JP2756111B2 - Seismic isolation device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device of a constrained peripheral type for mounting and supporting a structure to reduce an earthquake input and to prevent vibration. By enclosing the outer periphery of the columnar rubber-like body with a stacked arrangement of constraining members, a large rigidity capable of supporting a structure in the vertical direction is provided while maintaining a large deformation capability in the horizontal direction. The present invention relates to a seismic isolation device having a damping function. [0002] As a seismic isolation device for structures such as buildings,
Laminated rubber bearings have begun to be widely used, and they are roughly classified into three types. The first type is a laminated rubber bearing (a) in which rubber plates (1) and steel plates (2) of natural rubber or the like having a small compression set are alternately laminated and fixed as shown in FIGS. 9 (a) and 9 (b). It is. This type is
Since the ratio of the vertical compression stiffness to the horizontal shear stiffness is extremely large, the transmission of seismic energy to the structure is reduced while the structure, which is heavy against earthquake motion, is supported with good stability. [0003] The second type has a laminated structure of the first type of laminated rubber bearing, which has a vibration energy absorbing effect. Therefore, as shown in FIGS. This is a lead-laminated rubber bearing (b) in which a plug (3) is inserted.
issue〕. In this type, as shown in FIG. 11, the amplitude of vibration of a structure caused by an earthquake is reduced and rapidly attenuated by hysteresis due to plastic strain of lead encapsulated therein. [0004] The third type uses a high-damping rubber for the rubber plate (1) in the structure of the laminated rubber bearing (a) shown in FIGS. 9 (a) and 9 (b) to attenuate the laminated body itself. High damping laminated rubber bearing with function (c)
It is. The above-mentioned laminated rubber bearings (a), (b) and (c) have the following problems, respectively. The first type of laminated rubber bearing (a) has a very small vibration damping ability, so that if it is used as it is, the vibration amplitude of the structure at the time of an earthquake becomes large and lacks safety. Therefore, usually, dampers are separately arranged and used in parallel. In this case, the point of action of the restoring force and the point of action of the damping force are different, and there is a possibility that unnecessary torsional vibration may be applied to the structure. [0007] In the lead-laminated rubber bearing (b) of the second type, the lead plug (3) exhibits a large initial rigidity against microvibration as shown by the characteristic (S) in FIG. For this reason, the anti-vibration performance is poor, and traffic vibrations and the like generated due to the passage of vehicles and the like are transmitted. Therefore, it has been difficult to apply it to buildings and floors in which equipment that dislikes vibration is installed. In addition, there was also a problem that recovery to the origin after large deformation was slow due to plasticity of lead. In the third type of high damping laminated rubber bearing (c), the high damping rubber used has a large amount of creep and a poor restoring force against horizontal displacement, and thus has a problem of low reliability especially for long-term use. There is. Also, since the amount of creep differs for each high-damping laminated rubber bearing that is installed side by side, as a result of seismic isolation operation, the building will experience uneven settlement,
There is also a problem that unnecessary stress is generated in the structure. The present invention relates to the above laminated rubber bearing (a).
(B) Based on the actual circumstances of (c), the present invention is based on a fundamentally different structure / principle, and aims to propose a seismic isolation device in which the above problems are solved. [0010] The present invention proposes a newly proposed perimeter restraint type seismic isolation device which is provided at a lower portion of a structure so as to support a vertical load of the columnar rubber. The body, the ring-like rubber-like elastic body and the ring-shaped hard plate are stacked,
It is characterized in that it comprises a restraining body which is laminated and arranged in the height direction on the outer periphery of the rubber-like body with the friction-reducing material interposed therebetween and restrains the rubber-like body from protruding outside. In the above seismic isolation device, the columnar rubber-like body is constrained by the surrounding constraining body, thereby exhibiting high vertical rigidity and load supporting ability while having a large horizontal deformability. . Then, the restraining body and / or the rubber-like body exerts a vibration energy absorbing effect mainly by frictional damping. This vibration absorbing effect is also effective for fine vibration. In particular, the frictional damping by the above-mentioned restraining member is such that the difference between static friction and dynamic friction is small because the hard plate is laminated with the rubber-like elastic material via the anti-friction material, thereby minimizing vertical vibration and reducing noise. The damping effect can be obtained while keeping it to a minimum. Further, in the structure of the device according to the present invention, the point of action of the restoring force and the point of action of the damping force are the same, and unnecessary torsional vibration is not applied to the structure. From the above, the device of the present invention is a conventional laminated rubber bearing (a) as a damper-integrated seismic isolation device.
