Base isolation structure

Abstract

To provide a base isolation structure capable of preventing excessive pull-out force from acting on a base isolation bearing when an earthquake occurs.SOLUTION: A base isolation structure 10 comprises a first column 31A, a second column 31B, and a third column 31C placed on one street. The first column 31A, the second column 31B, and the third column 31C are arranged in this order on the street. A distance between the first column 31A and the second column 31B is greater than a distance between the second column 31B and the third column 31C. The base isolation structure 10 comprises a first base isolation bearing 41 supporting the first column 31A and a second base isolation bearing 42 supporting the second column 31B and the third column 31C. The third column 31C is supported by the second base isolation bearing 42 via a brace 33.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a seismic isolation structure. [Background technology]

[0002] A seismic isolation structure comprises a superstructure, a substructure, and seismic isolation bearings arranged between the superstructure and the substructure (see, for example, Patent Document 1). The substructure supports columns of the superstructure via the seismic isolation bearings. When an earthquake occurs, the seismic isolation bearings reduce the vibrations transmitted from the substructure to the superstructure, thereby protecting the superstructure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-217053 A Summary of the Invention [Problem to be solved by the invention]

[0004] When an earthquake occurs, a pull-out force acts on the columns depending on the shaking. In a seismic isolation structure, it is necessary to prevent excessive pull-out force from acting on the seismic isolation bearings when an earthquake occurs. [Means for solving the problem]

[0005] A seismic isolation structure that solves the above-mentioned problems is a seismic isolation structure comprising a first column, a second column, and a third column arranged on one street, wherein the first column, the second column, and the third column are arranged in that order on the street, the distance between the first column and the second column is greater than the distance between the second column and the third column, and the structure comprises a first seismic isolation bearing supporting the first column and a second seismic isolation bearing supporting the second column and the third column, and the third column is supported by the second seismic isolation bearing via a brace. Effect of the Invention

[0006] According to the present invention, it is possible to prevent excessive pull-out force from acting on a seismic isolation bearing when an earthquake occurs. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a seismic isolation structure as viewed from the side. [Diagram 2] FIG. 2 is a plan view showing the configuration of the seismic isolation structure as viewed from above. [Diagram 3] FIG. 3 is a cross-sectional view of a main part of a seismic isolation structure seen from the side, showing a modified example of the arrangement of braces. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Seismic isolation structure] An embodiment of a seismic isolation structure will be described with reference to Figs. 1 to 3. As shown in FIG. 1, a seismic isolation structure 10 includes a foundation 20, a frame 30, and a seismic isolation layer 40.

[0009] The foundation 20 is provided in an underground space formed by excavating the ground 11. The foundation 20 is made of reinforced concrete. The foundation 20 supports the frame 30 via a seismic isolation layer 40. [Frame] As shown in Fig. 1, the frame 30 is formed by joining various steel materials such as H-shaped steel, square steel pipes, steel plates, etc. The frame 30 is formed of columns 31 and beams 32 connected via joints.

[0010] As shown in FIG. 2, the frame 30 has street centers A to C extending in a first direction, and street centers 1 to 8 extending in a second direction intersecting the first direction. The second direction is perpendicular to the first direction, for example. The street centers A to C are arranged in this order in the second direction. The street centers 1 to 8 are arranged in this order in the first direction. The number of streets perpendicular to the street centers A to C is not limited, and may be seven or less, or nine or more.

[0011] The frame 30 includes a plurality of first columns 31A, a plurality of second columns 31B, and a plurality of third columns 31C as columns 31. The plurality of first columns 31A are arranged along a street center line A. The plurality of second columns 31B are arranged along a street center line B. The plurality of third columns 31C are arranged along a street center line C.

[0012] The first pillar 31A is arranged at each intersection of the grid center A and the grid center lines 1 to 8. The second pillar 31B is arranged at each intersection of the grid center B and the grid center lines 1 to 8. The third pillar 31C is arranged at each intersection of the grid center C and the grid center lines 1 to 8. That is, on the grid centers 1 to 8, the first pillar 31A, the second pillar 31B, and the third pillar 31C are arranged in this order on one street.

[0013] In the second direction, the distance D1 between the grid line A and the grid line B is greater than the distance D2 between the grid line B and the grid line C. That is, in each of the grid lines 1 to 8, the distance between the first column 31A and the second column 31B is greater than the distance between the second column 31B and the third column 31C.

[0014] For example, the distance D1 is a long span of 15 m or more and 25 m or less. For example, the distance D1 is about 20 m. For example, the distance D2 is 5 m or more and 10 m or less. For example, the distance D2 is about 7 m. For example, the distance D1 is more than twice the distance D2.

[0015] The frame 30 includes a first portion 30A and a second portion 30B. The first portion 30A is a portion located between the first pillar 31A and the second pillar 31B in the second direction. The second portion 30B is a portion located between the second pillar 31B and the third pillar 31C in the second direction.

[0016] In the seismic isolation structure 10, the living space in the first portion 30A is configured to be a column-free space. In the seismic isolation structure 10, a core portion consisting of elevators, stairs, machine rooms, etc. is mainly provided in the second portion 30B. Note that the first portion 30A and the second portion 30B may have an open atrium portion where multiple floors are continuous.

