JP6895262B2 - Seismic isolation structure - Google Patents

Description

The present invention relates to a seismic isolation structure.

A seismic isolation structure in which basic seismic isolation and intermediate layer seismic isolation are used in combination is known (see, for example, Patent Document 1).

Further, a seismic isolation structure in which the upper structure is supported via a sliding bearing on the stigma of the column of the lower structure is known (see, for example, Patent Document 2). In this sliding bearing, a sliding plate is provided on the superstructure and a sliding material is provided on the stigma of the column.

Japanese Unexamined Patent Publication No. 2004-316285 Japanese Unexamined Patent Publication No. 2008-280718

By the way, in a seismic isolation structure including an upper structure supported by a seismic isolation device and an overhanging portion overhanging from the upper structure, it is conceivable that the overhanging portion is supported by a column member via the seismic isolation device. ..

However, in this case, the bending moment acting on the column member from the overhanging portion may increase during an earthquake.

In consideration of the above facts, an object of the present invention is to reduce the bending moment acting on the column member from the overhanging portion at the time of an earthquake.

The seismic isolation structure according to the first aspect is arranged below the seismic isolation device, the superstructure supported by the seismic isolation device, the overhanging portion protruding from the superstructure, and the overhanging portion. It includes a pillar member and a sliding bearing provided on the pillar head of the pillar member and supporting the overhanging portion.

According to the seismic isolation structure according to the first aspect , the overhanging portion projects from the superstructure supported by the seismic isolation device. In addition, a pillar member is arranged below the overhanging portion. The overhanging portion is supported by the sliding bearing provided on the stigma of the column member.

Here, when the overhanging portion is supported by the pillar member via the laminated rubber bearing, the overhanging portion and the pillar member are connected via the laminated rubber bearing. Therefore, in the event of an earthquake, the bending moment transmitted from the overhanging portion to the column member via the laminated rubber bearing tends to increase.

On the other hand, the overhanging portion of the present invention is supported by a sliding bearing provided on the stigma of the column member, as described above. As a result, in the event of an earthquake, the overhanging portion slides with respect to the stigma of the column member, so that the bending moment transmitted from the overhanging portion to the column member via the sliding bearing is reduced.

Therefore, in the present invention, it is possible to reduce the bending moment acting on the column member from the overhanging portion at the time of an earthquake, as compared with the case where the overhanging portion is supported by the column member via the laminated rubber bearing.

The seismic isolation structure according to the second aspect is the seismic isolation structure according to the first aspect. With a sliding material that slidably supports.

According to the seismic isolation structure according to the second aspect , the sliding bearing has a sliding plate and a sliding material. The sliding plate is provided on the overhanging portion, and the sliding material is provided on the stigma of the column member.

Here, contrary to the present invention, when the sliding plate is provided on the stigma of the column member and the sliding material is provided on the overhanging portion, when the sliding material slides against the sliding plate during an earthquake, the sliding material is replaced with the sliding plate. The input position of the vertical load of the overhanging portion, which is input to the stigma of the column member via the above, changes. As a result, the bending moment acting on the column member from the overhanging portion may increase during an earthquake.

On the other hand, in the present invention, as described above, the sliding plate is provided on the overhanging portion, and the sliding material is provided on the capital of the column member. As a result, even if the sliding plate slides with respect to the sliding material during an earthquake, the input position of the vertical load of the overhanging portion input from the sliding plate to the stigma of the column member via the sliding material is less likely to change. Therefore, in the present invention, it is possible to reduce the bending moment acting on the column member from the overhanging portion at the time of an earthquake, as compared with the case where the sliding plate is provided on the stigma of the column member and the sliding member is provided on the overhanging portion. it can.

The seismic isolation structure according to the third aspect includes a plurality of substructures that support the upper structure via the plurality of the seismic isolation devices in the seismic isolation structure according to the first aspect or the second aspect. At least one of the seismic isolation devices is a laminated rubber bearing.

