JP7200048B2 - pile foundation structure - Google Patents

Description

The present invention relates to a pile foundation structure, and more particularly to a pile foundation structure capable of integrally joining a pile head portion of a pile body and a structural portion of the pile foundation in the foundation structure of various structures supported by pile bodies.

In the joint structure between the pile head of the pile body and the structural part such as the foundation beam and foundation footing of the reinforced concrete structure, the pile head and the structural part of the pile foundation are integrated to ensure a predetermined strength and rigidity. A large number of reinforcing bars are arranged in a narrow joint structure space, and laborious and complicated reinforcing bar arrangement work is required.

In order to solve this problem, a foundation structure is disclosed in which the rigidity of the pile head and the foundation footing is increased (Patent Document 1). In this foundation structure, a prescribed space (pile head insertion part) is secured at the outer peripheral position of the pile head, and a lower precast foundation member is installed, and a prescribed stress transmission member is provided in the pile head insertion part and placed in the space. By filling the 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 set to a sufficient horizontal cross-sectional area and burial depth to integrate with the footing member constructed thereon. there is Manufacture of this precast concrete member, delivery to the site, and installation are large-scale operations. In addition, since the joining of the pillars erected on the lower precast foundation member and the foundation beams, etc., and the construction of the footing members are all on-site work, a complicated work process is required.

On the other hand, a basic structure disclosed in Patent Document 2 has been proposed as a basic structure for reducing the number of work processes on site. This foundation structure consists of a structure in which a ring-cut steel pipe installed at the pile head and a joint structure are integrated. A ring-shaped steel pipe located in the lower part of the foundation structure is installed so as 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 is the joint structure of the upper part of the foundation structure, has joints with the foundation beams, supports the column bases of the erected columns, and structurally joins the foundation beam ends and the columns.

JP 2016-70028 A JP 2017-137711 A

The foundation structure disclosed in Patent Document 2 is a large-sized structure in which the round-cut steel pipe and the steel pipe or precast concrete cylinder constituting the footing of the joint structure are integrally constructed. , there is a problem that the installation work becomes large-scale and work efficiency is poor.

Therefore, the object of the present invention is to solve the problems of the conventional technology described above, and to provide a pile head connection pipe made of a steel pipe concrete composite structure that firmly supports the pile head, and a pile such as a foundation beam or a foundation footing. The structural reinforcement of the structural part of the foundation and the joint steel pipe in which the joint reinforcement to be joined is incorporated are integrally layered, and the foundation beam, etc. and the pile head can be structurally joined easily and reliably. To provide a pile foundation structure capable of saving labor and manpower.

In order to achieve the above object, the pile foundation structure of the present invention includes a pile driven with a pile head having a predetermined protruding length from the ground surface, and a structural portion of the pile foundation joined to the pile head. Then, the inner space has an annular shape in plan view, the pile head is installed on the lower ground surface so that it is positioned substantially at the center of the inner space, and the inner space is filled with filling concrete. A pile head connection pipe that supports the pile head, and a main reinforcement that is installed on a ground surface where the ground around the pile head connection pipe is backfilled and that is joined to the main reinforcement end of the structural part of the pile foundation. a structural part joint body having an outer shell steel pipe that holds jointing muscles and is filled with filling concrete in the pipe, wherein the structural part of the pile foundation is separated from the outer peripheral surface of the structural part joint body by a predetermined distance. is provided and installed, and integrated with the structural part joint body via joint concrete in a state where the main reinforcement end of the structural part of the pile foundation and the main reinforcement connecting reinforcement are joined, and the structural part joint body is connected to the outside It is characterized in that the filling concrete filled in the shell steel pipe is stacked vertically on the pile head joint pipe and joined to the pile head.

It is preferable that the pile head connection pipe is a precast concrete member of a composite steel pipe concrete structure composed of an outer skin steel pipe and an inner peripheral concrete portion.

It is preferable that the pile head joint pipe is provided with a reinforcing joint reinforcement located in the outer shell steel pipe.

It is preferable that the outer shell steel pipe has a through hole formed at a position of the pipe wall opposite to the position of the main reinforcing bar of the foundation beam of the structural portion of the pile foundation, and the connecting reinforcing bar of the main reinforcing bar is held in the through hole.

It is preferable that the outer shell steel pipe holds, in addition to the main-reinforcement connecting reinforcement, a column main-reinforcement connecting-reinforcement that is joined to a main reinforcement of a column erected on the upper surface of the structural part joint.

The structural portion of the pile foundation is preferably a reinforced concrete foundation beam or foundation footing.

