building

Abstract

To easily adjust a balance between force borne by a pile foundation and force borne by a spread foundation.SOLUTION: A building 1 has: a spread foundation 2; a plurality of pile foundations 3 connected to a lower face of the spread foundation 2; and a plurality of columns 4 connected to an upper face of the spread foundation 2. Positions of the pile foundations 3 are displaced from positions of the columns 4 in top view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to buildings, and in particular to the construction of foundation structures. [Background technology]

[0002] The foundation structure type of mid-high rise buildings and super high rise buildings is generally selected according to the strength of the ground (supporting ground) that directly supports the bottom surface of the building. When the supporting ground is strong, a spread foundation such as a slab foundation is often selected, but when the supporting ground is not strong enough, a pile foundation may be selected. Piles are usually installed so as to reach a strong stratum, so when the strong stratum is deep, the piles become long, and the cost of the piles increases. For this reason, in recent years, instead of conventional pile foundations, foundation structures that use a minimum number of friction piles in combination with a direct foundation to keep the settlement of the building within the required performance value are sometimes used. Such a foundation structure that is intermediate between a spread foundation and a pile foundation is sometimes called a piled raft foundation (Patent Document 1). A piled raft foundation does not need to be installed so that the piles reach a strong stratum, and the number of piles can be reduced in some cases, so it is considered to be an effective measure for reducing costs and shortening construction time. In a piled raft foundation, the pile foundation is also placed directly under the columns to effectively transfer the weight of the building to the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-19248 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a piled raft foundation, the load is shared between the spread foundation and the pile foundation, but because the pile foundation is located directly below the columns, a large force flows through the pile foundation, making it difficult to adjust the balance of forces borne by the pile foundation and the spread foundation.

[0005] The present invention aims to provide a building in which it is easy to adjust the balance of forces borne by the pile foundation and the spread foundation. [Means for solving the problem]

[0006] The building of the present invention has a spread foundation, a plurality of pile foundations connected to the lower surface of the spread foundation, and a plurality of columns connected to the upper surface of the spread foundation. is. A spread foundation consists of a foundation slab that supports multiple columns and pile foundations, and when viewed from above, the position of the pile foundations is offset from the position of the columns. Effect of the Invention

[0007] According to the present invention, a building can be provided in which the balance of forces borne by the pile foundation and the spread foundation can be easily adjusted. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a foundation structure of a building according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 2 is a partial perspective view showing the foundation structure of a building. [Diagram 5] FIG. 4 is a conceptual diagram illustrating the effect of the first embodiment. [Figure 6] FIG. 1 is a conceptual diagram showing the arrangement pattern of pile foundations. [Figure 7] FIG. 11 is a diagram showing a foundation structure of a building according to a second embodiment of the present invention. [Figure 8] FIG. 13 is a diagram showing a foundation structure of a building according to a modified example of the first and second embodiments. [Figure 9] FIG. 11 is a diagram showing a foundation structure of a building according to a third embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing a foundation structure of a building according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) Hereinafter, an embodiment of a building of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a foundation structure of a building according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along line BB in FIG. 1, and FIG. 4 is a partial perspective view showing the foundation structure of a building. In FIG. 1, columns are indicated by dashed lines. The building 1 has a spread foundation 2, a plurality of pile foundations 3 connected to the lower surface of the spread foundation 2, and a plurality of columns 4 connected to the upper surface of the spread foundation 2. The building 1 is generally rectangular in top view, but the shape of the building 1 is not limited. A plurality of columns 4 are provided at or near the intersections of the grid lines 1-5 and A-E of the building 1. The spread foundation 2 is a foundation beam configured in a lattice shape, and specifically has a plurality of support parts 21 that respectively support the plurality of columns 4, and a plurality of beams 22 that connect the plurality of support parts 21 to each other. The plurality of beams 22 extend along the grid lines 1-5 and A-E. The support part 21 is a rectangular parallelepiped that is generally square in top view. The pile foundation 3 is a friction pile or a tip-support pile. The pillar 4 is provided at the center of the support part 21 inside the building 1, at the outer corner of the support part 21 at the corner part of the building 1, and at the center of the peripheral part of the support part 21 at the peripheral part of the building 1 excluding the corner part. Each of the multiple support parts 21 also supports the pile foundation 3 arranged around the pillar 4 supported by the support part 21. A part or the whole of the pile foundation 3 may be supported by the beam 22. In this embodiment, the width W of the support part 21 is the same as the width W of the beam 22, and the height H of the support part 21 is also the same as the height H of the beam 22.

