Foundation structure of building

Abstract

To provide a foundation structure of a building having such an integral mat slab foundation that slab reinforcements are arranged in a lattice shape in plan view, which rationally improves strength and rigidity of the mat slab foundation while adopting a rational and simple configuration.SOLUTION: A mat slab foundation 8 has a first mat slab part 10 and a second mat slab part 20 which are adjacent to each other, wherein the arrangement direction of first slab reinforcements 12 and 13 arranged in the first mat slab part 10 and the arrangement direction of second slab reinforcements 22 and 23 arranged in the second mat slab part 20 are made different.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a foundation structure of a building provided with an integral mat slab foundation in which slab reinforcement is arranged in a lattice pattern in plan view.

Background Art

[0002] Conventionally, a foundation structure of a building provided with an integral mat slab foundation is known (see, for example, Patent Document 1). Such a mat slab foundation is configured to exhibit high strength and rigidity against the horizontal force transmitted from the superstructure during an earthquake in order to exhibit the required seismic isolation effect, particularly when the superstructure is supported via a plurality of seismic isolation devices. That is, the mat slab foundation generally has a relatively large concrete thickness, and slab reinforcement is arranged in a lattice pattern in plan view with a relatively dense reinforcement pitch at each of its upper end portion and lower end portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the foundation structure of a building provided with a conventional mat slab foundation, for example, even when the arrangement direction (bay direction or between-beam direction) of columns in the superstructure is not uniform, or when the integral mat slab foundation itself is irregular in plan view, the reinforcement direction of the slab reinforcement arranged in a lattice pattern in the mat slab foundation is two directions, one X direction and one Y direction orthogonal thereto. Therefore, in such a mat slab foundation, it is necessary to configure it to have sufficient strength and rigidity assuming that a horizontal force is input in a direction different from the X direction and the Y direction, which are the reinforcement directions of the slab reinforcement, from the superstructure during an earthquake. However, as a method for improving the bearing capacity and rigidity of a mat slab foundation, methods such as increasing the thickness of the concrete or increasing the slab reinforcement bars can be considered. However, these methods result in a very complex structure, causing problems such as increased costs and extended construction periods.

[0005] In view of this situation, the main problem of the present invention is to provide a technology that can reasonably improve the bearing capacity and rigidity of a mat slab foundation while adopting a reasonable and simple configuration in the foundation structure of a building equipped with an integral mat slab foundation in which slab reinforcement bars are arranged in a lattice pattern in plan view.

Means for Solving the Problem

[0006] A first characteristic configuration of the present invention is a foundation structure of a building equipped with an integral mat slab foundation in which slab reinforcement bars are arranged in a lattice pattern in plan view, wherein the mat slab foundation has a first mat slab portion and a second mat slab portion adjacent to each other, and the reinforcement direction of a first slab reinforcement bar, which is the slab reinforcement bar arranged in the first mat slab portion, and the reinforcement direction of a second slab reinforcement bar, which is the slab reinforcement bar arranged in the second mat slab portion, are different from each other.

[0007] According to this configuration, in an integral mat slab foundation, since it has a first mat slab portion and a second mat slab portion in which the reinforcement directions of the lattice-shaped slab reinforcement bars are different from each other, even when the column arrangement direction (bay direction or between-beam direction) in the superstructure is not uniform or when the mat slab foundation itself is irregular in plan view, the reinforcement directions of the slab reinforcement bars of each of the first mat slab portion and the second mat slab portion can be set to be different from each other and appropriate so as to exhibit high bearing capacity and rigidity against the horizontal force transmitted from the superstructure during an earthquake. Therefore, according to the present invention, it is possible to provide a technology that can reasonably improve the bearing capacity and rigidity of a mat slab foundation while adopting a reasonable and simple configuration in the foundation structure of a building equipped with an integral mat slab foundation in which slab reinforcement bars are arranged in a lattice pattern in plan view.

[0008] The second characteristic configuration of the present invention is that in the mat slab foundation, a boundary slab portion is constructed at the boundary between the first mat slab portion and the second mat slab portion, and the thickness of the boundary slab portion is made thinner than the thicknesses of the first mat slab portion and the second mat slab portion.

[0009] According to this configuration, since the thickness of the boundary slab portion is thinner than the thicknesses of the first mat slab portion and the second mat slab portion located on both sides sandwiching the boundary slab portion, the rigidity of the boundary slab portion becomes smaller than the rigidities of the first mat slab portion and the second mat slab portion. Therefore, by reducing the rigidity of the boundary slab portion where stress is likely to concentrate, the stress can be appropriately dispersed and the load of the superstructure can be supported on the mat slab foundation in a well-balanced manner.

