Basic Construction

Abstract

To omit a foundation beam stretched on a column base portion 50L of a steel column while suppressing damage to filling concrete filled in a steel pipe.SOLUTION: A foundation structure comprises: a pile 30 which is provided in a ground 10; a steel pipe 42 which surrounds a pile head 30H of the pile 30; a steel column 50 which is disposed on the pile head 30H and in which the column base portion 50L is inserted into the steel pipe 42; filling concrete 48 which is filled into the steel pipe 42 and in which the pile head 30H and the column base portion 50L are embedded; and a reinforcing shaped steel 60 which is embedded in the filling concrete 48, extends from the column base portion 50L of the steel column 50 to each of both sides, and has an end in an extending direction joined to the steel pipe 42.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a foundation structure.

Background Art

[0002] There is known a foundation structure including a pile provided in the ground, a steel pipe surrounding the pile head of the pile, a filling concrete filled in the steel pipe and in which the column foot of a column arranged on the pile is embedded, and a foundation beam penetrating the steel pipe and joined to the column foot of the column (see, for example, Patent Documents 1 to 3).

[0003] In this type of foundation structure, during an earthquake, a bending moment is transmitted between the column feet of adjacent steel columns via the foundation beam.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, depending on the site or ground conditions, it may be impossible to install a foundation beam between the column feet of adjacent steel columns. In this case, during an earthquake, a bending moment is not transmitted between the column feet of adjacent steel columns, and there is a possibility that the filling concrete filled in the steel pipe may be damaged.

[0006] In consideration of the above facts, an object of the present invention is to suppress damage to the filling concrete filled in the steel pipe and omit the foundation beam installed at the column foot of the steel column.

Means for Solving the Problems

[0007] Regarding the first aspect The foundation structure comprises a pile erected in the ground, a steel pipe surrounding the pile head of the pile, a steel column positioned on the pile head with its base inserted into the steel pipe, a filling concrete that fills the steel pipe and embeds the pile head and the base inside, and reinforcing steel sections embedded in the filling concrete, extending outwards from the base of the steel column on both sides, with their leading ends joined to the steel pipe.

[0008] First aspect In this foundation structure, a steel pipe surrounds the pile head of a pile installed in the ground. A steel column is placed on top of the pile head. The base of the steel column is inserted into the steel pipe. The steel pipe is also filled with concrete. The pile head and the base of the steel column are embedded in this concrete. In this way, the pile head and the base of the steel column are joined via the concrete.

[0009] Furthermore, reinforcing steel sections are embedded in the concrete filling. The reinforcing steel sections extend from the base of the steel column on both sides, and their ends in the direction of extension are joined to the steel pipes. As a result, during an earthquake, the bending moment acting on the steel column is transmitted to the steel pipes via the reinforcing steel sections on both sides. The bending moment transmitted to the steel pipes is then transmitted to the pile heads of the piles via the concrete filling. Therefore, damage to the concrete filling during an earthquake is suppressed.

[0010] Thus, in this invention, while suppressing damage to the concrete filling inside the steel pipe, it is possible to omit the foundation beams that are erected at the base of the steel column.

[0011] Regarding the second aspect The foundation structure is, Regarding the first aspect In the foundation structure, the inner circumferential surface of the steel pipe is circular in plan view, and the tip of the reinforcing steel is curved along the inner circumferential surface of the steel pipe in plan view and welded in a state where it abuts against the inner circumferential surface.

[0012] Second aspectIn the foundation structure described herein, the inner surface of the steel pipe is circular in plan view. Furthermore, the tip of the reinforcing steel is curved along the inner surface of the steel pipe in plan view and welded in a position where it abuts against the inner surface. As a result, during an earthquake, the bending moment acting on the steel column is transmitted to the steel pipe via the reinforcing steel.

[0013] Furthermore, by curving the tip of the reinforcing steel section to follow the inner circumference of the steel pipe in a plan view, the end of the reinforcing steel section can be easily welded to the inner circumference of the steel pipe. Therefore, the workability of the reinforcing steel section is improved.