[0017] The frame 30 includes beams 32 extending along a first direction and beams 32 extending along a second direction. Of the beams 32 extending along the second direction, beams 32A located in the first portion 30A are configured to have a longer span than beams 32B located in the second portion 30B.

[0018] As shown in Fig. 1, the first column 31A and the second column 31B are supported by the seismic isolation layer 40 further below the first beam 32C, which is located in the first story among the beams 32 included in the frame 30. The first beam 32C is located in the lowest stage among the beams 32 included in the frame 30. The first column 31A and the second column 31B extend from the seismic isolation layer 40 to the top story. The third column 31C extends from the first story to the top story.

[0019] The third column 31C is supported on the seismic isolation layer 40 via a brace 33. The brace 33 is bridged between a joint between the third column 31C and a second beam 32D located on a layer above the first beam 32C, for example, on the second layer, and a joint between the first beam 32C and the second column 31B. The brace 33 is disposed in each of the centerlines 1 to 8.

[0020] The frame 30 includes a vibration-resistant stud 34. The vibration-resistant stud 34 is disposed between the grid center A and the grid center B in the first portion 30A. The vibration-resistant stud 34 connects the beams 32 that connect the first column 31A and the second column 31B across one or more stories.

[0021] As one example, the vibration-resistant studs 34 are arranged on grid centers 1 and 8, which are located at each end in the first direction among the grid centers 1 to 8 (see FIG. 2). Furthermore, in the first portion 30A, the vibration-resistant studs 34 may be arranged at positions other than the grid centers 1 and 8, and for example, the vibration-resistant studs 34 may be arranged on any of the grid centers 2 to 7.

[0022] [Seismic isolation layer] As shown in FIG. 1, the seismic isolation layer 40 includes a first seismic isolation bearing 41 and a second seismic isolation bearing 42. The first seismic isolation bearing 41 and the second seismic isolation bearing 42 are, for example, laminated rubber bearings. The laminated rubber bearings also function as damping materials. The laminated rubber bearings may include lead plugs.

[0023] The first seismic isolation bearing 41 supports the first column 31A from directly below the first column 31A. The second seismic isolation bearing 42 supports the second column 31B and the third column 31C from directly below the second column 31B. The load of the third column 31C is transmitted to the second seismic isolation bearing 42 via the brace 33.

[0024] The seismic isolation layer 40 includes, for example, a seismic isolation damper 43. The seismic isolation damper 43 connects between the first beam 32C and the foundation 20. The seismic isolation damper 43 is disposed, for example, directly below the vibration-resistant stud 34. The seismic isolation damper 43 damps vibration of the frame 30 in the horizontal direction.

[0025] 1 illustrates the seismic isolation damper 43 for damping vibration in the second direction, but in addition to or instead of the seismic isolation damper 43, a seismic isolation damper 43 for damping vibration in the first direction may be provided. Also, the seismic isolation damper 43 may be omitted.

[0026] As shown in Fig. 2, a plurality of first seismic isolation bearings 41 and a plurality of second seismic isolation bearings 42 are arranged in the seismic isolation structure 10. As an example, the first seismic isolation bearings 41 are arranged directly below each of the first columns 31A at each intersection of the street center A and the street center lines 1 to 8. As an example, the second seismic isolation bearings 42 are arranged directly below each of the second columns 31B at each intersection of the street center B and the street center lines 1 to 8. In Fig. 2, the first seismic isolation bearings 41 and the second seismic isolation bearings 42 are indicated by two-dot chain lines.

[0027] [Operation of the embodiment] In the frame 30, the distance between the second column 31B and the third column 31C in the second direction is smaller than the distance between the first column 31A and the second column 31B. If the first column 31A to the third column 31C are supported by different seismic isolation bearings, and the seismic isolation bearing supporting the second column 31B is used as a fulcrum, the moment acting on the seismic isolation bearing supporting the third column 31C is smaller than the moment acting on the seismic isolation bearing supporting the first column 31A. Therefore, when the second column 31B is used as a fulcrum, the pull-out force acting on the third column 31C is likely to be larger than the moment acting on the seismic isolation bearing supporting the third column 31C when an earthquake occurs. Therefore, when the first column 31A to the third column 31C are supported by different seismic isolation bearings, a large pull-out force is likely to act on the seismic isolation bearing supporting the third column 31C. In this case, the smaller the distance (distance D2) between the second column 31B and the third column 31C is relative to the distance (distance D1) between the first column 31A and the second column 31B, the more likely it is that a large pull-out force will act on the seismic isolation bearing supporting the third column 31C.

[0028] In this regard, in the present embodiment, in each of the centerlines 1 to 8, the first column 31A is supported by the first seismic isolation bearing 41, and the second column 31B and the third column 31C are supported by the second seismic isolation bearing 42. Therefore, in the event of an earthquake, a sufficient moment acts on the first seismic isolation bearing 41 and the second seismic isolation bearing 42 to resist the pull-out force.