According to the seismic isolation structure according to the third aspect , the superstructure is supported by the substructure via a plurality of seismic isolation devices. Further, at least one of the plurality of seismic isolation devices is a laminated rubber bearing. As a result, the seismic force acting on the upper structure during an earthquake is transmitted to the lower structure via the laminated rubber bearings.

On the other hand, the overhanging portion protruding from the superstructure is supported by the stigma of the column member via a sliding bearing. Therefore, the seismic force acting on the overhanging portion is mainly transmitted from the upper structure to the lower structure via the laminated rubber bearing. Therefore, it is possible to improve the seismic performance of the overhanging portion while reducing the bending moment acting on the column member from the overhanging portion during an earthquake.

As described above, according to the seismic isolation structure according to the present invention, it is possible to reduce the bending moment acting on the column member from the overhanging portion at the time of an earthquake.

It is an elevation view which shows the seismic isolation structure which concerns on one Embodiment. (A) and (B) are partially enlarged elevation views of FIG. 1 showing sliding bearings. It is a partially enlarged elevation view corresponding to FIG. 2 which shows the sliding bearing which concerns on a comparative example. It is a partially enlarged elevation view corresponding to FIG. 2A which shows the modification of the seismic isolation structure which concerns on one Embodiment.

Hereinafter, the seismic isolation structure according to the embodiment will be described with reference to the drawings.

(Seismic isolation structure, foundation)
FIG. 1 shows the seismic isolation structure 10 according to the present embodiment. The seismic isolation structure 10 includes a foundation 12, a plurality of laminated rubber bearings 14, and an upper structure 16. The foundation 12 as the substructure is, for example, a pressure plate made of reinforced concrete. The foundation 12 is provided at the excavation bottom (root cutting bottom) where the ground G is excavated (root cutting). The structure of the foundation 12 is not limited to the pressure plate, and its structure can be changed as appropriate.

(Laminated rubber bearing)
The plurality of laminated rubber bearings 14 are installed on the upper surface 12U of the foundation 12. Further, the plurality of laminated rubber bearings 14 are arranged in two horizontal directions. The superstructure 16 is supported by these laminated rubber bearings 14. A seismic isolation layer 18 in which a plurality of laminated rubber bearings 14 are installed is formed between the foundation 12 and the superstructure 16. The laminated rubber bearing 14 is an example of a seismic isolation device.

(Superstructure)
The superstructure 16 has a plurality of floors (plurality of layers). The superstructure 16 is supported by a plurality of laminated rubber bearings 14 so as to be horizontally displaceable with respect to the foundation 12. An overhanging portion 20 is provided on the side surface 16S on one side of the superstructure 16.

(Overhanging part)
The overhanging portion 20 has, for example, a frame formed of columns and beams inside. The overhanging portion 20 projects from a predetermined floor (for example, the second floor or higher) of the upper structure 16 onto the ground G on the outer periphery of the foundation 12, and forms an external space 22 on the lower side thereof. The external space 22 is used as a parking space for a truck or the like, for example. The overhanging portion 20 is supported by a plurality of pillar members 30.

(Pillar member)
The pillar member 30 is arranged on the lower side of the overhanging portion 20 on the tip portion 20T side in the overhanging direction (arrow H direction). Although not shown, a plurality of pillar members 30 are provided in the depth direction of the paper surface of FIG. Each pillar member 30 is erected on a pillar member foundation 32 provided on the ground G and is supported by the pillar member foundation 32.

The overhanging portion 20 can be supported by at least one pillar member 30. Further, the arrangement of the pillar member 30 is not limited to the tip portion 20T side of the overhanging portion 20, and can be appropriately changed.

(Foundation for pillar members)
The pillar member foundation 32 is provided at a position away from the foundation 12, and is separate from the foundation 12. The pillar member foundation 32 may be, for example, an independent foundation provided for each pillar member 30, a continuous foundation (cloth foundation) over a plurality of pillar members 30, or the like. Also,

(Slip bearing)
A sliding bearing 40 is provided on the pillar head 30U of the pillar member 30. That is, in the seismic isolation structure 10, the laminated rubber bearing 14 and the sliding bearing 40 are used together. Further, a stigma seismic isolation structure is applied to the column member 30. The sliding bearing 40 supports the tip portion 20T side of the overhanging portion 20. In other words, the overhanging portion 20 is supported by the stigma 30U of the column member 30 via the sliding bearing 40. As a result, the overhanging portion 20 can be displaced in the horizontal direction with respect to the pillar member 30.

