Building structure

Abstract

To provide a building structure that enhances seismic isolation on a first floor above ground.SOLUTION: A building structure equipped with seismic isolation devices 25 includes a plurality of lower foundations 12 joined to pile heads of piles 11 embedded in the ground to be placed on the ground surface. The building structure also includes a slab 20 constituting an upper floor structure of the second floor F2 supported by the seismic isolation devices 25 installed on the lower foundations 12, and a lower floor structure of the first floor F1 suspended from the upper floor structure of the second floor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to building structures equipped with seismic isolation devices. [Background technology]

[0002] Buildings are designed with seismic isolation devices placed at the pile heads to prevent damage in the event of an earthquake (see, for example, Patent Document 1). In the seismic isolation method for existing structures described in Patent Document 1, the foundation beams are separated from the superstructure, which is the ground floor skeleton, at the level of the top surfaces of the existing foundation beams. Then, new floor beams for the lowest floor are installed at the bottom of the superstructure, and seismic isolation devices are interposed between the superstructure and the existing foundation beams. Furthermore, if necessary, the entire superstructure is raised higher than before the renovation to ensure the height of the lowest floor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-13290 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, a seismic isolation device is fixed to a lower foundation exposed above ground level, and the first floor of a building is supported on the seismic isolation device. In such a building configuration, if the first floor of the building is located at a high position, a staircase from above ground level is required. If this staircase is located on the first floor (lower floor) within the building and the first floor of the building is made into a second floor above ground level, a configuration that takes into account seismic isolation for the staircase and safety standards for the first floor above ground level is required. [Means for solving the problem]

[0005] The building structure that solves the above problem is a building structure equipped with seismic isolation devices, and includes a plurality of lower foundations that are joined to the heads of piles buried in the ground and placed on the ground surface, an upper floor structure with two above-ground floors that is supported by the seismic isolation devices installed on the lower foundations, and a lower floor structure with one above-ground floor that is suspended from the upper floor structure. [Effects of the Invention]

[0006] According to the present invention, the seismic isolation performance of the lower floor structure on the first above-ground floor can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view illustrating the first floor of a building according to an embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view of a main part of a building according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a building structure will be described below with reference to Figures 1 to 3. Here, the configuration of a building constructed on ground that is susceptible to soft liquefaction (weakening) will be described.

[0009] 1 is a plan view of the first floor of a building 10, FIG. 2 is a vertical cross-sectional view of a main part of the building 10, and FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. As shown in Fig. 2, the building 10 includes a plurality of piles 11 buried in the ground G1 and is supported by these piles 11. A seismic isolation pit is provided in a space at a predetermined interval between the ground surface and a slab 20 on an upper floor of the building 10. In this embodiment, this seismic isolation pit is a space on the first above-ground floor F1 of the building 10, and is, for example, a space with a height of about 5 m.

[0010] On the first above-ground floor F1, lower foundations (pile caps, etc.) 12 are provided, joined to the tops (pile heads) of the piles 11. In this embodiment, the lower ends of the lower foundations 12 are buried in the ground G1. One seismic isolation device 25 is installed on each lower foundation 12. Laminated rubber bearings are used as these seismic isolation devices 25. These seismic isolation devices 25 support the slab 20 of the building 10 via upper foundations 21 and column connecting beams joined to the upper foundations 21. The slab 20 and column connecting beams constitute the upper floor structure.

[0011] The slab 20 forms the ceiling of the first floor F1 and the floor of the second floor F2. Above the second floor F2, a slab 50 is placed, which is integrally fixed and supported by beams 51. The slab 50 forms the ceiling of the second floor F2 and the floor of the third floor F3.

[0012] As shown in FIG. 1, on the first above-ground floor F1, a plurality of blocks BL1, each composed of a plurality of lower foundations 12, are arranged spaced apart from one another. Each block BL1 is formed by connecting a plurality of lower foundations 12 by foundation beams 15. Each block BL1 is configured, for example, so that some of the lower foundations 12, which serve as nodes, are connected to adjacent lower foundations 12 by foundation beams 15 in two axial directions in a plane. For example, the block BL1 has a shape such as a square frame (a square-shaped frame). In this embodiment, no foundation slab is provided on the ground surface, and each block BL1 is arranged on the first above-ground floor F1 spaced apart from adjacent blocks BL1 without being connected to them. Therefore, the first above-ground floor F1 is a non-rigid floor, and the slab 20 of the building 10 is supported by a plurality of blocks BL1 spaced apart from one another.

[0013] The building 10 has thin rectangular parallelepiped exterior walls 41, 42, 43, and 44. Specifically, the exterior walls 41 to 44 have both ends joined to the ends of the other exterior walls 41 to 44, thereby covering the periphery of the building 10 in the shape of a rectangular frame. Furthermore, gravel is spread inside the exterior walls 41 to 44 and outside the above-mentioned blocks BL1. Each exterior wall 41 to 44 is provided so as to connect the lower foundations 12 lined up around the periphery of the building 10 in a plan view. Foundation beams 15 connecting the lower foundations 12 lined up around the periphery of the building 10 together with the exterior walls 41 to 44 constitute the exterior wall structure.

