JP3671317B2 - Seismic isolation mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic isolation mechanism suitable for reducing the input of seismic motion in, for example, various structures, particularly high-rise buildings and tower-like structures.
[0002]
[Prior art]
In recent years, various seismic isolation devices have been developed in various structures such as buildings in order to minimize shaking and damage caused by the occurrence of an earthquake.
[0003]
As this seismic isolation device, a so-called laminated rubber having a structure in which viscoelastic bodies and steel plates are alternately laminated in the vertical direction is frequently used. Laminated rubber, for example, is interposed between the foundation of a structure and the structure body constructed on this foundation, and when a large horizontal external force is input due to an earthquake or the like, the viscoelastic body is moved horizontally. By deforming, the external force is attenuated and the structure body is prevented from shaking.
[0004]
[Problems to be solved by the invention]
However, the conventional seismic isolation device as described above has the following problems.
Laminated rubber that is frequently used as a seismic isolation device has a viscoelastic body that has a sufficiently high strength against a compressive force in the vertical direction but a low strength against a tensile force. Therefore, if the vertical tensile force acts excessively on the laminated rubber, there is a problem that the viscoelastic body is broken and cannot function as a seismic isolation device.
As a case where a large tensile force acts in the vertical direction, for example, when the ratio of height to width (so-called aspect ratio, tower ratio) is large, such as a tower structure or a skyscraper, In the case where buoyancy is applied by strong wind such as a roof, laminated rubber may be disposed on the outer periphery of the building.
[0005]
Due to such problems, conventionally, for example, the aspect ratio of the structure must be suppressed to about 3 to 3.5 so that excessive tensile force does not act on the laminated rubber. It was a big design constraint. However, as is well known, after the Great Hanshin Earthquake, there has been an increasing demand to provide seismic isolation performance for high-rise buildings and buildings with very large aspect ratios.
[0006]
The present invention has been made in consideration of the above points, and even when a large tensile force is applied in the vertical direction, it does not lose its seismic isolation function, and it is a high-rise building or a structure having a very large aspect ratio. It is an object to provide a seismic isolation mechanism that can be applied to the above.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a seismic isolation mechanism in which a laminated rubber for attenuating horizontal vibrations is arranged in two upper and lower stages between a structure and its foundation, and the upper laminated rubber and The lower rubber layer is fixed to the lower surface of the structure and the upper surface of the foundation, respectively, and the lower surface of the upper rubber layer and the upper surface of the lower rubber layer are not joined to each other. The sheer key is fitted into the concave portions formed in the lower surface central portion of the laminated rubber and the upper surface central portion of the lower laminated rubber, and is not restricted in the vertical direction .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An example of an embodiment of the seismic isolation mechanism according to the present invention will be described below with reference to FIG.
[0011]
1 shows a basic part of a structure to which the seismic isolation structure according to the present invention is applied. In this figure, reference numeral 1 denotes a structure such as a building, and 2 denotes a ground for supporting the structure 1. The foundations 3 and 3 are seismic isolation mechanisms provided between the bottom of the structure 1 and the foundation 2, respectively.
[0012]
As shown in this figure, on the lower surface 1a of the structure 1 and the upper surface 2a of the foundation 2, attachment plates 4 are integrally attached to the anchor members 5, 5,.
[0013]
The seismic isolation mechanism 3 has a configuration in which a laminated rubber (seismic isolation device) 6 is provided in a plurality of stages, for example, two stages, between upper and lower mounting plates 4 and 4.
[0014]
Each laminated rubber 6 has the same structure as that of the prior art, and is configured such that an attenuation member 9 is sandwiched between an upper plate 7 and a lower plate 8 made of, for example, a metal or the like. The damping member 9 has a smaller diameter than the upper plate 7 and the lower plate 8 and has a hole 10 formed in the center, and spacers 12A and 12B fixed to the upper plate 7 and the lower plate 8 with bolts 11 respectively. In the middle, the steel plates 13 and the viscoelastic bodies 14 are alternately stacked over a plurality of layers in the vertical direction.
The steel plate 13 may be a normal steel material, for example, a vibration-damping steel plate or the like. The viscoelastic body 14 includes, for example, rubber asphalt rubber, high-damping rubber, superplastic rubber (a plastic property that absorbs energy and converts it into heat, and a rubber elasticity that provides follow-up to large deformation. A specially blended polymer composite material (for example, manufactured by Bridgestone Corporation) and the like having high damping performance are used.
