JPH11210827A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively isolate the vibration of even structures with a small support load such as low buildings by a compact and low cost device. SOLUTION: Slide plates 10 and 11 opposing to each other are fixed to an upperstructure 12 and substructure 13, and movable pieces 16 comprising a material 16b whose faces abutting on the slide plates are slidable on the slide plates are slidably provided between the slide plates, and energizing means 19 and 20 which horizontally energize each of the movable pieces are also provided between these movable pieces 16 and the upperstructure 12 and substructure 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seismic isolation device interposed between an upper structure and a lower structure in various seismic isolation structures.

[0002]

2. Description of the Related Art In recent years, in various structures, a seismic isolation device is interposed in a foundation portion, a middle level, and the like of the structure to attenuate vibrations that are to propagate from the ground to the structure due to an earthquake or the like. Therefore, various seismic isolation structures have been developed to reduce the stress and deformation generated in the structural body.
Conventionally, as a seismic isolation device used for such a seismic isolation structure, a laminated rubber bearing system, a sliding bearing system, or a rolling bearing system is generally known. The seismic isolation structure is configured by combining a plurality of types of seismic isolation devices.

[0003] Here, the laminated rubber bearing system is one in which rubber is surrounded in a laminated manner through a metal plate inside, and the laminated rubber is elastically deformed in a shearing direction and transmitted to an upper structure during an earthquake. In addition to alleviating horizontal seismic forces, the natural structure of the superstructure is lengthened to suppress stress and deformation occurring in the structure. Further, as shown in FIG. 9, the above-mentioned seismic isolation device of a sliding bearing system has a sliding plate 2 mounted on a lower structure 1 and a columnar structure fixed to the lower surface of an upper structure 3 and arranged opposite to the sliding plate 2. It comprises a body 4 and a sliding member 5 made of a material such as Teflon, which is integrally attached to the lower end surface of the columnar body 4 and slidably provided on the sliding plate 2.

[0004] In the seismic isolation device having the above-described sliding bearing, when the lower structure is horizontally displaced during an earthquake, the sliding member 5 slides on the sliding plate 2, and the frictional force generated at the time of sliding causes the sliding member 5 to slide. A horizontal seismic force acting on the upper structure 3 is attenuated to ensure the soundness of the upper structure 3. In addition, the rolling bearing system has a rolling member such as a roller interposed between the upper structure and the lower structure to prevent the horizontal displacement of the lower structure generated during an earthquake from being transmitted to the upper structure. Things.

[0005]

The conventional seismic isolation device described above is relatively easy to select and design for a device having a large supporting load, such as a middle-to-high-rise structure. For a structure having a low supporting load such as a structure having a very low layer, there are various problems as described below. First, in the case of a laminated rubber-based seismic isolation device, it is necessary to increase the diameter of the bearing in order to secure a desired amount of deformation in order to buffer the transmission of vibration to the upper structure. It is difficult to prolong the natural period of the data.

Further, in a seismic isolation device using a sliding bearing, as shown in FIGS. 9 and 10, it is necessary to secure a displacement δ generated at the time of an anticipated earthquake around the sliding member 5. Even if it is a low-rise structure,
However, it is necessary to use a large size, and there is a problem that economic efficiency is inferior. Furthermore, the seismic isolation device of the rolling bearing system has a problem that the mechanism is complicated and the cost is high.

SUMMARY OF THE INVENTION The present invention has been made to effectively solve the problems of the conventional seismic isolation device described above, and is effective for a structure having a small supporting load such as a low-rise building by using a compact and inexpensive device. It is an object of the present invention to provide a seismic isolation device capable of achieving such seismic isolation.

[0008]

According to a first aspect of the present invention, there is provided a seismic isolation device according to the present invention, wherein sliding plates facing each other are fixed to an upper structure and a lower structure, and the sliding plates are interposed between the sliding plates. A movable member whose contact surface is slidably provided with a slidable material is provided between the movable member and the upper structure and the lower structure. It is characterized by providing a force means.

Here, the invention according to claim 2 is characterized in that the urging means is an elastic rubber or a spring material. According to a third aspect of the present invention, in the first or second aspect, the coefficient of friction between the sliding plate of the upper structure and the movable element and the coefficient of friction between the sliding plate of the lower structure and the movable element are different. The friction coefficients are different from each other.