BRIEF DESCRIPTION OF THE DRAWINGS The top view and side view which showed the external appearance shape of one Embodiment of the pile foundation structure of this invention. Fig. 1(b) is a cross-sectional plan view showing an example of the internal configuration of the structural part joint and the beam joint along the II-II cross-sectional line of the pile foundation structure shown in Fig. 1(b). Fig. 1(a) is a side cross-sectional view showing an example of the internal configuration of a structural part joint and a beam joint steel pipe taken along the III-III sectional line of the pile foundation structure shown in Fig. 1(a). The side sectional view and plane sectional view of the pile head connection pipe which comprises the pile foundation structure of this invention. Fig. 3 is a cross-sectional plan view showing a fixed state of the pile head portion by the pile head joint pipe (Fig. 3 V-V cross-sectional line). FIG. 4 is a cross-sectional plan view showing the reinforcement arrangement of the outer shell steel pipe. Side cross-sectional view and side view showing the bar arrangement state of the outer shell steel pipe. Explanatory diagrams showing the construction procedure of the pile foundation structure of the present invention (No. 1: (a) to (c)). Explanatory drawing (the 2: (d), (e)) which showed the construction procedure of the pile foundation structure of this invention. Explanatory drawing (the 3: (f), (g)) which showed the construction procedure of the pile foundation structure of this invention.

Hereinafter, the configuration of the pile foundation structure of the present invention will be described with reference to the accompanying drawings. Each figure in FIG. 1 shows, as an embodiment of the pile foundation structure 10 of the present invention, the pile foundation structure 10 in which the foundation beams 15 arranged vertically and horizontally in a plan view and the pile heads 2 of the pile bodies 1 are joined. A part of the external shape is shown. The pile foundation structure 10 of the present invention, as shown in FIG. It is mainly composed of a structural part joint 30 for joining a foundation beam 15 and a pile head joint pipe 20 as one aspect of the structural part of the pile foundation, which is structurally integrally constructed on the upper surface. Four base beams 15 arranged vertically and horizontally in a cross shape in a plan view (FIG. 1(a)) are joined to the side surface of the structural joint 30 via joint concrete 46. As shown in FIG. Furthermore, a precast concrete column (1,000 mm square) 40 is erected on the top surface of the structural joint 30 (FIG. 1(b)).

The pile body 1 of this embodiment is made of a steel pipe pile with a pile outer diameter of 1,000 mmφ, and the pile head 2 is filled with filling concrete (not shown) for stiffening. The ground on which the pile head 2 is located is, as shown in FIGS. The pile head connecting pipe 20 is placed on the leveled concrete 7 laid on the ground surface 5b so as to surround the pile head 2 in a long protruding state.

The foundation beam 15 of this embodiment is made of a precast reinforced concrete member with a beam length of 2,000 mm and a beam width of 1,000 mm. It is arranged vertically and horizontally around the body 30 so as to form a cross when viewed from above with a predetermined spaced portion 16 taken, placed on leveling concrete 6 laid on the ground surface 5a, and joined concrete 46 It is structurally rigidly joined to the structural part joint body 30 via the .

The configuration of the pile head joint pipe 20 of this embodiment will be described with reference to FIGS. The pile head connection pipe 20 is placed on the ground surface 5b lowered so as to cover the side of the pile head 2 of the pile body 1, and is connected to the structure part connection body 30 described later and the pile head of the pile body 1. It is the main constituent member for joining the part 2 . As shown in FIGS. 4(a) and 4(b), the pile head joint pipe 20 is a cylindrical body having a circular internal space 22 in plan view. This cylindrical body is a precast concrete member having 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 skin steel pipe 21 . The outer sheath 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 skin steel pipe 21 and the inner peripheral concrete 24, it is preferable to dispose various dowels and studs (not shown) on the inner surface of the outer skin steel pipe 21. As shown in FIG. The diameter of the internal space 22 of the pile head joint pipe 20 is set in consideration of the construction error of the position of the driven pile. For example, the diameter of the internal space 22 is 15% or more of the pile outer diameter, and a predetermined clearance is provided. The foundation beam 15 can be installed with high accuracy. Fig. 4(c) shows that a rectangular steel pipe is used for the outer skin steel pipe 21 of the pile head joint pipe 20, and the inner circumference A modified example in which concrete 24 is formed is shown. In this case, vertical reinforcements 25, which will be described later, can be arranged in a straight line, and hoop reinforcements 27 (described later) combined with the vertical reinforcements 25 can also be square-shaped, as shown in FIG. Since the bar arrangement is not complicated compared to the case shown, the bar arrangement work can be facilitated on site.

Furthermore, as shown in FIGS. 2 and 5, filling concrete 23 is placed between the pile head 2 and the pile head connection pipe 20 (FIG. 4(a)). Integration with the pile head joint pipe 20 is achieved.