(B) Demonstrates the same or better performance as (c). Since the columnar rubber-like body is used alone, it is possible to use a rubber of a type that could not be used in the case of a laminated structure as the rubber-like body. First, the basic concept of the seismic isolation device A of the present invention will be described. FIGS. 1 to 3 show three basic structural examples (A1), (A2) and (A3) of a seismic isolation device A, which are arranged in a stacked manner around a columnar rubber-like body (11). Restraining body (1
The structure 2) is different from each other. Here, the columnar rubber-like body (11) which is disposed at the center and receives the vertical load of the structure,
When high damping rubber is used, the dynamic strain rate is 0.5 at 0.5 Hz.
% Loss at −10 to 40 ° C. (TANδ) is 0.1%.
Those in the range of 1 to 1.5 are preferred. If the loss (TANδ) exceeds 1.5, the vibration damping performance in the vertical direction at 10 Hz or more deteriorates, and if it is 0.1 or less, it does not contribute much to the improvement of the damping performance in the horizontal shear direction. The following basic configuration examples (A1) (A2) (A
The structure of each restraining body (12) in 3) will be described sequentially. A first configuration example (A) shown in FIGS.
The restraining body (12) of 1) fixes a one-sided clerk of a ring-shaped rubbery elastic plate (13) having a small compression set and a ring-shaped restraining plate (14) such as a steel plate as a restraining material, It is laminated with an anti-friction material (15) in between. Here, the term "fixing" includes laminating or vulcanizing adhesion. The restraining body (12) of the second configuration example (A2) shown in FIGS. 2A and 2B has a ring-shaped rubber-like elastic plate (16) having a small compression set on the front and back surfaces. A ring-shaped restraining plate (17) such as a steel plate, which is a restraining material, is fixed one by one to form a three-layer structure, which is laminated with an anti-friction material (15) interposed therebetween. The restraining body (12) of the third configuration example (A3) shown in FIGS. 3A and 3B is provided on the front and back surfaces of a ring-shaped restraining plate (18) such as a steel plate as a restraining material. A three-layer structure in which ring-shaped rubbery elastic plates (19) having a small compression set are fixed one by one and laminated with an antifriction material (15) interposed therebetween. Here, the restraining plate (14) which is the restraining material is used.
(17) and (18) only need to be those having high rigidity and high breaking strength, and materials other than steel plates can be used. The rubber-like elastic plates (13), (16) and (19) having a small compression set may be elastic members having properties similar to those of the rubber material. Desirable amount of compression set for exerting the effective function of the restraining body (12) is JIS-
It is 35% or less by 70 ° C.-22HR heat treatment based on K6301, and particularly those having 20% or less show good properties. The friction reducing material (15) may be any material that reduces the difference between the static friction and the dynamic friction between the restraining plates. For example, the friction reducing material (15) is impregnated with a resin having a small friction coefficient such as silicone grease or Teflon, or a lubricant. Components are used. The mounting of these lubricants (15) is performed by applying, coating, or fixing them to the sliding surface of a restraining plate or a rubber-like elastic plate according to their properties. The constraining body (12) is not limited to the above-described configuration example. In other words, a rubber-like elastic plate having a spacer function is fixed to a hard constraining plate, which is a constraining member. What is necessary is just to be sandwiched and laminated. For example, if the rubber-like body (11) is prismatic, the planar shape of the restraining body (12) is a corresponding square shape. In addition, the restraint (1
In the case 2), the restraining plate to which the rubber-like elastic plate is fixed may be spirally bent to be in a laminated state. Next, a description will be given of a production example embodying the above basic configuration example with reference to FIGS. 4 and 5, and the characteristics obtained thereby will be described. The seismic isolation device (20), which is the first example of manufacture shown in FIG. 4, is a device (A) of the basic configuration described earlier with reference to FIG.