[0010] The third characteristic configuration of the present invention is that in the mat slab foundation, a boundary slab portion is constructed at the boundary between the first mat slab portion and the second mat slab portion, and the first mat slab portion and the second mat slab portion are joined by joining bars arranged at a height different from that of the first slab bars and the second slab bars in the boundary slab portion.

[0011] According to this configuration, the first mat slab portion and the second mat slab portion can be appropriately joined and integrated by the joining bars arranged at a height that avoids interference with the first slab bars and the second slab bars in the boundary slab portion. Therefore, the first slab bars are arranged so as to be retained within the region of the first mat slab portion without extending to the second mat slab portion side, while the second slab bars are arranged so as to be retained within the region of the second mat slab portion without extending to the first mat slab portion side, and interference between the first slab bars and the second slab bars can be appropriately avoided, so that the reinforcement arrangement state in the boundary slab portion can be simplified.

[0012] The fourth characteristic configuration of the present invention is that in the superstructure supported by the mat slab foundation, the arrangement direction of the columns in the first superstructure part supported by the first mat slab part and the arrangement direction of the columns in the second superstructure part supported by the second mat slab part are in different directions from each other. The reinforcement direction of the first slab reinforcement is along the arrangement direction of the columns in the first superstructure part. The reinforcement direction of the second slab reinforcement is along the arrangement direction of the columns in the second superstructure part.

[0013] According to this configuration, when the arrangement directions of the columns in the first superstructure part and the second superstructure part are different from each other, the reinforcement directions of the first slab reinforcement and the second slab reinforcement are along the arrangement directions of the columns in the first superstructure part and the second superstructure part respectively. Therefore, when an earthquake occurs, the first mat slab part and the second mat slab part can exhibit high load-bearing capacity and rigidity against the horizontal forces transmitted from the first superstructure part and the second superstructure part respectively.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0015] An embodiment of the building's foundation structure according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the foundation structure of the building 1 in this embodiment (hereinafter referred to as "this foundation structure") includes an integral mat slab foundation 8. Such a mat slab foundation 8 supports the superstructure 3 via a plurality of seismic isolation devices 6, as also shown in Fig. 2, and is configured to exhibit high strength and rigidity against the horizontal force transmitted from the superstructure 3 during an earthquake in order to exert the necessary seismic isolation effect. That is, although the details of the mat slab foundation 8 will be described later, as shown in Figs. 2 and 3, the thickness of the concrete is relatively large, and slab reinforcement bars 12, 13, 22, 23 are arranged in a grid pattern with a relatively dense reinforcement pitch in plan view at the upper and lower ends thereof respectively.

[0016] In the building 1 equipped with this foundation structure, as shown in Fig. 1, in the superstructure 3, the arrangement directions of the columns 4 and the foundation footings 5 supporting them are not uniform, and the mat slab foundation 8 itself is configured irregularly in plan view. And in this foundation structure, a configuration for reasonably improving the strength and rigidity of the mat slab foundation 8 is adopted while adopting a reasonable and simple configuration without adopting methods such as further increasing the thickness of the concrete or increasing the slab reinforcement bars, and the details thereof will be described below.

[0017] The mat slab foundation 8 has a first mat slab portion 10 and a second mat slab portion 20 adjacent to each other. The first mat slab portion 10 is a portion where the arrangement directions of the columns 4 and the foundation footings 5 in plan view in the first superstructure portion 3A of the superstructure 3 supported thereby are mainly in the X1 direction and the direction along the Y1 direction orthogonal thereto. On the other hand, the second mat slab portion 20 is a portion where the arrangement directions of the columns 4 and the foundation footings 5 in plan view in the second superstructure portion 3B of the superstructure 3 supported thereby are mainly in the X2 direction and the direction along the Y2 direction orthogonal thereto.

[0018] In the upper structure 3, the X1 direction and the Y1 direction along the arrangement direction of the columns 4 and the foundation footings 5 mainly in the first upper structure portion 3A supported by the first mat slab portion 10, and the X2 direction and the Y2 direction along the arrangement direction of the columns 4 and the foundation footings 5 mainly in the second upper structure portion 3B supported by the second mat slab portion 20 are different from each other, and for example, have an angular difference of about 45 degrees in plan view.

