Hang head joint structure

Abstract

To provide a pile head joint structure comprising a pile cap in which there is no risk of interference of pile cap bars embedded inside a pile cap in a lattice shape in plan view and lower end main bars of a foundation beam with a pile head anchoring bars, in which workability of bar arrangement is preferable, and which has excellent quality.SOLUTION: A pile head joint structure 200 comprises: a steel square cylindrical member 50 with a rectangular shape in plan view which is arranged around a pile head 14 of a pile 10 with a circular shape in plan view; and a plurality of pile head anchoring bars 17 fixed to each side plate 51 of the square cylindrical member 50 and protruding upward. A concrete pile cap 20 with a rectangular shape in plan view comprising pile cap bars 25, 26, 27 arranged in a lattice shape in plan view is arranged above the pile 10. The pile head anchoring bars 17 are fastened inside the pile cap 20.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pile head joint structure. [Background technology]

[0002] In the pile head joint structure between the pile head and pile cap, the pile head anchorage bars extending upward from the pile head are buried within the pile cap, and pile cap bars such as braces, base bars, and horizontal reinforcement bars are buried within the pile cap. As a result, various rebars become overly densely intertwined within the pile cap, which creates issues such as rebars that make it impossible or difficult to arrange them during construction.

[0003] Here, an example of a conventional pile head joint structure 100 will be described with reference to Figures 1 and 2. Here, Figure 1 is a vertical cross-sectional view of the conventional pile head joint structure, and Figure 2 is a cross-sectional view taken along the line II-II in Figure 1, cut at the level of the lower end main reinforcement of the foundation beam.

[0004] The pile forming the pile head joint structure 100 in the illustrated example is a precast pile 10 (SC pile, a high-strength concrete pile with an outer steel pipe), which is a pile in which a cylindrical high-strength concrete pile 12 is placed inside a cylindrical steel pipe 11 by centrifugal compaction. The lower ends of multiple pile head anchorage bars 17 are fixed to the upper outer surface 13 of the steel pipe 11 at intervals around the periphery by flare welding or the like, and the multiple pile head anchorage bars 17 protrude upward from the top end 15 of the SC pile 10. The multiple pile head anchorage bars 17 may be welded to an end steel plate (not shown) on the top end 15 of the SC pile 10, or may be threadedly connected to a joint coupler (not shown) attached to the upper outer surface of the steel pipe 11. In either case, multiple pile head anchorage bars 17 are fixed at intervals around the periphery of the pile, which is circular in plan view.

[0005] The pile head 14 of the SC pile 10 installed in the ground G is embedded in a cubic (or rectangular) reinforced concrete pile cap 20 via its underside 21. Inside the pile cap 20, a plurality of U-shaped base reinforcements 25 are arranged below it to form a lattice pattern in plan view, as shown in Figures 1 and 2, and a plurality of U-shaped hook reinforcements 26 are arranged above it to form a lattice pattern in plan view, as shown in Figure 1, and parallel lateral reinforcements 27 are arranged on the four side surfaces 22, as shown in Figures 1 and 2. The rising portions of the base reinforcements 25 and the hanging portions of the hook reinforcements 26 overlap each other by a predetermined length.

[0006] As shown in Fig. 2, in the illustrated example, reinforced concrete foundation beams 30 extending laterally are fixed to three of the four side surfaces 22 of the pile cap 20. As shown in Figs. 1 and 2, a plurality of upper end main reinforcements 31 and lower end main reinforcements 32 of each foundation beam 30 are fixed inside the pile cap 20.

[0007] As shown in Figures 1 and 2, a square column 40 made of reinforced concrete and having a square shape in plan view (an example of a rectangle in plan view) is fixed to the upper surface 23 of the pile cap 20, and multiple main column reinforcements 41, which are arranged inside the square column 40 along the outline of the square shape in plan view, are fixed from the upper surface 23 of the pile cap 20 to the interior.

[0008] As is clear from Figure 2, inside the pile cap 20, particularly at the bottom, the base reinforcement 25 arranged in a grid pattern, the lower end main reinforcement 32 of each foundation beam 30, and multiple column main reinforcement 41 arranged along the outline of a square in plan view are intertwined, and furthermore, multiple pile head anchorage reinforcement 17 arranged circumferentially in the circular plan view are also intertwined.