Corresponding to 1), between a fixing plate (21) (21) fixed to an upper structure and a lower structure, a columnar rubber-like body (11) and a constraining body (12) surrounding the same. Is fixed. The rubber-like body (11) has pressure receiving plates (2
2) (22) was embedded and bonded, and the material used was natural rubber or high-damping rubber, isobutylene-isoprene rubber having a tan δ of about 0.3. In addition, the restraint (1
2) Constraining plate (14) and rubbery elastic plate (13)
The thickness ratio is 2: 1 and a silicone grease having a viscosity of 300,000 cSc (at 25 ° C.) or a Teflon resin sheet is used as the anti-friction material (15). Next, a seismic isolation device (23), which is a second example of manufacture shown in FIG. 5, has a basic configuration example (A) described earlier with reference to FIG.
The difference from the one shown in FIG. 4 is that the restraining body (12) has a three-layer structure in which a rubber-like elastic body (16) is sandwiched between two restraining plates (17) and (17). Are laminated. The thickness ratio between each restraining plate (17) and the rubber-like elastic plate (16) is 1: 1. Load-displacement curves measured for the first fabrication example shown in FIG. 4 were as shown in FIGS. 6, 7 and 8, respectively. Here, FIG. 6 shows a rubber-like body (11).
Shows the characteristics when the material is natural rubber (NR) and the anti-friction material (15) is silicone grease. FIG. 7 shows a rubber-like body (1).
The material of 1) is a high damping rubber (IIR), and an anti-friction material (15)
Shows the characteristics when is silicone grease. FIG. 8 shows characteristics when the material of the rubber-like body (11) is a high-damping rubber and the anti-friction material (15) is a Teflon resin sheet. The second
In the production example (23), when the materials of the rubber-like body (11) and the anti-friction material (15) are selected in the same manner as in the above-described example,
Similar characteristics were obtained. These are shown in FIG.
In comparison with the load-displacement curve of the lead-laminated bearing (b) shown in Fig. 7, it can be seen that the rigidity with respect to minute displacement is small, and the anti-vibration effect is exhibited even with minute vibration. Table 1 shows a comparison of these values. [Table 1] That is, the seismic isolation device A has a shear rigidity at a horizontal displacement of 2 mm that is 1/3 or more of that of the lead-laminated rubber bearing (c).
It is 1/6, which indicates that very good damping performance is exhibited for microvibration. Further, the damping constant h proportional to the area surrounded by the hysteresis force exceeds the generally required damping constant of the seismic isolation device of 0.1 in each of the production examples. In particular, in a production example in which silicone grease and a high-damping rubber are used in combination (FIG. 7), the damping action due to the viscosity of the silicone grease is added to increase the value to 0.17, thereby obtaining a favorable effect. Next, regarding the vertical / shear (horizontal) rigidity ratio Kv / KH, which is a basic characteristic required for seismic isolation, the above-described production example using natural rubber and silicone grease (FIG. 6) and the natural type shown in FIG. Table 2 shows a comparison with the laminated rubber bearing (a) using rubber. [Table 2] According to Table 2, the vertical loading capacity shows the same performance,
The horizontal shear stiffness KH is smaller than that of the embodiment of the present invention, and the stiffness ratio Kv / KH reaches about twice. From this, it can be said that the seismic isolation capacity is higher than the conventional one. By comparing the numerical data in Tables 1 and 2 above, the seismic isolation device A of the present invention has both a vibration damping effect and a seismic isolation effect as compared with the conventional laminated rubber bearing.
