Base isolation repair method

Abstract

In a base isolation repair method in which a base isolation device is installed between an upper structure and a lower structure and the upper structure is supported by the lower structure via the base isolation device, a technique for appropriately supporting a vertical load of a floor structure portion cut end portion without adding a new column passing through the floor structure portion cut end portion in the lower structure when a core structure portion is separated from the lower structure in a state of being connected to the upper structure in a form in which the floor structure portion of the lower structure is separated from the core structure portion is provided.SOLUTION: In a separation process for separating an existing building into an upper structural body 10 and a lower structural body 20, a permanent cut end support 40 for supporting a vertical load while allowing horizontal movement is provided on a core structural part 11 with respect to a floor structural part cut end 21a of a floor structural part 21 of the lower structural body 20 separated from the core structural part 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation retrofitting method including a separation process for separating an existing building into an upper structure and a lower structure, and a seismic isolation device installation process for installing a seismic isolation device between the upper structure and the lower structure and supporting the upper structure on the lower structure via the seismic isolation device. [Background technology]

[0002] A seismic isolation retrofitting method is known in which an existing building is separated into an upper structure and a lower structure, a seismic isolation device is installed between the upper structure and the lower structure, and the upper structure is supported by the lower structure via the seismic isolation device (see, for example, Patent Document 1). In the seismic isolation renovation method described in Patent Document 1, an existing building has a core structure that forms a vertical hole (elevator shaft 30) inside that extends between the upper structure (structure main body 20) and the lower structure (foundation 10), and the floor structure (slab 26) of the lower structure is separated from the core structure, separating the core structure from the lower structure while still connected to the upper structure, and installing a seismic isolation device between the core structure and the lower structure so that the core structure is supported by the lower structure via the seismic isolation device. In other words, in the seismic isolation renovation method described in Patent Document 1, the cut end of the floor structure part of the lower structure that has been separated from the core structure part is left as a floor structure part that continues to the core structure part, and the cut end of the floor structure part is supported in a cantilevered state by the existing columns of the lower structure and protrudes toward the outer surface of the core structure part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-193772 Summary of the Invention [Problem to be solved by the invention]

[0004] In the seismic isolation retrofitting method described in Patent Document 1, it is necessary to support the vertical load of the cut end of the floor structure, especially when the cut end of the floor structure protrudes significantly from the existing column. In order to support the vertical load of the cut end of the floor structure, it is possible to add a new column that passes through the cut end of the floor structure in the substructure, but adding a new column not only complicates the renovation work and prolongs the construction period, but also poses the problem of the living space in the substructure being narrowed by the new column.

[0005] In view of this situation, the main object of the present invention is to provide a technology for appropriately supporting the vertical load of the cut end of the floor structure part in a seismic isolation retrofitting method in which an existing building is separated into an upper structure and a lower structure, a seismic isolation device is installed between the upper structure and the lower structure, and the upper structure is supported by the lower structure via the seismic isolation device, in which the floor structure part of the lower structure is separated from the core structure part, and the core structure part is separated from the lower structure while still connected to the upper structure, without adding a new column in the lower structure that passes through the cut end of the floor structure part. [Means for solving the problem]

[0006] A first characteristic configuration of the present invention includes a separation step of separating an existing building into an upper structure and a lower structure; a seismic isolation device installation process for installing a seismic isolation device between the upper structure and the lower structure and supporting the upper structure on the lower structure via the seismic isolation device, The existing building has a core structure portion that forms a vertical hole extending between the upper structure and the lower structure, In the separation step, a floor structure portion of the lower structure is separated from the core structure portion, and the core structure portion is separated from the lower structure while being connected to the upper structure; In the seismic isolation device installation step, a seismic isolation device is installed between the core structure and the substructure, and the core structure is supported by the substructure via the seismic isolation device, In the separation process, a permanent cut end support is provided in the core structure portion to support a vertical load while allowing horizontal movement of the cut end of the floor structure portion, which is the cut end of the floor structure portion of the lower structure that has been separated from the core structure portion.

