Pile head joint structure

Abstract

To provide a pile head joint structure which facilitates welding work at a construction site, can shorten a welding work time, and exhibits excellent strength.SOLUTION: A pile head joint member 1 includes: a disk-like lid member 10 for closing an opening of an upper end face of a pile head part P1; an annular first flange 11 surrounding an outer peripheral part of the lid member 10; a backing strip 13 for backing a gap part between the lid member 10 and the first flange 11 from the pile head part P1; a welding part W provided in the gap part; a second flange 12 arranged so as to be overlapped on the first flange 11; a plurality of through holes provided so as to penetrate through the first flange 11 and the second flange 12; and a plurality of anchor bolts 15 fastened so as to sandwich the first flange 11 and the second flange 12 through the plurality of through holes.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a pile head joint structure that is constructed at the joint between the head of a pile material driven into the ground and a reinforced concrete foundation constructed above it during foundation work for a relatively large reinforced concrete structure. [Background technology]

[0002] A wide variety of techniques have been developed and implemented for pile head joint structures. For example, Patent Document 1 describes a pile head structure that includes a base plate portion formed of multiple plate-like members so as to circumferentially surround the outer periphery of a steel pipe pile, a backing metal that is attached to the outer periphery of the steel pipe pile and on which the plate-like members are placed, and a welded portion that joins the inner periphery of the plate-like members to the outer periphery of the steel pipe pile.

[0003] Furthermore, for example, Patent Document 2 describes a pile head joint structure for a winged steel pipe pile, in which pile head bearing fittings made of two or more arc-shaped steel plates are arranged in a ring shape around the outer periphery of the pile head of the winged steel pipe pile, with gaps between each pile head bearing fitting and adjacent pile head bearing fittings, and are attached so that they protrude like a brim in a direction perpendicular to the pile axis, and the pile head is embedded in concrete. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-3507 A [Patent Document 2] JP 2013-241731 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the pile head structure described in Patent Document 1, a plurality of arc plates are placed on a backing metal attached to the outer circumferential surface of a steel pipe pile, and the inner peripheral edges of the arc plates are welded to the outer circumferential surface of the steel pipe pile to form a base plate portion that circumferentially surrounds the outer circumferential surface of the steel pipe pile. Therefore, at the construction site, it is necessary to fix the arc plates placed on the backing metal with a jig so that they do not move during the welding work, or to have another worker support the arc plates, which often makes the welding work complicated and increases the welding work time.

[0006] Similarly, in the pile head joint structure of the winged steel pipe pile described in Patent Document 2, multiple pile head bearing fittings made of arc-shaped steel plates are attached in a brim-like manner to the pile head of the winged steel pipe pile by welding, so at the construction site, the pile head bearing fittings must be fixed with a jig to prevent them from moving during welding work, or other workers must support the pile head bearing fittings, which makes the welding work more complicated and is likely to result in an increase in welding time.

[0007] Therefore, the present invention aims to provide a pile head joint structure that can facilitate welding work at a construction site, shorten the welding work time, and exhibit excellent strength. [Means for solving the problem]

[0008] The pile head joint structure of the present invention is a pile head joint structure formed by fixing a pile head joint member to the pile head of a pile material driven into the ground, and the pile head joint member comprises a disk-shaped cover member that closes the opening on the upper end surface of the pile head, a circular first flange that surrounds the outer periphery of the cover member, a backing metal that backs the gap between the cover member and the first flange from the pile head side, a welded portion provided in the gap, a second flange that is arranged on top of the first flange, a plurality of through holes that are provided to penetrate the first flange and the second flange, and a plurality of reinforcing bars that are fastened by sandwiching the first flange and the second flange through the plurality of through holes.

[0009] In the pile head joint structure of the present invention, a backing metal is tack welded to the pile head of the pile material driven into the ground, and a disk-shaped cover member and an annular first flange are welded in the gap between the cover member and the first flange to form a welded part. At this time, the disk-shaped cover member only needs to be placed on the upper end surface of the pile head so as to close the opening on the upper end surface of the pile head, and the annular first flange only needs to be placed on the backing metal so as to surround the outer periphery of the cover member, so that the welding work is easy. Then, the second flange is placed on top of the first flange, and multiple reinforcing bars are fastened through multiple through holes provided to penetrate the first flange and the second flange, thereby providing excellent strength, eliminating the need to weld the second flange, and shortening the welding time.