(Sliding board)
As shown in FIGS. 2A and 2B, the sliding bearing 40 has a sliding plate 42 and a sliding member 44. The sliding plate 42 is provided on the overhanging portion 20. Specifically, a base plate 26 is provided on the column base portion of the column 24 constituting the overhanging portion 20. The base plate 26 is appropriately reinforced by a plurality of reinforcing ribs 28. A sliding plate 42 is provided on the lower surface of the base plate 26. A beam 29 is joined to the pillar 24 of the overhanging portion 20.

The sliding plate 42 is formed in a plate shape and is joined in a state of being overlapped on the lower surface of the base plate 26. Further, the lower surface of the sliding plate 42 is a sliding surface 42L on which the sliding material 44, which will be described later, slides. Further, the sliding surface 42L is wider than the supporting surface 44U of the sliding material 44. The sliding surface 42L is made of a low friction material such as stainless steel or Teflon (registered trademark).

(Sliding material)
The sliding member 44 is provided on the pillar head 30U of the pillar member 30. The sliding material 44 has a supporting surface 44U that supports the sliding surface 42L of the sliding plate 42. The support surface 44U is formed of, for example, a low friction material such as stainless steel or Teflon (registered trademark). As a result, the sliding surface 42L of the sliding plate 42 can slide on the supporting surface 44U of the sliding material 44.

In the sliding bearing 40, at least one of the sliding surface 42L of the sliding plate 42 and the supporting surface 44U of the sliding material 44 can be formed of a low friction material. Further, reference numeral C shown in FIGS. 2 (A) and 2 (B) indicates a central axis (material axis) of the pillar member 30.

(Action)
Next, the operation of this embodiment will be described.

As shown in FIG. 1, according to the seismic isolation structure 10 according to the present embodiment, the superstructure 16 is provided with an overhanging portion 20. An external space 22 is formed under the overhanging portion 20. The external space 22 is used as, for example, a parking space for a truck or the like. As described above, in the present embodiment, by providing the overhanging portion 20 in the upper structure 16, the external space 22 can be easily formed on the outer peripheral portion of the upper structure 16.

Further, the superstructure 16 is supported by the foundation 12 via a plurality of laminated rubber bearings 14. On the other hand, the overhanging portion 20 is supported by the stigma 30U of the column member 30 via the sliding bearing 40. As a result, in the event of an earthquake, the superstructure 16 is displaced horizontally with respect to the foundation 12, and the overhanging portion 20 is displaced horizontally with respect to the column member 30. Therefore, the seismic forces Q1 and Q2 acting on the superstructure 16 and the overhanging portion 20 at the time of an earthquake are reduced.

Further, as a comparative example, for example, when a sliding bearing is provided on the column base portion of the column member 30, the column member 30 is displaced in the horizontal direction with respect to the column member foundation 32 at the time of an earthquake, so that the column member 30 It is necessary to provide a predetermined clearance around it.

On the other hand, the sliding bearing 40 of the present embodiment is provided on the stigma 30U of the column member 30. As a result, the column member 30 does not displace in the horizontal direction with respect to the column member foundation 32 at the time of an earthquake, so that it is not necessary to provide a predetermined clearance around the column member 30. Therefore, the effective space of the external space 22 can be expanded.

Here, as a comparative example, for example, when the overhanging portion 20 is supported by the column head 30U of the column member 30 via the laminated rubber bearing instead of the sliding bearing 40, the overhanging portion 20 and the column member 30 are made of laminated rubber. Connected via bearings. Therefore, in the event of an earthquake, the bending moment transmitted from the overhanging portion 20 to the column member 30 via the laminated rubber bearing tends to increase. When the bending moment transmitted from the overhanging portion 20 to the column member 30 increases, the required cross-sectional area of the column member 30 increases, and the reinforcement of the column member 30 increases.