[0014] Regarding the third aspect The foundation structure is, Regarding the first aspect In the foundation structure, the reinforcing steel has an upper flange portion and a web portion extending downward from the lower surface of the upper flange portion, and the end of the web portion on the steel pipe side is welded in a state where it is inserted into a slit formed in the steel pipe.

[0015] Third aspect According to the foundation structure described herein, the reinforcing steel section has an upper flange portion and a web portion extending downward from the lower surface of the upper flange portion. The end of this web portion on the steel pipe side is welded while inserted into a slit formed in the steel pipe. This ensures the joint strength between the reinforcing steel section and the steel pipe while improving the manufacturability of the steel pipe. [Effects of the Invention]

[0016] As described above, according to the present invention, it is possible to suppress damage to the concrete filling inside the steel pipe while eliminating the need for foundation beams installed at the base of the steel column. [Brief explanation of the drawing]

[0017] [Figure 1] This is a vertical cross-sectional view showing the foundation of a structure to which the foundation structure according to the first embodiment is applied. [Figure 2] This is a side view showing the foundation of the structure shown in Figure 1. [Figure 3] This is an example of a cross-sectional view along line 3-3 in Figure 1. [Figure 4] It is an exploded vertical sectional view showing the steel pipe and the reinforcing steel shown in FIG. 1 in an exploded manner. [Figure 5] It is an exploded side view showing the steel pipe and the reinforcing steel shown in FIG. 1 in an exploded manner. [Figure 6] It is a vertical sectional view corresponding to FIG. 2 showing the foundation of a structure to which a modified example of the foundation structure according to the first embodiment is applied. [Figure 7] It is a vertical sectional view showing the foundation of a structure to which the foundation structure according to the first embodiment is applied. [Figure 8] It is a sectional view taken along line 8 - 8 of FIG. 7. [Figure 9] It is a sectional view taken along line 9 - 9 of FIG. 7.

Mode for Carrying Out the Invention

[0018] (First Embodiment) First, the first embodiment will be described.

[0019] (Foundation Structure) In FIG. 1, a foundation 20 of a structure to which the foundation structure according to the first embodiment is applied is shown. The foundation 20 is a pile foundation. This foundation 20 includes piles 30, a footing 40, a steel column 50, and a plurality of reinforcing steels 60.

[0020] (Piles) The pile 30 is, for example, a concrete pile and is provided in the ground 10. The pile head 30H of this pile 30 protrudes upward from the bottom cut 10L of the excavation part where the ground 10 is excavated.

[0021] More specifically, waste concrete 12 is laid on the bottom cut 10L. The pile head 30H of the pile 30 penetrates the waste concrete 12 in the vertical direction and protrudes upward from the upper surface of the waste concrete 12. A footing 40 is provided on the pile head 30H of this pile 30.

[0022] Note that the piles 30 are not limited to concrete piles; steel piles or other types may also be used. Furthermore, the lean concrete 12 can be omitted as appropriate.

[0023] (Hooching) The footing 40 comprises a steel pipe 42 and filling concrete 48. The steel pipe 42 is, for example, a round steel pipe and is positioned on the lean concrete 12 with its axial direction being vertical. The steel pipe 42 also covers the pile head 30H of the pile 30 and surrounds the pile head 30H. Multiple base fittings 44 are provided at the lower end of the outer surface of the steel pipe 42.

[0024] The multiple base fittings 44 are formed, for example, from angles. In a plan view, these base fittings 44 are placed on the lean concrete 12 via a ring-shaped temporary mortar 14. The multiple base fittings 44 are each fixed by nuts 18 to multiple anchor members 16 that protrude upward from the lean concrete 12. In this way, the steel pipe 42 is fixed (positioned) to the lean concrete 12 via the multiple base fittings 44.

