JPH10102821A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a base isolation device such that the device is efficiently suitable for a small housing. SOLUTION: This base isolation device is formed such that flange sheets 15 and 16 are fixed on the upper and under surfaces of a lamination rubber part wherein a plurality of rubber sheets 12 and intermediate steel sheets 13 are alternately laminated. In this case, the lamination rubber part is formed in an annular shape in which a hollow cylinder part 20 extending through the upper and under surfaces thereof is formed. Further, an outside diameter ϕis set such that a perpendicular passing through a perpendicular load resultant force operation point during maximum shearing deformation is situated within the outer shape of the bottom of the lamination rubber part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device, and more particularly to a seismic isolation device suitable for application to a small-scale building such as a detached wooden house.

[0002]

2. Description of the Related Art In a seismic isolation structure such as a building, a laminated rubber isolator is an essential seismic isolation device. A general laminated rubber isolator has a cylindrical shape in which rubber plates and intermediate steel plates are alternately laminated. For this reason, in the laminated rubber isolator, the lateral deformation of the rubber plate is restrained by the intermediate steel plate, and bears the vertical load of the building without being substantially deformed by the vertical load. In addition, since the rubber plate has a low shear rigidity, it undergoes large shear deformation when subjected to a horizontal load. This alleviates the fact that the horizontal displacement during an earthquake is directly input to the building. By the way, conventionally, the seismic isolation structure has been developed mainly for application to a relatively rigid middle-rise building having a small natural period. It is important to set the layout and size of the laminated rubber isolators so that they can load the vertical load in a well-balanced manner according to the plan layout of the target building, and receive an almost uniform horizontal load and undergo shear deformation during an earthquake. is there. In the case of a middle-rise building, the vertical load borne by one laminated rubber isolator is generally 100 t / piece or more, and the shape and dimensions of each part are determined so that the structural stability can be maintained even when subjected to a horizontal load and shear deformation. ing.

[0003]

The laminated rubber isolator always has a design surface pressure of 50 to 100 kg due to the properties of the laminated rubber.
In the range of / cm2, appropriate compression deformation and shear deformation can be generated. For this reason, in a structure having a small vertical load at all times, such as a detached wooden house, FIG.
As shown in (b), one laminated rubber isolator 5
If the vertical load P borne by 0 is about P = 20t, the diameter φ becomes φ = 230 mm. At this time, the height H required for installing the laminated rubber isolator 50 is H = 25.
It is about 0 mm. When a horizontal force Q during an earthquake acts on the laminated rubber isolator 50 manufactured to such dimensions, a shear deformation δ occurs. In the case of a large earthquake, the maximum shear deformation amount δmax is as large as δmax = 200 mm. For this reason, as shown in FIG. 6C, the position of application of the vertical load P is eccentric, and the vertical line passing through the point of application deviates from the bottom outer shape of the laminated rubber isolator 50, and the laminated rubber isolator has an unstable structure. As a result, the seismic isolation device may be damaged, causing serious damage to the building.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to bear a small vertical load,
It is an object of the present invention to provide a seismic isolation device that exhibits appropriate shear deformation even in a horizontal direction load and stabilizes a structure during an earthquake.

[0005]

In order to achieve the above object, the present invention relates to a seismic isolation device in which a flange plate is fixed to upper and lower surfaces of a laminated rubber portion in which a plurality of rubber plates and intermediate steel plates are alternately laminated. The laminated rubber portion has an annular shape in which a hollow portion penetrating the upper and lower surfaces is formed, and an outer diameter of the laminated rubber portion is a vertical line passing through a vertical load resultant point of action during maximum shear deformation. It is characterized in that it is set to be within the outer shape of the bottom surface.

It is preferable that the laminated rubber portion is filled with a viscous material or a granular material in the hollow cylindrical portion.

[0007] It is preferable that a shear projection is protruded from the flange plate toward the inside of the hollow cylindrical portion so that shear energy is attenuated by resistance of the viscous or granular material.

Further, it is preferable that the laminated rubber portion is provided with an elasto-plastic member which plastically deforms following the shear deformation in the hollow cylindrical portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the seismic isolation device of the present invention will be described below with reference to the accompanying drawings. FIG.
(A) is a plane sectional view of the seismic isolation device of the present invention. The seismic isolation device 10 is classified as a laminated rubber isolator when classified according to the structure. In the following description, the laminated rubber isolator 10 will be described. In the laminated rubber portion 11, rubber plates 12 and intermediate steel plates having a predetermined thickness are alternately laminated.
The rubber plate 12 is manufactured by adding a reinforcing agent such as carbon black and a plasticizer such as petroleum oil to natural rubber as a raw material, adjusting mechanical properties and the like, and processing the plate into a predetermined plate shape. In the present embodiment, a JIS standard steel plate for general structure (mechanical property: SS400) is used as the intermediate steel plate 13. Further, the inner and outer surfaces of the laminated rubber portion 11 are covered with a covering rubber plate 14 for maintaining durability.

