JP2536924B2 - Seismic isolation support - Google Patents

Description

The present invention relates to a seismic isolation bearing that uses a high damping elastomer made of butyl rubber, NBR or the like as an energy absorbing device (hereinafter referred to as a damper).

[Conventional technology]

An upper structure such as a building is swingably supported horizontally on a lower structure such as its foundation to reduce the input acceleration of the earthquake and protect the upper structure from the destructive force of the earthquake. The following are known as seismic bearings.

FIG. 9 shows a seismic isolation bearing in which hard plates (1) such as steel plates and rubber-like elastic plates (2) having a small compression set are alternately laminated. The seismic isolation bearing (3) has an extremely large ratio of the elastic modulus in the vertical direction to the elastic modulus in the horizontal direction, so that the seismic isolation bearing (3) supports the building in a vertically stable manner so as to be swingable in the horizontal direction. Then, the natural vibration cycle of the building can be made longer than the cycle of the maximum amplitude component of the earthquake to reduce the acceleration response of the building during the earthquake. Since this seismic isolation bearing itself has almost no vibration energy absorption capability during seismic isolation operation, it is necessary to add a damper for energy absorption.

However, due to this damper, there are problems that the space occupied by the entire apparatus becomes large, many points of force act, the design becomes complicated, and the mounting cost becomes high. In addition, plastic dampers such as steel rod dampers that have been mainly used so far need to be replaced when they deteriorate to a certain extent and are used to some extent.

Therefore, as a seismic isolation bearing with integrated damper, Fig. 10 ~
The one shown in Fig. 12 was considered.

Fig. 10 shows the seismic isolation bearing (3) explained in Fig. 9.
It is a seismic isolation bearing that has a lead plug (4) as a damper in the center of the and has an energy absorption capacity.
-17984).

However, due to the lead plug (4), it is difficult for the upper structure to return to its original position after deformation, and the initial rigidity is too high, which causes a new problem of transmitting microvibration to the upper structure as it is.

Fig. 11 shows the seismic isolation bearing (3) explained in Fig. 9.
A high-damping elastomer (5) that absorbs vibration energy is used for the rubber elastic plate in the lead plug (4).
Seismic isolation bearing to remove the defects of
issue).

However, since the high-damping elastomer (5) directly supports the large vertical load of the superstructure, the seismic isolation bearing (6) has a large amount of creep, a large internal strain, and durability (life). There is a problem of being bad.

The seismic isolation bearing (8) shown in Fig. 12 is designed so that the high damping elastomer does not directly support the large vertical load of the superstructure. This is provided with a vertical through hole at the center of the seismic isolation bearing (3) described in FIG. 9, and a high damping elastomer (7) is put in this through hole to provide a vibration energy absorbing function (actually, (Kaisho 61-39705).

[Problems to be Solved by the Invention]

The seismic isolation bearing (8) shown in FIG. 12 seems to support the vertical load only by the laminated portion of the hard plate (1) such as a steel plate and the rubber-like elastic plate (2). However, in practice the high damping elastomer (7) also results in supporting vertical loads. This will be described. When a load is applied in the vertical direction, the rubber-like elastic plate (2) is compressed and the high damping elastomer (7) inside is also compressed and swells in the horizontal direction in the same manner as strain is generated. This periphery is restrained by a hard plate (1) and a rubber-like elastic plate (2). Therefore, the high-damping elastomer (7) also bears the vertical load similarly to the rubber-like elastic plate (2). Therefore, when an elastomer having a large creep amount is used inside, the creep strain amount of the entire bearing also increases. Due to the physical properties of the high-damping elastomer, the occurrence of creep strain is large. Therefore, the amount of creep of the seismic isolation bearing (8) shown in Fig. 12 is the same as that of the seismic isolation bearing (6) shown in Fig. 11.
Although it is less than that of the seismic isolation bearing (3) shown in FIG. Therefore, the internal strain caused by creep deteriorates the durability.

Therefore, it is an object of the present invention to realize a seismic isolation bearing having a small vertical creep deformation in the seismic isolation bearing using a high damping elastomer as a damper.

[Means for solving the problem]

The seismic isolation bearing provided by the present invention includes a support body in which hard plates having rigidity and rubber-like elastic plates having a small compression set are alternately laminated, and is provided around the support body in a non-adhesive state with respect to the support body. And a high damping elastomer fixed so as to be sandwiched between the upper and lower flanges of the support body.