[0029] [Effects of the embodiment] The effects of this embodiment will be described. (1) In one street, the first column 31A is supported by the first seismic isolation bearing 41, and the second column 31B and the third column 31C are supported by the second seismic isolation bearing 42. In this way, in the event of an earthquake, the frame 30 can be supported without applying a large pull-out force to a specific seismic isolation bearing.

[0030] (2) The second seismic isolation bearing 42 is disposed directly below the second column 31B, and the third column 31C is supported by the second seismic isolation bearing 42 via the brace 33. A larger load is applied to the second column 31B, which is located between the first column 31A and the third column 31C, than to the third column 31C. By disposing the second seismic isolation bearing 42 directly below the second column 31B, the relatively large load of the second column 31B can be suitably transmitted to the second seismic isolation bearing 42.

[0031] (3) The brace 33 is configured to connect the joint between the second column 31B and the first beam 32C located on the first story, and the joint between the third column 31C and the second beam 32D located on the second story. This allows the length of the brace 33 to be shorter than when the brace 33 is connected from a story above the second story. Also, compared to when the brace 33 is connected from a story above the second story, a larger portion of the third column 31C is supported from below by the brace 33, so the third column 31C can be stably supported.

[0032] (4) The seismic isolation structure 10 includes laminated rubber bearings as the first seismic isolation bearing 41 and the second seismic isolation bearing 42. In such a seismic isolation structure 10, the second column 31B and the third column 31C are supported by the second seismic isolation bearing 42, so that in the event of an earthquake, the frame 30 can be supported without applying a large pull-out force to a specific laminated rubber bearing.

[0033] (5) By providing the vibration-resistant studs 34 in the first portion 30A of the frame 30, vibration of the first portion 30A during an earthquake can be suppressed. [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0034] The frame 30 does not necessarily have to have the vibration-resistant studs 34 in the first portion 30A. Also, the frame 30 may have the vibration-resistant studs 34 in the second portion 30B. The first seismic isolation bearing 41 and the second seismic isolation bearing 42 may be sliding bearings. For example, some or all of the plurality of first seismic isolation bearings 41 and the plurality of second seismic isolation bearings 42 may be sliding bearings.

[0035] As shown in Fig. 3, the brace 33 may be configured to connect the joint between the second column 31B and the first beam 32C located on the first story, and the joint between the third column 31C and the third beam 32E located on a story higher than the second story (e.g., the third story). In this case, the extension direction of the brace 33 becomes closer to the vertical direction, so that the load of the third column 31C can be easily transmitted to the second seismic isolation bearing 42 via the brace 33. Note that, among the street cores 1 to 8, the brace 33 may be configured to connect from the second story in any of the streets, and the brace 33 may be configured to connect from a story higher than the second story in the other streets.

[0036] The second seismic isolation bearing 42 may be disposed between the second column 31B and the third column 31C in the second direction. In this case, the second column 31B is supported by the second seismic isolation bearing 42 via a brace 33 different from the brace 33 connected to the third column 31C. In other words, both the second column 31B and the third column 31C are supported by the second seismic isolation bearing 42 via different braces 33. In this case, the upper end of one brace 33 is connected to the second column 31B, the upper end of the other brace 33 is connected to the third column 31C, and the lower ends of the two braces 33 are disposed directly above the second seismic isolation bearing 42. According to this configuration, the extension direction of the brace 33 connected to the third column 31C is disposed closer to the vertical direction, so that the load of the third column 31C can be easily transmitted to the second seismic isolation bearing 42. [Explanation of symbols]

[0037] D1,D2...Distance, 10...Seismic isolation structure, 11...Ground, 20...Foundation, 30...Frame, 30A...1st part, 30B...2nd part, 31...Column, 31A...1st column, 31B...2nd column, 31C...3rd column, 32, 32A, 32B... Beam, 32C... 1st beam, 32D... 2nd beam, 32E... 3rd beam, 33... Brace, 34... Vibration-proof stud, 40... Seismic isolation layer, 41... 1st seismic isolation bearing, 42... 2nd seismic isolation bearing, 43... Seismic isolation damper.

Claims

1. A seismic isolation structure comprising a first column, a second column, and a third column arranged on one street, On the street, the first pillar, the second pillar, and the third pillar are arranged in this order, a distance between the first pillar and the second pillar is greater than a distance between the second pillar and the third pillar; A first seismic isolation bearing supporting the first column; a second seismic isolation bearing supporting the second column and the third column; The third column is supported by the second seismic isolation bearing via a brace. Earthquake-resistant structure.

2. The second seismic isolation bearing is disposed directly below the second column. The seismic isolation structure according to claim 1 .

3. The brace connects a joint between the second column and a beam located on the first floor and a joint between the third column and a beam located on the second floor. The seismic isolation structure according to claim 2.

4. The brace connects a joint between the second column and a beam located on the first floor and a joint between the third column and a beam located on a floor higher than the second floor. The seismic isolation structure according to claim 2.

5. The first seismic isolation bearing and the second seismic isolation bearing are laminated rubber bearings. A seismic isolation structure according to any one of claims 1 to 4.

Images