[0007] According to this configuration, when the floor structure portion of the lower structure is separated from the core structure, the core structure portion connected to the upper structure is separated from the lower structure. The cut end portion of the floor structure portion of the lower structure separated from the core structure is supported in a cantilevered manner by the existing columns of the lower structure and protrudes toward the outer periphery of the core structure, and therefore needs to support its load. Therefore, by providing the cut end support to the core structure, the vertical load of the cut end portion of the floor structure portion can be supported by the cut end support while allowing horizontal movement of the cut end support of the core structure portion connected to the upper structure relative to the cut end portion of the floor structure portion on the lower structure. Furthermore, the vertical load transmitted from the cut end portion of the floor structure portion through the cut end support to the core structure can be appropriately handled by being transmitted to the lower structure via the seismic isolation device supporting the core structure. Therefore, according to the present invention, in a seismic isolation renovation method in which an existing building is separated into an upper structure and a lower structure, a seismic isolation device is installed between the upper structure and the lower structure, and the upper structure is supported by the lower structure via the seismic isolation device, the floor structure portion of the lower structure is separated from the core structure portion, and when the core structure portion is separated from the lower structure while still connected to the upper structure, a technology can be provided for appropriately supporting the vertical load of the cut end of the floor structure portion without adding a new column in the lower structure that passes through the cut end of the floor structure portion.

[0008] The second characteristic configuration of the present invention is that the cut end support body is configured to have a jaw portion fixed to the side of the existing column of the core structure portion, and a sliding plate portion interposed between the underside of the cut end of the floor structure portion and the upper surface of the jaw portion, which transmits vertical load from the cut end of the floor structure portion to the jaw portion while allowing horizontal movement of the jaw portion relative to the cut end of the floor structure portion.

[0009] According to this configuration, by configuring the cut end support body to have the jaw portion and the sliding plate portion, the sliding plate portion can appropriately allow horizontal movement of the jaw portion relative to the cut end of the floor structure portion on the lower structure side, while the jaw portion can appropriately support the vertical load transmitted from the cut end of the floor structure portion on the lower structure side.

[0010] A third characteristic configuration of the present invention is that the cut end portions of the floor structure portion are cut end portions of a plurality of existing beams of the floor structure portion of the lower structure that are separated from the existing columns of the core structure portion, The point is that a new beam is erected between the cut ends of the plurality of existing beams at the cut ends of the floor structure portion.

[0011] According to this configuration, when the core structure connected to the upper structure is separated from the floor structure of the lower structure, the multiple existing beams of the floor structure are separated from the existing columns of the core structure, and the cut ends of the multiple existing beams are supported in a cantilevered state by the existing columns of the lower structure as cut ends of the floor structure, protruding toward the outer periphery of the core structure. Then, by erecting new beams between the cut ends of the multiple existing beams at the cut ends of the floor structure, the cut ends of the multiple existing beams are appropriately stiffened by the new beams, and the slab of the floor structure is appropriately supported by the existing beams and new beams, while the cut end supports provided on the core structure can appropriately support the vertical load while allowing horizontal movement of the existing beams, the new beams, and the slab supported by them. [Brief explanation of the drawings]

[0012] [Figure 1] Existing building frame diagram [Figure 2] Frame diagram of the building after separation [Figure 3] Frame diagram of seismically isolated building [Figure 4] Figure 1 shows a plan view of the seismic isolation floor of the existing building. [Figure 5] The plan of the seismic isolated floor of the seismic isolated building shown in Figure 3 [Figure 6] An enlarged plan view showing the support state for the cut end of the floor structure by the cut end supports in a seismically isolated building. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a seismic isolation retrofitting method according to the present invention will be described with reference to the drawings. The seismic isolation renovation method according to this embodiment (hereinafter referred to as "this seismic isolation renovation method"), details of which will be described later, is a method that is carried out on an existing building 1A as shown in Figure 1 to construct a seismically isolated building 1C as shown in Figure 3. That is, referring to Figures 1, 2, and 3, this seismic isolation renovation method includes a separation process which is performed on an existing building 1A (see Figures 1 and 4) to separate the existing building 1A into an upper structure 10 and a lower structure 20 to create a separated building 1B (see Figure 2), and a seismic isolation device installation process which is performed on the separated building 1B to install a seismic isolation device 50 between the upper structure 10 and the lower structure 20 and support the upper structure 10 on the lower structure 20 via the seismic isolation device 50 to create a seismic isolated building 1C (see Figures 3 and 5).

[0014] As shown in Figure 1, the existing building 1A has a core structure 11 that forms multiple elevator shafts 12 (an example of a shaft) inside, spanning the upper structure 10 and the lower structure 20 that will be separated in the separation process. Note that the core structure 11 forms shafts like the elevator shafts 12 inside, spanning the upper structure 10 and the lower structure 20, but in addition to the elevator shafts 12, a stairwell, a pipe shaft, etc. may also be formed inside.