In addition, the high damping elastomer is a laminated body in which rigid hard plates and plate-shaped high damping elastomers are alternately laminated and fixed, and the highly damping elastomer is arranged around the above supporting body in a non-adhesive state with respect to the supporting body. It can also be fixed so as to be sandwiched between the flanges of the support.

[Action]

The high-damping elastomer in the seismic isolation bearing of the present invention is arranged on the outer periphery of the bearing body that receives a vertical load in a non-bonded state to the bearing body, and is not constrained by the bearing body against deformation stress due to external force at the time of an earthquake. It has a high degree of freedom and can bulge outward freely. Therefore, it does not receive a vertical load, does not generate creep, and has a long life.

If a high damping elastomer is sandwiched between hard plates and is a non-bonded laminated body with the support, in addition to the above action, the vertical movement of the high damping elastomer is restricted, and the strain amount per unit volume against horizontal vibration is reduced. To increase. Therefore, the damping constant can be increased as compared with the case where no lamination is performed.

〔Example〕

The basic structure of the seismic isolation bearing (10) of the present invention is shown in FIG.
This seismic isolation bearing (10) forms a columnar bearing (13) by alternately laminating a rubber-like elastic plate (11) having a small compression set such as natural rubber and a hard plate (12) such as a steel plate. , Surrounding it with high damping elastomer (14). It is not necessary to provide a gap between the high-damping elastomer (14) and the support body (13), but they are not adhered. When the rubber-like elastic plate (11) having a small compression set has a high or low damping capacity, the amount and performance of the external high-damping elastomer (14) are changed to adjust.

Here, the rubber-like elastic plate (11) having a small compression strain, such as natural rubber, means an elastomer having a compression set of 25% or less. In addition, the high damping elastomer (14) is 25
Tan δ at 0.15 to 1.5 at ℃, 0.5Hz, ± 50% shear strain,
At that time, the absolute modulus | G ^* | refers to a product of ² to 21 kgf / cm ² .

This absolute elastic modulus | G ^* | is the absolute value of multiple elastic moduli Is. Where G ₁ is the storage elastic modulus, which is the quotient of the amplitude τo · cosδ in phase with the strain of stress divided by the strain amplitude γo, and G ₂ is the loss elastic modulus, which differs from the stress strain by 90 ° in phase. It is the quotient of the component amplitude τo · sinδ divided by the strain amplitude γo. Specific examples of the high-damping elastomer include butyl rubber and NBR.In addition to these, NR, SBR, BR, polynorbornene, silicone rubber, fluororubber, chlorobutyl rubber, chloroprene rubber, urethane elastomer or blends thereof. And the like, and includes a high-damping elastomer blend obtained by blending a reinforcing agent, a filler, a resin, a softening agent, and the like.

A specific manufacturing example of the basic structure shown in FIG. 1 will be described with reference to FIG.

The seismic isolation bearing (10a) shown in Fig. 2 has a rubber-like elastic plate (1
As 1), 39 pieces of natural rubber having a diameter R of 600 mmφ and 4 mm thickness are used, and 38 pieces of hard plates (12) sandwiched between the natural rubbers are made of 2 mm thick steel plate. ) Is formed. The high damping elastomer (14) concentrically arranged around this support (13) has an inner diameter of 620 mmφ and an outer diameter of 880 mm.
It has a cylindrical shape of φ. This high damping elastomer (1
4) has a tan δ of 0.53 at 25 ° C, 0.5 Hz, ± 50% shear strain.
Therefore, the absolute modulus of elasticity | G ^* | at that time is 7 kgf / cm ² of polynorbornene. A flange (15) having high strength is fixed to the upper and lower surfaces of the bearing (13) and the high damping elastomer (14).

When the damping constant h at the time of shear deformation in this manufacturing example was measured, a value of 0.12 could be obtained. A normal seismic isolation bearing has a damping constant h of 0.1 to 0.15, so 0.1
2 is a sufficient value. The damping constant h is a value indicating vibration damping performance such as vibration, Is represented by However, ΔW is energy consumed for each cycle of vibration, and W is input elastic energy. This will be explained with reference to the hysteresis loop (16) drawn by the horizontal displacement and its reaction force shown in FIG. 3. ΔW is the area surrounded by the hysteresis loop (16), and W is the area of the shaded portion.