Further, when the bending moment transmitted from the overhanging portion 20 to the column member 30 increases, the required yield strength of the column member foundation 32 that supports the column member 30 increases. As a countermeasure, for example, as shown by the alternate long and short dash line in FIG. 1, the ground G under the column member 30 is excavated, and the foundation 32 for the column member and the foundation 12 for the superstructure 16 are formed by a foundation beam or the like. By connecting, it is conceivable to increase the required yield strength of the pillar member foundation 32 and the like. However, excavation of the ground G and construction of foundation beams and the like are time-consuming.

On the other hand, the overhanging portion 20 of the present embodiment is supported by the stigma 30U of the column member 30 via the sliding bearing 40 as described above. As a result, in the event of an earthquake, the overhanging portion 20 slides with respect to the stigma 30U of the column member 30, so that the bending moment transmitted from the overhanging portion 20 to the stigma 30U of the column member 30 via the sliding bearing 40 becomes small. ..

Therefore, in the present embodiment, as compared with the case where the overhanging portion 20 is supported by the column head 30U of the column member 30 via the laminated rubber bearing, the bending moment acting on the column member 30 from the overhanging portion 20 at the time of an earthquake is increased. Can be reduced.

As a result, the required cross-sectional area of the column member 30 can be reduced, and the reinforcement of the column member 30 and the like can be reduced. Therefore, the construction cost of the pillar member 30 can be reduced, and the effective space of the external space 22 can be further expanded.

Further, by reducing the bending moment acting on the column member 30 from the overhanging portion 20 at the time of an earthquake, the required yield strength of the column member foundation 32 that supports the column member 30 can be reduced. Therefore, it is not necessary to excavate the ground G and connect the foundation 32 for the column member and the foundation 12 for the superstructure 16 with a foundation beam or the like. That is, in the present embodiment, the foundation 32 for the column member and the foundation 12 for the superstructure 16 can be separated. Therefore, the amount of excavation of the ground G is reduced, and the labor for constructing the foundation 32 for the column member is reduced.

Further, as shown in FIG. 2A, in the present embodiment, the sliding plate 42 is provided on the overhanging portion 20, and the sliding member 44 is provided on the stigma 30U of the column member 30. Here, FIG. 3A shows a sliding bearing 100 according to a comparative example. In the sliding bearing 100, contrary to the present embodiment, the sliding plate 42 is provided on the stigma 30U of the column member 30, and the sliding member 44 is provided on the overhanging portion 20.

In this case, as shown in FIG. 3B, when the sliding member 44 slides in the horizontal direction with respect to the sliding plate 42 at the time of an earthquake, the stigma 30U of the pillar member 30 from the sliding member 44 via the sliding plate 42. The input position of the vertical load N of the overhanging portion 20 input to is changed. As a result, the bending moment M acting on the column member 30 from the overhanging portion 20 may increase during an earthquake.

On the other hand, in the present embodiment, as shown in FIG. 2A, the sliding plate 42 is provided on the overhanging portion 20, and the sliding member 44 is provided on the stigma 30U of the column member 30. As a result, as shown in FIG. 2B, even if the sliding plate 42 slides horizontally with respect to the sliding material 44 during an earthquake, the pillar head of the pillar member 30 is passed from the sliding plate 42 via the sliding material 44. The input position of the vertical load N of the overhanging portion 20 input to 30U becomes difficult to change.

Therefore, in the present embodiment, the bending moment M (see FIG. 3B) acting on the column member 30 from the overhanging portion 20 at the time of an earthquake can be reduced as compared with the sliding bearing 100 according to the comparative example.

Further, as shown in FIG. 1, the superstructure 16 of the present embodiment is supported by the foundation 12 via a plurality of laminated rubber bearings 14. As a result, the seismic force Q1 acting on the superstructure 16 at the time of an earthquake is mainly transmitted to the foundation 12 via the plurality of laminated rubber bearings 14.

