Seismic isolation structure and construction method of seismic isolation structure

Abstract

To provide seismic isolation structure and a construction method of the seismic isolation structure that can improve work efficiency for installing the seismic isolation structure.SOLUTION: Seismic isolation structure 10, which is seismic isolation structure at a joint formed by a reinforced concrete column 91 and a steel beam 92, includes an upper foundation member 13 on a seismic isolation device 12. The upper foundation member 13 includes a precast RC foundation 30 with a recess 36 on an upper surface 13A into which lower ends 94A of column main re-bars 94 constituting the reinforced concrete column 91 can be inserted.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation structure and a method for constructing the seismic isolation structure. [Background technology]

[0002] Conventionally, for example, a seismic isolation structure has been disclosed in which a lower foundation member, a seismic isolation device, and an upper foundation member are stacked, as shown in Patent Document 1. This type of seismic isolation structure functions as a seismic isolation layer for the joints formed by the columns and beams, thereby improving the seismic isolation performance of the building. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7270816 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional seismic isolation structures, when a joint is constructed between a reinforced concrete column and a steel beam, it is not easy to arrange the main reinforcement of the column steel of the reinforced concrete column. Therefore, there is a need to improve the work efficiency of installing seismic isolation structures. [Means for solving the problem]

[0005] The seismic isolation structure that solves the above problem is a seismic isolation structure at a joint consisting of a reinforced concrete column and a steel beam, and includes an upper foundation member on a seismic isolation device, the upper foundation member including a precast RC foundation, and the upper surface of the precast RC foundation has a recess into which the lower ends of the main column reinforcement that constitutes the reinforced concrete column can be inserted.

[0006] A construction method for a seismic isolation structure that solves the above-mentioned problems is a construction method for a seismic isolation structure at a joint formed by a reinforced concrete column and a steel beam, wherein the seismic isolation structure comprises an upper foundation member on a seismic isolation device, the upper foundation member comprises a precast RC foundation, the upper surface of the precast RC foundation has a recess into which the lower ends of the main column reinforcement that constitutes the reinforced concrete column can be inserted, and the construction method for the seismic isolation structure includes inserting the lower ends of the main column reinforcement into the recess. [Effects of the Invention]

[0007] According to the present invention, the arrangement of the main column reinforcement of a reinforced concrete column becomes easier, thereby improving the work efficiency related to the installation of a seismic isolation structure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view showing an embodiment of a seismic isolation structure of the present invention. [Figure 2] FIG. 2 is an enlarged view of a main part of the seismic isolation structure shown in FIG. [Figure 3] FIG. 3 is a top view showing an embodiment of a seismic isolation structure of the present invention. [Figure 4] FIG. 4 is a flowchart showing an embodiment of the method for constructing a seismic isolation structure according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a seismic isolation structure and a construction method for a seismic isolation structure of the present invention will be described. In the drawings used in the following description, any horizontal direction perpendicular to the up-down direction Z of the drawings will be referred to as a first horizontal direction X, and a direction perpendicular to the up-down direction Z and the first horizontal direction X will be referred to as a second horizontal direction Y. Note that in the drawings, in order to facilitate understanding of the invention, some of the multiple component members may be represented and the remaining members may be omitted.

[0010] <Seismic isolation structure> First, a seismic isolation structure 10 of the present invention will be described with reference to Figures 1 to 3. The seismic isolation structure 10 is configured as a seismic isolation layer with a joint 90 between a building and the ground. The joint 90 is composed of a reinforced concrete column 91 and a steel beam 92. The seismic isolation structure 10 includes a lower foundation member 11, a seismic isolation device 12 on the lower foundation member 11, and an upper foundation member 13 on the seismic isolation device 12.

[0011] The reinforced concrete column 91 includes column main reinforcements 94 extending in the vertical direction Z. The column main reinforcements 94 are main reinforcements that constitute the reinforced concrete column 91. A plate nut 94B is screwed onto a lower end portion 94A of the column main reinforcement 94.

[0012] The steel beam 92 has an upper end 92A and a lower end 92B. In this embodiment, the steel beam 92 is an H-beam, but is not limited to this and may be in another form. A slab top 93 of the floor slab is formed above the upper end 92A of the steel beam 92. In this embodiment, a cover plate 14 is attached to the steel beam 92. The cover plate 14 will be described in detail later.

