JP7416606B2 - pile foundation structure - Google Patents

Description

The present invention relates to a pile foundation structure, and more particularly, to a pile foundation structure in which a pile head of a pile body and a structural part of a pile foundation can be integrally joined in the foundation structure of various structures supported by pile bodies.

In the joint structure between the pile head of the pile body and structural parts such as foundation beams and foundation footings of reinforced concrete structures, the pile head and the structural parts of the pile foundation should be integrated to ensure the specified strength and rigidity. A large number of reinforcing bars are arranged within a narrow space of a joint structure, requiring labor-intensive and complicated reinforcing work.

In order to solve this problem, a foundation structure in which the rigidity of the pile head and the foundation footing is increased is disclosed (Patent Document 1). In this foundation structure, a lower precast foundation member is installed by securing a predetermined space (pile head insertion part) at the outer circumference of the pile head, and a predetermined stress transmission member is provided at the pile cap insertion part to fill the space. By filling the pile with filler material, the pile head and the lower precast foundation member are integrated.

The lower precast foundation member disclosed in Patent Document 1 is a large precast concrete member that has a horizontal cross-sectional area and burial depth sufficient to be integrated with a footing member constructed on it. There is. Manufacturing these precast concrete members, transporting them to the site and installing them is a large-scale work. In addition, the joining of columns and foundation beams, etc. that will be erected on the lower precast foundation member, and the construction of footing members are all carried out on-site, which requires a complicated work process.

In contrast, a foundation structure disclosed in Patent Document 2 has been proposed as a foundation structure for reducing on-site work steps. This foundation structure consists of a structure that integrates a ring-cut steel pipe installed at the pile head and a joint structure. The ring-cut steel pipe located at the bottom of the foundation structure is installed to surround the pile head of the pile body, and the pile head is fixed and held by the concrete filled inside. The footing, which serves as a joint structure in the upper part of the foundation structure, has a joint with the foundation beam, supports the column base of the erected column, and structurally connects the end of the foundation beam and the column.

JP 2016-70028 Publication Japanese Patent Application Publication No. 2017-137711

The foundation structure disclosed in Patent Document 2 is a large structure in which the ring-cut steel pipe and the steel pipe or precast concrete cylinder that constitutes the footing of the joint structure are integrally constructed, so it is difficult to transport it to the site. However, there is a problem in that the installation work is extensive and work efficiency is poor.
SUMMARY OF THE INVENTION Therefore, the purpose of the present invention is to solve the problems of the conventional techniques described above, and to provide a pile head joint pipe made of a steel pipe concrete composite structure that firmly supports the pile head, and a pile head such as a foundation beam or footing that is connected in advance to the pile head. The structural reinforcement of the structural part of the foundation and the precast joint body made of precast concrete with built-in joint reinforcement are built integrally and stacked together, making it easy and easy to connect the foundation beams etc. and the pile heads structurally. The objective is to provide a pile foundation structure that can be reliably constructed and saves labor and manpower.

In order to achieve the above object, the pile foundation structure of the present invention includes a pile with a pile head protruding from the ground surface by a predetermined length, a structural part of the pile foundation connected to the pile head, and an inner skin of a steel pipe. An inner circumferential concrete portion of a predetermined thickness is integrally provided along the circumferential surface so that the inner space forms an annular shape in plan view, and the pile head is positioned approximately at the center of the inner space. A pile head joint pipe installed on a lowered ground surface, the internal space of which is filled with filler concrete to support the pile head, and a ground surface where the surrounding ground of the pile head joint pipe is backfilled. a precast joint that is installed in the pile foundation and holds a main reinforcement connecting reinforcement that is jointly connected to the main reinforcement end of the structural part of the pile foundation, and the structural part of the pile foundation is provided with a predetermined distance from the outer peripheral surface of the precast joint. The main reinforcement end of the structural part of the pile foundation and the main reinforcement connection reinforcement are connected to the precast connection body through connection concrete, and the pile head connection pipe is integrated with the precast connection body through connection concrete. It is characterized in that it is constructed by stacking the piles on top of each other and is connected to the pile head.

In the pile head joint pipe, it is preferable that joint vertical reinforcements be arranged in the inner circumferential concrete portion.

