JP2010270569A - Base isolation structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolation structure elastically constraining, even in case of an unexpected large earthquake, a significant deformation of a base isolation device without damage to a structure or the like. <P>SOLUTION: The base isolation structure includes: the base isolation device 4 mainly composed of an elastic body, provided between the structure 8 and a foundation 9 thereof fixedly to both; and deformation restricting devices 5 mainly composed of elastic body provided at predetermined intervals around the base isolation device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention particularly relates to a seismic isolation structure provided between a building and a foundation.

  Seismic isolation devices that are installed between the building and the foundation to protect the building by absorbing the impact and vibration of earthquakes are generally alternating between elastic plates with viscoelasticity such as rubber and rigid plates such as steel plates. In order to reduce the transmission of vibration to the building by elastically deforming it horizontally in the horizontal direction under the large deformation capacity due to the low shear modulus of elastic plates such as rubber Function.

  The amount of allowable deformation of such a seismic isolation device is predicted by earthquakes that have occurred in the past at the construction site of the building, the maximum seismic wave predicted from the nearby fault distribution, the structure of the building and / or the ground structure, etc. In general, the maximum shear deformation of the ground is allowed, and the structure is generally set so as to be within a shear deformation amount that can withstand earthquake vibration.

  However, in recent years, the amount of shear deformation of the seismic isolation device has been set by the occurrence of seismic waves that greatly exceed the predicted value, such as the Niigata Chuetsu-oki earthquake, and earthquakes that have occurred from faults that have not been discovered so far. In such a case, there was a high risk of the seismic isolation device being broken or the building being destroyed.

  For this reason, for example, Patent Documents 1 and 2 include both a seismic isolation device and a deformation limiting device that limits the shear deformation of this seismic isolation device between the building and the foundation. There has been proposed a technology that copes with unexpected deformation of an earthquake by limiting the maximum shear deformation amount of the seismic isolation device caused by the deformation limiting device.

  However, such a deformation limiting device has a structure in which a loosened steel wire or the like is connected to each of the building and the foundation thereof. If the steel wire is deformed until it becomes loose and becomes in tension, a shocking stress will be applied to the steel wire, etc., and eventually to the building. The stress breaks the steel wire and damages the building. There was a high risk of occurrence.

  On the other hand, in a building to which a seismic isolation device is applied, a clearance that allows deformation of the seismic isolation device etc. on the outer periphery of the building in consideration of the maximum amount of deformation that the seismic isolation device and the building undergo shear deformation. In many cases, there is a retaining wall that prevents the building from being pushed out of the site, and as a result of a large earthquake, the amount of shear deformation of the building etc. becomes larger than expected, and the amount of deformation increases. When the clearance exceeds the set clearance, the lower part of the building may collide with the retaining wall and be damaged.

JP 2003-343117 A JP 2004-36648 A

  The object of the present invention is to provide a seismic isolation structure that can elastically restrain a large deformation of a seismic isolation device without damaging a building even if an unexpected large earthquake occurs. There is to do.

  The seismic isolation structure according to the present invention is provided between a building and the foundation thereof, and is provided between the building and the foundation of the structure and fixed to both of them. A seismic isolation device mainly composed of a body and a deformation limiting device mainly composed of an elastic body are provided at a predetermined interval around the seismic isolation device.

  More preferably, in such a seismic isolation structure, the deformation limiting device is provided with a step in the height direction between the building or its foundation.

  Here, “the step is provided in the height direction” means a distance that does not directly contact the building or its foundation even if the seismic isolation device is sheared and reduced in height, and the seismic isolation device is excessively large. The distance required to maintain the deformation limiting device in a state where it can exhibit a buffering effect even when shearing is deformed.

  Preferably, the deformation limiting device is made of a laminated rubber including an elastic rubber and a rigid plate.

  And preferably, the predetermined interval between the seismic isolation device and the deformation limiting device is in a range of 90 to 100% with respect to the limit shear deformation amount of the building where the seismic isolation device is installed.

  In the seismic isolation structure of the present invention, a seismic isolation device mainly composed of an elastic body fixed between the building and the foundation thereof and a predetermined interval around the seismic isolation device. In this case, by enclosing it and including a deformation limiting device mainly composed of an elastic body, the horizontal direction of the seismic isolation device due to earthquake is illustrated in FIG. Until the amount of shear deformation reaches a predetermined interval (± B) between the seismic isolation device and the deformation limiting device, only the seismic isolation device undergoes shear deformation in the same way as ordinary laminated rubber with elastic rubber and rigid plates. When the deformation amount reaches a predetermined interval (± B), a part of the outer edge portion of the seismic isolation device comes into contact with the wall surface close to the seismic isolation device of the deformation limiting device, and the deformation amount becomes a predetermined interval ( If it exceeds ± B), the seismic isolation device and the deformation limiting device will shear at the same time, increasing the spring constant of the seismic isolation device. By a shearing force as the vibration input can be effectively supported by the small increase in the shear deformation amount.