[0013] The lower foundation member 11 is a reinforced concrete member and is connected to a foundation beam (not shown). The seismic isolation device 12 is provided on the lower foundation member 11 and supports the upper foundation member 13. The seismic isolation device 12 includes a laminated rubber 20, an upper flange 21, and a lower flange 22. The laminated rubber 20 is cylindrical in shape and supports the weight of the building while mitigating earthquake shaking.

[0014] The upper flange 21 is provided at the upper end 20A of the laminated rubber 20. The lower flange 22 is provided at the lower end 20B of the laminated rubber 20. The upper flange 21 and the lower flange 22 are each circular when viewed from above (i.e., when viewed from the vertical direction Z). The outer diameter of the upper flange 21 and the outer diameter of the lower flange 22 are each larger than the outer diameter of the laminated rubber 20.

[0015] The upper foundation member 13 is provided on the seismic isolation device 12 and includes a precast RC (reinforced concrete) foundation, U-shaped bars 31, hoops 32, a base plate 33, cap nuts 34, level-adjusting cap nuts 35, and level-adjusting bolts 35A. The upper foundation member 13 is configured so that its outer diameter is larger than the outer diameter of the reinforced concrete column 91 and the seismic isolation device 12 when viewed from above.

[0016] In this embodiment, the precast RC foundation 30 has a square shape when viewed from above, but the shape of the precast RC foundation 30 is not limited to this. The precast RC foundation 30 may be either on-site precast or factory precast. The upper surface 13A of the precast RC foundation 30 has a recess 36. The recess 36 is configured to allow the insertion of lower ends 94A of the column main reinforcement bars 94 that constitute the reinforced concrete column 91.

[0017] A plurality of U-shaped bars 31 are buried in the precast RC foundation 30. The U-shaped bars 31 include reinforcing bars extending in the first horizontal direction X and reinforcing bars extending in the second horizontal direction Y. The upper ends 31A of the U-shaped bars 31 protrude upward from the upper surface 13A of the precast RC foundation 30 and extend toward the joint 90.

[0018] The hoops 32 are reinforcing bars that act to reinforce against shear force and prevent cracks. The hoops 32 are embedded in the precast RC foundation 30 so as to extend horizontally, and are wrapped around the U-shaped bars 31.

[0019] The base plate 33 is a plate for attaching the precast RC foundation 30 to the seismic isolation device 12. The base plate 33 has a circular shape when viewed from above. The outer diameter of the base plate 33 is the same as the outer diameter of the upper flange 21 of the seismic isolation device 12. The base plate 33 is embedded in the precast RC foundation 30 so as to be exposed from the bottom surface 13B of the precast RC foundation 30. The base plate 33 exposed from the bottom surface 13B of the precast RC foundation 30 is in close contact with the upper flange 21 of the seismic isolation device 12.

[0020] The cap nuts 34 are nuts for connecting the seismic isolation device 12 and the upper foundation member 13. A plurality of cap nuts 34 are embedded in the precast RC foundation 30, and each cap nut 34 is arranged in a circular shape when viewed from above. The cap nuts 34 are configured so that a bolt (not shown) can be screwed onto them from below via a through hole 33A provided in the base plate 33.

[0021] The level-adjusting cap nut 35 is buried above the base plate 33 within the precast RC foundation 30. The level adjustment bolt 35A is a bolt that can be displaced in the vertical direction Z. By adjusting the position of the level adjustment bolt 35A in the vertical direction Z, the position of the steel beam 92 relative to the upper foundation member 13 can be adjusted.

[0022] The cover plate 14 is attached to the steel beam 92 so as to have a rectangular shape when viewed from above that can surround the seismic isolation device 12 and the column main reinforcement 94. The cover plate 14, together with the upper surface 13A of the precast RC foundation 30, defines an area 15 where concrete is poured.

[0023] As shown in Figure 2, a gap 16 is provided between the upper surface 13A of the precast RC foundation 30 and the lower end 14A of the cover plate 14, so that the lower end 14A of the cover plate 14 does not abut against the upper surface 13A of the precast RC foundation 30.

[0024] A covering member 17 is provided to cover the gap 16. The covering member 17 prevents concrete from flowing out of the gap 16 when concrete is poured into the area 15 defined by the upper surface 13A of the precast RC foundation 30 and the cover plate 14. In this embodiment, the covering member 17 is made of tape, but the covering member 17 may be made of a material other than tape as long as it can block the concrete that attempts to flow out of the gap 16.