The precast joint includes a pile head connection part that can be loosely fitted into the internal space of the pile head joint pipe, and a lower joint part including the main reinforcement joining reinforcement that is joined to the main reinforcement end of the structural part of the pile foundation. It is preferable that it is a precast reinforced concrete member consisting of an upper joint part on which a pillar can be placed erected on the upper surface.

A pile foundation structure as another invention includes a pile with a pile head protruding from the ground surface by a predetermined length, a structural part of the pile foundation connected to the pile head, and an internal space that has an annular shape in plan view. None, the pile head joint pipe is installed on the lowered ground surface so that the pile head is located approximately at the center of the internal space, and the internal space is filled with filler concrete to support the pile head. a pile head connection part that can be loosely fitted into the internal space of the pile head joint pipe; a lower joint part including a main reinforcement joint joined to the main reinforcement end of the structural part of the pile foundation; and an upper joint part on which the column to be installed can be placed, and the main reinforcement connecting reinforcement is installed on the ground surface where the surrounding ground is backfilled, and is jointly connected to the main reinforcement end of the structural part of the pile foundation. a precast joint that holds the main reinforcement of the column and a column main reinforcement connecting reinforcement to be joined, the structural part of the pile foundation is installed with a predetermined distance from the outer peripheral surface of the precast joint; The main reinforcement end of the structural part of the pile foundation and the main reinforcement connection reinforcement are integrated with the precast connection body through connection concrete in a state where they are connected, and are constructed to be stacked vertically with the pile head connection pipe. It is characterized in that it is joined to the pile head.

In the precast joint, a through hole is formed through which the joint vertical reinforcement installed in the pile head joint pipe can be inserted, and the joint longitudinal reinforcement is held in the through hole, and the joint vertical reinforcement is inserted into the pile head joint pipe. It is preferable that they be integrated.

Preferably, the structural part of the pile foundation is a reinforced concrete foundation beam or foundation footing.

BRIEF DESCRIPTION OF THE DRAWINGS The plan view and side view which showed the external shape of one Embodiment of the pile foundation structure of this invention. FIG. 2 is a plan cross-sectional view showing an example of the internal configuration of a precast joint and a beam joint along the II-II cross-sectional line of the pile foundation structure shown in FIG. 1(b). FIG. 2 is a side cross-sectional view showing an example of the internal configuration of a precast joint and a beam joint along the III-III cross-sectional line of the pile foundation structure shown in FIG. 1(a). FIG. 1 is a plan view and a side sectional view of a pile head joint pipe constituting the pile foundation structure of the present invention. A plan cross-sectional view (V-V cross-sectional line in FIG. 3) showing a state in which the pile head is fixed by the pile head joint pipe. FIG. 2 is a plan view showing the planar shape of a precast joined body. A side view and a side sectional view showing the side shape and reinforcement state of the precast joint. Explanatory diagrams (Part 1: (a) to (c)) showing the construction procedure of the pile foundation structure of the present invention. Explanatory diagrams (Part 2: (d), (e)) showing the construction procedure of the pile foundation structure of the present invention. Explanatory diagrams (part 3: (f), (g)) showing the construction procedure of the pile foundation structure of the present invention. A side sectional view showing a joined state (integrally fixed) of the pile head joint pipe and the precast joint. The side cross-sectional view which showed the joint state (semi-fixed) of the pile head joint pipe and the precast joint body.

Hereinafter, the structure of the pile foundation structure of the present invention will be explained with reference to the attached drawings. Each figure in FIG. 1 shows a pile foundation structure 10 in which foundation beams 15 arranged vertically and horizontally in plan view and a pile head 2 of a pile body 1 are joined, as an embodiment of the pile foundation structure 10 of the present invention. Part of the external shape is shown. As shown in FIG. 1(b), the pile foundation structure 10 of the present invention includes a pile head joint pipe 20 that constitutes a pile cap that covers the pile head 2 of the pile body 1; The main component is a precast joint body 30 made of precast reinforced concrete having a predetermined shape, which is structurally integrally joined to the upper surface and connects the foundation beam 15, which is one aspect of the structural part of the pile foundation, and the pile head joint pipe 20. composition. Four foundation beams 15 arranged vertically and horizontally in a cross shape when viewed from above (FIG. 1(a)) are joined to the side surface of the precast joined body 30 via joining concrete 46. The planar shape of the precast joined body 30 is approximately octagonal, with sides equal to the beam width of the foundation beam 15 connected by haunch-like hypotenuses. A precast concrete column (1,000 mm square) 40 with a square planar cross section is erected on the top end surface at the center of the upper surface of the approximately octagonal precast joined body 30 (FIG. 1(b)).

The pile body 1 of this embodiment consists of a ready-made pile with a pile outer diameter of 1,000 mmφ, for example, a concrete pile with an outer shell steel pipe. The pile head 2 of the pile body 1 is filled with filler concrete (not shown) and stiffened. As shown in FIGS. 1(b) and 3, the ground where this pile head 2 is located is excavated approximately 1 m below the original ground surface 5a, and the pile head 2 of the pile body 1 is lowered to the lower ground surface. The pile head joint pipe 20 is placed on leveled concrete 7 laid on the lowered ground surface 5b so as to surround the pile head 2.

The foundation beam 15 of this embodiment is made of a precast reinforced concrete member with a beam thickness of 2,000 mm and a beam width of 1,000 mm, and as shown in each figure in FIG. They are arranged vertically and horizontally around the installed precast joint 30 with predetermined spaced apart parts 16 so as to form a cross shape when viewed from above, and are placed on leveled concrete 6 laid on the ground surface 5a. and is structurally rigidly connected to each side of the precast joint 30 via joint concrete 46 cast in place.

The structure of the pile head joint pipe 20 of this embodiment will be explained with reference to FIG. 4. The pile head joint pipe 20 is placed on a lowered ground surface 5b (FIG. 1(b)) so as to cover the side of the pile head 2 of the pile body 1, and is connected to a precast joint 30 described later. This is the main component for joining the pile body 1 to the pile head 2. As shown in FIGS. 4(a) and 4(b), the pile head joint pipe 20 is made of a cylindrical body having a circular inner space 22 when viewed from above. This cylindrical body is a precast concrete member of a steel pipe concrete composite structure in which an inner peripheral concrete 24 of a predetermined thickness is integrally formed on the inner peripheral surface of an outer steel pipe 21. The outer skin steel pipe 21 of this embodiment has a diameter (outer diameter) of 1,700 mmφ, a height of 1,150 mm, and a plate thickness of 16 mm. In order to integrate the outer steel pipe 21 and the inner peripheral concrete 24, it is preferable to arrange various dowels and studs (not shown) on the inner surface of the outer steel pipe 21. The diameter of the internal space 22 of the pile head joint pipe 20 is set in consideration of the construction error in the position of the driven pile. For example, the diameter of the internal space 22 is set to 15% or more of the outside diameter of the pile to provide a predetermined clearance, and the installation position of the pile head joint pipe 20 is adjusted by absorbing deviations in the driving position of the pile body 1. The foundation beam 15 can be installed with high precision.

As shown in FIGS. 4(a) and 4(b), the inner circumferential concrete 24 of the pile head joint pipe 20 is provided at an angle of 45° with the beam joining direction (X, Y directions in FIG. 4(a)). At these positions, six vertical reinforcements 25 are arranged so as to protrude from the upper surface of the inner peripheral concrete 24. The reinforcement position of the vertical reinforcement 25 corresponds to the through hole 39 formed in the haunch portion (described later) of the precast joint 30 shown in FIG. When placed, each vertical reinforcement 25 is inserted into each through hole 39, and the through hole 39 is filled with a solidifying material (not shown) to integrate the precast joint 30 and the pile head joint pipe 20. It becomes a reinforcing joint reinforcement. As shown in FIGS. 2 and 5, filling concrete 23 is placed in the gap (internal space 22) between the pile head joint pipe 20 (FIG. 4(a)) and the pile head 2. The pile head joint pipe 20 and the pile head 2 are integrated.

The constituent members of the precast joint 30 that are integrally joined to the upper part of the pile head joint pipe 20 will be explained with reference to FIGS. 6 and 7. The precast joined body 30 is made of a precast reinforced concrete member in which reinforcement is arranged so that the joining reinforcements to be joined to the reinforcing bars of the beams and columns to be joined protrude from the concrete frame.

As shown in FIGS. 6 and 7(a), the precast joint 30 has two upper and lower stages: a beam joint 31 which is approximately octagonal in plan view, and a column joint 32 which is square in shape and has the same cross-section as the column. It is a precast reinforced concrete structure consisting of an integral structure. In this embodiment, the beam joint 31 is a corbel with a side of 250 mm cut out at the four corners other than the joint of the above-mentioned underground beam with a beam width of 1,000 mm, which is connected to the side surface of a square with a side of 1,500 mm. It has a substantially octagonal planar shape with a portion 31a and a height of approximately 950 mm. The column joint portion 32 has a cross section of a square column having a side of 1,000 mm when viewed from above, and has a height of approximately 600 mm. Note that this precast joined body 30 has predetermined structural reinforcement and assembly reinforcement (not shown) arranged so as to constitute a reinforced concrete structure having a predetermined strength and yield strength as a beam-column joint.

As shown in FIGS. 6 and 7, the precast joint 30 includes a beam main reinforcement connecting reinforcement 35 (35A) that connects and fixes the beam main reinforcement 17 of the foundation beam 15 (FIGS. 3 and 4) to the pile foundation part. , 35B) are reinforced. Six main beam connecting reinforcements 35 are arranged as two-stage reinforcement in the beam width direction in accordance with the joining positions of the four foundation beams 15, and are arranged in the vertical and horizontal directions when viewed from above. The upper beam main reinforcing reinforcement 35A is located approximately at the center in the height direction of the column joint 32 of the precast joint 30 corresponding to the reinforcement position of the upper main beam main reinforcement 17A of the foundation beam 15, and is provided at a predetermined length from the side surface of the column joint 32. The reinforcement is arranged so that it protrudes. The main beam reinforcement reinforcement 35B is arranged near the lower end in the height direction of the lower part of the precast joint 30 corresponding to the reinforcement position of the lower main beam reinforcement 17B of the foundation beam 15 so that a predetermined length protrudes from the lower side surface. There is.

Further, as shown in FIG. 7B, column main reinforcement connection reinforcements 36 are arranged using as guides the intersections of beam main reinforcement connection reinforcements 35 (35A, 35B) arranged vertically and horizontally. As shown in FIG. 7A, the upper end of the column main reinforcement connecting reinforcement 36 protrudes by a predetermined length from the upper surface of the column joint part 32 of the precast joint 30, and is placed on the upper surface of the precast joint 30. It is connected to the lower end of a main column reinforcement 43 of a concrete column 40 corresponding to a floor column via a mechanical joint 42 (FIG. 3). Furthermore, in order to maintain the reinforcement position of the column main reinforcement connecting reinforcement 36 arranged at a position corresponding to the corner of the column 40, a hoop reinforcement 37 having a □ shape in plan view connects the column main reinforcement connecting reinforcement 36. Reinforcement is arranged at predetermined intervals in the column height direction so as to surround the column. In addition, in the beam joint portion 31, in order to reinforce the vertical reinforcements 25 that serve as reinforcing joint reinforcements with the precast joint 30, a plurality of approximately octagonal hoop reinforcements 29 are arranged at predetermined intervals in the height direction. It's streaked.

Further, a pile cap connecting portion 38 is formed on the bottom surface of the precast joined body 30, as shown in FIG. 7(a). This pile head connection part 38 has a flat cylindrical shape having a diameter slightly smaller than the diameter of the internal space 22 of the pile head joint pipe 20 shown in each figure in FIG. When placed on the pile body 20, it is fitted into the internal space 22 so as to cover the filler concrete 23 cast around the pile head 2 of the pile body 1 and the top surface of the pile body 1 (Fig. 3). The clearance (gap) between the pile head 2 and the pile head 2 is filled with a solidifying material 50 (FIG. 11), and the precast joint 30 and the pile head joint pipe 20 are integrated.

The above-mentioned precast joint 30 is manufactured with the ends of the beam main reinforcement connecting reinforcements 35 of each part protruding from the side surface of the precast joint 30, as shown in FIGS. 6 and 7, for example, but the external dimensions is set based on the cargo platform dimensions of a vehicle that can be mounted on the vehicle. If there are no dimensional restrictions during transportation, the dimensions can be made larger than the above.

Hereinafter, the pile head joint pipe 20 made of the above-mentioned steel pipe concrete composite structure and the precast joint 30 are stacked vertically and constructed integrally, and the structural part of the pile foundation is joined to the pile head 2 of the pile body 1. The internal configuration of the pile foundation structure 10 of the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 shows an example of the internal configuration of a beam joint between the precast joint 30 and the foundation beam 15 of the pile foundation structure 10, and FIG. 3 shows the pile head joint pipe 20, precast joint 30, concrete column 40, and foundation. An example of the internal configuration of a beam joint with the beam 15 is shown.

As shown in FIG. 3, the pile head joint pipe 20 is installed on the ground surface 5b so as to surround the pile head 2 of the pile body 1 protruding from the lowered ground surface 5b, and the internal space 22 The pile body 1 is integrated with the pile head 2 by filling concrete 23 filled in the gap between the pile body 1 and the pile body 1 inside. The surrounding ground 5c of the pile head joint pipe 20 is backfilled to the installation level of the foundation beam 15 as a structural part of the pile foundation, and a precast joint 30 (for example, FIG. 7(a)) is placed on the leveled ground surface 5a. is placed. At this time, the vertical bars 25, which serve as reinforcing joint bars with the precast joint 30, which are erected on the pile head joint pipe 20, are inserted into the through holes 39 (FIG. 6) formed in the precast joint 30, and are passed through. The solidifying material 50 filled in the holes 39 functions to integrate the precast joint 30 and the pile head joint pipe 20 together with the hoop reinforcements 29 arranged in advance within the precast joint 30 .

A foundation beam 15 is joined to the side surface of the precast joined body 30 via a joining concrete 46. The foundation beam 15 is placed on leveled concrete 6 laid on a ground surface 5a that has been backfilled and leveled, and the beam main reinforcement 17 is connected to the beam main reinforcement connection reinforcement 35 of the precast joint 30 via the mechanical joint 18. Joint concrete 46 that connects the separated portion 16 between the precast joint 30 and the end face of the foundation beam 15 is cast as cast-in-place concrete and is joined to the precast joint 30.

As a result, the pile head 2 of the pile body 1, the pile head joint pipe 20, the precast joint 30, and the foundation beam 15 main body are integrally constructed and joined, and rigid connection of each member of the pile foundation structure 10 is realized. There is. The concrete strength of the jointed concrete 46 is set to be approximately 27 N/mm ² , but the concrete strength of this jointed concrete 46 is based on the design conditions of the pile foundation structure 10 as well as the concrete strength of the filler concrete 23 that is similarly poured on-site. It is preferable to set it appropriately.

The construction procedure for constructing the pile foundation structure 10 of the present invention will be explained below with reference to FIGS. 8(a) to (c), FIGS. 9(d) and (e), and FIGS. 10(f) and (g). .

A ready-made pile such as a steel pipe pile is driven as the pile body 1, and leveled concrete 7 is poured onto the ground surface 5b where the original ground 5a is lowered so as to ensure a predetermined protrusion length. Pile head treatment is performed by filling the pile with reinforcing concrete (not shown) over a predetermined height within the pile of the pile head 2 (FIG. 8(a)).

Place the pile head joint pipe 20 on the leveled concrete 7 so that the plane center of the pile head joint pipe 20 coincides with the regular position (pile center) of the pile body 1 (FIG. 8(b)). .

The gap between the internal space 22 of the pile head joint pipe 20 and the pile body 1 is filled with filling concrete 23. At this time, the pouring height of the filling concrete 23 is set slightly above the upper end of the pile head joint pipe 20 so that the pile head connecting part 38 of the precast joint body 30 connected to the upper part of the pile head joint pipe 20 can be installed. To a low position. Next, the surrounding ground 5c of the lowered part around the pile head joint pipe 20 is backfilled to the ground level 5a at the installation level of the structural part of the pile foundation (FIG. 8(c)).

The precast joint 30 is placed on the ground surface 5a where the surrounding ground 5c has been backfilled, and the vertical bars 25 erected on the pile head joint pipe 20 are inserted into the through holes 39 formed in the precast joint 30. (FIG. 9(d)). The longitudinal reinforcement 25 and the hoop reinforcement 29 (FIG. 7(b)) function as reinforcing joint reinforcement to integrate the precast joint 30 and the pile head joint pipe 20. Further, in the clearance (gap) between the pile head joint pipe 20 and the pile head joint part 38 of the precast joint 30, which are constructed one above the other, the filling concrete 23 and the pile head joint part 38 are integrated. For this purpose, a solidifying material 50 is filled along a filling path 49 which will be described later (FIG. 9(e)).

When placing the precast joint 30 on the ground surface 5a, the end position of the beam main reinforcement connecting reinforcement 35 protruding from the side surface of the precast joint 30 and the beam main reinforcement 17 to which the beam main reinforcement joining reinforcement 35 is connected (FIG. 9 It is important that the reinforcement position in (e)), that is, the axial direction of the foundation beam 15, match accurately.

Next, as shown in FIG. 9(e), leveled concrete 6 for installing the foundation beam 15 to be connected to the precast joint 30 is placed on the ground surface 5a, and the foundation beam 15 made of precast concrete is placed. , it is placed on the leveled concrete 6 directly facing the beam joint surface of the already installed precast joint 30 and separated by a predetermined distance 16. Furthermore, the ends of the beam main reinforcements 17 protruding from the ends of the foundation beams 15 and the beam main reinforcement joint reinforcements 35 of the precast joint 30 are connected by mechanical joints 18, and necessary stirrups 45 are arranged in the separated parts 16. Strain and install side formwork (not shown) corresponding to the width of the beam.

Joint concrete 46 having the same concrete strength as that of the foundation beam 15 is placed in the isolated part 16 surrounded by the side formwork. Simultaneously with the concrete pouring work of the joining concrete 46, a cast-in-place concrete part 47 is constructed to surround the precast joined body 30 and complete the external shape of the column-beam joint. As a result, the pile head 2 (pile cap) can be made into a rigid structure, and a pile foundation structure 10 can be constructed in which the pile head 2 and the foundation beam 15 are rigidly connected (FIG. 10(f)).

After the connection between each foundation beam 15 and the precast joint 30 is completed, as shown in FIGS. A precast concrete column 40 is built using the position as a guide, and each column main reinforcement connecting reinforcement 36 and the main reinforcement 43 of the precast concrete column 40 are connected by a mechanical joint 42. Note that the pillar 40 to be erected may be a reinforced concrete pillar constructed on site. In that case, the column main reinforcement and hoop reinforcement are built using the column main reinforcement connection reinforcement as a reference, and the form work is erected and concrete is poured to construct a reinforced concrete column.

In FIG. 11, the precast joint 30 is attached to the upper surface of the pile head joint pipe 20 so that each column main reinforcement joint reinforcement 36 of the pile head joint pipe 20 is inserted into the through hole formed in the precast joint 30. The solidification is performed along a filling path 49 that is connected vertically and is formed of a gap 48 between the convex pile head connecting portion 38 formed on the bottom surface of the precast joint body 30 and the top surface of the pile head joint pipe 20 and a through hole 39 . The state in which the material 50 is filled is shown. By solidifying the solidifying material 50 filled in this way, the precast joint 30 and the pile head joint pipe 20 are integrated.

FIG. 12 shows an embodiment in which the joint structure between the pile head 2 and the precast joined body 30 is semi-fixed. The pile head joint pipe 20 of the joint structure shown in the same figure is not provided with vertical reinforcements 25 as shown in FIG. The section 38 is placed in a predetermined position while maintaining a predetermined clearance (gap) 48 via a spacer (not shown), the clearance 48 is filled with a solidifying material 50, and the pile head joint pipe 20 and the precast joint 30 are connected. The period between is fixed. In this semi-fixed joint structure, the normal vertical load is supported by the pile via the pile head 2, but the bending moment generated on the pile head 2 during an earthquake is absorbed by the column-beam joint formed by the precast joint 30. is not transmitted.

Each of the attached drawings depicts how the foundation beam is joined to the precast joint 30 from four orthogonal directions; however, when viewed from above, the foundation beam is I-shaped (one direction), L-shaped (two directions), It can be applied to peripheral piles and corner piles that are joined to the pile head 2 in a T-shape (three directions). For example, when foundation beams are joined to form an L-shape, it is preferable to incorporate the main beam joining reinforcements into the precast joint so that they face two directions perpendicular to the extension direction of the foundation beams.

The above explanation has been given using the foundation beam 15 as an example of the structural part of the pile foundation to be joined to the precast joint 30, but it is also assumed that the structural part of the pile foundation may be a part of the foundation footing in addition to the foundation beam. can. In that case, it is preferable that the beam main reinforcement connecting reinforcement to be incorporated into the precast joint is provided at a position where a part of the reinforcement of the foundation footing can be reliably connected to the reinforcing bars on the precast joint.

Note that the present invention is not limited to the embodiments described above, and various changes can be made within the scope of each claim. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included within the technical scope of the present invention.

1 Pile body 2 Pile head 5a, 5b Ground surface 10 Pile foundation structure 15 Foundation beam (structural part)
16 Separation portion 17 Beam main reinforcement 20 Joint steel pipe 24 Inner circumferential concrete 25 Vertical reinforcement 30 Precast joint 35 Beam main reinforcement connection reinforcement 36 Column main reinforcement connection reinforcement 40 Precast concrete column 43 Column main reinforcement 46 Joint concrete

Claims (6)

A pile with a pile head that protrudes a predetermined length from the ground surface;
a structural part of a pile foundation that is connected to the pile head;
An inner peripheral concrete portion of a predetermined thickness is integrally provided along the inner peripheral surface of the outer skin steel pipe so that the internal space forms an annular shape when viewed from above, and the pile head is located approximately at the center of the internal space. a pile head joint pipe installed on a lowered ground surface so as to support the pile head with the internal space filled with filler concrete;
A precast joint body is installed on a ground surface in which the surrounding ground of the pile head joint pipe is backfilled, and holds a main reinforcement joint reinforcement that is jointly joined to a main reinforcement end of the structural part of the pile foundation,
The structural part of the pile foundation is installed with a predetermined distance from the outer circumferential surface of the precast joint, and joint concrete is applied with the main reinforcement ends of the structural part of the pile foundation and the main reinforcement connection reinforcement connected. A pile foundation structure, characterized in that it is integrated with the precast joined body via the precast joint, is built vertically overlapping the pile head joint pipe, and is joined to the pile head. The pile foundation structure according to claim 1, wherein the pile head joint pipe has joint longitudinal reinforcement arranged in the inner peripheral concrete portion. The precast joint includes a pile head connection part that can be loosely fitted into the internal space of the pile head joint pipe, and a lower joint part that includes the main reinforcement joining reinforcement that is joined to the main reinforcement end of the structural part of the pile foundation. 2. The pile foundation structure according to claim 1, wherein the pile foundation structure is a precast reinforced concrete member comprising an upper joint part on the upper surface of which a pillar can be placed. A pile with a pile head that protrudes a predetermined length from the ground surface;
a structural part of a pile foundation that is connected to the pile head;
The internal space has an annular shape when viewed from above, and the pile is installed on the lowered ground surface so that the head of the pile is located approximately at the center of the internal space, and the internal space is filled with filler concrete to form the pile. a pile head joint pipe that supports the head;
a pile head connection part that can be loosely fitted into the internal space of the pile head joint pipe; a lower joint part including a main reinforcement joint reinforcement joined to the main reinforcement end of the structural part of the pile foundation; and an upper joint part on which a column can be placed, and the main reinforcement connecting reinforcement and the pillar are installed on a ground surface where the surrounding ground is backfilled, and are jointly connected to the main reinforcement end of the structural part of the pile foundation. and a precast joint that holds the main reinforcement of the column and the column main reinforcement connecting reinforcement to be connected,
The structural part of the pile foundation is installed with a predetermined distance from the outer circumferential surface of the precast joint, and joint concrete is applied with the main reinforcement ends of the structural part of the pile foundation and the main reinforcement connection reinforcement connected. A pile foundation structure, characterized in that it is integrated with the precast joined body via the precast joint, is built vertically overlapping the pile head joint pipe, and is joined to the pile head. In the precast joint, a through hole is formed through which the joint vertical reinforcement installed in the pile head joint pipe can be inserted, and the joint longitudinal reinforcement is held in the through hole, and the joint vertical reinforcement is inserted into the pile head joint pipe. The pile foundation structure according to claim 1 or claim 4, wherein the pile foundation structure is integrated. The pile foundation structure according to claim 1 or 4 , wherein the structural part of the pile foundation is a reinforced concrete foundation beam or foundation footing.

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