  In general, a building with a seismic isolation device is provided with a retaining wall as described above, but a seismic isolation device is provided by providing a deformation limiting device at a predetermined interval from the seismic isolation device. Therefore, it is possible to prevent the lower part of the building from colliding with the retaining wall.

It is a figure which illustrates the shear deformation hysteresis of the seismic isolation apparatus of the seismic isolation structure of this invention. It is a side view which shows one Embodiment of the seismic isolation structure of this invention. It is a side view which shows typically the mode of a deformation | transformation of the seismic isolation structure shown in FIG. 2 when an earthquake generate | occur | produced. It is the schematic which has arrange | positioned the seismic isolation structure of this invention between the building and the foundation. (A) is a top view which shows one embodiment of the seismic isolation structure of this invention, (b) is a top view which shows other embodiment of the seismic isolation structure of this invention, (c) It is a top view which shows other embodiment of the seismic isolation structure of this invention.

Hereinafter, the seismic isolation structure of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a cross-sectional view in the width direction showing one embodiment of the seismic isolation structure of the present invention, and FIG. 3 schematically shows how the seismic isolation structure shown in FIG. 2 is deformed when an earthquake occurs. FIG.

  The illustrated seismic isolation structure 1 includes, for example, a plurality of disk-shaped rigid plates and a plurality of disk-shaped elastic rubbers that are alternately stacked, a stacked rubber 2 that extends in the vertical direction, A seismic isolation device 4 having a mounting face plate 3 that protrudes laterally from the laminated rubber 2 fixed to the upper end and the lower end is provided.

Here, the laminated rubber 2 is formed by laminating a rigid plate such as a steel plate and a member such as an unvulcanized rubber composition, and then firmly bonding them together by, for example, vulcanization and separating them carelessly. Or misalignment.
The laminated rubber 2 has a hollow portion at the center, and a seismic isolation plug can be press-fitted into the hollow portion. This seismic isolation plug is often made of lead as a whole, and when the laminated rubber 2 undergoes shear deformation due to the occurrence of an earthquake, the seismic isolation plug plastically deforms to generate vibration energy. It functions to absorb.

  The seismic isolation device 4 is attached to the building 8 and its foundation 9 by inserting bolts through bolt holes (not shown) formed in the mounting face plate 3, and the building 8 is supported via the seismic isolation device 4. The

When such a seismic isolation device 4 receives a horizontal shearing force due to vibration, the laminated rubber elastically shears and deforms as a whole, effectively absorbing vibration energy, damping performance, etc. The vibration can be quickly damped.
In addition, by alternately laminating the rigid plate and the elastic plate, even when a load is applied in the vertical direction, the compression of the laminated rubber is suppressed, and the elastic plate sufficiently shears and absorbs energy, Resilience can be demonstrated. As a result, the laminated rubber can exhibit the effect of suppressing the amount of shear deformation and increasing the upper and lower springs.

The seismic isolation structure 1 includes a deformation limiting device 5 mainly composed of an elastic body at a predetermined interval (B) around the seismic isolation device 4.
The deformation limiting device 5 has a predetermined interval (B) preferably in the range of 90 to 100% with respect to the limit shear deformation amount of the building where the seismic isolation device 4 is installed, and the step in the height direction is laminated, for example. A laminated rubber 6 extending in the vertical direction, which is concentric with the seismic isolation device 4 in the figure, mainly composed of an elastic body provided within a range of 0.9 to 0.95 in the height of the rubber 6, and the laminated rubber 6 It includes an attachment face plate 7 that protrudes laterally from the laminated rubber 6 fixed to the lower end. The deformation limiting device 5 is attached to the foundation 9 by inserting a bolt through a bolt hole (not shown) formed in the attachment face plate 7.

  With such a configuration, as shown in FIG. 3, when the deformation amount of the seismic isolation device 4 is deformed beyond a predetermined interval (B) during an earthquake, the seismic isolation device 4 and the deformation limiting device 5 are simultaneously subjected to shear deformation. Therefore, it is possible to restrict shear deformation rather than deforming the seismic isolation device 4 alone to surely prevent the seismic isolation device 4 from being deformed more than a predetermined amount, and both the seismic isolation device 4 and the deformation limiting device 5 gradually. Therefore, the building 8 is not subjected to a sudden force, and the acceleration received by the building 8 can be very small. As a result, the safety of residents can be ensured by a large earthquake.