[0010] When viewed from above (i.e., when viewed vertically from above to vertically below), the position of the pile foundation 3 is offset in plan from the position of the column 4. The pile foundation 3 is not provided directly below the column 4. FIG. 5(a) shows the relationship between the column 4, the pile foundation 3, and the foundation beam in this embodiment, and FIG. 5(b) shows the relationship between the column 4, the pile foundation 3, and the foundation beam in the comparative example. In the comparative example, one pile foundation (hereinafter, referred to as the column-sub-pile 5) is arranged directly below each column 4. Most of the vertical load transmitted from the column 4 is transmitted to the column-sub-pile 5, and the remainder is transmitted to the foundation beam. The foundation beam mainly bears the seismic force. The proportion of the vertical load transmitted from the column 4 to the column-sub-pile 5 can be adjusted by changing the pile diameter of the column-sub-pile 5, but the distribution of the vertical load transmitted to the foundation beam and the column-sub-pile 5 cannot be changed significantly. In contrast, in this embodiment, the vertical load from the column 4 is transmitted to the pile foundation 3 via the support part 21. Specifically, the vertical load from the column 4 becomes a shear force at the support part 21, part of this shear force is transmitted to the pile foundation 3 as a vertical load, and the remainder is transmitted to the ground from the support part 21 and the foundation beam. By changing the planar distance D between the column 4 and the pile foundation 3, the load transmitted from the column 4 to the pile foundation 3 can be adjusted to be larger, making it easy to adjust the balance of forces borne by the pile foundation 3 and the foundation beam.

[0011] FIG. 6 shows an arrangement pattern of the pile foundation 3. The number of pile foundations 3 arranged around one column 4 is not limited, and although multiple pile foundations 3 are preferable, one pile foundation may be used. FIG. 6(a) shows an arrangement pattern in which one pile foundation 3 is arranged. FIG. 6(b) and 6(c) show an arrangement pattern in which two pile foundations 3 are arranged. In the arrangement pattern of FIG. 6(b), it is easy to adjust the balance of the forces borne by the pile foundation 3 and the foundation beam. In the arrangement pattern of FIG. 6(c), it is easy to ensure the distance between the column 4 and the pile foundation 3, and it is easy to adjust the balance of the forces borne by the pile foundation 3 and the foundation beam, and the support part 21 can also adjust the balance of the forces borne by the pile foundation 3 and the foundation beam. FIG. 6(d) shows an arrangement pattern in which three pile foundations 3 are arranged. A pile foundation 3 with a large pile diameter is arranged on one side of the column 4, and two pile foundations 3 with smaller pile diameters are arranged on the other side of the column 4. FIG. 6(e) and 6(f) show an arrangement pattern in which four pile foundations 3 are arranged. In the arrangement pattern of Fig. 6(e), it is easy to adjust the balance of the forces borne by the pile foundation 3 and the foundation beams. In the arrangement pattern of Fig. 6(f), it is easy to ensure the distance between the columns 4 and the pile foundation 3, it is easy to adjust the balance of the forces borne by the pile foundation 3 and the foundation beams, and it is also possible to adjust the forces borne by the pile foundation 3 and the foundation beams at the support parts 21. Note that, as shown in Fig. 1, the arrangement pattern of the pile foundations 3 around the columns 4 may differ depending on the columns 4.