[0009] The base reinforcements 25 and the lower end main reinforcements 32 all extend in the X-axis and Y-axis directions, which are perpendicular to each other in plan view, and the multiple column main reinforcements 41 extend in the Z-axis, which is perpendicular to the X-Y plane, and are arranged on a rectangular outline parallel to the X-axis and Y-axis. In other words, the base reinforcements 25, the lower end main reinforcements 32, and the column main reinforcements 41 are all arranged in a lattice pattern parallel to the X-axis and Y-axis in plan view.

[0010] For these various rebars, multiple pile head anchorage bars 17 are arranged along the circumferential direction of the circle in plan view. Therefore, they are likely to interfere with the base reinforcement 25, bottom end main reinforcements 32, and column main reinforcements 41, especially the bottom end main reinforcements 32. For example, in Figure 2, of the eight pile head anchorage bars 17, six of them, indicated by dotted lines, interfere with other rebars. This makes rebar placement difficult because other rebars must be arranged to avoid interference with the pile head anchorage bars 17. For example, if adjacent bottom end main reinforcements 32 are closely spaced to avoid interference with the pile head anchorage bars 17, this can hinder the concrete filling ability during pile cap construction, leading to various issues, such as the creation of voids below the over-densely spaced reinforcement.

[0011] For the above reasons, in a pile head joint structure in which multiple pile head anchoring reinforcements protruding above the pile head of the pile are embedded in a concrete pile cap that is rectangular in plan view, there is a need for a pile head joint structure that is equipped with a pile cap that is easy to arrange reinforcement and of high quality, and that does not have the risk of interference between the pile head anchoring reinforcements and the pile cap reinforcement or the lower end main reinforcement of the foundation beam, which are embedded in a grid pattern in plan view inside the pile cap.

[0012] Patent Document 1 proposes a pile head joint structure for a concrete-filled steel pipe pile. Specifically, the structure includes a plurality of pile head reinforcing bars arranged at equal intervals along the outer periphery of the steel pipe at the pile head and embedded in foundation concrete. The steel bracket has a pair of opposing plate-like support sections arranged along the outer periphery of the steel pipe at the pile head in alignment with the arrangement of the pile head reinforcing bars, with the pile-side joint end at one end of the plate-like support section welded vertically to the outer periphery of the steel pipe, and the reinforcing bar-side joint end at the other end joined to the vertically oriented pile head reinforcing bars via a jointing means. The relationship between the tensile yield strength (pTy) of the steel pipe pile and the tensile yield strength (n × rTy) of the total number (n) of pile head reinforcing bars satisfies α × pTy ≥ n × rTy, taking into account the reduction rate (α) of the out-of-plane bending resistance of the steel pipe pile due to the outer diameter of the concrete-filled steel pipe and the bracket to which the pile head reinforcing bars are joined. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Patent No. 6335100 Summary of the Invention [Problem to be solved by the invention]

[0014] Even in the pile head joint structure of the steel pipe concrete pile described in Patent Document 1, the pile head reinforcing bars are fixed to multiple steel brackets arranged circumferentially in a circular plan view, so that multiple pile head reinforcing bars arranged circumferentially with a diameter larger than the outer diameter of the steel pipe concrete pile are embedded in the foundation concrete.As a result, the problem of interference with other reinforcing bars arranged in a grid pattern in a plan view inside the foundation concrete (in the above example, reinforcing bars corresponding to the pile cap reinforcement and the lower end main reinforcement of the foundation beam, etc.) remains unresolved.