  Further, by providing a step in the height direction of the deformation limiting device 5 with the seismic isolation device 4, the shear deformation of the seismic isolation device 4 can be suppressed independently without being affected by the deformation of the building 8 due to the earthquake. can do.

FIG. 4 is a schematic view in which the seismic isolation structure of the present invention is arranged between a building and a foundation.
The limit deformation of laminated rubber 6 for seismic isolation is generally 4 times the total thickness of rubber (shear strain 400%), and the laminated rubber 6 receives the weight (axial force) of the building during an earthquake. Therefore, the limit deformation changes depending on the relationship between the vertical axial force and the horizontal deformation amount. For example, the limit deformation is set to 2.5 to 3 to 5 times the total rubber thickness, The seismic isolation clearance D to the retaining wall 10 on the outer periphery is the deformation amount +50 to 150 mm (about 2.7 to 3.8 times the total rubber thickness), or 105 to 120 of the limit shear deformation amount of the building. Often in the range of%.

  And in the seismic isolation structure of this invention, even if an unexpected large earthquake occurs, the shear deformation amount of the building 8 will be suppressed below the limit shear deformation amount of the seismic isolation structure 1, and the building 8 and the clearance D between the retaining wall 10 provided on the outer peripheral portion of the building 8, and preferably the range of 90 to 100% is not exceeded with respect to the limit shear deformation amount of the building where the seismic isolation device 4 is installed. Therefore, a collision between the lower part of the building and the retaining wall can be avoided.

  In this seismic isolation structure 1, the deformation limiting device 5 can be, for example, a cylindrical rubber block or a structure in which an elastic body is provided only at one end of the contact portion of the seismic isolation device 4. A laminated rubber comprising a laminated plate and a rigid plate that can suppress compression in the vertical direction is particularly preferred.

  In addition, preferably, the predetermined distance between the seismic isolation device 4 and the deformation limiting device 5 is in a range of 90 to 100% with respect to the limit shear deformation amount of the building in which the seismic isolation device 4 is installed. Even when the seismic isolation device 4 is unexpectedly sheared and deformed without obstructing the deformation of 4, it is possible to avoid destruction of the seismic isolation device 4 and damage of the building, for example, due to a collision.

  That is, if it is less than 90%, the deformation limiting device 5 may function even during an earthquake of the predicted magnitude, and the original effect of the seismic isolation structure 1 of the building may not be exhibited. Then, the seismic isolation structure 1 may be deformed unexpectedly, and the seismic isolation device 4 may be destroyed before the deformation limiting device 5 contacts, or the building may collide with the retaining wall and be damaged. .

FIG. 5A is a top view showing one embodiment of the seismic isolation structure of the present invention, and FIG. 5B is a top view showing another embodiment of the seismic isolation structure of the present invention. ) Is a top view showing another embodiment of the seismic isolation structure of the present invention.
By the way, the deformation limiting device 5 is not only arranged on the outer periphery of the seismic isolation device 4 in a cylindrical shape concentric with the seismic isolation device 4 at a predetermined interval. It can be surrounded by the limiting device 15 and eight columnar deformation limiting devices 25 can be arranged.
Preferably, the deformation limiting device is arranged on the outer periphery of the seismic isolation device 4 in a cylindrical shape concentric with the seismic isolation device 4, so that the deformation limiting device can be limited in any direction even if the seismic isolation device 4 is sheared and deformed in any direction. The device can follow and buffer.

  The deformation limiting device can be installed not only on the building side but also on the foundation side to limit the shear deformation of the seismic isolation device.

DESCRIPTION OF SYMBOLS 1 Seismic isolation structure 2,6 Laminated rubber 3,7 Mounting face plate 4 Seismic isolation device 5,15,25 Deformation restricting device 8 Building 9 Foundation 10 Retaining wall

Claims (4)

A seismic isolation structure between the building and its foundation,
The seismic isolation device mainly composed of an elastic body provided between the building and the foundation thereof, and the elastic body with a predetermined interval around the seismic isolation device Seismic isolation structure comprising a deformation limiting device mainly composed of   The seismic isolation structure according to claim 1, wherein the deformation limiting device is provided with a step in a height direction between a building or a foundation thereof.   The seismic isolation structure according to claim 1 or 2, wherein the deformation limiting device comprises a laminated rubber including an elastic rubber and a rigid plate.   The immunity according to any one of claims 1 to 3, wherein a predetermined interval between the seismic isolation device and the deformation limiting device is in a range of 90 to 100% with respect to a limit shear deformation amount of a building provided with the seismic isolation device. Seismic structure.

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