Building structure

Abstract

The objective is to provide a building structure that can reduce the bending moment at the pile head transmitted from the steel pipe pile to the concrete foundation. [Solution] A building structure 1 characterized by comprising: a steel pipe pile 10 installed in the ground; a concrete foundation 20 installed on top of the steel pipe pile 10; a cap body 30 formed in a dome shape with a spherical outer surface, joined to the upper end 12 of the steel pipe pile 10 and embedded in the concrete foundation 20; and a lubricant 40 applied to the outer surface 31 of the cap body 30.

Description

Technical Field

[0001] The present invention relates to a building structure having steel pipe piles provided in the ground and a concrete foundation provided on the steel pipe piles.

Background Art

[0002] Conventionally, as a building structure, there is known one having steel pipe piles provided in the ground and a concrete foundation provided on the steel pipe piles (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional building structure, a plurality of reinforcing bars protruding upward from the pile head are joined to the steel pipe pile, and these reinforcing bars are connected to the concrete foundation, so that the steel pipe pile is rigidly joined to the concrete foundation. Therefore, when a horizontal load is applied to the building during an earthquake or the like, there is a problem that the bending moment of the pile head portion transmitted from the steel pipe pile to the concrete foundation increases.

[0005] When the bending moment of the pile head transmitted from the steel pipe pile to the concrete foundation increases, in order to cope with this, it is necessary to make the steel pipe pile and the concrete foundation into a larger structure with higher strength, and accordingly, the cost of the building structure increases.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a building structure capable of reducing the bending moment of the pile head transmitted from the steel pipe pile to the concrete foundation.

Means for Solving the Problems

[0007] The building structure of the present invention is characterized by comprising: steel pipe piles installed in the ground; a concrete foundation installed on the steel pipe piles; a cap body formed in a dome shape with a spherical outer surface, joined to the upper end of the steel pipe piles and embedded in the concrete foundation; and a lubricant applied to the outer surface of the cap body.

[0008] In the above configuration, the building structure of the present invention preferably has a splice member comprising three or more plate portions arranged radially with respect to the axis of the steel pipe pile, wherein each of the plate portions is joined to the steel pipe pile and the inner surface of the cap body. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a building structure that can reduce the bending moment at the pile head transmitted from the steel pipe pile to the concrete foundation. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a key part of the structure of a building according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is a cross-sectional view along line BB in Figure 1. [Figure 4] This is a cross-sectional view showing an enlarged view of area C in Figure 1. [Modes for carrying out the invention]

[0011] The following describes in detail the structure of a building according to one embodiment of the present invention, with reference to the drawings.

[0012] As shown in Figure 1, the building structure 1 includes steel pipe piles 10, a concrete foundation 20, a cap body 30, and a lubricant 40.

[0013] In this embodiment, the building structure 1 is an underground structure created by excavating the ground 2. However, the building structure 1 is not limited to an underground structure.

[0014] As shown in Figures 1 and 2, the steel pipe pile 10 is formed from a steel pipe with a circular cross-section and is installed underground by being driven into a pile hole 11 made in the ground 2. The building structure 1 according to this embodiment has multiple steel pipe piles 10, but for convenience, only one steel pipe pile 10 is shown in Figures 1 and 2.

[0015] The steel pipe pile 10 is entirely positioned inside the pile hole 11, and its upper end 12 is at the same height as the bottom surface 2a of the ground 2. In this embodiment, the inside of the steel pipe pile 10 is filled with concrete 13. In other words, in this embodiment, the steel pipe pile 10 is formed from a concrete-filled steel pipe.

[0016] The number of steel pipe piles 10 provided in the building structure 1 is not particularly limited. Furthermore, the steel pipe piles 10 may not have concrete 13 filled inside.

[0017] The concrete foundation 20 is constructed by pouring concrete onto the bottom surface 2a of the ground 2 and is placed on top of the steel pipe piles 10. Although not shown in detail, the concrete foundation 20 is made of reinforced concrete with reinforcing bars arranged inside. The reinforcing bars in the concrete foundation 20 are located only inside the concrete foundation 20 and do not protrude toward the steel pipe piles 10.