[0025] <Construction method of seismic isolation structure> Next, a construction method for the seismic isolation structure according to this embodiment will be described. The construction method for the seismic isolation structure according to this embodiment is a construction method for the seismic isolation structure 10 described above, and includes a seismic isolation structure construction process. The seismic isolation structure construction process includes an upper foundation member installation process, an upper foundation member attachment process, a steel beam installation process with cover plates, a column main reinforcement installation process, a covering process, and a concrete pouring process.

[0026] In the seismic isolation structure construction process according to this embodiment, the precast RC foundation 30 of the upper foundation member 13 is precast in a factory and transported to the construction site where the seismic isolation structure 10 is to be constructed. Then, after the seismic isolation device 12 is installed on the lower foundation member 11 at the site, the seismic isolation structure construction process is carried out. The seismic isolation structure construction process will be described in detail below with reference to FIG. 4.

[0027] In the seismic isolation structure construction process, first, the upper foundation member 13 is provided on the seismic isolation device 12 (upper foundation member installation process: step S10). Next, with the base plate 33 exposed from the bottom surface 13B of the precast RC foundation 30 positioned above the upper flange 21 of the seismic isolation device 12, a bolt (not shown) is screwed into the cap nut 34 through the through hole 33A to attach the upper foundation member 13 onto the upper flange 21 (upper foundation member attachment process: step S11).

[0028] Then, the steel beams 92 with cover plates 14 are installed (installation process of steel beams with cover plates: step S12). The steel beams 92 with cover plates 14 are those in which the cover plates 14 and the steel beams 92 are integrally formed in advance at a factory. The steel beams 92 are installed so that the cover plates 14 surround the seismic isolation devices 12 and the column main reinforcement bars 94 when viewed from above, and a gap 16 is provided between the upper surface 13A of the precast RC foundation 30 and the lower end 14A of the cover plates 14.

[0029] Furthermore, the lower end portions 94A of the column main reinforcement bars 94 are inserted into the recesses 36 formed in the upper surface 13A of the precast RC foundation 30 of the upper foundation member 13, thereby installing the column main reinforcement bars 94 (column main reinforcement installing step: step S13).

[0030] Next, a covering member 17 is attached so as to cover the gap 16 between the upper surface 13A of the precast RC foundation 30 and the lower end 14A of the covering plate 14 (covering step: step S14). Finally, concrete is poured into the area 15 defined by the upper surface 13A of the precast RC foundation 30 and the covering plate 14 (concrete pouring step: step S15).

[0031] <Actions and Effects of This Embodiment> The operation and effects of the above-described embodiment will be described. (1) The upper surface 13A of the precast RC foundation 30 of the upper foundation member 13 has a recess 36 into which the lower end portions 94A of the column main reinforcement bars 94 can be inserted. This makes it easier to determine the placement position of the column main reinforcement bars 94, and facilitates the arrangement of the column main reinforcement bars 94 of the reinforced concrete column 91.

[0032] (2) The level-adjusting cap nuts 35 and the level-adjusting bolts 35A can be used to adjust the positional relationship between the upper foundation member 13 and the steel beams 92. This makes it easy to ensure the erection accuracy of the steel beams 92.

[0033] (3) The steel beams 92 with cover plates 14 are arranged to surround the column main reinforcement bars 94 and the seismic isolation devices 12 when viewed from above. Concrete is poured into the area 15 surrounded by the cover plates 14 and the upper surface 13A of the precast RC foundation 30. Therefore, there is no need to add a separate structure to hold back the concrete when pouring it. This allows the upper foundation member 13 to be simplified into a flat plate shape, thereby reducing its weight.

[0034] (4) A gap 16 is provided between the upper surface 13A of the precast RC foundation 30 of the upper foundation member 13 and the lower end 14A of the cover plate 14. This ensures a clearance dimension when erecting the steel beam 92 with the cover plate 14, preventing the cover plate 14 from coming into contact with the precast RC foundation 30 and chipping the corners of the upper surface end 13C.

[0035] (5) A base plate 33 and a cap nut 34 are embedded in the precast RC foundation 30 of the upper foundation member 13, and the base plate 33 is exposed from the bottom surface 13B of the precast RC foundation 30. This makes it easier to adjust the position of the base plate 33 relative to the upper flange 21 of the seismic isolation device 12, making it easier to connect the seismic isolation device 12 and the upper foundation member 13.

[0036] (6) The base plate 33 of the upper foundation member 13 and the upper flange 21 of the seismic isolation device 12 are each circular in top view, and are arranged on the same circumference in top view. This eliminates the need for expensive heavy-duty corrosion-resistant coating to prevent corrosion of the base plate 33, as there is no exposed portion of the base plate 33.