On the other hand, the overhanging portion 20 projecting from the upper structure 16 is supported by the stigma 30U of the column member 30 via the sliding bearing 40. Therefore, the seismic force Q2 acting on the overhanging portion 20 at the time of an earthquake is mainly transmitted from the superstructure 16 to the foundation 12 via the plurality of laminated rubber bearings 14. Therefore, it is possible to improve the seismic performance of the overhanging portion 20 while reducing the bending moment acting on the column member 30 from the overhanging portion 20 at the time of an earthquake.

(Modification example)
Next, a modified example of the above embodiment will be described.

The mounting structure of the sliding bearing 40 is not limited to the above, and can be changed as appropriate. For example, as shown in FIG. 4, a sliding plate 42 may be provided (or fixed) on the lower surface of the reinforced concrete or steel-framed reinforced concrete footing 50 provided in the overhanging portion 20. Further, the overhanging portion 34 may be provided on the stigma 30U of the pillar member 30 that supports the sliding member 44.

The beam 29 on the sliding bearing 40 may or may not be provided with a haunch.

Further, in the sliding bearing 40 of the above embodiment, the sliding plate 42 is provided on the overhanging portion 20, and the sliding member 44 is provided on the stigma 30U of the column member 30, but on the contrary, the sliding plate is provided on the column member 30. It may be provided on the stigma 30U of the above, and a sliding material may be provided on the overhanging portion 20.

Further, the column member 30 may be a reinforced concrete structure, a steel-framed reinforced concrete structure, an S structure, a CFT structure, or the like.

Further, in the above embodiment, the foundation 32 for the column member and the foundation 12 for the upper structure 16 are separated. For example, the foundation 32 for the column member and the foundation 12 for the upper structure 16 are formed as a foundation beam. Or the like, or the foundation for the column member and the foundation for the superstructure 16 may be integrally formed like a solid foundation.

Further, in the above embodiment, the superstructure 16 is supported by the foundation 12 via a plurality of laminated rubber bearings 14, but the above embodiment is not limited to this. As the seismic isolation device that supports the superstructure 16, a laminated rubber bearing, a sliding bearing, a rolling bearing, or the like can be used.

By using at least one seismic isolation device as a laminated rubber bearing among the plurality of seismic isolation devices that support the superstructure 16, seismic forces Q1 and Q2 acting on the superstructure 16 and the overhanging portion 20 during an earthquake. Can be transmitted to the foundation 12 via the laminated rubber bearing.

Further, in the above embodiment, the superstructure 16 is supported by the foundation 12, but the above embodiment is not limited to this. The lower structure that supports the upper structure 16 may be, for example, an underground structure having an underground floor.

Further, the superstructure 16 of the above embodiment has a basic seismic isolation structure, but may be, for example, an intermediate floor seismic isolation structure or a stigma seismic isolation structure.

Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate. Of course, it can be carried out in various modes as long as it does not deviate.

10 Seismic isolation structure 12 Foundation (substructure)
14 Laminated rubber bearings (seismic isolation device)
16 Superstructure 20 Overhanging part 30 Pillar member 30U Pillar head 40 Sliding bearing 42 Sliding plate 44 Sliding material

Claims (4)

Seismic isolation device and
The superstructure supported by the seismic isolation device and
An overhanging portion protruding from the superstructure and
A pillar member arranged under the overhanging portion and
A sliding bearing provided on the stigma of the pillar member to support the overhanging portion, and
Equipped with a,
The overhanging portion is supported only by the pillar member via the sliding bearing.
Seismic isolation structure. The overhanging portion projects from the second floor or higher of the superstructure.
The seismic isolation structure according to claim 1. The slip bearing is
A sliding plate provided on the overhanging portion and
A sliding material provided on the stigma of the pillar member and slidably supporting the sliding plate,
Have,
The seismic isolation structure according to claim 1 or 2. A substructure that supports the superstructure via the plurality of seismic isolation devices is provided.
At least one of the plurality of seismic isolation devices is a laminated rubber bearing.
The seismic isolation structure according to any one of claims 1 to 3.

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