[0014] In this embodiment, openings 43a and 44a are provided in the exterior walls 43 and 44, respectively. These openings 43a and 44a serve as entrances to the elevator lobby 30 of the building 10. Penetrating holes 20h are formed in the slab 20 to correspond to the openings 43a and 44a.

[0015] Furthermore, an automatic door D1 is provided to close the openings 43a and 44a. The automatic door D1 is supported on the bottom surface 30b of the elevator lobby 30.

[0016] A lift lobby 30 is suspended from the upper floor structure of the building 10. The lift lobby 30 may be suspended from the slab 20 or from a column connecting beam. The lift lobby 30 is located between adjacent blocks BL1 in a plan view of the first floor F1 above ground, i.e., outside the rectangular frame shape. Specifically, as shown in FIG. 2, the upper end of the lift lobby 30 is fixed to the underside of the slab 20 around the hole 20h. The lift lobby 30 of this embodiment has a rectangular parallelepiped shape with the side facing the opening 44a (43a) and the top open. That is, the lift lobby 30 has a pair of opposing side portions 30s, a bottom portion 30b, and a back portion 30c. The bottom portion 30b connects the lower ends of the pair of side portions and functions as a lower floor structure of the building 10. The back portion 30c is located on the opposite side of the opening 44a (43a) and connects to the side portion 30s and the bottom portion 30b. Furthermore, a staircase 35 is fixed to the lift lobby 30.

[0017] As shown in Fig. 3, the staircase 35 includes a plurality of treads 35a. Both ends of each tread 35a are fixed to the side surface 30s of the elevator lobby 30. Note that in Fig. 3, for ease of viewing, the number of treads 35a is reduced and the treads 35a are shown thicker. Furthermore, the step that constitutes the lowest step of the stairs 35 is formed by the bottom surface portion 30 b of the elevator lobby 30 . When entering the building 10 configured as described above, first, the automatic door D1 is opened, and after going up the stairs 35, the person passes through the hole 20h to arrive at the second floor F2 above ground.

[0018] (Operation of the embodiment) Since the elevator lobby 30 on the first floor F1 is suspended from the upper floor structure on the second floor F2 supported by the seismic isolation device 25, the relative movement of the elevator lobby 30 with respect to the second floor F2 is suppressed.

[0019] According to this embodiment, the following effects can be obtained. (1) In this embodiment, the lower floor structure in the elevator lobby 30 on the first floor F1 is suspended from the upper floor structure on the second floor F2, which is supported by the seismic isolation device 25. This reduces the relative movement of the lower floor structure in the elevator lobby 30 with respect to the upper floor structure on the second floor F2, thereby improving the seismic isolation performance of the elevator lobby 30.

[0020] (2) In this embodiment, the elevator lobby 30 is provided with a staircase 35 leading to the second floor F2, and an entrance is provided corresponding to the staircase 35. As a result, by entering the building 10 through the openings 43a, 44a and climbing the staircase 35, one can quickly reach the second floor F2.

[0021] (3) In this embodiment, on the first above-ground floor F1, multiple blocks BL1, each consisting of multiple lower foundations 12 joined by foundation beams 15, are arranged spaced apart from one another. In ground G1 that is weakened by liquefaction or other factors, there is a risk of variations in shaking due to differences in vibrations in different parts of the ground. For this reason, the blocks BL1, which are spaced apart from one another, can absorb the variations in shaking, making it possible to construct the building 10 even on weakened ground G1.

[0022] (4) In this embodiment, automatic doors D1 supported by the lower floor structure of the elevator lobby 30 are placed in the openings 43a, 44a formed in the exterior walls 41 to 44 of the building 10. This improves the seismic isolation of the automatic doors D1.

[0023] (5) In this embodiment, a plurality of treads 35a constituting the stairs 35 are fixed to the side surface 30s of the elevator lobby 30. This allows the elevator lobby 30 to integrally form the floor portion of the first floor F1 and the stairs 35 leading from this floor portion to the second floor F2.

[0024] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. In the above embodiment, the lower floor structure of the building 10, together with a pair (two) of opposing side walls 30s and a rear wall 30c, constitutes the elevator lobby 30. The lower floor structure of the building 10 is not limited to this configuration, as long as it is a member suspended from (the slab 20 constituting) the upper floor structure on the second floor F2. For example, the lower floor structure of the building 10 may be configured to be joined only to the pair of side walls 30s and not to the rear wall 30c, or may be configured to be joined only to the rear wall 30c. However, a symmetrical configuration is preferable because it applies force evenly to the upper floor structure on the second floor. Furthermore, the lower floor structure of the building 10 may be configured by integrating a floor slab and stairs supported by multiple H-shaped steel beams suspended from the upper floor structure on the second floor.

