JP6898739B2 - 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, there is known a seismic isolation structure in which the upper structure is supported by a sliding bearing at the stigma of the column of the lower structure (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 having a seismic isolation structure main body built on a flat ground and an overhanging portion extending from the seismic isolation structure main body to an uphill slope side, the overhanging portion is supported by a pillar member via a seismic isolation device. Is possible.

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

As a countermeasure for this, for example, it is conceivable to excavate an uphill slope and connect the foundation for the main body of the seismic isolation structure and the foundation for the column member with a foundation beam or the like to increase the strength of the foundation for the column member.

However, excavation of slopes and construction of foundation beams are time-consuming.

In consideration of the above facts, an object of the present invention is to improve the workability of the column member while reducing the bending moment acting on the column member from the overhanging portion in the event of an earthquake.

The seismic isolation structure according to the first aspect includes a foundation provided on the first ground, a laminated rubber bearing provided on the foundation, a structure main body supported by the foundation via the laminated rubber bearing, and the structure. An overhanging portion extending from the object main body onto the second ground at a position higher than the first ground, a pillar member provided on the second ground, and the overhanging portion provided on the pillar head of the pillar member. With sliding bearings to support.

According to the seismic isolation structure according to the first aspect , a foundation is provided on the first ground. The structure body is supported on this foundation via laminated rubber bearings. Further, the structure main body is provided with an overhanging portion. The overhanging portion projects from the main body of the structure onto the second ground, which is higher than the first ground. A pillar member is provided on the second ground. 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 the stigma of the column member via a sliding bearing. 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, the bending moment acting on the column member from the overhanging portion during an earthquake is reduced as compared with the case where the overhanging portion is supported by the column member via the laminated rubber bearing. As a result, in the present invention, it is not necessary to excavate the second ground and connect the foundation for the structure main body and the foundation for the column member with a foundation beam or the like. Therefore, the workability of the column member is improved.

As described above, in the present invention, it is possible to improve the workability of the column member while reducing the bending moment acting on the column member from the overhanging portion at the time of an earthquake.

Further, as described above, the structure body is supported by the foundation via laminated rubber bearings. On the other hand, the overhanging portion 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 structure body to the foundation 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.

Further, by providing the pillar member on the second ground, the height (material shaft length) of the pillar member becomes lower than that in the case where the pillar member is provided on the first ground. Therefore, the bending strength of the column member can be increased.

The seismic isolation structure according to the second aspect is the seismic isolation structure according to the first aspect , wherein the second ground is an inclined ground having an uphill slope with respect to the first ground, and the pillar member is the above-mentioned pillar member. It is provided on a sloped ground and is supported by a pillar member foundation that is separate from the foundation.

According to the seismic isolation structure according to the second aspect , the second ground is a sloped ground having an uphill slope with respect to the first ground. A foundation for a column member is provided on the sloped ground, and the column member is supported by the foundation for the column member.

By providing the column member and the foundation for the column member on the inclined ground in this way, the height of the column member can be easily lowered as compared with the case where the column member and the foundation for the column member are provided on the first ground. it can. Therefore, the bending strength of the column member can be easily increased.

The seismic isolation structure according to the third aspect is the seismic isolation structure according to the first or second aspect , and the sliding bearings are provided on the sliding plate provided in the overhanging portion and the stigma head of the pillar member. It has a sliding material that slidably supports the sliding plate.

According to the seismic isolation structure according to the third aspect , the sliding bearing supporting the overhanging portion has a sliding plate and a sliding material. The sliding plate is provided on the overhanging portion. On the other hand, the sliding material is provided on the stigma of the column member and slidably supports the sliding plate.

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, a sliding plate is provided on the overhanging portion, and a sliding material is provided on the capital of the column member. Therefore, 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 difficult 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.

As described above, according to the seismic isolation structure according to the present invention, it is possible to improve the workability of the column member while reducing 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 an elevation view corresponding to FIG. 1 which shows the modification of the seismic isolation structure which concerns on one Embodiment. 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)
FIG. 1 shows the seismic isolation structure 10 according to the present embodiment. The seismic isolation structure 10 is provided over a flat ground 60 and a slope 70 of the ground G. The seismic isolation structure 10 includes a foundation 12, a plurality of laminated rubber bearings 14, and a structure main body 16.

(Basic)
The foundation 12 is, for example, a pressure plate made of reinforced concrete. The foundation 12 is provided on a flat ground (root cutting bottom) 60A formed by excavating (root cutting) the flat ground 60.

The structure of the foundation 12 is not limited to the pressure plate, and its structure can be changed as appropriate. The flat ground 60A is an example of the first ground.

(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 structure main body 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 structure main body 16. The laminated rubber bearing 14 is an example of a seismic isolation device.

(Structure body)
The structure main body 16 has a plurality of floors (plurality of layers). The structure main body 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 structure main body 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 structure main body 16 onto the sloped ground 70A of the sloped ground 70.

The sloped ground 70A has an upward slope with respect to the flat ground 60A, and exists at a position higher than the flat ground 60A. Therefore, the overhanging portion 20 projects from the upper part of the structure main body 16 toward the inclined ground 70A so as to avoid the inclined ground 70A. The overhanging portion 20 is supported by a plurality of pillar members 30. The sloped ground 70A is an example of the second ground.

(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 a slope 70 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 members 30 can be changed as appropriate.

(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.

(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 foundation 12 is provided on the flat ground 60A of the ground G. The structure main body 16 is supported on the foundation 12 via a plurality of laminated rubber bearings 14. Further, the structure main body 16 is provided with an overhanging portion 20. The overhanging portion 20 projects from the structure main body 16 onto the sloped ground 70A. A pillar member 30 is provided on the inclined ground 70A. The overhanging portion 20 is supported by a sliding bearing 40 provided on the pillar head 30U of the pillar member 30.