[0015] In the separation process, as shown in Fig. 2, temporary shoring 60 is appropriately placed, and then the existing building 1A is separated into the upper structure 10 and the lower structure 20. Specifically, on the seismic isolation floor 1a (the first floor in this embodiment), the temporary shoring 60 that supports the upper structure 10 is appropriately placed on the slab 4 of the lower structure 20, and then the first existing column 2A provided in an area other than the core structure section 11 is cut by the column cutting section 2a located on that seismic isolation floor 1a. Furthermore, on the core structure lower end floor 1b (the second basement floor in this embodiment), which is located below the seismic isolation floor 1a and at the lower end of the core structure 11, the second existing column 2B provided to the core structure 11 is cut at the column cutting portion 2b located on the core structure lower end floor 1b. Furthermore, on each floor between the seismic isolation floor 1a and the core structure lower end floor 1b, temporary shoring 60 supporting the existing beams 21A of the floor structure portion 21 connected to the core structure 11 is appropriately positioned on the slab 4 of the lower structure 20, and the floor structure portion 21 of the lower structure 20 that was connected to the core structure 11 is then cut from the core structure 11 at the floor structure cutting end portion 21a, which is the connection portion with the core structure 11. In this way, the core structure portion 11 is separated from the lower structure 20 while still connected to the upper structure 10. The support structure 60 appropriately placed in the separation process will be removed after the seismic isolation device installation process described below is carried out.

[0016] Furthermore, the floor structure section cut ends 21a are cut ends of multiple existing beams 21A of the floor structure section 21 that have been separated from the second existing column 2B of the core structure section 11. That is, the cut ends of the multiple existing beams 21A are supported in a cantilevered state by the first existing column 2A of the substructure 20 as floor structure section cut ends 21a and protrude toward the outer periphery of the core structure section 11. Then, new steel beams 35 are erected between the cut ends of the multiple existing beams 21A at the floor structure section cut ends 21a. As a result, the cut ends of the multiple existing beams 21A are appropriately stiffened by the new beams 35, and the slab 4 of the floor structure section 21 is appropriately supported by the existing beams 21A and the new beams 35. Furthermore, in this embodiment, as shown in FIG. 5 , new steel beams 36 are also provided between the existing beams 21A at both ends of the multiple existing beams 21A arranged in a vertical direction and the adjacent existing beams 3 of the substructure 20. Furthermore, new steel beams 37 are provided between the existing beams 21A at both ends of the multiple existing beams 21A arranged side by side in the left-right direction and the adjacent new beams 36. This further strengthens the cut ends of the multiple existing beams 21A.

[0017] The cut end 21a of the floor structure portion 21 of the lower structure 20 that was separated from the core structure portion 11 in the above separation process remains as a floor portion that connects to the core structure portion 11, and although not shown in the figure, an expansion joint that can ensure a fire compartment is interposed between the core structure portion 11 and the floor structure portion 21a, and a connecting passage is secured by the expansion joint. This floor structure portion cut end 21a is supported in a cantilevered state by the first existing column 2A of the substructure 20 and protrudes toward the outer peripheral surface of the core structure 11, so it is necessary to support the vertical load of this floor structure portion cut end 21a. In order to support the vertical load of the floor structure portion cut end 21a, it is possible to add a new column that passes through the floor structure portion cut end 21a in the substructure 20, but adding such a new column would not only complicate the renovation work and prolong the construction period, but would also pose the problem of the living space in the substructure 20 being narrowed by the new column. Therefore, in this seismic isolation renovation method, a configuration is adopted to appropriately support the vertical load of the cut end 21a of the floor structure portion without adding a new column that passes through the cut end 21a of the floor structure portion in the substructure 20, and the details of this configuration are explained below.

[0018] In the seismic isolation device installation process that is carried out after the separation process, as shown in Figures 3 and 5, a first seismic isolation device 51 is installed in a region other than the core structure 11 of the seismic isolation floor 1a at a location corresponding to the column cut section 2a between the upper structure 10 and the lower structure 20, and the upper structure 10 is supported by the lower structure 20 via the first seismic isolation device 51. Furthermore, a second seismic isolation device 52 is installed in a region below the core structure 11 on the core structure's lower end floor 1b at a location corresponding to the column cut section 2b between the core structure 11 and the lower structure 20, and the core structure 11 is supported by the lower structure 20 via the second seismic isolation device 52. Then, a permanent cut end support 40 is provided on the core structure 11 to support vertical loads while allowing horizontal movement for the cut end 21a of the floor structure 21 of the lower structure 20 that was separated from the core structure 11 in the separation process described above.