[0025] Note that the steel pipe 42 is not limited to a round steel pipe; for example, a square steel pipe may also be used. Also, the temporary mortar 14 and base metal fittings 44, etc., can be omitted as appropriate.

[0026] As shown in Figures 1 to 5, multiple slits (four in this embodiment) 46 are formed in the upper part of the steel pipe 42. The multiple slits 46 are arranged at intervals in the circumferential direction of the steel pipe 42. In this embodiment, the steel pipe 42 has four slits 46 formed in it. These slits 46 are positioned to divide the steel pipe 42 into four equal parts when viewed from above.

[0027] Each slit 46 extends downward from the upper end of the steel pipe 42 along the axial direction of the steel pipe 42. The lower end (tip) of each slit 46 is located above the upper end of the pile 30. The width of these slits 46 is slightly wider than the thickness of the web portion 66 of the reinforcing steel 60, which will be described later, and the web portion 66 is inserted into each slit 46.

[0028] As shown in Figure 1, the filling concrete 48 is filled inside the steel pipe 42. The pile head 30H of the pile 30, the column base 50L of the steel column 50, and parts of multiple reinforcing steel sections 60 (web section 66, lower flange section 64) are embedded in this filling concrete 48.

[0029] (pillar) The steel column 50 is formed, for example, from a square steel pipe. The base portion 50L of the steel column 50 is inserted into the steel pipe 42 and embedded in the filling concrete 48. In this way, the base portion 50L of the steel column 50 is connected to the pile head 30H of the pile 30 via the filling concrete 48.

[0030] Furthermore, the embedding length of the pile head 30H of the pile 30 relative to the filling concrete 48 is set to a length that allows stress (bending moment M) to be transmitted between it and the filling concrete 48.

[0031] The base portion 50L of the steel column 50 is provided with a pair of diaphragms 52 that face each other in the vertical direction. As an example, the pair of diaphragms 52 are through diaphragms.

[0032] Multiple (four in this embodiment) reinforcing steel sections 60 are joined to the base 50L of the steel column 50. In other words, the base 50L of the steel column 50 serves as the joint with the reinforcing steel section 60.

[0033] Furthermore, the steel column 50 is not limited to square steel pipes; it may also be formed from round steel pipes or H-shaped steel. Additionally, the steel column 50 may be, for example, the internal steel frame in a steel-reinforced concrete column.

[0034] (Reinforcement steel) As shown in Figure 3, multiple reinforcing steel sections 60 are arranged in a cross shape in a plan view. These reinforcing steel sections 60 are joined to the column base 50L of the steel column 50 from four directions. Each reinforcing steel section 60 is formed from an H-shaped steel section.

[0035] The reinforcing steel section 60 has an upper flange portion 62 and a lower flange portion 64 that face each other in the vertical direction, and a web portion 66 that connects the upper flange portion 62 and the lower flange portion 64. The web portion 66 extends downward from the center in the width direction on the lower surface of the upper flange portion 62 and is connected to the center in the width direction on the upper surface of the upper flange portion 62.

[0036] One end (base end) of the reinforcing steel section 60 is joined to the column base 50L of the steel column 50. Specifically, one end of the reinforcing steel section 60 is welded with its upper flange 62 and lower flange 64 abutting against a pair of diaphragms 52, and its web 66 abutting against the side surface of the column base 50L of the steel column 50.

[0037] A pair of reinforcing steel sections 60 extend from the base 50L of the steel column 50 to both sides. The leading ends of each reinforcing steel section 60 in the direction of extension are joined to the steel pipe 42. In this way, the base 50L of the steel column 50 is connected to the steel pipe 42 via multiple reinforcing steel sections 60.

[0038] Specifically, at the tip of the reinforcing steel section 60, the lower flange section 64 is absent, and the lower flange section 64 is not joined to the lower end 66L of the web section 66. The end of this web section 66 on the steel pipe 42 side is welded to the steel pipe 42 (the edge of the slit 46) while it is inserted into the slit 46 of the steel pipe 42. Furthermore, the lower end 66L of the web section 66 of the reinforcing steel section 60 reaches near the lower end (tip) of the slit 46. As a result, the slit 46 of the steel pipe 42 is blocked by the web section 66 of the reinforcing steel section 60.