The laminated rubber portion 11 has a hollow annular shape as shown in FIG. 1A, and the upper and lower surfaces of the hollow annular portion are disc-shaped as shown in FIG. The laminated rubber isolator 10 is supported so as to be sandwiched between the flanges. Note that the flanges attached to the upper and lower surfaces may be formed in a square shape corresponding to the size of the intersection point of the beams.

FIG. 1 shows a laminated rubber isolator 1 shown in each figure.
At 0, a vertical load equivalent to that of the laminated rubber isolator 50 shown in FIG. 6 is applied, and the cross-sectional area of the pressure-receiving rubber surface is set so as to generate stable shear deformation in a state where the same surface pressure is applied. Outer diameter φ1 is φ1 = 400m
m, the inner diameter φ2 is φ2 = 330 mm. At this time, when the height H of the laminated rubber portion 11 is set to H = 250 mm, the vertical line passing through the vertical load resultant force application point is within the outer shape of the bottom surface of the laminated rubber portion 11 even at the time of the maximum shear deformation. Can be secured. In this case, the width t of the annular portion
It is necessary to ensure that buckling does not occur even when a vertical load acts as an eccentric load. In addition, when the horizontal load acts, the entire laminated rubber undergoes shear deformation so as to form a uniform shear deformation angle, and at the time of maximum shear variation, a vertical line passing through the point of application of the resultant force of the vertical load is within the outer diameter φ1 of the laminated rubber, that is, the bottom surface It is necessary to set the shear stiffness to the extent that it is located within the outer shape.

FIG. 2 shows four hollow cylindrical hollow portions 2 having an area equivalent to the pressure receiving area shown in FIG.
1 is an embodiment in which the number 1 is provided. As shown in FIG. 2A, a substantially cross-shaped partition wall portion 22 is formed at the center of the laminated rubber portion 11. This allows for excellent shear deformation without bending when a horizontal load is applied. Although four hollow cylinders are shown in FIG. 2, it goes without saying that more hollow cylinders 21 may be formed in consideration of workability.

FIG. 3 shows intermediate steel plates 13A and 13B to be laminated.
Are concentrically arranged inside and outside of the inner and outer intermediate steel plates 13.
This shows a modification in which an annular rubber portion 17 consisting of only a rubber layer is formed between A and 13B. The vertical load is borne by the laminated portion of the rubber plate 12 and the intermediate steel plates 13A and 13B. At this time, the annular rubber portion 17 is also deformed by the applied vertical load, but the lateral deformation is prevented by the intermediate steel plate 13 located inside and outside the annular rubber portion 17, and the vertical displacement is reduced by the laminated rubber isolator shown in FIG. It is equivalent to 10. Further, when a horizontal load is applied, the annular rubber portion 17 resists shearing together with the portion having the intermediate steel plate 13, so that an effective area against shear deformation can be increased. Therefore, bending deformation and the like can be reliably suppressed.

FIG. 4 shows that the damper 30 is incorporated into the seismic isolation device 10 using the above-described natural rubber-based laminated rubber to provide a damping performance so as to suppress an excessive relative displacement between the building and the ground caused during an earthquake. FIG. FIG. 4A shows an example in which an elastic-plastic damper 31 is accommodated in a hollow portion in the laminated rubber isolator 10. The elasto-plastic damper 31 is an elasto-plastic deformation material substantially equal to the height of the laminated rubber, as shown in FIG. The elasto-plastically deformable material is accommodated in a hollow state on the upper surface of the lower flange via the support plate 32 in an upright state.
1a is supported by a ball seat plate 33 attached to the lower surface of the upper flange 15. In the present embodiment, a steel rod is used as the elastic-plastic deformation material. When the laminated rubber isolator 10 is subjected to shear deformation, bending is applied to the steel bar to cause bending deformation. Vibration energy is absorbed by the bending elastic-plastic deformation. Stainless steel is preferred as the steel rod. The strength and dimensions are preferably set so as to satisfy the yield shear force and the critical deformation calculated from conditions such as the design natural period of the building, the hysteresis of the laminated rubber isolator 10 provided around the building, and the allowable displacement. . As the elasto-plastically deformable material, a steel rod, a lead rod, a rod processed from carbon fiber, or the like can be used. Further, a structure capable of accommodating a plurality of small-diameter steel rods may be employed to adjust the number of accommodations so as to adjust the damper performance.

FIG. 4B shows an example in which a viscous damper is sealed in a hollow portion in the laminated rubber isolator 10. As shown in FIG. 1B, this viscous material damper is one in which a viscous material is sealed in a closed space. Examples of the viscous material include a polymer-based viscous material, oil and fat, and an inorganic filler. Since there is liquidity,
It is necessary to prevent liquid leakage from occurring. Therefore, in order to form the above-mentioned closed space, it is preferable to use an elastic container, a bag, or the like that can follow the shear deformation of the laminated rubber isolator 10.