[0015]
Each such laminated rubber 6 is damped by the deformation of the viscoelastic body 14 sandwiched between the steel plates 13 and 13 positioned above and below the horizontal relative movement between the upper plate 7 and the lower plate 8. The damper effect is exhibited.
[0016]
Such a laminated rubber 6 is composed of the upper plate 7 of the upper laminated rubber 6A and the lower plate 8 of the lower laminated rubber 6B. And the anchor member 5, that is, the lower surface 1 a of the structure 1 and the upper surface 2 a of the foundation 2.
[0017]
Further, the upper plate 7 and the spacer 12A of the upper laminated rubber 6A, and the lower plate 8 and the spacer 12B of the lower laminated rubber 6B are respectively provided with a concave portion 17 having a diameter larger than that of the hole 10 by a central portion. 18 is formed, and a sheer key 19 is fitted in the recesses 17 and 18. Thereby, a shearing force in the horizontal direction is transmitted by the shear key 19 between the structure 1 and the upper laminated rubber 6A and between the foundation 2 and the lower laminated rubber 6B. . In this part, the structure 1 and the upper laminated rubber 6 </ b> A, and the foundation 2 and the lower laminated rubber 6 </ b> B are also restrained in the vertical direction by the mounting bolts 15.
[0018]
The lower plate 8 and spacer 12B of the upper laminated rubber 6A and the upper plate 7 and spacer 12A of the lower laminated rubber 6B are formed with recesses 20 and 21 having a larger diameter than the hole 10 at the center. A sheer key (transmission member) 22 is fitted in the recesses 20 and 21. Thus, a shearing force in the horizontal direction is transmitted by the shear key 22 between the upper laminated rubber 6A and the lower laminated rubber 6B. The upper laminated rubber 6A and the lower laminated rubber 6B are not joined by bolts or the like, and are not restricted in the vertical direction and are allowed to move in the vertical direction.
[0019]
In such a seismic isolation mechanism 3, when a horizontal external force is input due to an earthquake or the like, a foundation 2 that vibrates integrally with the ground, and a structure 1 supported on the foundation 2 via the seismic isolation mechanism 3. Relative displacement in the horizontal direction occurs. Then, the relative displacement between the structure 1 and the foundation 2 is transmitted to the laminated rubbers 6A and 6B of the seismic isolation mechanism 3 through the shear keys 19, 19, and 22. Then, in each of the upper laminated rubber 6A and the lower laminated rubber 6B, a relative displacement is generated in the horizontal direction between the upper plate 7 side and the lower plate 8 side. It is attenuated by the deformation of the viscoelastic body 14.
[0020]
When an external force in the vertical direction is input, if the external force is in a direction in which the foundation 2 and the structure 1 are close to each other in the vertical direction, a compression force is applied to the laminated rubbers 6A and 6B of the seismic isolation mechanism 3. Is transmitted.
[0021]
On the other hand, when the external force is in the direction in which the foundation 2 and the structure 1 are separated from each other in the vertical direction, the upper laminated rubber 6A and the lower laminated rubber 6B are restrained in the vertical direction. Therefore, a tensile force does not act on the laminated rubbers 6A and 6B.
[0022]
According to the above-described seismic isolation mechanism 3, the upper and lower laminated rubber 6 </ b> A and 6 </ b> B are provided between the structure 1 and the foundation 2, and the structure 1 and the foundation 2 are interposed between the laminated rubber 6 </ b> A and 6 </ b> B. It is configured to be jointed by a shear key 22 that transmits a horizontal relative displacement and allows a vertical relative displacement. Thereby, the seismic isolation effect can be demonstrated with respect to the vibration of a horizontal direction similarly to the conventional seismic isolation apparatus. And when big tensile force acts on the seismic isolation mechanism 3, tensile force does not act on laminated rubber 6A, 6B, and it can prevent that the viscoelastic body 14 fractures | ruptures and loses a seismic isolation function. Further, by adopting a structure in which a tensile force does not act on the seismic isolation mechanism 3, the displacement of the structure 1 that acts as a tensile force at the position of the seismic isolation mechanism 3 is compressed into the seismic isolation mechanism 3 at other positions. Since this acts as a force, the stress can be redistributed by this, and therefore the structure 1 can be reliably prevented from falling.
