JP6441028B2 - Seismic isolation structure - Google Patents

Description

  The present invention relates to a building having a seismic isolation structure, for example.

  Traditionally, there are seismically isolated buildings. This building includes, for example, a lower housing such as a foundation, a plurality of seismic isolation devices installed on the lower housing, and an upper housing provided on these seismic isolation devices. This seismic isolation device has an isolator and a damper. Of these, the isolator supports the load of the upper housing and moves the upper structure slowly in the horizontal direction during an earthquake. The types of isolators include laminated rubber, sliding bearings and rolling bearings. Here, the sliding bearing includes an elastic sliding bearing using an elastic body as a part of the bearing.

  By the way, when the upper frame is reinforced concrete and is long in a predetermined direction in plan view (hereinafter, this horizontal direction is referred to as the longitudinal direction), after the construction of the upper frame is completed, the frame concrete shrinks due to hydration reaction or drying, The amount of drying shrinkage alone is 400 to 600 μm for several years, and it is calculated to shrink by 4 to 6 cm in a building with a side of 100 m. In buildings that are not seismically isolated, the foundation is constrained by the ground, so the entire building does not shrink so much. However, in base-isolated buildings, the upper housing is placed on the lower housing via elastically deformable elastic bodies, horizontally displaceable sliding bearings, rolling bearings, etc. Because of the large difference, the amount of contraction between the upper and lower housings will vary greatly over time. When contraction progresses, the outer periphery of the upper housing may move inward. Then, in the vicinity of the outer periphery of a building with a long side, the upper part of the laminated rubber is pulled by the concrete and sheared horizontally, which is not only bad in appearance, but also remains after the initial contraction has subsided. As a result, the seismic isolation performance of the building may be reduced. In addition, the column core of the upper frame and the pile core of the lower frame may be displaced, and an excessive force exceeding the design assumption may be applied to the pile and the foundation.

In order to solve this problem, for example, the following method has been proposed.
Before constructing the upper frame, the upper part of the seismic isolation device is displaced in the horizontal direction by the amount of shrinkage of the concrete at the outer periphery of the building (see Patent Document 1).
Specifically, the upper part of the seismic isolation device is previously displaced in the horizontal direction by an amount equal to the amount of concrete shrinkage that occurs after the construction of the upper frame, in the direction opposite to the direction displaced by concrete shrinkage, and the mounting member Thus, this displacement is kept in the holding state. Then, after the upper casing is constructed, this holding state is released. Therefore, when the frame concrete contracts, the upper part of the seismic isolation device returns to its original proper position.

In addition, although the subject and objective differ, the method of arrange | positioning a seismic isolation apparatus in the center part of a building and arrange | positioning a rolling support in the outer peripheral part of a building is shown (refer patent document 2). The rolling bearing includes upper and lower support plates and balls interposed between the support plates.
According to this method, even if the concrete frame contracts and the outer peripheral part of the building moves inward, the rolling bearing ball rolls, so that it seems that the rolling bearing is not deformed.

JP 2006-97325 A JP-A-9-242818

However, the method disclosed in Patent Document 1 has the following problems.
Actually, since the concrete frame of the upper frame is constrained by the exterior material and the interior material, it is difficult to predict the shrinkage amount of the concrete frame, and it takes several years to complete the contraction.
Further, since the elastic member of the seismic isolation device is deformed while supporting the building load, it is necessary to apply a large force in order to displace the upper part of the elastic member in the horizontal direction, and the work is extremely difficult. In addition, when the vertical load is not applied to the seismic isolation device, it is highly possible that the upper surface of the elastic member is inclined when displaced in the horizontal direction.
Therefore, when the concrete frame contracts, the seismic isolation device is still deformed and the seismic isolation performance may be lowered.

  Moreover, in patent document 2, since the upper housing is supported through the ball | bowl of a rolling support in the outer peripheral part of a building, it resists the horizontal force which acts on a building only with the seismic isolation device of a building center part at the time of an earthquake. As a result, it may be difficult to maintain the stability of the outer periphery of the building. Rolling bearings using balls and the like have a small pressure receiving area and require machining of parts, and the load that can be supported is limited. Therefore, it is difficult and rarely used for buildings larger than detached houses.

  An object of this invention is to provide the base isolation structure which can maintain the stability of a building outer peripheral part, suppressing the fall of base isolation performance, even if a frame concrete contracts.

  The seismic isolation structure according to claim 1 includes an upper housing (e.g., a seismic isolation device 20 </ b> A, 20 </ b> B described later) provided on a lower housing (e.g., a foundation 10 described later). It is a seismic isolation structure that supports a building body 30) to be described later, and at least the seismic isolation device (for example, a seismic isolation device 20B described later) at the outermost position in the longitudinal direction of the seismic isolation device is used as a sliding bearing. Features.

