plates 2 are bonded.
Hardening occurs at a deformation rate of 400%, and breakage occurs at 400%.
It is assumed that the material enters the plastic deformation region at a deformation rate exceeding 1000% and does not lose its load carrying capacity up to 1000%. In that case, 1
When the rubber-like elastic plates are not bonded,
Looking at the deformation rate of the entire laminated rubber support (1000-40)
The breaking limit of the laminated rubber bearing can be increased by 0) / 8%. In addition, the effect of suppressing the hardening is increased until the non-adhesive rubber-like elastic plate is deformed to 1000%.
It is obtained by deforming the non-adhesive rubber-like elastic plate more than the bonded rubber-like elastic plate. decide.

[0025]

According to the laminated rubber bearing of the present invention, a single or a plurality of non-adhesive layers are introduced at the upper and lower ends or in the middle of the laminated rubber bearing of the adhesive type. By compensating for the shortcomings of the type and securing the advantages, the spring performance can be dramatically improved, and the degree of freedom in designing adaptively to the required spring performance can be increased.

Further, since the vulcanization bonding step can be performed in a divided state, the manufacturing cost can be reduced as compared with the full bonding type by increasing the heating efficiency and the like.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a side view showing a second embodiment of the present invention.

FIG. 3 is a side view (a) and a plan view (b) showing the structure of a laminated rubber bearing body.

FIG. 4 is a side view showing a building using a laminated rubber bearing.

FIG. 5 is a diagram showing seismic isolation characteristics of a vulcanized adhesive type laminated rubber bearing.

FIG. 6 is a diagram showing seismic isolation characteristics in the case of a single layer of a non-adhesive laminated rubber bearing.

FIG. 7 is a diagram showing seismic isolation characteristics of a non-adhesive laminated rubber bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated rubber bearing body 2 Rubbery elastic plate 2x Non-adhesive rubbery elastic plate 3 Rigid plate 3a Connected steel plate (rigid plate) 4 Laminate 5 Flange plate 6 Through hole 7 Mounting hole 8 Heavy object (upper part) Structure) 9 Foundation (substructure)

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 22, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

The meaning that the joining surface between the rubber-like elastic plate and the rigid plate is made non-adhesive means that one surface is made non-adhesive and the other surface is made other than the case where the front and back surfaces of the rubber-like elastic plate are made non-adhesive. When the surface is bonded, another thin rubber is stuck to the rubber-like elastic plate, and the bonding surface between this thin rubber and the rigid plate is not bonded.
Including the case. These are for hardening and breaking
This is because it has the effect of the present invention.

Claims (3)

[Claims] 1. A laminated rubber bearing body comprising a rubber-like elastic plate and a rigid plate which are alternately laminated, and which mounts and supports a heavy object so as to be capable of swinging in the horizontal direction. On the other hand, the joint surface between the rubber-like elastic plate and the rigid plate must be in the range necessary for suppressing the hardening of the rubber-like elastic plate and preventing breakage within the range where the horizontal spring constant does not become unstable. A laminated rubber bearing, characterized in that it is bonded and another bonding surface is bonded. 2. The laminated rubber bearing according to claim 1, wherein a rubber-like elastic plate joined to the rigid plate in a non-adhesive manner is disposed at an end of the laminated body. 3. A seismic isolation building characterized in that an upper structure is mounted on a lower structure using the laminated rubber bearing according to claim 1 or 2.