JPH09196116A - Base isolator of structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the buckling of a base isolating laminated rubber in a large deformation without damaging the base isolating characteristic even when a structure is light in a base isolator of the structure. SOLUTION: In a base isolator of a building which is interposed between a foundation 2 and a building 4 and provided with a base isolating laminated rubber 6 to movably support a building 4 in the horizontal direction, a slidable steel plate 8 is provided on a bottom surface 4a of the building 4, a slidably supporting body 10 having a clearance of the prescribed quantity A is provided in the vertical direction between the foundation and the slidable steel plate 8, and the slidable supporting body 10 is brought into slidable contact with the slidable steel plate 8 and supports the slidable steel plate 8 when the foundation 2 is displaced in the horizontal direction relative to the building 4 in an earthquake, and the base isolating laminated rubber 6 is settled by the prescribed quantity A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation structure for a structure, and more particularly to a seismic isolation support structure having a seismic isolation support in which elastic layers and rigid plate layers are alternately laminated in plural layers. It is about.

[0002]

2. Description of the Related Art As a seismic isolation support for preventing the propagation of earthquake vibrations to buildings and machinery, an elastic layer made of rubber or the like and a rigid plate layer made of steel or the like are alternately laminated in multiple layers. Seismic supports are known. This type of seismic isolation support is generally called seismic isolation laminated rubber, which prevents the propagation of vibration to the structure by horizontal elastic deformation of the elastic layer, and at the same time, seismic isolation support and structure. The vibration of a structure caused by an earthquake is suppressed by making the natural period of the vibration system consisting of (hereinafter referred to as "seismic isolation period") longer than the period of horizontal vibration of the earthquake. Generally, the seismic isolation period T _f is expressed by the following equation (1). T _f = 2π (W / (g · K _f )) ^1/2 (1) where W: weight of structure g; gravitational acceleration K _f ; horizontal spring constant of base-isolated laminated rubber where K _f is represented by the following equation (2). K _f = A · G / h (2) where A is the cross-sectional area of the elastic layer G is the shear elastic modulus of the elastic layer h is the height of the elastic layer

[0003]

As can be seen from the above equation (1), the seismic isolation period T _f is proportional to the square root of the weight W of the structure and inversely proportional to the square root of the horizontal spring constant K _f , so that the wooden house In order to lengthen the seismic isolation period T _f in a lightweight structure having a small weight W as shown in the formula (2),
It is necessary to reduce the horizontal elastic constant K _f by reducing the shear elastic modulus G of the elastic layer, reducing the diameter of the elastic layer, or increasing the height h. Normally, the height h of the elastic layer must be increased, and the seismic isolation laminated rubber has a strong (slender) shape. Therefore, if the foundation is largely displaced horizontally with respect to the structure during an earthquake, the seismic isolation laminated The rubber may buckle and may not support the structure sufficiently. In order to prevent this buckling, the elastic force of the elastic layer may be increased or the seismic isolation laminated rubber may be thickened. However, in such a case, the seismic isolation cycle T _f becomes short as described above. However, the inconvenience that the seismic isolation characteristic deteriorates occurs.

The present invention has been made in view of the above-mentioned conventional problems. Even in a lightweight structure, the seismic isolation support can be reliably buckled during large deformation without impairing the seismic isolation characteristics. The purpose is to provide a seismic isolation structure for structures that can be prevented.

[0005]

The present invention has the following configuration to achieve the above object. That is, according to the invention of claim 1, the structure is interposed between the foundation and the structure to support the structure so as to be movable in the horizontal direction, and the elastic layers and the rigid plate layers are alternately laminated in a plurality of layers. In a seismic isolation structure for a structure including a seismic isolation support, an upper slide body provided on a bottom surface of the structure and a lower slide body provided on the foundation between the foundation and the structure. A seismic isolation structure for a structure is characterized in that the weight of the structure is shared by the sliding support means and the seismic isolation support body by interposing a sliding support means consisting of According to a second aspect of the present invention, a predetermined amount of gap is formed between the upper slide body and the lower slide body in the vertical direction, and the lower slide body has the foundation with respect to the structure during an earthquake. The structure according to claim 1, wherein when the seismic isolation support body is displaced in a horizontal direction and the seismic isolation support body is depressed by the predetermined amount, the seismic isolation support body slidably contacts the upper slide body and supports the upper slide body. It is a seismic isolation structure.

Usually, when the foundation is displaced in the horizontal direction with respect to the structure during an earthquake, the seismic isolation support which supports the structure is submerged due to the horizontal shear deformation. The distance between and the structure is narrowed.

According to the present invention, when the seismic isolation support is depressed by the gap (the predetermined amount) between the upper slide on the structure side and the lower slide support on the foundation side, The sliding body and the lower sliding body contact and slide with each other, and at the same time, the lower sliding body bears a part of the vertical load due to the weight of the structure. Accordingly, after the upper slide body and the lower slide body are in contact with each other, even if the foundation is further displaced in the horizontal direction, the seismic isolation support does not sink more than a predetermined amount. Therefore, by setting this predetermined amount according to the horizontal allowable deformation amount of the seismic isolation support, it is possible to reliably prevent buckling of the seismic isolation support during large deformation. The “allowable deformation amount” here means the horizontal displacement amount of the seismic isolation support when the structure can be stably supported only by the seismic isolation support.