It has been shown to have equal or better performance. According to the present invention, a seismic isolation device having a large vertical loading capacity that can be replaced with a conventional laminated rubber bearing can be provided by using a rubber material that is not laminated. In particular, the seismic isolation device of the present invention does not use a material having a large initial rigidity such as lead in order to obtain a damping function. Is wide and the characteristics can be arbitrarily designed in a wide range. Therefore, in addition to seismic isolation and vibration isolation of buildings, it is also suitable for seismic isolation and isolation of floors in buildings, and seismic isolation and isolation of power transmission equipment and general equipment. Further, a high damping function can be obtained by the damping action of the restraining body that does not cause noise.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first basic structure (A) of a seismic isolation device A of the present invention.
It is the top view (a) and sectional drawing (b) which showed 1). FIG. 2 shows a second basic structure (A) of the seismic isolation device A of the present invention.
2A and 2B are a plan view and a cross-sectional view, respectively. FIG. 3 shows a third basic structure (A) of the seismic isolation device A of the present invention.
It is the top view (a) and sectional drawing (b) which showed 3). FIG. 4 is a cross-sectional view showing a manufacturing example in which the basic structure example (A1) shown in FIG. 1 is embodied. FIG. 5 is a cross-sectional view showing a manufacturing example in which the basic structure example (A2) shown in FIG. 2 is embodied. FIG. 6 is a load-displacement curve when natural rubber is used as a rubber-like body and silicone grease is used as an anti-friction material in the specific production example shown in FIG. FIG. 7 is a load-displacement curve when a high-damping rubber is used as the rubber-like body and silicone grease is used as an anti-friction material in the specific production example shown in FIG. FIG. 8 is a load-displacement curve when a high-damping rubber is used as a rubber-like body and a Teflon sheet is used as an anti-friction material in the specific production example shown in FIG. 9 is a plan view and a sectional view of a conventional laminated rubber bearing (a) and a high damping laminated rubber bearing (c). FIG. 10 is a plan view and a sectional view of a lead-laminated rubber bearing (b). 11 is a load-displacement line of the lead-laminated rubber bearing (b) shown in FIG. [Description of Signs] 11 Rubber-like body 12 Restrictors 13, 16, 19 Rubber-like elastic plates 14, 17, 18 Restrictor 15 Antifriction material 20 First production example (A1) 23 Second production example (A2) 22 Pressure receiving plates A1, A2, A3 Basic configuration example of seismic isolation device of the present invention

Continued on the front page. (72) Mitsuo Miyazaki 3-3-306, Tsurugashima-cho, Iruma-gun, Saitama (72) Inventor Fumiaki Arima 3-9-7 Chiyoda, Sagamihara-shi, Kanagawa May Corp. (72) Inventor Tanaka Hisaya 2-37-23 HG Tateshina 205, Higashi-dori, Oyama-shi, Tochigi Prefecture (58) Field surveyed (Int.Cl. ⁶ , DB name) E04H 9/02 331 E04B 1/36 F16F 15/04

Claims (1)

(57) [Claims] At the lower part of the structure, a columnar rubber-like body is provided, and an annular rubber-like elastic body arranged on the outer periphery of the rubber-like body and a ring-like hard plate are superimposed, sandwiching an anti-friction material, A seismic isolation device characterized by comprising a restraining body which is stacked and arranged on the outer periphery of a rubber-like body in a height direction and restrains the rubber-like body from protruding outside. 2. At the bottom of the structure, a columnar rubber-like body arranged to support the vertical load, an annular rubber-like elastic body and an annular hard plate are stacked, A seismic isolation device characterized by comprising a restraining body which is arranged on the outer periphery of a body in the height direction and restrains the rubber body from protruding outside.