[0039] Furthermore, when the end of the web portion 66 on the steel pipe 42 side is inserted into the slit 46 of the steel pipe 42, the lower surface of the upper flange portion 62 at the tip of the reinforcing steel section 60 rests on (contacts) the upper end of the steel pipe 42. The end of this upper flange portion 62 (the end on the steel pipe 42 side) is welded to the upper end of the steel pipe 42. In this way, the column base portion 50L of the steel column 50 is connected to the steel pipe 42 via multiple reinforcing steel sections 60.

[0040] The reinforcing steel section 60 may be formed, for example, by cutting (notching) the lower flange portion 64 of the end of a rolled H-beam along the width direction, or by using a built H-beam in which the lower flange portion 64 is shorter than the upper flange portion 62. Furthermore, the end of the upper flange portion 62 of the reinforcing steel section 60 does not need to be welded to the upper end of the steel pipe 42.

[0041] (action) Next, the operation of the first embodiment will be described.

[0042] As shown in Figure 1, the steel pipe 42 surrounds the pile head 30H of the pile 30 installed in the ground 10. A steel column 50 is positioned on top of the pile head 30H of the pile 30. The column base 50L of the steel column 50 is inserted into the steel pipe 42. The steel pipe 42 is filled with concrete 48. The pile head 30H of the pile 30 and the column base 50L of the steel column 50 are embedded in this concrete 48.

[0043] As a result, the pile head 30H of the pile 30 and the column base 50L of the steel column 50 are connected via the filling concrete 48. Therefore, during an earthquake, stress is transmitted between the pile head 30H of the pile 30 and the steel column 50.

[0044] In this case, depending on the site and ground conditions, it may not be possible to erect a foundation beam between the column bases 50L of adjacent steel columns 50. In this case, during an earthquake, the bending moment M may not be transmitted between the column bases 50L of adjacent steel columns 50, and the concrete filling 48 in the steel pipes 42 may be damaged.

[0045] As a countermeasure, multiple reinforcing steel sections 60 are embedded in the concrete filling 48 of this embodiment. The multiple reinforcing steel sections 60 extend from the base 50L of the steel column 50 to both sides, and their ends in the direction of extension are joined to the steel pipe 42.

[0046] Specifically, the end of the web portion 66 of the reinforcing steel section 60 that faces the steel pipe 42 is welded in a state where it is inserted into a slit 46 formed in the steel pipe 42. In addition, the upper flange portion 62 at the tip of the reinforcing steel section 60 is welded to the upper end of the steel pipe 42.

[0047] As a result, during an earthquake, the bending moment M acting on the steel column 50 is transmitted to the steel pipe 42 via the reinforcing steel section 60. The bending moment M transmitted to the steel pipe 42 is then transmitted to the pile head 30H of the pile 30 via the filling concrete 48. Therefore, damage to the filling concrete 48 during an earthquake is suppressed.

[0048] Thus, in this embodiment, while suppressing damage to the concrete filling 48 in the steel pipe 42, the foundation beam erected on the column base 50L of the steel column 50 can be omitted.

[0049] Furthermore, if a lower flange portion 64 exists at the end of the reinforcing steel section 60, a large opening corresponding to the width of the lower flange portion 64 is required in the steel pipe 42, which increases the time and effort required to manufacture the steel pipe 42. In addition, when pouring the filling concrete 48, the large opening formed in the steel pipe 42 must be closed to prevent the filling concrete 48 from leaking, which complicates the structure of the joint between the reinforcing steel section 60 and the steel pipe 42.