[0019] As shown in FIGS. 2 and 3, first slab reinforcements 12 and 13 are arranged in a lattice pattern in plan view at the upper end portion and the lower end portion of the first mat slab portion 10, respectively. The reinforcement directions of the first slab reinforcements 12 and 13 are the X1 direction and the Y1 direction along the arrangement direction of the columns 4 and the foundation footings 5 mainly in the first upper structure portion 3A supported by the first mat slab portion 10 so as to exhibit high strength and rigidity against the horizontal force transmitted from the first upper structure portion 3A during an earthquake.

[0020] On the other hand, second slab reinforcements 22 and 23 are arranged in a lattice pattern in plan view at the upper end portion and the lower end portion of the second mat slab portion 20, respectively. The reinforcement directions of the second slab reinforcements 22 and 23 are the X2 direction and the Y2 direction along the arrangement direction of the columns 4 and the foundation footings 5 mainly in the second upper structure portion 3B supported by the second mat slab portion 20 so as to exhibit high strength and rigidity against the horizontal force transmitted from the second upper structure portion 3B during an earthquake.

[0021] That is, the reinforcement directions (X1 direction and Y1 direction) of the first slab reinforcements 12 and 13 arranged in the first mat slab portion 10 are different from the reinforcement directions (X2 direction and Y2 direction) of the second slab reinforcements 22 and 23 which are the slab reinforcements arranged in the second mat slab portion 20. By this, in each of the first mat slab portion 10 and the second mat slab portion 20, high strength and rigidity can be exhibited against the horizontal forces transmitted from the first superstructure portion 3A and the second superstructure portion 3B respectively during an earthquake. Further, when adopting a configuration in which the superstructure 3 is supported by the mat slab foundation 8 via a plurality of seismic isolation devices 6, the necessary seismic isolation effect can be exhibited by the plurality of seismic isolation devices 6.

[0022] As shown in FIG. 1, in the mat slab foundation 8, a boundary slab portion 30 is constructed at the boundary between the first mat slab portion 10 and the second mat slab portion 20. That is, of the regions on both sides sandwiching this boundary slab portion 30, one region is the first mat slab portion 10 and the other region is the second mat slab portion 20. And, the arrangement directions of the columns 4 and the foundation footings 5 in the first superstructure portion 3A supported by the first mat slab portion 10 are different from the arrangement directions of the columns 4 and the foundation footings 5 in the second superstructure portion 3B supported by the second mat slab portion 20. Then, a location where the foundation footings 5 are close to each other with the boundary slab portion 30 in between occurs. From this, it is necessary to suppress the stress concentration in the mat slab foundation 8 due to the concentration of the foundation footings 5.

[0023] Therefore, in the present embodiment, as shown in FIG. 2, the thickness of the boundary slab portion 30 is made thinner than the thicknesses of the first mat slab portion 10 and the second mat slab portion 20. Specifically, the upper surface of the boundary slab portion 30 is positioned below the upper surfaces of the first mat slab portion 10 and the second mat slab portion 20, and the lower surface of the boundary slab portion 30 is positioned above the lower surfaces of the first mat slab portion 10 and the second mat slab portion 20.

[0024] Then, the rigidity of the boundary slab portion 30 becomes smaller than the rigidities of the first mat slab portion 10 and the second mat slab portion 20. Due to the reduction in rigidity of the boundary slab portion 30 where such stress is likely to concentrate, the stress transmitted to the boundary slab portion 30 is appropriately dispersed, and the load of the superstructure 3 is supported by the mat slab foundation 8 in a well-balanced manner.

[0025] As shown in FIGS. 2 and 4, joining bars 32 and 33 are arranged in a lattice pattern in plan view as slab bars at the upper end portion and the lower end portion of the boundary slab portion 30, respectively. In the present embodiment, the arranging directions of these joining bars 32 and 33 are the same as the arranging directions (X1 direction and Y1 direction) of the first slab bars 12 and 13 in the first mat slab portion 10. Incidentally, the arranging directions of these joining bars 32 and 33 can be appropriately changed. For example, they may be the same as the arranging directions (X2 direction and Y2 direction) of the second slab bars 22 and 23 in the second mat slab portion 20.

[0026] The joining bars 32 and 33 arranged in the boundary slab portion 30 extend into the first mat slab portion 10 and the second mat slab portion 20. And because the joining bars 32 and 33 extend into the first mat slab portion 10 and the second mat slab portion 20, the first mat slab portion 10 and the second mat slab portion 20 are joined and integrated.