Further, since the relatively sliding upper and lower sliding bodies come into contact with each other, the coefficient of friction between the sliding contact surfaces of the two becomes a dynamic coefficient of friction, and the two slide with good sliding characteristics. Move. Therefore, the increase in the horizontal rigidity of the entire seismic isolation structure is small, and the seismic isolation characteristics are not affected.

Therefore, even with a lightweight structure, it is possible to reliably prevent the seismic isolation support from buckling during large deformation without impairing the seismic isolation characteristics.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view of the seismic isolation structure according to the present embodiment, FIG. 2 is a side view of the seismic isolation structure according to the present embodiment, and FIG. 3 is a side view of the seismic isolation structure according to the present embodiment. It is a figure which shows the state which the laminated rubber carried out shear deformation.

The seismic isolation structure of this embodiment is shown in FIGS.
As shown in FIG. 2, a seismic isolation laminated rubber (corresponding to a seismic isolation support) 6 which is interposed between the foundation 2 and the building (an example of a structure) 4 and movably supports the building 4 in the horizontal direction is provided. In the seismic isolation structure provided, a sliding bearing means 7 is further provided between the foundation 2 and the building 4, and the weight of the building 4 is shared by the sliding bearing means 7 and the seismic isolated laminated rubber 6. . Then, the sliding support means 7 is provided with a sliding plate 8 (an example of an upper sliding body) 8 provided on the bottom surface 4a of the building 4 and the sliding plate 8 so that a vertical gap of a predetermined amount A is provided between the foundation 2 and the sliding plate 8. The sliding support body (an example of a lower sliding body) 10 provided in the. Hereinafter, the configuration of each member will be described in detail.

The seismic isolation laminated rubber 6 is constructed by alternately laminating an elastic layer 6a made of rubber or the like and a rigid plate layer 6b made of a steel plate or the like into a plurality of layers.
It is arranged at each of the four corners of a. Therefore, when the weight of the building 4 is about 20 tons, a shared load of about 5 tons is applied to each seismic isolation laminated rubber 6.
The uppermost elastic layer 6a and the lowermost elastic layer 6a of the seismic isolation laminated rubber 6 are fixed to the bottom surface 4a of the building 4 and the foundation 2 via the upper flange 6c and the lower flange 6d, respectively. The elastic layer 6a is preferably made of a highly damping rubber having excellent flexibility when the shape thereof is a disc shape, and when the shape is a ring shape, the highly damping rubber is formed on the outer shell part made of natural rubber. Those filled with are desirable.

The sliding steel plate 8 has a substantially circular shape in plan view and is preferably impregnated with a molybdenum disulfide lubricant. The sliding steel plate 8 is fixed to the central portion of the bottom surface 4a of the building 4, and its material is preferably high hardness stainless steel such as SUS440C having excellent corrosion resistance in consideration of corrosion.

The sliding support 10 is in sliding contact with the sliding steel plate 8 and the sliding steel plate 8 when the foundation 2 is displaced in the horizontal direction with respect to the building 4 during the earthquake and the seismic isolation laminated rubber 6 is depressed by a predetermined amount A. Is to support. That is, the sliding support 10
Is a substantially columnar shape having an outer diameter smaller than that of the sliding steel plate 8, and is erected on the foundation 2 so as to be positioned on the same central axis as the sliding steel plate 8. A disc-shaped low friction material 10a made of, for example, a Teflon-based material is fixed to the upper end of the slide support 10.

The predetermined amount A is the distance between the lower surface of the sliding steel plate 8 and the upper surface of the low friction material 10a and is set to about 1 cm. This predetermined amount A is set according to the horizontal allowable deformation amount of the seismic isolation laminated rubber 6, and the “allowable deformation amount” here means that the building 4 is stably supported only by the seismic isolation laminated rubber 6. It means the horizontal displacement of the base-isolated laminated rubber 6 when possible.

Next, the operation of this embodiment configured as described above will be described. Due to the vibration of the earthquake, the foundation 2 receives the vibration energy and moves horizontally (on the right side of the paper in Fig. 3).
Seismically isolated laminated rubber 6 supporting the building 4 when displaced to
The elastic layer 6a undergoes shear deformation in the horizontal direction and sinks due to this shear deformation. Then, when the seismic isolation laminated rubber 6 sinks, the bottom surface 4a of the building 4 descends and approaches the foundation 2, and when the seismic isolated laminated rubber 6 sinks by the predetermined amount A, the sliding support 10 is lowered. The upper surface of the friction material 10a and the lower surface of the sliding steel plate 8 of the building 4 contact and slide with each other.