[0050] In contrast, in this embodiment, the lower flange portion 64 is not present at the tip of the reinforcing steel section 60, and the lower flange portion 64 is not joined to the lower end portion 66L of the web portion 66. As a result, the end of the web portion 66 on the steel pipe 42 side can be easily inserted into the slit 46 of the steel pipe 42. Furthermore, the web portion 66 can easily close the slit 46.

[0051] In other words, in this embodiment, since it is sufficient to form a slit 46 in the steel pipe 42 with a width and length corresponding to the web portion 66 of the reinforcing steel 60, the manufacturability of the steel pipe 42 is improved. Furthermore, since the end of the steel pipe 42 at the web portion 66 and the steel pipe 42 can be easily welded together, the welding quality is also improved.

[0052] Thus, in this embodiment, it is possible to improve the manufacturability of the steel pipe 42 while ensuring the joint strength between the reinforcing steel 60 and the steel pipe 42.

[0053] In this embodiment, the reinforcing steel section 60 is formed from an H-shaped steel section, and the lower flange portion 64 at the end of the reinforcing steel section 60 is omitted. However, as shown in the modified example in Figure 6, for example, it is also possible to form the reinforcing steel section 70 from a T-shaped steel section.

[0054] Specifically, the reinforcing steel section 70 has an upper flange portion 72 and a web portion 74 extending downward from the lower surface of the upper flange portion 72. The end of the web portion 74 of the reinforcing steel section 70 on the steel pipe 42 side is welded in a state where it is inserted into the slit 46 of the steel pipe 42.

[0055] By forming the reinforcing steel section 70 using T-shaped steel in this way, the manufacturability of the reinforcing steel section 70 is improved.

[0056] Furthermore, in the modified example shown in Figure 6, multiple studs 76 are provided on the web portion 74 of the reinforcing steel section 70. By embedding these studs 76 in the filling concrete 48, the unity between the reinforcing steel section 70 and the filling concrete 48 is enhanced. Therefore, the efficiency of transmitting the bending moment M between the column base 50L of the steel column 50 and the steel pipe 42 can be improved.

[0057] The stud 76 may be provided not only on the web portion 74, but also on the lower surface of the upper flange portion 72. Furthermore, the stud 76 may be provided only as needed and can be omitted as appropriate. In addition, the stud 76 may be provided as appropriate on the reinforcing steel 60 of the first embodiment described above, and on the reinforcing steel 80 of the second embodiment described later. The stud 76 is also an example of a shear force transmission member.

[0058] Furthermore, in the above embodiment, a slit 46 is formed in the steel pipe 42 into which the web portion 66 of the reinforcing steel 60 is inserted. However, the steel pipe 42 may also have a notch formed therein, in addition to the slit 46, into which the upper flange portion 62 of the reinforcing steel 60 is positioned.

[0059] (Second embodiment) Next, a second embodiment will be described. In the second embodiment, components and the like that have the same configuration as in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0060] Figure 7 shows the foundation 20 of a structure to which the foundation structure according to the second embodiment is applied. In the second embodiment, the leading ends of the reinforcing steel sections 80 that extend from the column base 50L of the steel column 50 are welded to the inner circumferential surface 42S of the steel pipe 42 in a butted position.

[0061] Specifically, as shown in Figures 8 and 9, the steel pipe 42 is formed from a round steel pipe, and its inner circumferential surface 42S is circular in plan view. Note that the steel pipe 42 does not have the slit 46 (see Figure 3) found in the first embodiment.

[0062] On the other hand, the ends of the upper flange portion 82 and the lower flange portion 84 at the tip of the reinforcing steel section 80, that is, the ends of the upper flange portion 82 and the lower flange portion 84 on the steel pipe 42 side, are curved in plan view along the inner circumferential surface of the steel pipe 42 and are welded in a state where they abut against the inner circumferential surface 42S. In addition, the end of the web portion 86 of the reinforcing steel section 80 on the steel pipe 42 side is welded in a state where it abuts against the inner circumferential surface 42S of the steel pipe 42. As a result, the column base portion 50L of the steel column 50 is connected to the steel pipe 42 via multiple reinforcing steel sections 80.