Here, the overhanging portion 20 projects from the upper part of the structure main body 16 onto the inclined ground 70A so as to avoid the inclined ground 70A. As a result, it is not necessary to excavate the sloped ground 70A, so that the construction cost can be reduced.

Further, the structure main body 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 structure main body 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 structure main body 16 and the overhanging portion 20 at the time of an earthquake are reduced.

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. In this case, for example, as shown by the alternate long and short dash line in FIG. 1, the pillar member is formed by excavating the slope 70 and connecting the foundation 32 for the column member and the foundation 12 for the structure main body 16 with a foundation beam or the like. It is conceivable to increase the required strength of the foundation 32. However, excavation of slope 70 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.

Further, by reducing the bending moment acting on the column member 30 from the overhanging portion 20, 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 slope 70A and connect the foundation 32 for the column member and the foundation 12 for the structure main body 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 structure main body 16 can be separated. Therefore, the amount of excavation of the sloped ground 70A is reduced, and the labor for constructing the foundation 32 for the column member is reduced.

As described above, in the present embodiment, it is possible to improve the workability of the column member 30 and the column member foundation 32 while reducing the bending moment acting on the column member 30 from the overhanging portion 20 at the time of an earthquake.

Further, as shown in FIG. 1, the structure main body 16 is supported by the foundation 12 via a plurality of laminated rubber bearings 14. As a result, the seismic force Q1 acting on the structure main body 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 structure main body 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 structure main body 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.

Further, by providing the pillar member 30 on the inclined ground 70A, the height (material shaft length) of the pillar member 30 can be easily lowered as compared with the case where the pillar member 30 is provided on the flat ground 60A. Therefore, the bending strength of the column member 30 can be easily increased.

Further, as shown in FIG. 2A, in the sliding bearing 40 of 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 horizontally with respect to the sliding plate 42 during an earthquake, the sliding member 44 moves from the sliding member 44 to the stigma 30U of the column member 30 via the sliding plate 42. The input position of the vertical load N of the overhanging portion 20 to be input changes. 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.

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

The overhanging portion 20 of the above-described embodiment projects from the structure main body 16 onto the sloped ground 70A, but the above-described embodiment is not limited to this. For example, as shown in FIG. 4, the overhanging portion 20 may overhang from the structure main body 16 onto the flat ground 90A of the flat ground 90.

Specifically, the foundation 12 of the seismic isolation structure 80 is provided on the flat ground (bottom surface) 82A of the underground space 82 formed by excavating the flat ground 60 of the ground G. The structure main body 16 is supported on the foundation 12 via a plurality of laminated rubber bearings 14. The flat ground 82A is an example of the first ground.

The structure main body 16 has a basement floor 16L arranged underground and a ground floor 16U arranged above ground. An overhanging portion 20 is provided on the ground floor 16U of the structure main body 16. The overhanging portion 20 projects from the above-ground floor 16U of the structure main body 16 onto the flat ground 90A outside the underground space 82.

The flat ground 90A is arranged at a position higher than the flat ground 82A of the underground space 82. Further, the flat ground 90A is provided with a pillar member 30 and a pillar member foundation 32 for supporting the pillar member 30. The overhanging portion 20 is supported by a sliding bearing 40 provided on the pillar head 30U of the pillar member 30. The flat ground 90A is an example of the second ground.

In this way, the overhanging portion 20 may be made to overhang on the flat ground 90A located at a position higher than the flat ground 82A of the underground space 82. In this case as well, the workability of the column member 30 can be improved while reducing the bending moment acting on the column member 30 from the overhanging portion 20 at the time of an earthquake, as in the above embodiment.

Further, in the above embodiment, the sloped ground 70A is not excavated, but the sloped ground 70A may be excavated within a range not to be equal to or less than the flat ground 60A. In this case, the excavated slope 70A may be provided with, for example, a foundation beam connecting the foundation 32 for the column member and the foundation 12 for the structure main body 16.

Next, the mounting structure of the sliding bearing 40 is not limited to the one described above, and can be appropriately changed. For example, as shown in FIG. 5, 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.

Next, 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. It may be provided in the stigma 30U of 30 and the sliding material may be provided in 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 structure main body 16 is supported by the foundation 12 via a plurality of laminated rubber bearings 14, but the above embodiment is not limited to this. Of the seismic isolation devices that support the structure main body 16, at least one seismic isolation device may be a laminated rubber bearing, and the other seismic isolation devices may be sliding bearings, rolling bearings, or the like.

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 14 Laminated rubber bearing 16 Structure body 20 Overhanging part 30 Pillar member 30U Pillar head 32 Foundation for pillar member 40 Sliding bearing 42 Sliding plate 44 Sliding material 60A Flat ground (first ground)
70A slope (second ground)
80 Seismic isolation structure 82A Flat ground (first ground)
90A flat ground (second ground)

Claims (4)

The foundation provided on the first ground and
Laminated rubber bearings provided on the foundation
The structure body supported by the foundation via the laminated rubber bearing,
An overhanging portion extending from the main body of the structure onto the second ground at a position higher than the first ground,
The pillar member provided on the second ground 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 main body of the structure onto the second ground.
The seismic isolation structure according to claim 1. The second ground is a sloped ground having an uphill slope with respect to the first ground.
The pillar member is provided on the sloped ground and is supported by a pillar member foundation that is separate from the foundation.
The seismic isolation structure according to claim 1 or 2. 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, and
Have,
The seismic isolation structure according to any one of claims 1 to 3.

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