[0037] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0038] The construction method for the seismic isolation structure 10 is a construction method for a joint 90 formed between a reinforced concrete column 91 and a steel beam 92, in which the seismic isolation structure 10 includes an upper foundation member 13 on a seismic isolation device 12, and the upper foundation member 13 includes a precast RC foundation 30 having a recess 36 on its upper surface 13A into which the lower ends of the column main reinforcement 94 constituting the reinforced concrete column 91 can be inserted. The construction method may further include steps other than those described above, as long as it includes inserting the lower ends of the column main reinforcement 94 into the recess 36. The order of the steps included in the construction process for the seismic isolation structure 10 described above may be arbitrary. For example, the covering step may be performed before the column main reinforcement installation step. Furthermore, the steel beam installation step with cover plates may be performed after the column main reinforcement installation step.

[0039] The base isolation device 12 and the upper foundation member 13 may be connected via headed studs by adding and attaching headed studs to the base plate 33. Also, a fixing material such as a fixing anchor bolt may be added and attached to the cap nut 34.

[0040] The cover plate 14 may have any shape as long as it is configured to at least surround the reinforced concrete column 91 and the seismic isolation device 12 when viewed from above. The cover plate 14 may be configured, for example, by joining together a plurality of plate-shaped steel plates.

[0041] [Note] The technical concepts grasped from the above-described embodiment and modified examples will be described below. (A) A seismic isolation device is provided which is connected to the upper foundation member below the upper foundation member, the seismic isolation device having an upper flange which is circular when viewed from above, the upper foundation member having a base plate which is exposed from the bottom surface of the precast RC foundation of the upper foundation member and which is connected to the upper flange of the seismic isolation device.

[0042] (B) The base plate and the upper flange are each circular in top view, and the outer diameter of the base plate and the outer diameter of the upper flange are the same and are provided on the same circumference.

[0043] (C) The upper foundation member is provided with a level adjustment cap nut and a level adjustment bolt for adjusting the position of the upper foundation member relative to the steel beam. (D) The level-adjusting cap nut and the level-adjusting bolt are provided above the base plate. [Explanation of symbols]

[0044] X...first horizontal direction, Y...second horizontal direction, Z...vertical direction, 10...seismic isolation structure, 11...lower foundation member, 12...seismic isolation device, 13...upper foundation member, 13A...top surface, 13B...bottom surface, 13C...top end, 14...covering plate, 14A...lower end, 15...area, 16...gap, 17...covering member, 20...laminated rubber, 20A...upper end, 20B...lower end, 21...upper flange, 22...lower flange, 30...plate Recast RC foundation, 31...U-shaped bar, 31A...upper end, 32...hoop, 33...base plate, 33A...through hole, 34...cap nut, 35...leveling cap nut, 35A...leveling bolt, 36...recess, 90...joint, 91...reinforced concrete column, 92...steel beam, 92A...upper end, 92B...lower end, 93...top of slab, 94...main column bar, 94A...lower end, 94B...plate nut.

Claims

1. A seismic isolation structure at a joint composed of a reinforced concrete column and a steel beam, An upper foundation member on the seismic isolation device is provided, the upper foundation member comprises a precast reinforced concrete foundation; The upper surface of the precast RC foundation has a recess into which the lower ends of the main reinforcement bars constituting the reinforced concrete column can be inserted, forming a seismic isolation structure.

2. A construction method for a seismic isolation structure at a joint composed of a reinforced concrete column and a steel beam, The seismic isolation structure includes an upper foundation member on a seismic isolation device, the upper foundation member comprises a precast reinforced concrete foundation; The upper surface of the precast RC foundation has a recess into which the lower end of the column main reinforcement constituting the reinforced concrete column can be inserted, The construction method for a seismic isolation structure includes inserting lower ends of the main column reinforcement into the recesses.

3. The construction method for a seismic isolation structure according to claim 2 , wherein the upper foundation member is provided with a level-adjusting cap nut and a level-adjusting bolt.

4. The steel beam is a steel beam with a cover plate, The steel beam is provided so that the cover plate surrounds the seismic isolation device and the column main reinforcement; 4. The construction method for a seismic isolation structure according to claim 2 or 3, further comprising pouring concrete into an area defined by the cover plate and the upper surface of the precast RC foundation.

5. Providing the steel beam so that a gap is provided between the lower end of the cover plate and the upper surface of the precast RC foundation; The construction method for a seismic isolation structure according to claim 4, further comprising covering the gap with a covering member.

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