[0012] When multiple pile foundations 3 are arranged, the pile diameter of each pile foundation 3 can be smaller than the pile diameter of the pile immediately below the column 5 (or the pile foundation 3 arranged around the column 4). If the cross-sectional area of ​​the multiple pile foundations 3 and the cross-sectional area of ​​the pile immediately below the column 5 are the same, when two pile foundations 3 are provided, the pile diameter of the pile foundations 3 can be about 70% of the pile diameter of the pile immediately below the column 5. However, the total circumference is about 140% of the pile immediately below the column 5, so the friction force around the pile foundations 3 increases. Similarly, when three pile foundations 3 are provided, the pile diameter of the pile foundations 3 is about 58% of the pile diameter of the pile immediately below the column 5, and the total circumference is about 173% of the pile immediately below the column 5. When four pile foundations 3 are provided, the pile diameter of the pile foundations 3 is about 50% of the pile diameter of the pile immediately below the column 5, and the total circumference is about 200% of the pile immediately below the column 5. In this way, the more pile foundations 3 are installed, the greater the circumference of the pile foundations 3, and therefore the total area of ​​the sides of the pile foundations 3, and the greater the friction force that can be borne. As a result, it becomes possible to shorten the length of the friction piles 3, which leads to reduced costs and shorter construction times.

[0013] The pile foundation 3 may be a cast-in-place construction pile, but existing piles can also be used, especially when multiple pile foundations 3 are arranged around the pillar 4. The piles 5 directly below the pillar are cast-in-place construction piles. Since the existing piles have a fixed length, the required number of existing piles are joined together with joints. The pile foundations 3 around one pillar 4 are constructed one by one, which may be effective in shortening the construction period because it does not require reinforcing bars or pouring concrete on site. In addition, existing piles are inexpensive, so it may also be effective in reducing costs.

[0014] Second embodiment FIG. 7(a) is a partial perspective view showing a foundation structure of a building 1 according to a second embodiment of the present invention, FIG. 7(b) is a partial plan view of the foundation structure, and FIG. 7(c) is a partial cross-sectional view of the foundation structure. Each of the multiple supports 21 has a larger cross-sectional area than the beam 22 connected to the support 21. The cross-sectional area of ​​the beam 22 is the area of ​​a cross section perpendicular to the extension direction of the beam 22, and the cross-sectional area of ​​the support 21 is the area of ​​a cross section parallel to the cross section of the beam 22. The width W of the support 21 is the same as the width W of the beam 22 connected to the support 21, but the height H1 of the support 21 is larger than the height H2 of the beam 22 connected to the support 21, and the bottom surface of the support 21 protrudes downward from the bottom surface of the beam 22. The support 21 also supports the pile foundation 3 arranged around the column 4 supported by the support 21. Since the rigidity of the support 21 is increased compared to the first embodiment, the vertical load of the column 4 is transmitted to the pile foundation 3 more efficiently. That is, as the height H1 of the support portion 21 increases, the load transmission efficiency increases, and more load is transmitted to the pile foundation 3. In this embodiment, not only the distance between the column 4 and the pile foundation 3 but also the height H1 (rigidity) of the support portion 21 can be adjusted, making it easier to adjust the balance of forces borne by the pile foundation 3 and the foundation beams.