Further, the invention according to claim 4 is characterized in that the slidable material in the mover according to any one of claims 1 to 3 is formed by a rigid body, On the other hand, in the invention according to claim 5, an elastic member capable of supporting an axial force acting on the mover and capable of being deformed in the horizontal direction is interposed between the slidable materials of the mover. It is characterized by having.

[0011] In the seismic isolation device according to any one of claims 1 to 5, each of the abutting surfaces is formed of a slidable material between the sliding plates fixed to the upper structure and the lower structure. Is provided slidably, and furthermore, between the mover and the upper structure and the lower structure, biasing means for biasing the mover in the horizontal direction is provided, so that the horizontal seismic force generated during an earthquake is reduced. When the frictional force is larger than the frictional force determined by the product of the axial force acting on the mover and the friction coefficient between the sliding plate of the upper and lower structures, the lower structure and the upper structure and both surfaces between the mover and the upper structure , Respectively, causing slip. When a relative displacement occurs between the upper and lower structures and the mover due to the slip, a spring reaction force determined by a product of each relative displacement amount and a spring constant of each urging means is generated. Is a force for returning the upper structure and the mover to the original position. As a result, the above-mentioned sliding friction and spring suppress the stress and deformation generated in the upper structure.

At this time, since the mover slides with respect to the lower structure and the upper structure slides further with respect to the mover, it is assumed that the mover is positioned around the upper and lower slide plate movers. Since it is sufficient to secure a margin of 1/2 of the displacement amount generated at the time of the earthquake, the size of the slide plate can be set smaller than before. Therefore, according to the above seismic isolation device, it is possible to reduce the seismic force and to reduce the size of the sliding plate to almost half that of the conventional one. In this case, it is possible to effectively achieve seismic isolation by using a compact device. In addition, the mover can be returned to the original position after the earthquake by the urging means.

Here, as the urging means, various members which generate a reaction force by an elastic force with respect to an assumed horizontal displacement during an earthquake can be applied. If an elastic rubber or a spring material is used, the above-mentioned effects can be achieved by a general-purpose member without complicating the device, which is preferable.

By the way, if the coefficient of friction between the sliding plate of the upper structure and the mover is the same as the coefficient of friction between the sliding plate of the lower structure and the mover, a certain level of horizontal earthquake When a force is applied, sliding occurs simultaneously between the upper and lower structure and the mover. For example, as in the invention according to claim 3, the material of the upper and lower ends of the mover,
If the friction coefficient at the contact surfaces of each other is set to be different by changing the material of the sliding plates of the upper and lower structures, for example, the slip occurs on the smaller friction coefficient against the acting seismic force, Then, a slip occurs in the one having the larger friction coefficient. As a result, during a moderate earthquake,
Only one side of the contact surface between the upper and lower structures and the mover slips, and it becomes possible to provide a seismic isolation device of a two-stage mechanism in which slippage occurs on both upper and lower surfaces of the mover for the first time during a large earthquake.

Further, in the invention according to any one of the first to third aspects, a constant axial force is always applied to an intermediate portion of the mover whose upper and lower ends which are in contact with the slide plate are made of a slidable material. From the standpoint of bearing, it is preferable that the shaft is formed of a rigid body such as an iron material as in the invention of claim 4, but the portion is further formed of a shaft such as laminated rubber as in the invention of claim 5. If an elastic member capable of supporting a force and capable of being deformed in the horizontal direction is interposed, a seismic isolation device of an elastic sliding bearing can be provided.

[0016]

1 to 4 show an embodiment of a seismic isolation device according to the present invention and its operation. In FIGS. 1 and 2, reference numerals 10 and 11 denote bolts 1 at positions facing the upper structure 12 and the lower structure 13, respectively.
4 shows a sliding plate fixed by 4 and 15; The sliding plates 10 and 11 are selected from materials having a desired coefficient of friction such as a stainless steel plate, a fluorinated resin baked steel plate, a chromium-plated steel plate, a fluororesin (PTFE) material such as Teflon, and a polyacetal material. A mover 16 is slidably provided between the plates 10 and 11.