The high damping elastomer (14) of the present invention does not necessarily have to be a single piece as shown in FIGS. 1 and 2. It suffices that the high-damping elastomer (14) be arranged around the support body (13) in a state where it can be deformed in the horizontal direction by the vibration during the base isolation operation. For example, if the high damping elastomer is used as a laminate, the damping constant can be further increased. This concrete manufacturing example will be described with reference to FIG.

The seismic isolation bearing (10b) shown in FIG. 4 is obtained by laminating the high damping elastomer (14) portion of the seismic isolation bearing (10a) shown in FIG. 2, and the other portions are shown in FIG. The material, size and shape of the seismic isolation bearing (10a) are the same. This laminated body (14a) of high-damping elastomer uses 20 sheets of high-damping elastomer (7.8) with a thickness of 7.8 mm, and a steel plate (18) with a thickness of 4 mm is sandwiched between them as a hard plate and fixed and laminated. It is a thing. The outer diameter of this laminate (14a) is the same as that of the high damping elastomer (14) shown in FIG.
It has a cylindrical shape of 620 mmφ and an outer diameter of 880 mmφ. The material of the high damping elastomer plate (17) is also shown in FIG. Same as high damping elastomer (14), ie 25 ℃, 0.5Hz, ± 50
The tan δ at% shear strain is 0.53 and the absolute elastic modulus at that time is 7
It is a polynorbornene of kgF / cm ² . As the hard plate (18), a steel plate or the like may be used, but it is preferable to use a non-combustible or flame-retardant material having low thermal conductivity in order to improve fire resistance performance.

In this fabrication example, the high damping elastomer laminate (14a) requires the layers to be secured together. However, the support (1
Each layer in 3) does not necessarily have to be fixed. This is because each layer becomes stuck when a large vertical load is applied.

When the damping constant of the base isolation bearing (10b) shown in Fig. 4 during shear deformation was measured, a value of 0.14 was obtained. This is the second
It is increasing from the seismic isolation bearing (10a) shown in the figure.

The high damping elastomer (14) or laminated body (14)
As shown in FIG. 5, a) is fixed to the upper and lower flanges (15) by using, for example, mounting plates (19) (19) vulcanized and bonded to the upper and lower surfaces thereof. As shown in the figure, in this flange, the support body (13) and the high-damping elastomer (14) to the laminate (14a) may be the same body or different bodies.

Further, the high damping elastomer (14) or the laminate (14a) thereof may be provided with at least one cut portion (20) as shown in FIG. 6, for example. This split structure enables retrofitting to existing seismic isolation bearings. This construction allows for high damping elastomers (14)
Alternatively, since the laminate (14a) is packaged, unlike the case where the high damping elastomer is arranged inside, the high damping elastomer having a different outer diameter can be replaced even afterward. Therefore, the damping performance of the seismic isolation bearing can be changed later. In addition, since the laminated portion can be manufactured independently of the high damping elastomer, it is easy.

In the present invention, the high damping elastomer (14) or the laminated body (14a) thereof is arranged on the outer periphery of the support body (13) in order to give the high damping elastomer a swellable space. This concept is applied to the seismic isolation bearing (8) shown in FIG. 12 as a conventional example, and as shown in FIG.
It is conceivable to make the inner diameter of a) larger than the outer diameter of the high damping elastomer (7). However, in the case where the high damping elastomer (7) is incorporated in this way, the free surface of the portion where the rubber-like elastic plate and the hard plate are laminated can also be formed inside, so that the vertical rigidity of the support (8a) is significantly reduced. Therefore, in order to obtain the required vertical rigidity, it is necessary to increase the cross-sectional area of the laminated bearing bodies (8a), which makes the outer diameter of the seismic isolation bearing too large to be practical.

Further, the seismic isolation bearing of the present invention, as a result of disposing the high damping elastomer (14) or the laminated body (14a) around the bearing body (13), supports the fire resistance performance, that is, the weight of the building during a fire. At the same time, it has the function of protecting the bearing from fire. In particular, in the case of a system in which normal heat insulating material is arranged around the bearing, if a fire occurs after the heat insulating material is damaged due to a large shaking of the earthquake, it will not protect the bearing, so it is truly seismic isolated. I couldn't make a structure. With this method, the high-damping elastomer will not be damaged even if it is subjected to a large quake, so it is possible to respond to a fire after the earthquake. Also, by replacing the high damping elastomer after the fire ends, the bearing can be reused without any damage.