[0015] FIG. 8 shows various modified examples. FIG. 8(a) shows a plan view of the first modified example, and FIG. 8(b) shows a cross-sectional view of the first modified example. The width W1 of the support part 21 is larger than the width W2 of the beam 22 connected to the support part 21. The height of the support part 21 and the beam 22 are the same. The planar shape of the support part 21 is preferably a square, but the shape is not limited. Since the planar area of ​​the support part 21 is larger, the adjustment range of the distance between the column 4 and the pile foundation 3 increases. This makes it easier to adjust the balance of the forces borne by the pile foundation 3 and the foundation beam. FIG. 8(c) shows a plan view of the second modified example, and FIG. 8(d) shows a cross-sectional view of the second modified example. The width W1 of the support part 21 is larger than the width W2 of the beam 22 connected to the support part 21, and the height H1 of the support part 21 is larger than the height H2 of the beam 22. Compared to the first modified example, the height H1 (rigidity) of the support part 21 can be adjusted, making it easier to adjust the balance of the forces borne by the pile foundation 3 and the foundation beam. Fig. 8(e) shows a plan view of the third modified example, and Fig. 8(f) shows a cross-sectional view of the third modified example. The support portion 21 or the beam 22 has a cross-sectional area increase portion 23 that individually supports the pile foundation 3. As shown in Fig. 8(f), the height H3 of the cross-sectional area increase portion 23 is greater than the height H4 of the other portions, and the cross-sectional area increase portion 23 has greater rigidity than the surroundings. For this reason, by adjusting the planar size and height H3 of the cross-sectional area increase portion 23 (the protruding length from the bottom surface of the beam 22), it is easy to adjust the balance of forces borne by the pile foundation 3 and the foundation beam.

[0016] (Third embodiment) FIG. 9(a) is a partial perspective view showing a foundation structure of a building 1 according to a third embodiment of the present invention, FIG. 9(b) is a partial plan view of the foundation structure, and FIG. 9(c) is a partial cross-sectional view of the foundation structure. The spread foundation of this embodiment is a foundation slab (mat foundation), and specifically, has a plurality of support parts 21 that respectively support a plurality of columns 4, and a general part 24 (floor slab) that connects the plurality of support parts 21 to each other. The thickness of the support part 21 and the general part 24 of the column 4 are the same. According to this embodiment, the vertical load of the column 4 is transmitted to the pile foundation 3 through the general part 24, so that the balance of the forces borne by the pile foundation 3 and the foundation slab can be adjusted by adjusting the distance between the column 4 and the pile foundation 3 and the thickness (rigidity) of the general part 24.

[0017] FIG. 10(a) is a partial perspective view showing the foundation structure of the building 1 according to a modified example of the third embodiment of the present invention, FIG. 10(b) is a partial plan view of the foundation structure, and FIG. 10(c) is a partial cross-sectional view of the foundation structure. Each of the multiple support parts 21 also supports the pile foundation 3 arranged around the column 4 supported by the support part 21, and the multiple support parts 21 have a larger cross-sectional area than the general part 24. Specifically, the height H5 of the support part 21 is larger than the height H6 of the general part 24 connected to the support part 21, and the bottom surface of the support part 21 protrudes downward from the bottom surface of the general part 24. Therefore, by adjusting the distance between the column 4 and the pile foundation 3 and the planar size and height of the support part 21 (the protruding length of the support part 21 from the bottom surface of the general part 24), it is easy to adjust the balance of the forces borne by the pile foundation 3 and the foundation slab. [Explanation of symbols]

[0018] 1. Building 2 Direct foundation 3 Pile Foundation 4 Pillars 21 Support part 22 Beam 23 Cross-sectional increase 24 General section

Claims

1. A building having a spread foundation, a plurality of pile foundations connected to a lower surface of the spread foundation, and a plurality of columns connected to an upper surface of the spread foundation, The spread foundation comprises a foundation slab supporting the plurality of columns and the pile foundation, A building in which the position of the pile foundation is misaligned with the position of the pillar when viewed from above.

2. The building according to claim 1 , wherein a plurality of said pile foundations are arranged around one of said columns.

3. The building described in claim 1 or 2, wherein the foundation slab has a plurality of support sections that support each of the plurality of columns and support the pile foundation arranged around the columns, and a general section that connects the plurality of support sections to each other, and the plurality of support sections are thicker than the general section.

4. The building according to any one of claims 1 to 3, wherein the pile foundation is a precast pile.

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