[0018] The concrete foundation 20 may have a configuration that includes a foundation beam portion 21. In this embodiment, the foundation beam portion 21 of the concrete foundation 20 is positioned on top of the steel pipe pile 10.

[0019] The cap body 30 is formed in a dome shape with a spherical outer surface and is joined to the upper end 12 of the steel pipe pile 10 and embedded in the concrete foundation 20.

[0020] As shown in FIGS. 1 and 3, in this embodiment, the cap body 30 has a hemispherical shape in which the outer surface 31 is a convex hemispherical surface upward and the inner surface 32 is a concave hemispherical surface upward by pressing a steel plate. The lower end 33 of the cap body 30 is joined to the upper end 12 of the steel pipe pile 10 by being welded to the upper end 12 of the steel pipe pile 10. The entire upper end 12 of the steel pipe pile 10 is covered by the cap body 30. The cap body 30 protrudes above the bottom surface 2a of the ground 2, and the whole of it is embedded in the concrete foundation 20. The portion of the concrete foundation 20 where the cap body 30 is embedded is a concave portion 22 having a shape corresponding to the outer surface 31 of the cap body 30.

[0021] By embedding the cap body 30 joined to the upper end 12 of the steel pipe pile 10 in the concrete foundation 20, the transmission of the horizontal force between the steel pipe pile 10 and the concrete foundation 20 is carried out by the bearing pressure of the cap body 30 embedded in the concrete foundation 20.

[0022] Note that the cap body 30 is not limited to being formed by pressing a steel plate. For example, it may be formed of a material other than a steel plate, a casting made of iron, or the like, and may be formed by other materials and construction methods. Further, the shape of the cap body 30 may be appropriately changed as long as the outer shape is a dome shape with a spherical surface. For example, when formed by casting, the outer surface 31 is a convex hemispherical surface upward and the lower surface is a hemispherical shape with a flat surface.

[0023] In this embodiment, a splice member 50 is joined to the steel pipe pile 10 and the cap body 30. As shown in Figures 1, 2, and 3, the splice member 50 has four plate portions 51 arranged radially around the axis O of the steel pipe pile 10, and its cross-section perpendicular to the vertical direction is cross-shaped. To join the splice member 50, the steel pipe pile 10 is provided with four slits 14 that extend downward from the upper end of the steel pipe pile 10 and are arranged at equal intervals in the circumferential direction. The width of each slit 14 corresponds to the width of the plate portion 51. The plate portion 51 has a rectangular plate-shaped lower portion 51a, and each lower portion 51a is inserted into the corresponding slit 14, and the portion of the lower portion 51a that protrudes radially outward from the slit 14 is welded to the outer surface of the steel pipe pile 10, thereby joining each plate portion 51 to the steel pipe pile 10. Furthermore, the upper portion 51b of each plate portion 51 is fan-shaped, with its outer peripheral end having an arc shape corresponding to the inner surface 32 of the cap body 30. Each plate portion 51 is joined to the cap body 30 by welding the outer peripheral edge of the upper portion 51b to the inner surface 32 of the cap body 30.

[0024] In this configuration, the interlocking member 50 is joined to the steel pipe pile 10 and the cap body 30, allowing the axial force of the steel pipe pile 10 to be effectively transmitted by the cap body 30.

[0025] The lower end 33 of the cap body 30 is a larger diameter circle than the upper end 12 of the steel pipe pile 10, and the radially inner portion of the lower end 33 is positioned on the upper end 12 of the steel pipe pile 10. The radially outer portion of the lower end 33 of the cap body 30 is positioned on the upper end of the portion of the lower part 51a of the plate portion 51 that protrudes radially outward from the steel pipe pile 10. The cap body 30 is welded to the outer circumference of the upper end 12 of the steel pipe pile 10 at its lower end 33 and also joined to the upper end of the lower part 51a of the plate portion 51 by welding. Since the interlocking member 50 has a cross-shaped cross in the vertical direction, concrete 13 inside the steel pipe pile 10 can be filled from between adjacent plate portions 51 before joining the cap body 30 to the upper end 12 of the steel pipe pile 10.

[0026] Furthermore, the interlocking member 50 is not limited to having four plates, as long as it has three or more plate portions 51 arranged radially around the axis O.