[0015] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a pile head joint structure in which a plurality of pile head anchoring reinforcements protruding above the pile head of the pile are embedded in a concrete pile cap that is rectangular in plan view, in which there is no risk of interference between the pile head anchoring reinforcements and the pile cap reinforcement or the lower end main reinforcement of the foundation beam, which are embedded in a lattice pattern inside the pile cap in plan view, and which is equipped with a pile cap that has good reinforcing bar arrangement workability and is of excellent quality. [Means for solving the problem]

[0016] In order to achieve the above object, one aspect of the pile head joint structure according to the present invention is as follows: The pile head anchoring bar is provided with a rectangular steel cylindrical member in plan view, which is arranged around the pile head of a circular pile in plan view, and a plurality of pile head anchoring bars fixed to each side plate of the cylindrical member and protruding upward. A concrete pile cap having a rectangular shape in plan view and equipped with pile cap reinforcement arranged in a grid pattern in plan view is disposed above the pile, and the pile head anchoring reinforcement is fixed inside the pile cap.

[0017] According to this configuration, a rectangular steel tube member is arranged around the top of a circular pile in plan view. The multiple pile head anchorage reinforcing bars, fixed to each side panel of the tube member, are embedded inside the pile cap. Therefore, the multiple pile head anchorage reinforcing bars are positioned along the outline of the rectangle in plan view. This eliminates or prevents interference between the pile cap reinforcement, embedded in a grid pattern inside the pile cap in plan view, and the pile head anchorage reinforcing bars positioned along the outline of the rectangle in plan view. This improves the workability of rebar placement. Furthermore, the lack of gap-free placement improves the concrete filling during pile cap construction, resulting in a high-quality pile cap-equipped joint structure.

[0018] Furthermore, compared to conventional structures in which the pile head anchoring bars are fixed to the outer periphery of the pile, the pile head anchoring bars are fixed to square tubular members with larger planar dimensions than the pile, which increases the distance between the pile and each pile head anchoring bar in plan view (increasing the distance between stress centers), and due to the longer stress center distance, it becomes possible to reduce the number of pile head anchoring bars compared to conventional structures.

[0019] Here, the "rectangular plan view" of the steel rectangular tubular member and the pile cap includes a square plan view and a rectangular plan view. For example, they should be aligned so that the center of the circular pile in plan view, the centroid of the square tubular member in plan view, and the centroid of the square pile cap in plan view coincide with each other, and the sides of the rectangular tubular member in plan view and the corresponding sides of the pile cap are parallel to each other.

[0020] As mentioned above, pile cap reinforcement includes various types of reinforcing bars such as braced bars, base bars, and horizontal reinforcement bars. Furthermore, the pile cap anchoring bars may be fixed to the inside surface of each side plate of the rectangular tubular member, or to the outside surface of each side plate, and may be fixed by welding such as flare welding, or by screwing the lower end of the pile cap anchoring bars into joint couplers fixed to each side plate.

[0021] In addition, it is preferable that the pile head anchoring reinforcement is buried inside the pile cap with part of the pile head and the upper part of the square tube member buried inside the pile cap, thereby integrating the pile head, square tube member and pile cap.

[0022] Another aspect of the pile head joint structure according to the present invention is as follows: The gap between the inner surface of the square tube member and the outer surface of the pile is filled with a filler material that hardens.

[0023] According to this aspect, the gap between the inner surface of the square tube member and the outer surface of the pile (outer surface of the pile head) is filled with and hardened filler, which integrates the square tube member and the pile, improves stress transfer between the pile and the pile cap, and forms a pile head joint structure with even higher joint strength. Furthermore, during construction, the square tube member is placed in the excavated area around the pile that has already been installed in the ground, and various pile cap reinforcement bars and the like are then placed on top of it, and the positioning of the square tube member relative to the pile head during this construction can be done with the filler.

[0024] Another aspect of the pile head joint structure according to the present invention is as follows: The filler is characterized in that it is non-shrinkage mortar.

[0025] According to this aspect, the filler filling and hardening in the gap between the inner surface of the rectangular tubular member and the outer surface of the pile is non-shrinkage mortar, which suppresses drying shrinkage of the filler and suppresses the occurrence of gaps between the inner surface of the rectangular tubular member and the outer surface of the pile. For example, when ordinary concrete or mortar is used as the filler, there is a risk of drying shrinkage, and the drying shrinkage of the filler causes gaps between the pile and the filler or between the rectangular tubular member and the filler, which may make it impossible to ensure the integrity of the pile and the rectangular tubular member through the filler. However, by using non-shrinkage mortar, such problems can be solved.