The movable element 16 is formed by bonding a resin material 16b such as Teflon slidable to the slide plates 10 and 11 to the upper and lower ends of a central portion 16a made of a rigid body such as a steel material to be integrated. It is composed. Also,
Annular mounting plates 17 and 18 are provided upright on the outer peripheral portions of the sliding plates 10 and 11, respectively.
A plurality of springs (biasing means) 19 and 20 are disposed at equal intervals in the circumferential direction between the movable members 7 and 18 and the opposing side surfaces of the mover 16.

In the seismic isolation device having the above configuration,
Sliding plate 1 fixed to upper structure 12 and lower structure 13
A movable member 16 having a resin material 16b slidable with respect to the sliding plates 10 and 11 is provided at upper and lower ends of the movable member 16 so as to be slidable.
8, springs 19 and 20 are provided to urge the mover 16 in the horizontal direction, so that the horizontal seismic force Q generated during an earthquake acts on the mover 16 as shown in FIG. When the frictional force μ ₂ · N, μ ₁ · N, which is determined by the product of the axial force N and the friction coefficients μ ₂ , μ ₁ between the sliding plates 10, 11 of the upper and lower structures 12, 13, Slip occurs between the lower structure 13 and the upper structure 12 and the mover 16. When a relative displacement occurs between the upper and lower structures and the mover due to the slip, a spring reaction force k determined by a product of the relative displacement δ ′ and the spring constants k ₂ and k ₁ of the springs 19 and 20. ₂ · δ ′ and k ₁ · δ ′ are generated, and the reaction force becomes a force for returning the upper structure 12 and the mover 16 to the original positions. As a result, the horizontal seismic force acting on the upper structure 12 is reduced, and the stress and deformation generated in the upper structure 12 are suppressed.

Further, as shown in FIGS. 3 and 4, if the friction coefficients μ ₂ and μ ₁ and the spring constants k ₂ and k ₁ are the same, the maximum amount of displacement generated during an assumed earthquake δ
In contrast, the mover 16 slides on the lower structure 13 by 1 / 2δ, and the upper structure 12 is further displaced by 1 / 2δ in the same direction with respect to the mover 16. For this reason, the upper and lower sliding plates 10,
11 around the movable element 16
/ 2 is enough to secure the margin.
The dimensions of 0 and 11 can also be reduced to almost half of the conventional size, so that even when applied to a low-rise structure,
It is possible to effectively achieve seismic isolation with a compact device.

In addition, the sliding plates 10 and 11 and the mover 16
By appropriately selecting the material of the resin material 16b or the spring constants of the springs 19 and 20, it is possible to set the seismic isolation device having the optimum damping effect and restoring effect for easily assumed earthquakes. In addition, the degree of freedom in design is greatly improved. Further, the movable element 1 is formed by the springs 19 and 20.
6 can be returned to the original position.

In the above embodiment, the case where the springs 19 and 20 are used as the urging means of the mover 16 has been described. However, the present invention is not limited to this. On the other hand, various members that generate a reaction force by an elastic force are applicable. For example, instead of the springs 19 and 20, as in another embodiment shown in FIGS. 5 and 6, the urging means of the mover 16 is provided between the mover 16 and the mounting plates 17 and 18. An elastic rubber 30 in the shape of a circular plate is provided, or an elastic rubber 31 formed in a plate shape is interposed at the position where the springs 19 and 20 are provided, as in the modification shown in FIG. Is shown in FIG.
A plurality of elastic rubbers 32 formed in a plate shape extending in an arc shape may be interposed between the outer periphery of the mover 16 and the mounting plates 17 and 18 at equal intervals in the circumferential direction. Incidentally, these springs 19, 10 and elastic rubbers 30, 3
By using 1, 32, the above operation can be achieved by a general-purpose member without complicating the device.