[0010] Here, since the second flange is disk-shaped, excellent strength can be exhibited by overlapping the disk-shaped second flange on the annular first flange and fastening a plurality of reinforcing bars.

[0011] It is desirable to have a groove on the underside of the second flange to avoid the welded part. With this, when the second flange is placed on top of the first flange after forming a welded part in the gap between the cover member and the first flange, the groove on the underside of the second flange avoids the welded part, eliminating the need to scrape off the excess welded part after welding.

[0012] Alternatively, the second flange can be configured to be annular so as to avoid the welded portion. With this, when the second flange is placed on top of the first flange after the welded portion is formed in the gap between the cover member and the first flange, the annular second flange avoids the welded portion, eliminating the need to scrape off the excess welded portion after welding.

[0013] Alternatively, a configuration can be adopted in which a third annular flange is provided between the first flange and the second flange to avoid the welded portion. With this, when the second flange is placed on top of the first flange after a welded portion is formed in the gap between the cover member and the first flange, the third annular flange provided between the first flange and the second flange avoids the welded portion, eliminating the need for the task of removing the excess welded portion after welding.

[0014] In addition, the pile head joint structure of the present invention preferably has a reinforcing member provided so that the second flange straddles its center in the radial direction. This reinforcing member reinforces the second flange, and together with the first flange fastened by a plurality of reinforcing bars, the second flange can exhibit excellent strength. Effect of the Invention

[0015] (1) The pile head joint member comprises a disk-shaped cover member that closes the opening on the upper end surface of the pile head, a circular first flange that surrounds the outer periphery of the cover member, a backing metal that backs the gap between the cover member and the first flange from the pile head side, a welded portion provided in the gap, a second flange that is placed on top of the first flange, a plurality of through holes that pass through the first flange and the second flange, and a plurality of reinforcing bars that are fastened to sandwich the first flange and the second flange through the plurality of through holes. This facilitates welding work at the construction site and shortens the welding work time, resulting in a pile head joint structure that exhibits excellent strength.

[0016] (2) Since the second flange is disk-shaped, the disk-shaped second flange can be stacked on top of the annular first flange and multiple reinforcing bars can be fastened to it, thereby providing excellent strength.

[0017] (3) By providing a groove on the underside of the second flange to avoid the welded portion, the work of removing the excess welded portion after welding is not required, improving workability.

[0018] (4) Since the second flange has a circular shape that avoids the welded portion, the work of removing the excess weld from the welded portion after welding is not required, improving workability.

[0019] (5) By providing the annular third flange between the first flange and the second flange to avoid the welded portion, the work of removing the excess welded portion after welding is not required, improving workability.

[0020] (6) Since the second flange has a reinforcing member arranged radially across its center, the second flange is reinforced and, together with the first flange fastened by multiple reinforcing bars, can exhibit even greater strength. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a perspective view showing a main part of the pile head joint structure in the first embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the pile head joint structure of FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of the pile head joint structure of FIG. 1. [Figure 4] 2A and 2B are diagrams showing the state of the pile head joint structure in FIG. 1 before the reinforcing bar material is fastened, in which (A) is a plan view and (B) is a cross-sectional view. [Diagram 5] 5A and 5B are views showing the first flange in FIG. 4, in which (A) is a plan view and (B) is a cross-sectional view. [Figure 6] FIG. 4 is a cross-sectional view showing a modified example of the pile head joint structure in the first embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of a pile head joint structure in a second embodiment of the present invention. [Figure 8] 8A and 8B are views showing the second flange of FIG. 7, in which (A) is a plan view and (B) is a cross-sectional view. [Figure 9] FIG. 11 is a cross-sectional view of a pile head joint structure in a third embodiment of the present invention. [Figure 10] 10A and 10B are views showing the second flange of FIG. 9, in which (A) is a plan view and (B) is a cross-sectional view. [Figure 11]FIG. 11 is a cross-sectional view of a pile head joint structure in a fourth embodiment of the present invention. [Figure 12] 12A and 12B are views showing the third flange of FIG. 11, in which (A) is a plan view and (B) is a cross-sectional view. [Figure 13] FIG. 13 is a cross-sectional view of a pile head joint structure in a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] <Embodiment 1> Figure 1 is an oblique view showing the main parts of the pile head joint structure in the first embodiment of the present invention, Figure 2 is an exploded oblique view of the pile head joint structure of Figure 1, Figure 3 is a cross-sectional view of the pile head joint structure of Figure 1, and Figure 4 is a diagram showing the state of the pile head joint structure of Figure 1 before the reinforcement material is tightened, where (A) is a plan view and (B) is a cross-sectional view, and Figure 5 is a diagram showing the first flange of Figure 4, where (A) is a plan view and (B) is a cross-sectional view.

[0023] As shown in Figures 1 to 4, the pile head joint structure in the first embodiment of the present invention is formed by fixing a pile head joint member 1 to the pile head P1 of a steel pipe pile P as a pile material driven into the ground. The pile head joint member 1 includes a disk-shaped cover member 10 that closes an opening P2 on the upper end surface of the pile head P1, an annular first flange 11 that surrounds the outer periphery of the cover member 10, and a second flange 12 that is arranged overlapping the first flange 11.

[0024] The cover member 10 is made of a steel plate formed in a disk shape slightly larger than the opening P2 of the pile head P1 and slightly smaller than the outer diameter of the pile head P1. In other words, the cover member 10 can be placed on the upper end surface of the back head P1. As shown in FIG. 5, the first flange 11 is made of a steel plate formed in an annular shape with an opening 11A in the center that is slightly larger than the cover member 10. A groove 11B of 30 to 45° is provided in the opening 11A. The cover member 10 and the first flange 11 are backed by a backing metal 13 and welded onto the pile head P1.

[0025] The second flange 12 is made of a steel plate formed into a disk shape having the same diameter as the outer diameter of the first flange 11. The second flange 12 has a rib 14 provided as a reinforcing material across its center in the radial direction. In this embodiment, the rib 14 is a strip-shaped steel plate that is crossed in a crisscross shape at the center of the second flange 12 and is welded to the second flange 12 in advance at a factory. The first flange 11 and the second flange 12 are also provided with a plurality of through holes 15A through which a plurality of anchor bolts 15 serving as reinforcing bars pass.

[0026] The pile head joint structure in this embodiment is formed on site by the following procedure. (1) A backing metal 13 is tack-welded to the pile head P1 of a steel pipe pile P driven into the ground. At this time, the top surface of the backing metal 13 is aligned with the top surface of the pile head P1. (2) The disk-shaped cover member 10 and the annular first flange 11 are welded in the gap between the cover member 10 and the first flange 11 to form a welded joint W. At this time, the disk-shaped cover member 10 only needs to be placed on the upper end surface of the pile head P1 so as to close the opening P2 on the upper end surface of the pile head P1, and the annular first flange 11 only needs to be placed on the backing metal 13 so as to surround the outer periphery of the cover member 10, so the welding work is easy.

[0027] (3) The excess weld of the weld zone W is removed so that the excess weld does not protrude from the top surfaces of the cover member 10 and the first flange 11. (4) The second flange 12 is placed on top of the first flange 11. (5) Anchor bolts 15 are passed through a plurality of through holes 15A provided in first flange 11 and second flange 12, and are fixed in place by tightening washers 16 and nuts 17 from above and below. (6) The fixing plate 18 is fixed to the anchor bolt 15 using a washer 16 and a nut 17. Alternatively, the fixing plate 18 may be fixed to the anchor bolt 15 using only the nut 17.

[0028] Thus, in the pile head joint structure of this embodiment, the disk-shaped cover member 10 only needs to be placed on the upper end surface of the pile head P1 so as to close the opening P2 on the upper end surface of the pile head P1, and the annular first flange 11 only needs to be placed on the backing metal 13 so as to surround the outer periphery of the cover member 10, and the cover member 10 and the first flange 11 are stably held on the pile head P1. Therefore, the welding work can be performed by a single worker, the welding work is simplified, and the welding work time can be shortened.

[0029] Furthermore, by placing the second flange 12, which has ribs 14 provided in advance, on top of the first flange 11 and fastening a plurality of anchor bolts 15 through a plurality of through holes 15A provided so as to penetrate the first flange 11 and the second flange 12, the first flange 11 and the second flange 12 are integrated together, thereby providing excellent strength. At this time, welding of the second flange 12 is not required, and therefore the welding time is also reduced.

[0030] 6, a configuration in which a third flange 19 is sandwiched between the first flange 11 and the second flange 12 can also be used. The third flange 19 is made of a steel plate formed into a disk shape having the same outer diameter as the first flange 11. The third flange 19 is provided with a plurality of through holes 15A through which a plurality of anchor bolts 15 serving as reinforcing bars penetrate together with the first flange 11 and the second flange 12.

[0031] In this way, by sandwiching the third flange 19 between the first flange 11 and the second flange 12 and fastening the multiple anchor bolts 15 through the multiple through holes 15A, the first flange 11, the second flange 12, and the third flange 19 are integrated, so that excellent strength can be exhibited. At this time, welding of the second flange 12 and the third flange 19 is not necessary, so the welding time is also shortened.

[0032] <Embodiment 2> Fig. 7 is a cross-sectional view of a pile head joint structure in a second embodiment of the present invention, and Fig. 8 is a view showing the second flange of Fig. 7, where (A) is a plan view and (B) is a cross-sectional view. In this embodiment, the same components as those described above are given the same reference numerals, and detailed explanations thereof will be omitted.

[0033] As shown in Fig. 7, the pile head joint structure in the second embodiment of the present invention is a pile head joint member 2 equipped with a second flange 22 instead of the second flange 12 in the above-mentioned first embodiment. As shown in Fig. 8, the second flange 22 has a groove portion 22A on the lower surface thereof to avoid the welded portion W. In addition, the second flange 22 is provided with a plurality of through holes 15A through which the anchor bolts 15 as a plurality of reinforcing bar materials penetrate together with the first flange 11.

[0034] When using the pile head joint member 2 of the above configuration, when the second flange 22 is placed on top of the first flange 11, the excess weld W is contained within the groove portion 22A, eliminating the need for the work of scraping off the excess weld W in the above-mentioned step (3), thereby improving workability.

[0035] <Embodiment 3> Fig. 9 is a cross-sectional view of a pile head joint structure in a third embodiment of the present invention, and Fig. 10 is a view showing the second flange of Fig. 9, where (A) is a plan view and (B) is a cross-sectional view. In this embodiment, the same components as those described above are given the same reference numerals, and detailed explanations thereof will be omitted.

[0036] As shown in Fig. 9, the pile head joint structure in the third embodiment of the present invention is a pile head joint member 3 equipped with a second flange 32 instead of the second flange 12 in the above-mentioned first embodiment. As shown in Fig. 10, the second flange 32 is made of a steel plate formed in an annular shape having at its center an opening 32A that is slightly larger than the opening 11A of the first flange 11. A groove 32B of 30 to 45° is provided in the opening 32A.

[0037] Moreover, in the pile head joint structure in the third embodiment of the present invention, the cover member 10 is replaced with a cover member 30 having a thickness obtained by overlapping the first flange 11 and the second flange 32.

[0038] When using the pile head joint member 3 of the above configuration, when the second flange 32 is placed on top of the first flange 11, the excess weld W is contained within the opening 32A of the annular second flange 32 and is avoided, eliminating the need for the work of scraping off the excess weld W in the above-mentioned step (3), thereby improving workability.

[0039] <Fourth embodiment> Fig. 11 is a cross-sectional view of a pile head joint structure in a fourth embodiment of the present invention, and Fig. 12 is a view showing the third flange of Fig. 11, (A) being a plan view and (B) being a cross-sectional view. In this embodiment, the same components as those described above are given the same reference numerals, and detailed description thereof will be omitted.

[0040] As shown in Fig. 11, the pile head joint structure in the fourth embodiment of the present invention is a pile head joint member 4 equipped with a third flange 49 instead of the third flange 19 in the above-mentioned first embodiment. As shown in Fig. 12, the third flange 49 is made of a steel plate formed in an annular shape having an opening 49A at its center that is slightly larger than the opening 11A of the first flange 11. The third flange 49 is also provided with a plurality of through holes 15A through which a plurality of anchor bolts 15 as reinforcing bar members pass together with the first flange 11 and the second flange 12.

[0041] When using the pile head joint member 4 having the above-mentioned configuration, by placing the third flange 49 on top of the first flange 11, the excess weld W fits within the opening 49A of the annular third flange 49 and is avoided, so it is possible to further overlap the second flange 12 on top of this. Therefore, the work of scraping off the excess weld W in the above-mentioned step (3) is not necessary, improving workability.

[0042] <Embodiment 5> 13 is a cross-sectional view of a pile head joint structure according to a fifth embodiment of the present invention. In this embodiment, the same components as those described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0043] In the first to fourth embodiments, the upper surface of the backing metal 13 is aligned with the upper surface of the pile head P1, but it is also possible to configure the upper surface of the backing metal 13 to be slightly shifted downward (inward) from the upper surface of the pile head P1 as shown in Fig. 13. The upper surface of the first flange 11 placed on the backing metal 13 is aligned with the upper surface of the cover member 10.

[0044] In this case, a welded portion W is formed by welding the gap between the outer peripheral surface of the pile head P and the first flange 11. The disk-shaped cover member 10 only needs to be placed on the upper end surface of the pile head P1 so as to close the opening P2 on the upper end surface of the pile head P1, and the annular first flange 11 only needs to be placed on the backing metal 13 so as to surround the outer peripheral portion of the cover member 10, so the welding work is easy. Also, the cover member 10 only needs to be held on the pile head P1, and is fixed on the pile head P1 by the excess weld W. The excess weld W should not protrude from the upper surfaces of the cover member 10 and the first flange 11. If it does protrude, the excess weld W is scraped off.

[0045] In the pile head joint structure in this embodiment, the thickness of the first flange 11 can be made thick. There is no upper limit to the thickness of the first flange 11 and the second flange 12. Also, the thickness of the cover member 10 can be made thin. [Industrial Applicability]

[0046] INDUSTRIAL APPLICABILITY The pile head joint structure of the present invention can be widely used in industrial fields such as civil engineering and construction as a construction technique for foundation work of reinforced concrete structures such as office buildings, large commercial facilities, and public structures. [Explanation of symbols]

[0047] 1,2,3,4 Pile head joint members 10,30 Lid member 11 First flange 12,22,32 Second flange 13 Backing plate 14 Ribs 15 Anchor bolt 16 Washer 17 Nut 18 Fixing plate 19,49 Third flange P steel pipe pile P1 Pile head W Welding

Claims

1. A pile head joint structure formed by fixing a pile head joint member to the pile head of a pile material driven into the ground, The pile head joint member is A disk-shaped lid member that closes the opening on the upper end surface of the pile head; a first flange having an annular shape surrounding an outer periphery of the cover member; A backing metal that backs the gap between the cover member and the first flange from the pile head side; A welded portion provided in the gap; A second flange disposed over the first flange; A plurality of through holes provided to penetrate the first flange and the second flange; a plurality of reinforcing bars that are fastened to the first flange and the second flange by sandwiching them through the plurality of through holes; A pile head joint structure equipped with a

2. The pile head joint structure according to claim 1 , wherein the second flange is disk-shaped.

3. The pile head joint structure according to claim 2 , further comprising a groove on the underside of the second flange to avoid the welded portion.

4. The pile head joint structure according to claim 1 , wherein the second flange is annular and avoids the welded portion.

5. The pile head joint structure according to claim 1 , further comprising a third flange having an annular shape between the first flange and the second flange to avoid the welded portion.

6. The pile head joint structure according to any one of claims 1 to 5, wherein the second flange has a reinforcing member arranged radially across its center.

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