[0026] In another aspect of the pile head joint structure according to the present invention, A shear key is attached to at least one of the inner surface of the square tube member and the outer surface of the pile, and the shear key is embedded inside the filler material.

[0027] According to this aspect, a shear key is attached to at least one of the inner surface of the square tubular member and the outer surface of the pile, and the shear key is embedded inside the filler, which improves the shear resistance of the shear key and makes it possible to form a pile head joint structure with even greater joint strength. Here, "a shear key is attached to at least one of the inner surface of the square tubular member and the outer surface of the pile" includes a configuration in which a shear key is attached to both, and a configuration in which a shear key is attached to either one.

[0028] In another aspect of the pile head joint structure according to the present invention, The square tube member is characterized in that it is formed from either a square steel pipe or a joint of multiple steel plates.

[0029] According to this aspect, since the square tube member is formed from a square steel pipe, it is possible to relatively easily manufacture the square tube member by cutting a regular square steel pipe to the desired length. On the other hand, since the square tube member is formed from a joint body formed by welding or the like of multiple steel plates (four steel plates, two L-shaped steel plates, one L-shaped steel plate and two steel plates, etc.), it is possible to add variety to the shape and form of the square tube member, for example, by joining steel plates of different thicknesses.

[0030] In another aspect of the pile head joint structure according to the present invention, The pile cap is characterized in that the main beam reinforcement of the concrete foundation beam extends from at least one side surface of the pile cap to the inside.

[0031] According to this aspect, even when the main beam reinforcement of the foundation beam (upper end main reinforcement and lower end main reinforcement) extends from the side surface of the pile cap to the interior, it is possible to suppress or prevent interference between the multiple pile head anchorage reinforcement protruding upward from the side surface of the square tubular member and the main beam reinforcement. Here, "the main beam reinforcement of the foundation beam extends from at least one side surface of the pile cap to the interior" includes a configuration in which the main beam reinforcement extends to the pile cap from a foundation beam fixed to all four sides of a pile cap that is rectangular (cubic or rectangular parallelepiped) in plan view, as well as a configuration in which the main beam reinforcement extends to the pile cap from a foundation beam fixed to any three, any two, or any one side.

[0032] In another aspect of the pile head joint structure according to the present invention, A concrete rectangular pillar in plan view is erected on the upper surface of the pile cap, A plurality of main column reinforcements arranged inside the rectangular column along the outline of a rectangle in plan view extend from the top surface of the pile cap to the inside.

[0033] According to this aspect, even if multiple column main reinforcements arranged along the outline of a rectangle in plan view inside the square column extend from the top surface of the pile cap to the interior, it is possible to suppress or prevent interference between multiple pile cap anchorage reinforcements protruding upward from the side of the square tubular member and the column main reinforcement.In the case of a seismically isolated building, the reinforcing bars of the seismic isolation device extend from the top surface of the pile cap to the interior instead of the square column and the column main reinforcement, but in this specification, the reinforcing bars of this seismic isolation device are assumed to be steel bars equivalent to the above-mentioned column main reinforcement.

[0034] In another aspect of the pile head joint structure according to the present invention, The pile is characterized in that it is one of precast piles including at least steel pipe piles, PHC piles, PRC piles, and SC piles, and cast-in-place piles.

[0035] According to this aspect, regardless of whether the pile is a precast pile or a cast-in-place pile, the pile head anchoring reinforcement is not fixed directly to the pile, making it possible to arrange the pile head anchoring reinforcement around the pile heads of piles of various shapes. [Effects of the Invention]

[0036] As can be understood from the above explanation, according to the pile head joint structure of the present invention, in a pile head joint structure in which a plurality of pile head anchoring reinforcements protruding above the pile head of the pile are embedded in a concrete pile cap that is rectangular in plan view, there is no risk of interference between the pile head anchoring reinforcements and the pile cap reinforcement or the lower end main reinforcement of the foundation beam, which are embedded in a lattice pattern inside the pile cap in plan view, and it is possible to provide a pile head joint structure equipped with a pile cap that is easy to arrange reinforcement and has excellent quality. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a longitudinal cross-sectional view of an example of a conventional pile head joint structure. [Figure 2] 2 is a cross-sectional view taken along the line II-II in FIG. 1, taken at the level of the lower end main reinforcement of the foundation beam. [Figure 3] FIG. 1 is a longitudinal cross-sectional view of an example of a pile head joint structure according to an embodiment. [Figure 4] 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, taken at the level of the lower end main reinforcement of the foundation beam. [Figure 5] FIG. 4 is a cross-sectional view taken along arrows VV in FIG. 3, taken at the midpoint of the pile cap. [Figure 6] FIG. 10 is a vertical cross-sectional view of another example of a pile head joint structure according to an embodiment. [Figure 7] FIG. 1 is a process diagram of an example of a construction method for a pile head joint structure according to an embodiment. [Figure 8] 7, this is a process diagram of an example of a construction method for a pile head joint structure according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, an example of a pile head joint structure according to an embodiment will be described together with a construction method of the pile head joint structure with reference to the accompanying drawings. Note that in this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant explanation.

[0039] [Pile head joint structure according to the embodiment] First, an example of a pile head joint structure according to the first embodiment will be described with reference to Fig. 3 to Fig. 6. Here, Fig. 3 is a longitudinal cross-sectional view of an example of a pile head joint structure according to the embodiment. Also, Fig. 4 is a view taken along arrows IV-IV in Fig. 3, and is a cross-sectional view cut at the level of the lower end main reinforcement of the foundation beam, and Fig. 5 is a view taken along arrows VV in Fig. 3, and is a cross-sectional view cut at the midpoint of the pile head. Furthermore, Fig. 6 is a longitudinal cross-sectional view of another example of a pile head joint structure according to the embodiment.

[0040] As already explained with reference to Figures 1 and 2, in the conventional pile head joint structure 100, multiple pile head anchoring bars 17 are welded and joined at intervals around the circumferential direction of the upper outer surface 13 of the SC pile 10, whereas in the pile head joint structure 200 shown in Figure 3, instead of directly fixing the pile head anchoring bars 17 to the upper outer surface 13 of the SC pile 10, multiple pile head anchoring bars 17 are welded and joined to each side plate 51 of a steel square tube member 50 that is rectangular in plan view and arranged around the pile head 14 of the pile 10.

[0041] The pile cap 20 in the illustrated example is a cube, and the square tube member 50 has a square shape in plan view. The square tube member 50 is formed of, for example, a square steel pipe.

[0042] Furthermore, the pile 10 is an SC pile, which is included in precast piles, but it may be a steel pipe pile other than an SC pile, a PHC pile, a PRC pile, or the like, or may be a cast-in-place pile.

[0043] As shown in Figure 5, pile head anchoring bars 17 are fixed to each inner surface 55 of the four side plates 51 of the rectangular tubular member 50 by flare welding or the like. In the illustrated example, eight pile head anchoring bars 17 are fixed to a total of eight locations: the four corners and the center of each side plate 51, but the fixing locations and number of pile head anchoring bars 17 are not limited to the illustrated example. In particular, compared to conventional structures in which the pile head anchoring bars 17 are directly fixed to the piles, the distance between the piles 10 and each pile head anchoring bar 17 in plan view is longer, and as a result of the longer distance between the stress centers, the number of pile head anchoring bars 17 can be reduced compared to conventional pile head joint structures.

[0044] As shown in Figure 5, the square tube member 50 is arranged so that the center O of the SC pile 10 and the centroid O of the square tube member 50 coincide with each other, and each side surface 22 of the pile cap 20 and each corresponding side plate 51 of the square tube member 50 are parallel to each other. When the square tube member 50 is arranged in this manner, each side plate 51 of the square tube member 50 is perpendicular to the longitudinal direction of the corresponding foundation beam 30, as shown in Figure 5.

[0045] Therefore, as shown in Figure 4, interference between the base reinforcement 25 of the pile cap 20, which is square in plan view, and the lower end main reinforcement 32 (an example of a beam main reinforcement) of the foundation beam 30 extending inside the pile cap 20, and each pile head anchoring reinforcement 17 fixed to each side panel 51 of the square tube member 50 is suppressed or prevented.

[0046] Specifically, as shown in Figure 4, the base reinforcement 25 is arranged in a grid pattern (X-axis direction and Y-axis direction) inside the pile cap 20 when viewed from above, and the lower end main reinforcement 32 of the foundation beam 30 also extends along the X-axis direction and Y-axis direction when viewed from above inside the pile cap 20.

[0047] In contrast, in the pile head joint structure 200, the pile head anchoring reinforcements 17 are arranged along each side plate 51 parallel to the X-axis direction and Y-axis direction of the square tubular member 50, which is square in plan view, rather than along the outer periphery of the SC pile 10, which is circular in plan view, so that they are less likely to interfere with the base reinforcement 25 and the lower end main reinforcement 32, which also extend in the X-axis direction and Y-axis direction.

[0048] In addition, in the pile head joint structure 200, a filler 60 is filled and hardened between the inner surface 55 of the square tubular member 50 and the upper outer surface 13 of the SC pile 10.

[0049] By filling and hardening the gap between the inner surface 55 of the square tube member 50 and the upper outer surface 13 of the SC pile 10, the square tube member 50 and the SC pile 10 are integrated, the stress transmission between the SC pile 10 and the pile cap 20 is improved, and a pile head joint structure 200 with even higher joint strength is formed.

[0050] Here, non-shrinkage mortar is suitable as the filler 60. When the filler 60 is non-shrinkage mortar, drying shrinkage of the filler 60 is suppressed, and the occurrence of gaps due to drying shrinkage of the filler between the inner surface 55 of the square tube member 50 and the upper outer surface 13 of the SC pile 10 is suppressed.

[0051] In addition, as shown in the pile head joint structure 200A in Figure 6, shear keys 58, 18 may be attached to both the inner surface 55 of the square tube member 50 and the upper outer surface 13 of the SC pile 10, and the shear keys 58, 18 may be buried inside the filler material 60.

[0052] In this way, both the square tube member 50 and the SC pile 10 are equipped with shear keys 58, 18, and the shear keys 58, 18 are embedded inside the filler material 60, so that the shear resistance of the shear keys 58, 18 improves the stress transmission between the SC pile 10 and the pile cap 20, resulting in the formation of a pile head joint structure 200A with even higher joint strength.

[0053] [Construction method of pile head joint structure according to the embodiment] Next, an example of a construction method for a pile head joint structure according to the embodiment will be described with reference to Figures 7, 8, and 3. Figures 7, 8, and 3 are process diagrams of an example of a construction method for a pile head joint structure according to the embodiment, respectively. Figures 4, 5, etc. will also be referenced as appropriate.

[0054] As shown in Fig. 7, first, the SC pile 10 is installed in the ground G. There are various installation methods for the SC pile 10 depending on the properties of the ground G and the surrounding environment, and methods such as driving and embedding (pre-boring, core excavation, rotation, etc.) can be applied.

[0055] After the SC pile 10 is installed in the ground G, the surface of the ground G is excavated to expose the pile head 14. Next, square tubular members 50, each having a pile head anchoring bar 17 fixed to the inner surface 55 of each side plate 51, are arranged around the pile head 14 and placed on the excavated bedding surface.

[0056] As already explained with reference to Figure 5, the square tube member 50 is aligned with the SC pile 10 by aligning the center O of the SC pile 10 with the centroid O of the square tube member 50, and by positioning the square tube member 50 so that each side surface 22 of the pile cap 20 and each corresponding side panel 51 of the square tube member 50 are parallel to each other.

[0057] Then, in order to prevent the aligned square tube member 50 from shifting out of position, a filler material 60 is filled into the gap between the inner surface 55 of the square tube member 50 and the upper outer surface 13 of the SC pile 10. That is, as already explained, filling the gap between the square tube member 50 and the SC pile 10 with the filler material 60 is intended to improve stress transfer between the SC pile 10 and the pile cap 20 from a structural standpoint, and to prevent the aligned square tube member 50 from shifting out of position from a construction standpoint.

[0058] After the filled filler 60 has hardened, as shown in Figure 8, the base reinforcement 25, brace reinforcement 26, and horizontal reinforcement 27 (all pile cap reinforcement) of the pile cap 20 are arranged so as not to interfere with each pile head anchorage reinforcement 17, and the main beam reinforcement 31, 32 of the foundation beam 30 are arranged, and further the main column reinforcement 41 of the column 40 is arranged.

[0059] 4, the base reinforcement 25 is arranged in a grid pattern (in the X-axis and Y-axis directions) inside the pile cap 20 in a plan view, and the lower end main reinforcement 32 of the foundation beam 30 also extends from the X-axis and Y-axis directions inside the pile cap 20 in a plan view. Furthermore, since the pile head anchoring reinforcement 17 is aligned along each side plate 51 that is parallel to the X-axis and Y-axis directions of the square tubular member 50, the base reinforcement 25 and lower end main reinforcement 32, which also extend in the X-axis and Y-axis directions, are less likely to interfere with the pile head anchoring reinforcement 17, improving the workability of arranging the reinforcing bars.

[0060] After the reinforcing bars of each component have been arranged, concrete is poured in the order of, for example, the pile cap 20, the foundation beam 30, and the column 40, and the pile head joint structure 200 shown in Figure 3 is constructed by allowing the fresh concrete to harden.

[0061] In this way, the construction method for the pile head joint structure 200 not only improves the workability of arranging each reinforcing bar, but also eliminates the dense tangle of the reinforcing bars, which improves the filling properties of the concrete, making it possible to construct a pile head joint structure 200 equipped with a high-quality pile cap.

[0062] The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0063] 10: SC pile (piles, precast piles) 11: Steel pipe 12: High-strength concrete 13: Upper outer surface 14:Pile head 15: Top 17: Pile head anchorage 18: Share Key 20: Pile cap 21: Bottom surface 22: Side 23:Top surface 25: Base reinforcement (pile cap reinforcement) 26: Hakama muscle (pile cap muscle) 27: Horizontal reinforcement 30: Foundation beam 31: Top main reinforcement (beam main reinforcement) 32: Bottom main reinforcement (beam main reinforcement) 40: Pillar 41:Column main reinforcement 50: Square tube member 51: Side panel 55:Inner self 58: Share Key 60: Filler (non-shrinkage mortar) 200,200A: Pile cap joint structure G: Ground

Claims

1. The pile head anchoring bar is provided with a rectangular steel cylindrical member in plan view, which is arranged around the pile head of a circular pile in plan view, and a plurality of pile head anchoring bars fixed to each side plate of the cylindrical member and protruding upward. A pile head joint structure characterized in that a concrete pile cap having a rectangular shape in plan view and pile cap reinforcement arranged in a grid pattern in plan view is placed above the pile, the square tubular member is embedded in the pile cap so that its upper part is at a height that does not interfere with the pile cap reinforcement, and the pile head anchoring reinforcement is fixed inside the pile cap.

2. 2. The pile head joint structure according to claim 1, wherein a filler material is filled and hardened in the gap between the inner surface of the square tube member and the outer surface of the pile.

3. The pile head joint structure according to claim 2, characterized in that the filler is non-shrinkage mortar.

4. A pile head joint structure as described in claim 2 or 3, characterized in that a share key is attached to at least one of the inner surface of the square tube member and the outer surface of the pile, and the share key is embedded inside the filler material.

5. The pile head joint structure according to any one of claims 1 to 4, characterized in that the square tube member is formed from either a square steel pipe or a joint of multiple steel plates.

6. 6. The pile head joint structure according to claim 1, wherein the main beam reinforcement of the concrete foundation beam extends from at least one side surface of the pile cap to the inside.

7. A concrete rectangular pillar in plan view is erected on the upper surface of the pile cap, A pile head joint structure according to any one of claims 1 to 6, characterized in that a plurality of column main reinforcements arranged inside the square column along the outline of a rectangle in a plan view extend from the top surface of the pile cap to the inside.

8. The pile head joint structure according to any one of claims 1 to 7, characterized in that the pile is one of prefabricated piles including at least a steel pipe pile, a PHC pile, a PRC pile, and a SC pile, and a cast-in-place pile.

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