Since the sliding steel plate 8 is thus supported by the sliding support 10 and both slide on each other, after the upper surface of the low friction material 10a and the lower surface of the sliding steel plate 8 contact each other, the foundation 2 is moved horizontally. Even if it is further displaced, the seismic isolation laminated rubber 6 does not sink more than the predetermined amount A, and the vertical load acting on the sliding support 10 increases as the foundation 2 is displaced in the horizontal direction. Therefore, the seismic isolated laminated rubber 6 can be displaced in the horizontal direction and buckling is prevented in advance.
Perform the desired seismic isolation function. As described above, the elastic layer 6a of the base-isolated laminated rubber 6 is sheared and deformed in the horizontal direction, so that resonance with the vibration cycle due to an earthquake can be avoided, and at the same time, the vibration of the building 4 can be reduced by using the high damping rubber together. Attenuated.

Further, in the present embodiment, since the sliding support 10 and the sliding steel plate 8 are brought into contact with each other while being relatively displaced, the friction between the sliding contact surfaces of both of them has already been reached from the time when the contact pressure at which they start to contact each other is zero. Since the coefficient is the dynamic friction coefficient,
The upper surface of the low friction material 10a and the lower surface of the sliding steel plate 8 slide on each other with good sliding characteristics. Moreover, if the sliding steel plate 8 impregnated with the molybdenum disulfide-based lubricant and the low-friction material 10a procured from the Teflon-based material are brought into sliding contact with each other, the friction coefficient between the two becomes very small, and seismic isolation is achieved. The increase in horizontal rigidity of the entire structure is small. Therefore, the seismic isolation characteristics are not affected.

This embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment. For example, the present embodiment is an example of a case where the structure is a lightweight building such as a wooden building, but the present invention is
The present invention is not limited to such a seismic isolation structure of a building, and can be widely applied to other structures regardless of material, weight, construction method and the like. Further, in this embodiment, the sliding support 1
Although 0 is provided on the foundation 2 side and the sliding steel plate 8 is provided on the building 4 side, the sliding support 10 may be provided on the building 4 side and the sliding steel plate 8 may be provided on the foundation 2 side. When the slide support 10 is provided on the side of the foundation 2 (see FIG. 2), the slide support 10 is covered with the large-diameter slide steel plate 8, and thus the slide support 10 is provided.
It is possible to obtain the advantageous effect that foreign matter such as dust is less likely to adhere to the upper surface (the sliding contact surface of the low-friction material 10a) of the sliding support plate 10 on the building 4 side. Since the large-diameter sliding steel plate 8 receives the sliding support body 10 when the sliding support body 10 and the sliding support body 10 slide, the supporting portion on the side of the building 4 is always the central portion (center of gravity position) on the bottom surface 4a,
Therefore, the effect that the building 4 can be stably supported is obtained.

Further, the sliding bearing means 7 may be arranged at the four corners of the bottom surface 4a, the seismic isolation laminated rubber 6 may be arranged at the center of the bottom surface 4a, and the sliding bearing means 7 may be arranged so as to always be in contact with each other. . In this case, the friction in the sliding bearing means 7 becomes static friction at the start of sliding, but since the weight of the building 4 is shared by the sliding bearing means 7 and the seismic isolation laminated rubber 6, the sliding bearing means 7 makes good sliding contact. .

[0021]

As described above, according to the present invention, it is possible to prevent the seismic isolation support from buckling during large deformation by preventing the seismic isolation support from sinking more than the predetermined amount. Can be prevented. In addition, since the friction coefficient between the sliding contact surfaces of the upper slide body and the lower slide body is the dynamic friction coefficient, the increase in horizontal rigidity of the entire seismic isolation structure is small and the seismic isolation characteristics may be affected. Absent.

[Brief description of the drawings]

FIG. 1 is a plan view of a seismic isolation structure according to the present embodiment.

FIG. 2 is a side view of the seismic isolation structure according to the present embodiment.

FIG. 3 is a side view of the seismic isolation structure according to the embodiment,
It is a figure which shows the state which the base isolation laminated rubber shear-deformed.

[Explanation of symbols]

 2 foundation 4 building (an example of structure) 4a bottom surface 6 seismic isolation laminated rubber (equivalent to seismic isolation support) 6a elastic layer 6b rigid plate layer 7 sliding bearing means 8 sliding steel plate 10 sliding support 10a low friction material A location Quantitative

Claims (2)

[Claims] 1. A seismic isolation device which is interposed between a foundation and a structure to support the structure so as to be movable in the horizontal direction, and in which elastic layers and rigid plate layers are alternately laminated in a plurality of layers. In a seismic isolation structure for a structure including a support, a slip formed between an upper slide body provided on a bottom surface of the structure and a lower slide body provided on the base between the foundation and the structure. A seismic isolation structure for a structure, characterized in that the supporting means is interposed so that the weight of the structure is shared by the sliding supporting means and the seismic isolation support. 2. A vertical gap is formed between the upper slide body and the lower slide body in a vertical direction, and the base of the lower slide body is horizontal to the structure when an earthquake occurs. When the seismic isolation support is depressed by the predetermined amount,
The seismic isolation structure for a structure according to claim 1, wherein the seismic isolation structure is in sliding contact with the upper slide body and supports the upper slide body.