[0027] As shown in Figure 4, the lubricant 40 is applied to the outer surface 31 of the cap body 30. In this embodiment, the lubricant 40 is a coating type, also known as a friction cutter or concrete pipe manicure. The lubricant 40 is applied to the entire outer surface 31 of the cap body 30, forming a special polymer layer over the entire space between the outer surface 31 of the cap body 30 and the recess 22 of the concrete foundation 20. By forming a special polymer layer with the lubricant 40 over the entire space between the outer surface 31 of the cap body 30 and the recess 22 of the concrete foundation 20, adhesion between the outer surface 31 of the cap body 30 and the recess 22 of the concrete foundation 20 is prevented, and the frictional resistance between the outer surface 31 of the cap body 30 and the recess 22 of the concrete foundation 20 is reduced compared to the case where the lubricant 40 is not applied.

[0028] Furthermore, the lubricant 40 is not limited to those that form the special polymer layer described above; various materials can be used as long as they can be applied to the outer surface 31 of the cap body 30 to prevent the outer surface 31 of the cap body 30 from sticking to the recess 22 of the concrete foundation 20, and reduce the frictional resistance between the outer surface 31 of the cap body 30 and the recess 22 of the concrete foundation 20.

[0029] As described above, in the building structure 1 according to this embodiment, the steel pipe pile 10 is not integrated with the concrete foundation 20 by embedding the cap body 30, which is joined to its upper end 12, into the concrete foundation 20. Instead, it is connected to the concrete foundation 20 via the cap body 30. Furthermore, the cap body 30 joined to the upper end 12 of the steel pipe pile 10 is formed in a dome shape with a spherical outer surface, and a lubricant 40 is applied to its outer surface 31 to reduce frictional resistance against the concrete foundation 20. As a result, in the building structure 1, the steel pipe pile 10 is substantially configured such that its pile head is pinned to the concrete foundation 20. Therefore, even if the cap body 30 fixed to the upper end 12 of the steel pipe pile 10 receives a horizontal load from the concrete foundation 20 during an earthquake or the like, causing the steel pipe pile 10 to bend, the cap body 30 will slide and rotate relative to the concrete foundation 20, preventing the bending of the steel pipe pile 10 from being transmitted to the concrete foundation 20, thereby reducing the bending moment of the pile head transmitted from the steel pipe pile 10 to the concrete foundation 20.

[0030] Furthermore, when a horizontal load is applied to the building structure 1, the bending moment at the pile head transmitted from the steel pipe pile 10 to the concrete foundation 20 can be reduced. As a result, the cost of the building structure 1 can be reduced by decreasing the diameter of the steel pipe pile 10 or by reducing the thickness of the concrete foundation 20.

[0031] Furthermore, in this embodiment, the building structure 1 is configured to include three or more plate sections 51 arranged radially around the axis O of the steel pipe pile 10, and each plate section 51 has a splice member 50 joined to the steel pipe pile 10 and the inner surface 32 of the cap body 30. This allows the axial force of the steel pipe pile 10 to be effectively transmitted by the cap body 30. As a result, the cost of the building structure 1 can be further reduced by making the diameter of the steel pipe pile 10 supporting the concrete foundation 20 smaller.

[0032] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0033] 1. Building structure 2 Ground 2a Bottom 10 Steel pipe pile 11 Pile holes 12 Top 13 Concrete 14 slits 20 Concrete foundation 21 Foundation beam section 22 recess 30 cap bodies 31 External surface 32 Inner surface 33 Bottom end 40 Sliding material 50 Insertion Member 51 Plate section 51a Lower part 51b Upper part O axis

Claims

1. Steel pipe piles installed underground, A concrete foundation is provided on top of the aforementioned steel pipe pile, A cap body formed in a dome shape with a spherical outer surface, joined to the upper end of the steel pipe pile and embedded in the concrete foundation, A building structure characterized by having a lubricant applied to the outer surface of the cap body.

2. The building structure according to claim 1, comprising a splice member having three or more plate portions arranged radially with respect to the axis of the steel pipe pile, wherein each of the plate portions is joined to the steel pipe pile and the inner surface of the cap body.

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