[0019] As shown in Figures 3 and 6, the cut end support 40 is composed of a jaw portion 41 fixed to the side of the second existing column 2B of the core structure portion 11, and a sliding plate portion 42 interposed between the underside of the cut end portion 21a of the floor structure portion and the upper surface of the jaw portion 41. The jaw portion 41 is newly constructed as an integral part of the reinforced concrete structure. The jaw portion 41 includes a column-fixed portion 41a, which is integrally fixed to the second existing reinforced concrete column 2B using connecting rebars or anchors, and a cut-end support portion 41b, which protrudes laterally from the upper end of the column-fixed portion 41a and has the slide plate 42 attached to its upper surface. Furthermore, the column-fixed portion 41a extends over at least three sides of the outer periphery of the second existing column 2B, including the side facing the cut end 21a of the floor structure and the sides adjacent to both sides of that side, thereby firmly securing the second existing column 2B. The vertical height of the column-fixed portion 41a in the jaw portion 41 is set sufficiently longer than the vertical height of the cut-end support portion 41b to ensure appropriate load transfer to the second existing column 2B. At the lower end floor 1b of the core structure, the jaw portion 41 is constructed integrally with the upper foundation of the newly constructed second seismic isolation device 52. The sliding plate portion 42 is configured as a known sliding support that transmits vertical load from the floor structure cut end portion 21a to the jaw portion 41 while allowing horizontal movement of the jaw portion 41 relative to the floor structure cut end portion 21a.

[0020] By providing such cut end supports 40 to the core structure 11, the vertical load of the floor structure cut end 21a can be supported by the cut end supports 40 while allowing horizontal movement of the cut end support 40 on the core structure 11 side connected to the upper structure 10 relative to the floor structure cut end 21a on the lower structure 20 side. The vertical load transmitted from the floor structure cut end 21a through the cut end supports 40 to the core structure 11 can be transmitted to the lower structure 20 via the second seismic isolation device 52 that supports the core structure 11, and can be appropriately handled.

[0021] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

[0022] (1) In the above embodiment, the vertical shaft formed inside the core structure 11 of the existing building 1A is an elevator shaft 12, but the vertical shaft is not limited to an elevator shaft 12 and may be a vertical shaft of another form, such as a void.

[0023] (2) In the above embodiment, the jaw portion 41 of the cut end support 40 is made of reinforced concrete, but it can also be configured as a steel frame bracket fixed to the second existing column 2B with anchor bolts.

[0024] (3) In the above embodiment, new steel beams 35, 36, and 37 were installed at the cut ends of multiple existing beams 21A, but the material and installation state of the new beams 35, 36, and 37 can be changed as appropriate, or some or all of them can be omitted. [Explanation of symbols]

[0025] 1A Existing building 2B Second existing pillar (existing pillar) 10 Superstructure 11 Core structure 12 Elevator shaft (vertical shaft) 20 Lower structure 21 Floor structure section 21A Existing beam 21a Floor structure cut end 35 New beam 36 New beam 37 New beam 40 Cut end support 41 Chin 41a Top side 42 Slide plate 50 Seismic isolation device 51 First seismic isolation device (seismic isolation device) 52 Second seismic isolation device (seismic isolation device)

Claims

1. A separation process to separate the existing building into an upper structure and a lower structure; a seismic isolation device installation process for installing a seismic isolation device between the upper structure and the lower structure and supporting the upper structure on the lower structure via the seismic isolation device, The existing building has a core structure portion that forms a vertical hole extending between the upper structure and the lower structure, In the separation step, a floor structure portion of the lower structure is separated from the core structure portion, and the core structure portion is separated from the lower structure while being connected to the upper structure; In the seismic isolation device installation step, a seismic isolation device is installed between the core structure and the substructure, and the core structure is supported by the substructure via the seismic isolation device, In the separation process, a permanent cut end support is provided in the core structure, which supports vertical loads while allowing horizontal movement of the cut end of the floor structure, which is the cut end of the floor structure of the lower structure that has been separated from the core structure.

2. 2. The seismic isolation renovation method according to claim 1, wherein the cut end support comprises a jaw portion fixed to the side of the existing column of the core structure portion, and a sliding plate portion interposed between the underside of the cut end of the floor structure portion and the upper surface of the jaw portion, which transmits vertical loads from the cut end of the floor structure portion to the jaw portion while allowing horizontal movement of the jaw portion relative to the cut end of the floor structure portion.

3. the cut end portions of the floor structure are cut end portions of a plurality of existing beams of the floor structure of the lower structure that have been separated from the existing columns of the core structure, The seismic isolation retrofitting method according to claim 1 or 2, wherein a new beam is erected between the cut ends of the plurality of existing beams at the cut ends of the floor structure portion.

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