[0025] In the above embodiment, the elevator lobby 30 suspended from the upper floor structure of the second floor F2 is provided with the stairs 35. The elevator lobby 30 may also be provided with other elevator mechanism structures (e.g., escalators, ramps, etc.) that connect to the second floor F2.

[0026] In the above embodiment, the lift lobby 30 is fixed to the upper floor structure on the second floor F2. The configuration for suspending the lower floor structure from the upper floor structure on the second floor is not limited to this. For example, an engagement portion may be provided around the periphery of the floor slab that constitutes the lower floor structure, and this engagement portion may be suspended so as to engage with the edge of an opening in the upper floor structure on the second floor.

[0027] In the above embodiment, the automatic door D1 is arranged to close the openings 43a and 44a. The door that closes the openings 43a and 44a may be a door other than the above, such as a manual sliding door. The lower floor structure embodied in the bottom surface 30b of the elevator lobby 30 may further include an elevator pit below the floor surface of the lower floor structure to accommodate elevator equipment. With this configuration, the space of the elevator lobby 30, which has improved seismic isolation, functions as an elevator hall. The lower floor structure on the first floor suspended from the upper floor structure on the second floor may be changed to a floor slab in the elevator lobby. The elevator lobby 30 may be arranged within the rectangular frame shape of one block BL1 in a plan view of the first floor above ground. In this case, to allow access to the elevator lobby 30 from outside, some of the foundation beams 15 may be opened or the foundation beams 15 between the lower foundations 12 may be omitted. The responses of the lower foundations 12 during an earthquake are close within one block BL1 to the extent that the lower foundations 12 are connected to the foundation beams 15, and are more likely to diverge between different blocks BL1. The responses of the upper floor structures during an earthquake are more likely to be close within one block BL1 than between different blocks BL1. Therefore, if one lower floor structure is arranged within the rectangular frame shape of one block BL1, the seismic isolation of the lower floor structure can be further improved. The exterior walls 41 to 44 of the building 10 may be provided with vertical and horizontal reinforcement located outside the main reinforcement of the foundation beams 15, and the exterior walls 41 to 44 may be constructed in a state where they are integrated with the foundation beams 15 by fixing these vertical and horizontal reinforcement to the foundation beams 15. In the above embodiment, laminated rubber bearings are used as the seismic isolation device 25, but the present invention is not limited to this. For example, sliding bearings, rolling bearings, etc. may also be used.

[0028] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. (a) The first floor above ground is a seismic isolation pit, 4. The building structure according to claim 3, wherein the block portion is formed in a rectangular frame shape in a plan view in which the plurality of lower foundations are connected by the foundation beams. (b) the lower floor structure includes the bottom surface portion; 5. The building structure according to any one of claims 1 to 4 or (a), characterized in that the upper end of the side portion is joined to the upper floor structure and thereby suspended from the upper floor structure. (c) A building structure according to (a) above, in which the lower floor structure is located outside the rectangular frame shape in a plan view of the first floor above ground. (d) the building structure of claim 1, wherein the subfloor structure further comprises an elevator pit. [Explanation of symbols]

[0029] D1...automatic door, F1...1st floor above ground, F2...2nd floor above ground, F3...3rd floor above ground, G1...ground, BL1...block, 10...building, 11...pile, 12...lower foundation, 15...foundation beam, 20...slab that makes up the upper floor structure, 20h...hole, 21...upper foundation, 25...seismic isolation device, 30...lift lobby, 30b...bottom part of the lower floor structure, 30c...back part, 30s...side part, 35...stairs, 35a...tread, 41,42,43,44...exterior wall, 43a,44a...opening, 50...slab, 51...beam.

Claims

1. A building structure equipped with a seismic isolation device, a plurality of sub-foundations disposed on the ground surface and connected to the pile heads of the piles buried in the ground; an upper floor structure of the second floor above ground supported by the seismic isolation device installed on the lower foundation; A building structure comprising: a first-floor lower floor structure suspended from the upper floor structure.

2. A staircase leading to the upper floor structure is fixed to the lower floor structure, 2. The building structure according to claim 1, wherein an entrance corresponding to the staircase is provided on the first floor above ground.

3. The building structure described in claim 1, characterized in that the exterior wall structure of the building on the first floor above ground comprises foundation beams that join the lower foundations together and an exterior wall having an entrance opening that leads to the lower floor structure.

4. The building comprises a plurality of blocks that are independent of each other, The block is configured in a rectangular frame shape in a plan view by a plurality of the lower foundations and foundation beams connecting the lower foundations to each other, The lower foundation is placed on the ground surface without a foundation slab, The building structure according to any one of claims 1 to 3, characterized in that the lower floor structure is arranged within one of the blocks having the rectangular frame shape in plan view.

Images