FIG. 4C shows an example in which a friction damper is accommodated in a hollow portion in the laminated rubber isolator 10. This friction damper is, as shown in FIG.
It has a configuration in which loose granular materials 35 are densely accommodated. Since these granular materials 35 are housed in the space in contact with each other, when the laminated rubber isolator 10, that is, the hollow cylindrical portion is sheared, the internal granular materials 35 move so as to be displaced little by little while meshing. Due to this movement, the granular materials 35 come into contact with each other to absorb energy.
The shape of the granular material 35 may be a spherical shape or an angular random shape. For example, various materials such as steel balls processed to a predetermined diameter, other metal balls, synthetic resin balls, ceramic balls, and the like can be used as long as the material has a strength not to be broken by contact pressure. In addition, although individual shapes and dimensions are different,
Natural aggregates and artificial aggregates classified into a predetermined particle size range can also be used. As the diameter and the particle diameter of the granular material 35 to be used, it is preferable to adopt appropriate values in advance by a shear deformation experiment or the like. When airtightness is ensured, the granular material 35
It is also possible to fill the viscous body 34 in a space other than the above.
Also in this case, it is preferable to grasp the damper performance by an experiment. FIG. 4D shows a modification in which a substantially cylindrical shearing projection 36 is protruded from upper and lower flanges 15 and 16 in a hollow cylindrical portion filled with granular material 35.
The shearing projection 36 is used when the hollow cylindrical portion is deformed by shearing.
5 moves in the interior filled with 5 as the flange 15 slides. At this time, the granular material 35 around the shear protrusion 36 becomes a resistance, and the shear energy is rapidly attenuated. Thereby, a very efficient damper effect is exhibited. Also in this case, the shear rigidity of the laminated rubber isolator 10 needs to be set to such an extent that the internal shear protrusion 36 does not hit the inner surface of the laminated rubber.

FIG. 5 shows an embodiment in which the elastic-plastic damper 31 shown in FIG. 4A is installed in four hollow cylindrical hollow portions 21 formed in the laminated rubber isolator 10. It is. In the present invention, since the volume of the hollow portion formed in the laminated rubber portion 11 is large, it is uneconomical to accommodate a lead plug of the same size as the hollow portion and to expect the lead plug to undergo shear deformation as in the related art. . It is economical to use an elasto-plastic damper 31 such as a steel rod which is largely bent and deformed in the space of the hollow portion.

In the above description, the laminated rubber isolator 10 as a seismic isolation device has been described using natural rubber as an example.
A high attenuation laminated rubber may be used for the laminated rubber. Synthetic rubber such as chloroprene rubber can also be used in the same manner as natural rubber because it also exhibits appropriate shear deformation characteristics.

[0019]

As is apparent from the above description, according to the present invention, it is possible to provide a seismic isolation device that can obtain a seismic isolation effect with appropriate specifications even in a small-scale house such as a detached house. This has the effect.

[Brief description of the drawings]

FIG. 1 is a plan sectional view and a side sectional view showing an embodiment of a seismic isolation device according to the present invention.

FIG. 2 is a plan sectional view and a side sectional view showing another embodiment of the seismic isolation device according to the present invention.

FIG. 3 is a plan sectional view and a side sectional view showing another embodiment of the seismic isolation device according to the present invention.

FIG. 4 is a side sectional view showing another embodiment of the seismic isolation device according to the present invention.

FIG. 5 is a plan sectional view and a side sectional view showing another embodiment of the seismic isolation device according to the present invention.

FIG. 6 is a plan sectional view and a side sectional view showing an example of a conventional seismic isolation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Seismic isolation device (laminated rubber isolator) 11 Laminated rubber part 12 Rubber plate 13 Intermediate steel plate 20, 21 Hollow part 30 Damper

Claims (5)

[Claims] 1. A seismic isolation device in which a flange plate is fixed to upper and lower surfaces of a laminated rubber portion in which a plurality of rubber plates and intermediate steel plates are alternately laminated, wherein the laminated rubber portion is a hollow cylinder penetrating the upper and lower surfaces. It has an annular shape with a part formed, and its outer diameter is
A seismic isolation device characterized in that a vertical line passing through a vertical load resultant force point at the time of maximum shear deformation is set within the outer shape of the bottom surface of the laminated rubber portion. 2. The seismic isolation device according to claim 1, wherein said laminated rubber portion has said hollow cylindrical portion filled with a viscous material. 3. The seismic isolation device according to claim 1, wherein said laminated rubber portion has a granular material filled in said hollow cylindrical portion. 4. A shear projection projecting from said flange plate toward said hollow cylindrical portion.
Or the seismic isolation device according to claim 3. 5. The seismic isolation device according to claim 1, wherein the laminated rubber portion is provided with an elasto-plastic member which plastically deforms following the shear deformation in the hollow cylindrical portion.