According to the present invention, when the shrinkage of the concrete occurs after the construction of the upper frame, at least the seismic isolation device at the outermost position in the longitudinal direction among the seismic isolation devices of the building is used as the sliding bearing, so that the bearing slides on the sliding plate. Even if the upper housing contracts, the sliding bearing does not remain deformed and the force applied to the upper housing is reduced. In addition, the column core of the upper frame and the pile core of the lower frame do not shift, so that the upper frame can be kept stable, and the pile and foundation parts are not subjected to excessive force exceeding the design assumptions. Seismic isolation performance does not deteriorate.
Therefore, unlike the prior art, it is not necessary to predict the amount of shrinkage of the concrete, or it is not necessary to deform the seismic isolation device in advance.

  The seismic isolation structure according to claim 2 is provided on a projecting portion (for example, a projecting portion 41 described later) projecting horizontally from the upper housing and the lower housing or the ground, and abuts on an upper surface of the projecting portion. A contact portion (for example, a contact portion 42 described later).

By the way, at the time of an earthquake, a force acts on the outer peripheral portion of the upper casing in a floating direction, and the support of the upper casing may become unstable. However, according to the present invention, the upper casing is provided with the protruding portion that protrudes in the horizontal direction, and the lower casing or the ground is provided with the contact portion that contacts the upper surface of the protruding portion. Therefore, even if a lifting force acts on the outer periphery of the upper housing, the upper surface of the protruding portion protruding from the upper housing is pressed by the contact portion, so that the outer periphery of the upper housing does not float, and the upper housing Can be supported stably.
Further, when a horizontal force is applied to the upper housing, the projecting portion moves while contacting the contact portion, so that there is no hindrance to the movement of the upper housing.

  ADVANTAGE OF THE INVENTION According to this invention, even if a frame concrete shrink | contracts, stability of a building outer peripheral part can be maintained, suppressing the fall of a seismic isolation performance.

It is a schematic diagram which shows the cross section of the longitudinal direction of the building which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the behavior of the longitudinal direction at the time of the concrete shrinkage | contraction of the building which concerns on the said embodiment. It is a schematic diagram which shows the cross section of the longitudinal direction of the building which concerns on 2nd Embodiment of this invention. It is the side view and front view of the guide mechanism of the seismic isolation structure which concern on the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
Drawing 1 is a mimetic diagram showing the section of the longitudinal direction of building 1 to which the seismic isolation structure concerning a 1st embodiment of the present invention was applied. In this embodiment, all the longitudinal sections have the same structure, and the number of spans in the short direction is smaller than the number of spans in the longitudinal direction.
The building 1 includes a foundation 10 as a lower casing, a plurality of seismic isolation devices 20A and 20B provided on the foundation 10, and a building main body as an upper casing provided on the seismic isolation devices 20A and 20B. 30.
The building body 30 extends in the longitudinal direction, i.e., the left-right direction in FIG. 1, has a rigid frame structure composed of a reinforced concrete column member and a beam member, and is supported by the seismic isolation devices 20 </ b> A and 20 </ b> B.

The seismic isolation devices 20A and 20B are arranged along the left-right direction in FIG. Of these seismic isolation devices 20A and 20B, the seismic isolation device 20A is disposed on the longitudinal center side of the building 1, and the seismic isolation devices are disposed on both ends in the longitudinal direction of the building 1 and on the inner side, that is, on the outer peripheral side. A device 20B is arranged.
In the present embodiment, all longitudinal sections have the same structure, and the seismic isolation devices 20B are arranged at both longitudinal ends and inside thereof.
The seismic isolation device 20 </ b> A is a laminated rubber 21.

  The seismic isolation device 20 </ b> B includes a sliding plate 22 attached to the foundation 10 and a sliding bearing 23 attached to the building body 30 and sliding on the sliding plate 22. Here, the sliding bearing includes an elastic sliding bearing using an elastic body as a part of the bearing, and in this embodiment, an elastic sliding bearing is used as all the sliding bearings 23.