This fire resistance is further explained. For example, as shown in FIG. 8, a seismic isolation bearing (10) is covered with a high-damping elastomer (21) having a thickness of 60 mm with a gap of 10 mm, and ceramics are vertically arranged. In a fireproof test conducted by placing a fiber fireproof coating (22) and putting it in a heating furnace,
No change was observed in the performance after the 3-hour fire resistance test required for the fire resistance performance of the structure. Therefore, the thickness of the high damping elastomer to be mounted is 40 mm or more, more preferably 60 mm.
I just need more. The seismic isolation that is actually manufactured so that the thickness of the high damping elastomer (14) or the laminate (14a) of the seismic isolation bearings (10a) and (10b) shown in FIGS. 2 and 4 is 130 mm. Since the thickness of the high-damping elastomer of the bearing is usually considerably larger than the above-mentioned value of 40 to 60 mm, the seismic isolation bearing of the present invention will have sufficient fire resistance performance without special consideration.

In order to further improve fire resistance performance, flame retardant elastomers such as silicone rubber, fluororubber and chlorobutyl are used for the high damping elastomer, and antimony oxide, organic phosphate ester, chlorinated paraffin, inorganic salts are used for the high damping elastomer. Addition-type flame retardants such as, and those to which reaction-type flame retardants such as tetra-bromo-bisphenol A are added may be used.

Further, by using a color mixture in the high-damping elastomer, it is possible to provide a bearing having fashionability.

〔The invention's effect〕

According to the present invention, a bearing and a damper can be integrated, and a seismic isolation bearing having the same creep amount as that of a conventional laminated rubber bearing using natural rubber and a large damping capacity can be realized.

Further, the high-damping elastomer arranged around the bearing as a damper also exhibits a fire resistance function, and the seismic isolation bearing of the present invention is also highly reliable in this respect.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the seismic isolation bearing of the present invention, FIG. 2 is a sectional view showing a concrete manufacturing example of the seismic isolation bearing shown in FIG. 1, and FIG. 3 is a high damping elastomer. FIG. 4 is a cross-sectional view showing a hysteresis loop for explaining a damping constant, FIG. 4 is a sectional view showing a concrete manufacturing example of the base isolation bearing of the present invention using laminated high damping elastomers, and FIG. 5 is a mounting structure of high damping elastomers. FIG. 6 is a cross-sectional view showing an example, and FIG. 6 is an explanatory view of a structure in which a high-damping elastomer is divided and attached to a support. FIG. 7 is a reference example for comparison with the present invention, and is a cross-sectional view showing a seismic isolation bearing in which a high-damping elastomer is internally provided with a gap. FIG. 8 is a sectional view for explaining a fire resistance test conducted on the seismic isolation bearing of the present invention. 9 to 12 are cross-sectional views showing different structural examples of conventional seismic isolation bearings. (1) …… Hard plate, (2) …… Rubber-like elastic plate, (13) …… Supporting body, (14) …… High damping elastomer, (14a) …… High damping elastomer laminate.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiaki Miyamoto 5-25-3 Kawamata, Takarazuka-shi, Hyogo Prefecture (72) Inventor Mitsuo Miyazaki 3-3-3-3, Tsurugashima-cho, Iruma-gun, Saitama Inventor Arima Fumiaki 3-9-7 Chiyoda, Sagamihara-shi, Kanagawa May Corp. (72) Inventor Yuji Mitsusaka 2-3-5 Shin-Sayama, Sayama-shi, Saitama Sumitomo Construction Daiichi Sayama Dormitory (56) References JP-A-64- 29540 (JP, A)

Claims (2)

(57) [Claims] 1. A support body in which hard plates having rigidity and rubber-like elastic plates having a small compression set are alternately laminated, and the support body is disposed around the support body in a non-adhesive state with respect to the support body. A seismic isolation bearing comprising a high-damping elastomer fixed so as to be sandwiched between upper and lower flanges. 2. A support body formed by alternately laminating a rigid hard plate and a rubber-like elastic plate having a small compression set, and a rigid hard plate and a plate-like high damping elastomer which are alternately laminated and fixed. A seismic isolation bearing, comprising: a laminated body which is disposed around the support body in a non-adhesive state with respect to the support body and is fixed so as to be sandwiched by a flange of the support body.