According to the seismic isolation device, if the materials of the upper and lower ends of the mover and the materials of the sliding plates of the upper and lower structures are changed so that the friction coefficients are different from each other, the earthquake can be prevented. Depending on the scale, a two-stage seismic isolation device that performs single-sided sliding and double-sided sliding can be realized. For example, the friction coefficient mu ₂ above and below the sliding surface, of the mu _1, when the friction coefficient mu ₁ of the lower surface side is set smaller than the frictional coefficient mu ₂ on the upper surface side, with respect to seismic force acting on the lower structure 13, First, a slip occurs between the slide plate 11 having a small coefficient of friction and the mover 16, and then a slide occurs between the mover 16 having a large coefficient of friction and the slide plate 10. Therefore, during a moderate earthquake, only one surface between the lower structure 13 and the mover 16 slips, and for the first time during a large earthquake, slippage occurs between the mover 16 and the upper and lower structures 12, 13. It can be a device.

Further, in the above-described embodiment, only the case where the intermediate portion 16a of the mover 16 is formed of a steel material has been described. However, the intermediate portion 16a can support an axial force such as a laminated rubber. In addition, if it is constituted by an elastic member which can be deformed in the horizontal direction, it is possible to provide a seismic isolation device of an elastic sliding bearing.

[0024]

As described above, according to the seismic isolation device of any one of the first to fifth aspects, the horizontal seismic force to act on the upper structure causes the sliding friction and the sliding friction on the upper and lower surfaces of the mover. The spring attached to the mover can suppress the stress and deformation generated in the upper structure, and furthermore, around the mover of the slide plate located above and below, each half of the displacement amount generated at the time of the anticipated earthquake can be reduced. Since it is enough to secure a margin, even when applied to a low-rise structure, the seismic isolation can be effectively achieved by a compact device, and the mover can be moved after the earthquake by the urging means. It can be returned to the original position.

In particular, according to the third aspect of the present invention, the upper and lower surfaces of the mover are set to have different friction coefficients, so that during a moderate earthquake, the upper and lower structures and the mover may be in contact with each other. According to the invention as set forth in claim 5, the seismic isolation device of the two-stage mechanism in which only one side of the contact surface slips and slips on the upper and lower surfaces of the mover only at the time of a large earthquake can be obtained. By interposing an elastic member capable of supporting such an axial force, an effect that a seismic isolation device of an elastic sliding bearing can be obtained can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a seismic isolation device of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a diagram for explaining the operation of the seismic isolation device of FIG. 1;

FIG. 4 is a longitudinal sectional view showing a state in which the seismic isolation device of FIG. 1 is maximally displaced during an earthquake.

FIG. 5 is a longitudinal sectional view showing another embodiment of the present invention.

FIG. 6 is a cross-sectional view of FIG.

FIG. 7 is a transverse sectional view showing a modification of FIG. 6;

FIG. 8 is a transverse sectional view showing another modification of FIG.

FIG. 9 is a longitudinal sectional view showing a conventional seismic isolation device using a sliding bearing.

FIG. 10 is a longitudinal sectional view showing a state in which the seismic isolation device of FIG. 9 is maximally displaced during an earthquake.

[Explanation of symbols]

 10, 11 Sliding plate 12 Upper structure 13 Lower structure 16 Mover 16a Central part 16b Resin 19, 20 Spring (biasing means) 30, 31, 32 Elastic rubber (biasing means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masayoshi Kuno 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Taisei Corporation

Claims (5)

[Claims] 1. A sliding member opposed to each other is fixed to an upper structure and a lower structure, and a movable element formed of a material whose contact surface with the sliding plate is slidable is interposed between the sliding plates. A seismic isolation device, which is freely provided, and further includes an urging means for urging the mover in a horizontal direction between the mover and the upper structure and the lower structure. 2. The seismic isolation device according to claim 1, wherein said urging means is an elastic rubber or a spring material. 3. A coefficient of friction between the sliding plate of the upper structure and the mover and a coefficient of friction between the sliding plate of the lower structure and the mover are different from each other. Item 4. The seismic isolation device according to item 1 or 2. 4. The space between the slidable materials of the mover,
2. The method according to claim 1, wherein the first member is formed of a rigid body.
4. The seismic isolation device according to any one of items 1 to 3. 5. An elastic member capable of supporting an axial force acting on the mover and being deformable in a horizontal direction is interposed between the slidable materials of the mover. The seismic isolation device according to any one of claims 1 to 3, wherein: