Hangtou Semi-Rigid Joint Structure

Abstract

To provide a pile head semi-rigid joint structure which can reduce shear force transmitted to a pile head part from a foundation and flexural stress.SOLUTION: A pile head semi-rigid joint structure includes: a foundation 2 positioned below a structure; a pile body 3 which is penetrated into a ground G and is arranged so as to be separated from a lower end 21 of the foundation 2; a joint part 8 including a reinforcement steel pipe 4 surrounding the periphery of a pile head part 34 of the pile body 3, and a filling part 6 formed so as to fill the inside of the reinforcement steel pipe 4 with a filler 61; and an edge cutting part 5 which is arranged between the foundation 2 and the joint part 8, is brought into contact with the lower end 21 of the foundation 2 and an upper end part 81 of the joint part 8, and has a contact surface 512 formed so as to be larger than an upper end face 42 of the reinforcement steel pipe 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pile head semi-rigid joint structure.

Background Art

[0002] Conventionally, as a method of joining a pile supporting a structure and a structure foundation, a pile head semi-rigid joint structure that does not completely restrain the rotation of the pile head is known. The pile head semi-rigid joint structure can distribute the bending moments of the pile head and the middle part of the pile in a well-balanced manner by controlling the degree of fixation against the rotation of the pile head, and is a structure that improves the seismic performance of the pile foundation. In a conventional pile head semi-rigid joint structure, a configuration in which the pile head is buried in the foundation and constructed integrally, as in Patent Document 1, for example, is common.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the pile head semi-rigid joint structure having the above configuration, since the foundation and the pile head are integrated, when an external force due to an earthquake or wind acts on the building, there is a problem that the shear force and bending stress transmitted from the foundation to the integrated pile head are large. Therefore, there is a risk of breakage at the joint between the pile head and the foundation due to large shear force and bending stress acting on the pile head. In particular, since existing piles may not consider the horizontal resistance during an earthquake, a conventional pile head semi-rigid joint structure using existing piles has a problem that the shear force transmitted to the pile head becomes larger than the allowable value of the existing pile.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a pile head semi-rigid joint structure capable of reducing the shear force and bending stress transmitted from the foundation to the pile head.

Means for Solving the Problem

[0006] To achieve the above object, the pile head semi-rigid joint structure according to the present invention includes a foundation located below a structure, a pile body that is penetrated into the ground and arranged away from the lower end of the foundation, a reinforcing steel pipe that surrounds the periphery of the pile head of the pile body, and a filling portion formed by filling a filler inside the reinforcing steel pipe. The joint portion includes a filling portion, and an edge-cutting portion that is arranged between the foundation and the joint portion, abuts against the lower end of the foundation and the upper end of the joint portion, and has a contact surface formed larger than the upper end surface of the reinforcing steel pipe.

[0007] With the above configuration, the pile body and the foundation are joined by the joint portion, so that a pile head semi-rigid joint structure in which the pile head is not completely restrained against external forces can be obtained. In the pile head semi-rigid joint structure, the joint portion and the foundation are edge-cut by the edge-cutting portion, and the pile body, the joint portion, and the foundation are formed as separate bodies. Therefore, the shear force and bending stress transmitted from the foundation to the pile head can be reduced. Therefore, even when a large shear force acts on the pile body from the foundation, the pile body can be prevented from breaking.

[0008] Further, in the pile head semi-rigid joint structure according to the present invention, the filling portion may have a tapered portion that inclines in a direction of increasing diameter downward from the upper end portion, and the upper end surface of the tapered portion abuts against the contact surface of the edge-cutting portion and is formed smaller than the upper surface of the cutting portion where the upper end of the pile body is smoothly cut.

[0009] With the above configuration, the pile head semi-rigid joint structure can reduce the rotational rigidity of the joint portion by forming the upper end surface of the tapered portion with a smaller cross section than the upper surface of the cutting portion. Therefore, the bending stress generated in the pile body can be made smaller, and even when a large bending stress acts on the pile body from the foundation, the pile body can be prevented from being bent and broken.

[0010] Further, in the pile head semi-rigid joint structure according to the present invention, the edge-cutting portion may be provided between the foundation and the joint portion, and may include a steel plate formed larger than the upper end surface of the tapered portion.

[0011] With the above configuration, in the pile head semi-rigid joint structure, since a steel plate is provided between the foundation and the joint portion, unevenness between the foundation and the joint portion can be prevented, and the contact portion between the foundation and the joint portion can be made uniform. Therefore, the stress acting on the contact portion can be made uniform, and damage to the contact portion due to the action of local stress can be prevented. Further, since the steel plate has a small friction coefficient, the shear resistance of the contact portion can be improved.

[0012] Further, the pile head semi-rigid joint structure according to the present invention may have an L-shaped outer shape and may include a plurality of bar reinforcements that are connected at equal intervals in plan view to the upper surface of the steel plate and fixed to the foundation.

[0013] With the above configuration, the pile head semi-rigid joint structure can improve the fixing property between the steel plate and the foundation, and thus can prevent the occurrence of displacement of the position due to the action of a large horizontal displacement or the like.

[0014] Further, in the pile head semi-rigid joint structure according to the present invention, the edge-cutting portion is disposed between the lower end portion of the foundation and the reinforcing steel pipe, and has an outer edge-cutting portion provided at the periphery of the tapered portion, and the outer edge-cutting portion may be formed larger than the opposing surface of the reinforcing steel pipe.

[0015] With the above configuration, the foundation and the joint portion can be reliably edge-cut and separated even in a configuration in which a part of the reinforcing steel pipe protrudes outward from the end portion of the tapered portion in plan view, and a part of the cross section of the reinforcing steel pipe in plan view is formed larger than the tapered portion.

[0016] Further, the pile head semi-rigid joint structure according to the present invention may include a waste concrete layer provided at the peripheral portion of the pile body and abutting against the lower end portion of the reinforcing steel pipe, and a crushed stone layer provided at the peripheral portion of the pile body and abutting against the lower portion of the waste concrete layer.

[0017] With the above configuration, the pile head semi-rigid joint structure can be configured to be firmly supported at the lower end of the reinforcing steel pipe by the discarded concrete layer and the crushed stone layer. Therefore, it is possible to prevent displacement of each part due to settlement of the ground at the installation location of the reinforcing steel pipe.

Effects of the Invention

[0018] According to the present invention, it is possible to provide a pile head semi-rigid joint structure capable of reducing the shear force and bending stress transmitted from the foundation to the pile head.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0020] Hereinafter, the pile head semi-rigid joint structure according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios. As shown in FIG. 1, the pile head semi-rigid joint structure 1 according to the present embodiment includes a foundation 2, a pile body 3, a reinforcing steel pipe 4, a cutoff part 5, and a filling part 6.

[0021] The foundation 2 is placed on the ground G and supports a structure newly constructed above the foundation 2. The foundation 2 of the present embodiment is composed of a column (not shown) and a pile cap, and the lower part of the pile cap is placed on the ground G. The configuration of the foundation 2 is not limited to the above, and it may be a footing foundation in which a foundation slab is placed on the ground G.

[0022] As shown in FIGS. 1 and 2(a), the pile body 3 is provided by being penetrated into the ground G as an existing pile 3 that supported a structure removed before the foundation 2 was placed on the ground G (hereinafter, the "pile body 3" is referred to as the "existing pile 3"). The existing pile 3 has a cylindrical shape, and the central axis of the cylinder is provided substantially coinciding with the vertical direction.

[0023] The existing pile 3 is a cast-in-place concrete pile directly constructed in a circular bored hole 31 formed by excavating the ground G in plan view. The existing pile 3 has a concrete pile portion 32 and a steel cage 33 disposed inside the concrete pile portion 32. The existing pile 3 is provided by arranging the steel cage 33 at a predetermined position in the bored hole 31 and placing a known concrete material without gaps to form the concrete pile portion 32.

[0024] The existing pile 3 is located below the foundation 2, and a cut portion 35 is formed at the upper end 341 of the pile head 34 that is smoothly cut in the radial direction of the pile body 3 and is in close proximity to and facing the foundation 2. The cut portion 35 is formed at a position separated by a distance D1 from the lower end portion 21 of the foundation 2 in the penetration direction of the existing pile 3.

[0025] The steel cage 33 includes a plurality of hoop bars 331 and a plurality of main bars 332. In the existing pile 3, the steel cage 33 is arranged in the concrete pile portion 32, and by fixing the concrete pile portion 32 and the steel cage 33, the pile bearing capacity can be improved.

[0026] The hoop bars 331 have an annular outer shape in plan view, and a plurality of them are arranged at regular intervals in the penetration direction of the existing pile 3. The main bars 332 abut against the inner edge portions 331a of the respective hoop bars 331, and a plurality of them are arranged at regular intervals in the circumferential direction of the hoop bars 331. The plurality of hoop bars 331 and the plurality of main bars 332 are connected at the contact portions at the inner edge portions 331a to form the steel cage 33.

[0027] The reinforcing steel pipe 4 is formed in a circular shape in plan view, and the diameter in plan view is formed larger than the diameter in plan view of the existing pile 3. The reinforcing steel pipe 4 protrudes upward from the upper end 341 and surrounds a part of the pile head 34 and the filling part 6 in plan view. A gap 7 in an annular shape in plan view is formed between the reinforcing steel pipe 4 and the existing pile 3. The pile head semi-rigid joint structure 1 can eliminate construction errors when they occur during the construction of the pile head semi-rigid joint structure 1 due to the gap 7.

[0028] The edge-cutting part 5 is arranged between the foundation 2 and the reinforcing steel pipe 4. In the present embodiment, the edge-cutting part 5 includes a steel plate 51 arranged between the foundation 2 and the filling part 6, and an outer-edge edge-cutting part 52 arranged between the lower end part 21 and the upper end part 41 of the reinforcing steel pipe 4. The steel plate 51 is arranged above the outer-edge edge-cutting part 52.

[0029] The steel plate 51 is a rectangular and plate-shaped stainless steel plate in plan view. The steel plate 51 has high rigidity. The friction coefficients of the upper surface 511 and the lower surface 512 of the steel plate 51 are smaller than the friction coefficient of the lower end surface 211 of the lower end part 21.

[0030] The outer-edge edge-cutting part 52 has a hollow circular shape in plan view. The outer-edge edge-cutting part 52 is formed larger than the upper end surface 42 of the upper end part 41 of the opposing reinforcing steel pipe 4. A tapered part 522 that inclines in a direction of increasing diameter from the upper end inner peripheral edge part 521b of the hollow hole 521 along the inner peripheral surface 521a toward the lower end inner peripheral edge part 521c of the hollow hole 521 is formed on the inner peripheral surface 521a of the hollow hole 521 of the outer-edge edge-cutting part 52.

[0031] The filling part 6 is provided inside the reinforcing steel pipe 4 and the outer-edge edge-cutting part 52. Also, the filling part 6 is provided between the existing pile 3 and the steel plate 51. That is, the filling part 6 is surrounded by the existing pile 3, the reinforcing steel pipe 4, and the edge-cutting part 5. The filling part 6 is formed by filling, without gaps, the location surrounded by the existing pile 3, the reinforcing steel pipe 4, and the edge-cutting part 5 including the hollow hole 521 and the gap 7 with a filling material 61. The filling material 61 is a known concrete material. By forming the filling part 6, the existing pile 3 and the reinforcing steel pipe 4 can be integrated.

[0032] The filling part 6 has a tapered part 64 formed on the upper outer peripheral surface 62 that abuts against the outer edge cutting part 52, which slopes in a direction of increasing diameter downward from the peripheral edge part 631 of the contact part 63 with the lower surface 512 along the upper outer peripheral surface 62 to the depth of the lower end part 523 of the outer edge cutting part 52. The contact part 63 is the upper end part 63 of the filling part 6.

[0033] As shown in Fig. 2(b), the upper end surface 641 of the tapered part 64 abuts against the lower surface 512 and is formed smaller than the cutting surface 351 which is the upper surface of the cutting part 35. The tapered part 522 and the tapered part 64 have substantially matching tapered shapes and abut against each other. The reinforcing steel pipe 4 and the filling part 6 are provided as the joint part 8 between the pile head part 34 and the foundation 2.

[0034] As shown in Fig. 1, between the lower end 642 of the tapered part 64 and the upper end 341 of the existing pile 3, distribution steel bars 65 and a plurality of spacers 66 are provided in the filling part 6. The distribution steel bars 65 and the plurality of spacers 66 are installed before filling the filling material 61.

[0035] The distribution steel bars 65 are formed in a grid shape in plan view, installed on the plurality of spacers 66, ensuring a predetermined cover in the vertical direction and arranged above the cutting surface 351. The distribution steel bars 65 are formed so as not to contact the inner peripheral surface of the reinforcing steel pipe 4.

[0036] The plurality of spacers 66 are arranged at predetermined intervals on the cutting surface 351. The spacers 66 include, for example, known block-type spacers with a groove formed on the upper surface for placing steel bars. The plurality of spacers 66 may further have spacers that ensure a predetermined horizontal cover with respect to the reinforcing steel pipe 4. For example, a hollow disk-shaped spacer with a hole formed for inserting a steel bar close to the inner peripheral surface of the reinforcing steel pipe 4 can be mentioned.

[0037] In the pile head semi-rigid joint structure 1, by providing the distribution steel bars 65 in the filling part 6 with the above configuration, the bearing capacity of the filling part 6 against external forces can be improved, and cracking of the filling part 6 can be prevented.

[0038] The steel plate 51 is provided between the lower end portion 21, the upper end portion 81 of the joint portion 8, and the upper end portion 524 of the outer edge cutting portion 52. The upper surface 511 of the steel plate 51 abuts against the lower end portion 21, and the lower surface 512 abuts against the upper end surface 82 of the joint portion 8 and the upper end surface 525 of the outer edge cutting portion 52 (hereinafter, the "upper end surface 82" is referred to as the "abutting surface 82"). The lower surface 512 of the steel plate 51 is formed larger than the abutting surface 82. With the above configuration, as shown in Fig. 2(c), the steel plate 51 completely cuts off the lower end surface 211 of the foundation 2 and the abutting surface 82 of the joint portion 8. Further, the lower surface 512 is the abutting surface of the steel plate 51 with the abutting surface 82.

[0039] The outer edge cutting portion 52 completely cuts off the foundation 2, the steel plate 51, and the upper end portion 41 of the reinforcing steel pipe 4 at the periphery of the tapered portion 522. The outer edge cutting portion 52 is also used as a disposable formwork when placing the filling material 61 to form the filling portion 6.

[0040] With the above configuration, a joint portion 8 is formed between the foundation 2 and the existing pile 3, and a pile head semi-rigid joint structure 1 in which the foundation 2 and the joint portion 8 are completely cut off by the cutting portion 5 is formed. Further, the foundation 2, the joint portion 8, and the existing pile 3 are formed as separate bodies.

[0041] A disposable concrete layer G1 that abuts against the lower end portion 43 of the reinforcing steel pipe 4 and a crushed stone layer G2 that abuts against the lower part of the disposable concrete layer G1 are provided on the peripheral portion 36 of the existing pile 3. The disposable concrete layer G1 and the crushed stone layer G2 are laminated in the ground G to support the pile head semi-rigid joint structure 1. The disposable concrete layer G1 and the crushed stone layer G2 are formed with a compaction strength such that the ground G does not sink due to the pile head semi-rigid joint structure 1.

[0042] The steel plate 51 has an L-shaped outer shape on the upper surface 511, and a plurality of whisker ribs 9 joined at equal intervals in plan view are provided on the upper surface 511. The plurality of whisker ribs 9 are arranged at equal intervals on the peripheral portion 511a of the upper surface 511.

[0043] In FIGS. 1 and 2, the dimensions of each component provided in the pile head semi-rigid joint structure 1 are exaggerated for the sake of explanation. However, the actual dimensions are, for example, the existing pile 3 has a diameter D2 of 1000 mm, and the reinforcing steel pipe 4 has a diameter D3 of 1200 mm and a thickness T1 of 12 mm. Further, by arranging the existing pile 3 with the above dimensions at the center of the reinforcing steel pipe 4 in plan view, the annular gap 7 in plan view is formed with a radial length L1 of 88 mm.

[0044] Next, the operation and effects of the pile head semi-rigid joint structure 1 according to the above-described embodiment of the present invention will be described with reference to the drawings.

[0045] In the pile head semi-rigid joint structure 1 according to the present embodiment, since the joint portion 8 formed by the reinforcing steel pipe 4 and the filling portion 6 is disposed between the foundation 2 and the existing pile 3, the pile head portion 34 is not completely restricted against external forces having directions such as the rotational direction and the shear direction. The pile head semi-rigid joint structure 1 is provided with a cut-off portion 5 between the foundation 2 and the joint portion 8, so that the foundation 2, the existing pile 3, and the joint portion 8 are formed as separate bodies completely cut off by the cut-off portion 5. With the above configuration, the pile head semi-rigid joint structure 1 can reduce the shear force and bending stress transmitted from the foundation 2 to the pile head portion 34 of the existing pile 3. Therefore, even when an excessive shear force acts on the foundation 2 with respect to the existing pile 3, it is possible to prevent the existing pile 3 from breaking.

[0046] On the upper outer peripheral surface 62 of the filling portion 6, a tapered portion 64 is formed that inclines in a direction of increasing diameter downward from the peripheral edge portion 631 of the contact portion 63 with the lower surface 512 along the upper outer peripheral surface 62 to the depth of the lower end portion 523 of the outer edge cut-off portion 52 from the contact portion 63. The upper end surface 641 of the tapered portion 64 abuts against the lower surface 512 and is formed smaller than the cut surface 351 which is the upper surface of the cutting portion 35. With the above configuration, in the pile head semi-rigid joint structure 1, since the contact surface 82 of the joint portion 8 is formed smaller than the cut surface 351 by the tapered portion 64, the rotational rigidity of the joint portion 8 can be reduced. Therefore, the pile head semi-rigid joint structure 1 can reduce the bending stress generated in the existing pile 3, and can prevent the existing pile 3 from bending and breaking even when an excessive bending stress acts on the foundation 2 due to the existing pile 3. Due to the tapered shape of the tapered portion 64, the joint portion 8 can also prevent the loss and cracking of the corners of the joint portion 8.

[0047] The steel plate 51 is provided between the lower end portion 21, the upper end portion 81 of the joint portion 8, and the upper end portion 524 of the outer edge cut portion 52. The upper surface 511 abuts against the lower end portion 21, and the lower surface 512 abuts against the contact surface 82 and the upper end surface 525. The lower surface 512 of the steel plate 51 is formed larger than the contact surface 82. With the above configuration, the lower end surface 211 of the foundation 2 and the contact surface 82 of the joint portion 8 can be completely cut off by the steel plate 51. In the pile head semi-rigid joint structure 1, the provision of the high-rigidity steel plate 51 can prevent unevenness with the joint portion 8 and make the contact portion 513 with the joint portion 8 in a uniform state. Therefore, the stress acting on the contact portion 513 can be made uniform, and damage to the contact portion 513 due to the action of local stress can be prevented. Since the friction coefficient of the steel plate 51 is smaller than the friction coefficient of the foundation 2, the shear force resistance of the contact portion 513 against the shear force transmitted from the foundation 2 to the existing pile 3 can be improved.

[0048] The steel plate 51 has an L-shaped outer shape on the upper surface 511, and a plurality of whisker ribs 9 joined at equal intervals in plan view are provided on the upper surface 511. The plurality of whisker ribs 9 are arranged at equal intervals on the peripheral edge portion 511a of the upper surface 511. With the above configuration, the pile head semi-rigid joint structure 1 can improve the fixing property between the foundation 2 and the steel plate 51, so that the occurrence of displacement of the installation position of the steel plate 51 due to the action of a large horizontal displacement or the like can be prevented.

[0049] The outer edge cut portion 52 is provided at the peripheral edge of the tapered portion 64, disposed between the lower end portion 21 and the lower surface 512 and the upper end portion 41 of the reinforcing steel pipe 4, and the tapered portion 522 and the tapered portion 64 are in contact with each other. The outer edge cut portion 52 is formed in a circular shape in plan view and is formed larger than the upper end surface 42 which is the opposing surface to the lower end portion 523 of the outer edge cut portion 52 of the reinforcing steel pipe 4. With the above configuration, the pile head semi-rigid joint structure 1 can surely cut the edge between the foundation 2 and the joint portion 8 by the outer edge cut portion 52 and make them separate bodies.

[0050] On the peripheral portion 36 of the existing pile 3, a discarded concrete layer G1 that abuts against the lower end portion 43 of the reinforcing steel pipe 4 and a crushed stone layer G2 that abuts against the lower part of the discarded concrete layer G1 are provided. From the above configuration, the pile head semi-rigid joint structure 1 can be configured such that the lower end portion 43 is firmly supported by the configuration in which the discarded concrete layer G1 and the crushed stone layer G2 are laminated. Therefore, it is possible to prevent displacement of the installation positions of the respective parts due to settlement of the ground at the installation location of the reinforcing steel pipe 4 or the like.

[0051] With the pile head semi-rigid joint structure 1 according to the present embodiment, it becomes possible to easily reuse the existing pile 3 as the pile body of the newly installed foundation 2. By reusing the existing pile 3, it is possible to reduce the construction cost of the structure, shorten the construction period, and reduce the environmental load such as vibration, noise associated with the new installation of the pile, and the disposal of the existing pile.

[0052] As described above, the embodiment of the pile head semi-rigid joint structure according to the present invention has been described. However, the present invention is not limited to the above embodiment and can be appropriately changed without departing from the gist thereof. For example, in the above embodiment, the existing pile 3, the joint portion 8, and the outer edge cut portion 52 are formed in a circular shape in plan view, but they may be formed in a rectangular shape in plan view.

[0053] For example, in the above embodiment, the tapered portion 64 is formed on the upper outer peripheral surface 62 which is a part of the outer peripheral surface of the filling portion 6. However, the tapered portion 64 may be formed according to the configuration of the filling portion 6. For example, a configuration in which the tapered portion 64 is formed on the entire outer peripheral surface of the filling portion 6 may be adopted.

[0054] For example, in the above-described embodiment, the edge cutting portion 5 includes a steel plate 51 and an outer edge cutting portion 52, but the edge cutting portion 5 may be configured by a steel plate 51 formed larger than the upper end surface 42.

[0055] For example, in the above-described embodiment, a plurality of whisker streaks 9 are provided on the upper surface 511 of the steel plate 51, but a configuration may also be adopted in which bolt holes are drilled in the steel plate 51 and anchor bolts penetrating the steel plate 51 are driven into the foundation 2.

[0056] For example, in the above-described embodiment, a discarded concrete layer G1 and a crushed stone layer G2 are provided below the reinforcing steel pipe 4, but a configuration may also be adopted in which the crushed stone layer G2 is formed by dividing it into two layers according to the size of the particle diameter of the crushed stone.

Explanation of Reference Numerals

[0057] 1 Pile head semi-rigid joint structure 2 Foundation 3 Existing pile (pile body) 4 Reinforcing steel pipe 5 Edge cutting portion 6 Filling portion 8 Joint portion 9 Whisker streak 21 Lower end portion 34 Pile head portion 35 Cutting portion 36 Peripheral portion 42 Upper end surface (opposing surface) 43 Lower end portion 51 Steel plate 52 Outer edge cutting portion 61 Filling material 63 Contact portion (upper end portion) 64 Tapered portion 81 Upper end portion 351 Cutting surface (upper surface) 512 Lower surface (contact surface) 641 Upper end surface G Ground G1 Discarded concrete layer G2 Crushed stone layer

Claims

1. A foundation located below a structure, a pile body that is driven into the ground and is arranged away from the lower end of the foundation, a reinforcing steel pipe that surrounds the periphery of the pile head of the pile body, and a filling portion formed by filling a filler inside the reinforcing steel pipe, and a joint portion including the same, a cut-off portion that is arranged between the foundation and the joint portion, abuts against the lower end of the foundation and the upper end of the joint portion, and has a contact surface formed larger than the upper end surface of the reinforcing steel pipe, comprising, a pile head semi-rigid joint structure.

2. The filling portion has a tapered portion that slopes in a direction of increasing diameter downward from the upper end portion, the upper end surface of the tapered portion abuts against the contact surface of the cut-off portion, and is formed smaller than the upper surface of a cut-off portion where the upper end of the pile body is smoothly cut, The pile head semi-rigid joint structure according to Claim 1.

3. The cut-off portion is provided between the foundation and the joint portion and includes a steel plate formed larger than the upper end surface of the tapered portion, The pile head semi-rigid joint structure according to Claim 2.

4. having an L-shaped outer shape, and including a plurality of bar reinforcements that are connected at equal intervals in plan view to the upper surface of the steel plate and fixed to the foundation, The pile head semi-rigid joint structure according to Claim 3.

5. The cut-off portion is arranged between the lower end of the foundation and the reinforcing steel pipe and has an outer edge cut-off portion provided at the periphery of the tapered portion, the outer edge cut-off portion is formed larger than the opposing surface of the reinforcing steel pipe, The pile head semi-rigid joint structure according to any one of Claims 2 to 4.

6. a discarded concrete layer provided at the peripheral portion of the pile body and abutting against the lower end of the reinforcing steel pipe, a crushed stone layer provided at the peripheral portion of the pile body and abutting against the lower part of the discarded concrete layer, comprising, The pile head semi-rigid joint structure according to any one of Claims 1 to 5.

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