The seismic isolation devices 20 </ b> A and 20 </ b> B hold a state in which the building body 30 can move in the horizontal direction with respect to the foundation 10 while supporting the building body 30 from below by taking a reaction force on the foundation 10.
And when the horizontal force acts on the building main body 30 at the time of an earthquake, 20 A of seismic isolation apparatuses deform | transform the laminated rubber 21, and relieve | moderate seismic force.
Further, the seismic isolation device 20B has an elastic body that deforms when a small horizontal force is applied to the building body 30 during an earthquake, relieves the seismic force, and when a large horizontal force is applied, the sliding bearing 23 Slides on the sliding plate 22 to relieve the seismic force.
In this building 1, as shown in FIG. 2, after the building main body 30 is constructed, the frame concrete contracts, and the building main body 30 is displaced in the direction of the arrow in FIG. 2. This displacement increases as it approaches the outer peripheral portion of the building 1, but in the seismic isolation device 20 </ b> B on the outer peripheral portion side of the building 1, since the sliding support 23 slides on the sliding plate 22, deformation of the sliding support 23 is suppressed. Is done. Even if the building body 30 contracts, no deformation remains in the sliding bearing 23, and the force applied to the building body 30 is also reduced. In addition, the pillar core of the building body 30 and the pile core of the foundation 10 do not shift, so that the stability of the building body 30 can be maintained, and an excessive force exceeding the design assumption is not applied to the pile or foundation part. The seismic isolation performance of building 1 does not deteriorate.
In the present invention, for example, the seismic isolation device at the outermost position at both ends in the longitudinal direction where the amount of contraction is large may be a sliding bearing, and includes a case where some sliding bearings are also arranged in the central portion in the longitudinal direction. It is.

According to this embodiment, there are the following effects.
(1) Since it is not necessary to predict the amount of shrinkage of concrete or to previously deform the seismic isolation device as in the prior art, it is possible to prevent a decrease in seismic isolation performance.
Further, since the seismic isolation device 20B on the outer periphery of the building is configured to include the sliding plate 22 and the sliding support 23, when a horizontal force acts on the building body 30 during an earthquake, the sliding support 23 on the sliding plate 22 is provided. Because of the sliding, the stability of the building body 30 can be maintained.

[Second Embodiment]
Drawing 3 is a mimetic diagram showing the section of the longitudinal direction of building 1A to which the seismic isolation structure concerning a 2nd embodiment of the present invention was applied. FIG. 4 is a side view and a front view of the guide mechanism 40.
In this embodiment, the point which provided the guide mechanism 40 in 1 A of buildings differs from 1st Embodiment.
That is, the guide mechanism 40 is provided at least at the left and right locations in FIG. 3 on the outer wall surfaces at both ends in the length direction of the building 1A.

The guide mechanism 40 includes a protruding portion 41 that protrudes in the horizontal direction from the building body 30, and an abutting portion 42 that is provided on the foundation 10 and contacts the upper surface of the protruding portion 41.
The protruding portion 41 has a rod shape and extends along the length direction of the building 1.
The contact portion 42 includes a pair of support columns 421 provided on the foundation 10 and a horizontal member 422 that connects the upper ends of the support columns 421. The lower surface of the horizontal member 422 is in contact with the upper surface of the protruding portion 41.

  According to this guide mechanism 40, when a horizontal force acts on the building main body 30, the protruding portion 41 moves while contacting the contact portion. At this time, even if a lifting force acts on the outer peripheral portion of the building main body 30, the upper surface of the protruding portion 41 protruding from the building main body 30 is pressed by the contact portion 42.

According to the present embodiment, in addition to the above (1), there are the following effects.
(2) Even if a lifting force acts on the outer peripheral portion of the building main body 30, the upper surface of the projecting portion 41 protruding from the building main body 30 is pressed by the contact portion 42, so that the outer peripheral portion of the building main body 30 is The building body 30 can be stably supported without floating.
Further, when a horizontal force is applied to the building main body 30, the projecting portion 41 moves while contacting the contact portion 42, so that there is no hindrance to the movement of the building main body 30.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

1, 1A ... Building 10 ... Foundation (lower housing)
20A, 20B ... Seismic isolation device 21 ... Laminated rubber (first seismic isolation device)
22 ... Slip plate 23 ... Slide support (second seismic isolation device)
30 ... Building body (upper frame)
DESCRIPTION OF SYMBOLS 40 ... Guide mechanism 41 ... Protruding part 42 ... Contact part 421 ... Post 422 ... Horizontal member

Claims (2)

A seismic isolation structure that supports the upper chassis with a plurality of seismic isolation devices provided on the lower chassis,
The upper casing is a ramen structure having a plurality of spans in the longitudinal direction;
Seismic isolation structure wherein the seismic isolation device positioned on at least one span of the longitudinal ends of the upper skeleton are sliding bearings.   The base isolation device according to claim 1, further comprising: a projecting portion that protrudes in a horizontal direction from the upper housing; and a contact portion that is provided on the lower housing or the ground and contacts the upper surface of the projecting portion. Construction.

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