[0027] Furthermore, in the boundary slab portion 30, the joining bars 32 and 33 are arranged at different heights from the first slab bars 12 and 13 of the first mat slab portion 10 and the second slab bars 22 and 23 of the second mat slab portion 20 in order to avoid interference therewith.

[0028] 〔Alternative Embodiment〕 Another embodiment of the present invention will be described. Incidentally, the configurations of the respective embodiments described below are not limited to being applied alone, and can also be applied in combination with the configurations of other embodiments.

[0029] (1) In the above-described embodiment, an example in which this foundation structure is applied to a building 1 in which the upper structure 3 is supported by a mat slab foundation 8 via a plurality of seismic isolation devices 6 has been described. However, for example, this foundation structure can also be applied to a building in which the upper structure 3 is supported by the mat slab foundation 8 without passing through the seismic isolation devices 6.

[0030] (2) In the above-described embodiment, at the boundary between the first mat slab portion 10 and the second mat slab portion 20 in the mat slab foundation 8, a boundary slab portion 30 having a thickness smaller than those of these mat slab portions 10 and 20 is provided. However, such a boundary slab portion 30 can be appropriately omitted. Further, when omitting the boundary slab portion 30, the slab bars 12, 13, 22, 23 on one side of the first mat slab portion 10 and the second mat slab portion 20 can be extended to the other side, so that the first mat slab portion 10 and the second mat slab portion 20 can be directly joined.

[0031] (3) In the above-described embodiment, the upper surface of the boundary slab portion 30 is positioned below the upper surfaces of the first mat slab portion 10 and the second mat slab portion 20, and the lower surface of the boundary slab portion 30 is positioned above the lower surfaces of the first mat slab portion 10 and the second mat slab portion 20, so that the thickness of the boundary slab portion 30 is made smaller than the thicknesses of the first mat slab portion 10 and the second mat slab portion 20. However, for example, after making the upper surface or the lower surface of the boundary slab portion 30 flush with the upper surface or the lower surface of the first mat slab portion 10 and the second mat slab portion 20, the thickness of the boundary slab portion 30 may be made smaller than the thicknesses of the first mat slab portion 10 and the second mat slab portion 20.

[0032] (4) In the above-described embodiment, joining bars 32, 33 are arranged at heights different from those of the first slab bars 12, 13 and the second slab bars 22, 23 in the boundary slab portion 30. However, within a range where interference with the first slab bars 12, 13 and the second slab bars 22, 23 does not pose a problem, the arrangement height of the joining bars 32, 33 can be appropriately changed.

Description of Reference Numerals

[0033] 1 Building 3 Superstructure 3A First superstructure part (superstructure) 3B Second superstructure part (superstructure) 6 Seismic isolation device 8 Mat slab foundation 10 First mat slab part 12, 13 First slab reinforcement (slab reinforcement) 20 Second mat slab part 22, 23 Second slab reinforcement (slab reinforcement) 30 Boundary slab part 32, 33 Connecting reinforcement

Claims

1. A building foundation structure comprising an integral mat slab foundation in which slab reinforcement is arranged in a grid pattern in plan view, wherein the mat slab foundation has a first mat slab portion and a second mat slab portion adjacent to each other, and a building foundation structure in which the reinforcement direction of a first slab reinforcement, which is the slab reinforcement arranged in the first mat slab portion, and the reinforcement direction of a second slab reinforcement, which is the slab reinforcement arranged in the second mat slab portion, are different from each other.

2. In the mat slab foundation, a boundary slab portion is constructed at the boundary between the first mat slab portion and the second mat slab portion, and the thickness of the boundary slab portion is made thinner than the thicknesses of the first mat slab portion and the second mat slab portion. The building foundation structure according to Claim 1.

3. In the mat slab foundation, a boundary slab portion is constructed at the boundary between the first mat slab portion and the second mat slab portion, and the first mat slab portion and the second mat slab portion are joined by joining reinforcement arranged at a height different from that of the first slab reinforcement and the second slab reinforcement in the boundary slab portion. The building foundation structure according to Claim 1 or 2.

4. In the superstructure supported by the mat slab foundation, the column arrangement direction in the first superstructure portion supported by the first mat slab portion and the column arrangement direction in the second superstructure portion supported by the second mat slab portion are different from each other, the reinforcement direction of the first slab reinforcement is along the column arrangement direction in the first superstructure portion, and the reinforcement direction of the second slab reinforcement is along the column arrangement direction in the second superstructure portion. The building foundation structure according to Claim 1 or 2.

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