In this way, when the structure 1 has a large aspect ratio, which has been difficult to make a seismic isolation structure in the past, or when buoyancy acts by a strong wind such as a large roof, Even when the seismic mechanism 3 is arranged on the outer periphery of the structure 1, the seismic isolation performance can be imparted by applying the seismic isolation mechanism 3, and the added value of the structure 1 can be improved. Can be increased.
[0023]
In addition, about each structure quoted in the said embodiment, if it is in the range which does not deviate from the main point of this invention, the structure is not limited.
For example, the material, shape, and installation position of the shear keys 19 and 22 are not particularly limited as long as they can transmit a shearing force in the horizontal direction and allow a relative displacement in the vertical direction. In particular, in the above embodiment, the sheer key 22 is arranged between the upper and lower laminated rubbers 6A and 6B. However, for example, this is arranged on either one or both of the laminated rubbers 6A and 6B. The same effect can be obtained.
[0024]
As for the structure and material of the laminated rubber 6, an optimal one may be adopted as long as a high damper effect can be obtained. Further, as the seismic isolation device, other seismic isolation devices may be adopted as long as the same seismic isolation effect as that of the laminated rubber 6 can be obtained.
[0025]
Further, the laminated rubber 6 is arranged in two upper and lower stages, but the upper laminated rubber 6A and the lower laminated rubber 6B may have different numbers of laminated stages of the steel plate 13 and the viscoelastic body 14. Of course, such a laminated rubber 6 may be arranged in only one stage or in three or more stages.
[0026]
In addition, by installing the seismic isolation mechanism 3 below the earthquake-resistant wall of the structure 1, the rigidity of the earthquake-resistant wall can be controlled.
[0027]
In addition to this, the structure 1 and the structure of the foundation 2 are not limited at all, and any structure may be used. Of course, the above seismic isolation structure can have the same effect not only for earthquakes but also for strong winds.
[0028]
【The invention's effect】
As described above, according to the seismic isolation mechanism according to the present invention, the laminated rubber is disposed in two upper and lower stages between the structure and the foundation, and the upper laminated rubber and the lower laminated rubber are respectively Fixed to the lower surface of the structure and the upper surface of the foundation, the lower surface of the laminated rubber on the upper stage side and the upper surface of the laminated rubber on the lower stage side are not joined, and the lower surface central portion of the laminated rubber on the upper stage side and the lower stage Shear keys are fitted in the recesses formed at the center of the upper surface of the laminated rubber on the side, and are not restricted in the vertical direction . As in this, the shear keys, and transmits the horizontal relative displacement between the structure and the foundation, by a configuration allowing vertical relative displacement, the laminated rubber, vertical and horizontal shear force Only the compression force acts, and the vertical tensile force does not act. As a result, the seismic isolation mechanism can exhibit the seismic isolation effect against horizontal vibration as in the past, as well as the seismic isolation function even when a large tensile force acts on the laminated rubber. It has a structure that can prevent losing. Therefore, a structure having a large aspect ratio, a structure that has buoyancy due to a strong wind, such as a large roof, or a laminated rubber , which has been difficult to achieve a seismic isolation structure in the past, is disposed on the outer periphery of the structure. In some cases, it is possible to provide seismic isolation performance, and it is possible to enhance the earthquake resistance and increase the added value of the structure. Furthermore, by installing such a seismic isolation mechanism below the seismic wall, it is possible to control the rigidity of the seismic wall.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view showing an example of a seismic isolation mechanism according to the present invention.
[Explanation of symbols]
1 Structure 2 Foundation 3 Seismic Isolation Mechanism 6 Laminated Rubber (Seismic Isolation Device)
22 Shear key (transmission member)

Claims (1)

It is a seismic isolation mechanism in which laminated rubber that dampens horizontal vibrations is arranged in two upper and lower stages between the structure and its foundation ,
The upper laminated rubber and the lower laminated rubber are fixed to the lower surface of the structure and the upper surface of the foundation, respectively.
The lower surface of the laminated rubber on the upper side and the upper surface of the laminated rubber on the lower side are not joined, and are formed at the center of the lower surface of the laminated rubber on the upper side and the center of the upper surface of the laminated rubber on the lower side, respectively. A seismic isolation mechanism characterized in that a shear key is fitted in the recessed portion and is not restricted in the vertical direction .

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