[0063] In this embodiment, the upper surface of the upper flange portion 82 of the reinforcing steel 80 is exposed from the filling concrete 48. However, the upper surface of the upper flange portion 82 of the reinforcing steel 80 may be embedded in the filling concrete 48.

[0064] (action) Next, the operation of the second embodiment will be described.

[0065] As shown in Figures 8 and 9, in this embodiment, the inner circumferential surface 42S of the steel pipe 42 is circular in plan view. Furthermore, the leading ends of the reinforcing steel sections 80 that extend from the base 50L of the steel column 50 on both sides are curved in plan view along the inner circumferential surface 42S of the steel pipe 42 and welded in a state where they abut against the inner circumferential surface 42S.

[0066] As a result, during an earthquake, the bending moment M acting on the steel column 50 is transmitted to the steel pipe 42 via the reinforcing steel sections 80 on both sides. The bending moment M transmitted to the steel pipe 42 is then transmitted to the pile head 30H of the pile 30 via the filling concrete 48. Therefore, damage to the filling concrete 48 during an earthquake is suppressed.

[0067] Thus, in this embodiment, while suppressing damage to the concrete filling 48 in the steel pipe 42, the foundation beam erected on the column base 50L of the steel column 50 can be omitted.

[0068] Furthermore, by curving the ends of the upper flange portion 82 and the lower flange portion 84 at the tip of the reinforcing steel section 80 along the inner circumferential surface 42S of the steel pipe 42 in a plan view, the ends of the reinforcing steel section 80 can be easily welded to the inner circumferential surface 42S of the steel pipe 42. Therefore, the workability of the reinforcing steel section 80 is improved.

[0069] In this embodiment, the reinforcing steel 80 is formed from H-shaped steel, but the reinforcing steel 80 may also be formed from T-shaped steel.

[0070] (modified version) Next, modifications of the first and second embodiments described above will be explained. In the following explanation, various modifications will be described using the first embodiment as an example, but these modifications can also be appropriately applied to the second embodiment.

[0071] In the first embodiment described above, four reinforcing steel sections 60 are joined to the base 50L of the steel column 50. However, two reinforcing steel sections 60 arranged in a straight line in a plan view may be joined to the base 50L of the steel column 50, or three reinforcing steel sections 60 may be joined.

[0072] Although one embodiment of the present invention has been described above, the present invention is not limited to these embodiments, and various modifications may be used in appropriate combinations with one embodiment, and of course, the invention can be implemented in various forms without departing from the spirit of the present invention. [Explanation of symbols]

[0073] 10 Ground 30 stakes 30H pile head 42 Steel pipe 42S Inner surface (inner surface of steel pipe) 46 slits 48. Filling concrete 50 Steel columns 50L column base 60 Reinforced steel sections 62 Upper flange section 66 Web Department 70 Reinforcement steel 72 Upper flange section 74 Web Department 80 Reinforced steel sections

Claims

1. Piles that are installed in the ground, A steel pipe surrounding the pile head of the aforementioned pile, A steel column is positioned on the pile head, and its base is inserted into the steel pipe, The steel pipe is filled with concrete, in which the pile head and the column base are embedded, A reinforcing steel section is embedded in the aforementioned concrete, extending outwards from the base of the steel column on both sides, with its leading edge in the extension direction joined to the steel pipe. Equipped with, The reinforcing steel has an upper flange portion and a web portion extending downward from the lower surface of the upper flange portion. The end of the web portion on the steel pipe side is welded while inserted into a slit formed in the steel pipe. The lower surface of the upper flange portion is placed on the upper end of the steel pipe. Basic structure.

2. The inner circumferential surface of the steel pipe is circular in shape when viewed from above. The tip of the reinforcing steel section is curved in plan view along the inner circumferential surface of the steel pipe and is welded in a position where it abuts against the inner circumferential surface. The foundation structure according to claim 1.

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