As shown in FIGS. 4(a) and 4(b), vertical reinforcements 25 are arranged in the inner peripheral concrete 24 of the pile head joint pipe 20 at predetermined intervals in the circumferential direction. The vertical reinforcement 25 protruding from the upper surface of the inner peripheral concrete 24 serves as a reinforcement joint reinforcement with a structural part joint 30 to be described later. Further, hoop reinforcements 26 are arranged in the vicinity of the surface of the inner peripheral concrete 24 at predetermined intervals in the height direction of the concrete, and function as reinforcing reinforcements for the pile head 2 .

Constituent members of the structural portion joint 30 constructed on the upper portion of the pile head joint pipe 20 will be described with reference to FIGS. 6 and 7. FIG. The structural part joint 30 is filled in the outer shell steel pipe 31, which holds the joint bars to be joined with the reinforcing bars of the beams and columns to be joined and serves as the outer shell member of the steel pipe concrete composite structure. Filling concrete 33 is the main configuration.

The shell steel pipe 31 is a circular steel pipe having a diameter (outer diameter) of 1,800 mm, a height of 2,000 mm, and a plate thickness of 19 mm, as shown in FIGS. As shown in FIGS. 6 and 7, the outer shell steel pipe 31 is provided with beam main reinforcement connecting reinforcements 35 for fixing the beam main reinforcements 17 of the foundation beams 15 to the pile foundation portion. The beam main reinforcing bar connecting bars 35 are incorporated in the outer shell steel pipe 31 so as to be inserted into through holes formed in the outer shell steel pipe 31 corresponding to the reinforcing positions of the beam main reinforcing bars 17 of the foundation beam 15 and held. In this embodiment, as shown in FIGS. 6 and 7A, six main beam connecting bars 35 arranged in the beam width direction in accordance with the connecting positions of the four base beams 15 are attached to the upper end of the beam. , are arranged vertically and horizontally in two stages as reinforcing bars at the bottom. Further, column main reinforcing bar connecting bars 36 are arranged using the intersections of the beam main reinforcing bar connecting bars 35 as guides. As shown in FIG. 3 , the upper ends of these column main reinforcement reinforcements 36 are joined to the lower ends of the column main reinforcements 43 of the precast concrete columns 40 placed on the upper surface of the structural part joint 30 via mechanical joints 42 . be done. In addition, as shown in FIG. 7(a), in order to maintain the reinforcement position of the column main reinforcement connecting reinforcement 36 arranged at the position corresponding to the corner of the column 40, the square shape is formed in plan view. Hoop reinforcements 37 are arranged at predetermined intervals in the column height direction so as to surround the column main reinforcement connecting reinforcements 36 . In order to reinforce the vertical reinforcement 25 that serves as a reinforcement joint reinforcement with the structural joint 30, ring-shaped hoop reinforcements 27 are bound to assembly reinforcements (not shown) and arranged at predetermined intervals in the column height direction. It is muscled.

Furthermore, an opening 38 as shown in FIG. These openings 38 allow the filling concrete 33 filled in the outer shell steel pipe 31 and a part of the joint concrete 46 that joins the foundation beam 15 made of precast concrete to be directly adhered to each other. 15 and structural assembly 30 to ensure shear resistance. Furthermore, a stiffening steel material 39 is arranged so as to straddle the opening 38 . This stiffening steel material 39 prevents the rigidity of the steel pipe 31 from being lowered due to the cross-sectional defect caused by the formation of the opening.

The external dimensions of the outer shell steel pipe 31 described above are, for example, as shown in FIGS. is set based on the dimensions of a vehicle that can be mounted on the vehicle with the ends of the outer shell steel pipes 31 protruding from the side surfaces thereof. If there are no size restrictions during transportation, the size may be larger than the above.

Filling concrete 33 is filled in the outer shell steel pipe 31 after installation at the site, and the structure joint 30 exhibits predetermined rigidity and strength as a steel pipe concrete composite structure composed of the outer shell steel pipe 31 and the filling concrete 33. be able to. The concrete strength of the filling concrete 23, 33 is set to about 27 N/mm ² , but the concrete strength of the concrete (filling concrete 23, 33, joint concrete 46) of each part to be cast on site is the same as that of the pile foundation structure 10. It is preferable to set appropriately according to the design conditions.

Hereinafter, the pile head joint pipe 20 and the structural part joint 30 made of the above-mentioned steel pipe concrete composite structure are stacked vertically and integrally constructed, 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 configured to do so will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 shows an internal configuration example of the beam joint between the structural part joint 30 and the foundation beam 15 of the pile foundation structure 10, and FIG. shows an example of the internal configuration of the beam joint.

As shown in FIG. 3, the pile head connection pipe 20 is installed so as to surround the pile head 2 of the pile body 1 protruding from the ground surface 5b that has been lowered, and is connected to the pile body 1 in the internal space 22. The pile body 1 is integrated with the pile head 2 by filling concrete 23 filled in the gap. The ground surrounding the pile head joint pipe 20 is backfilled to the installation level of the structural portion of the pile foundation, and the outer shell steel pipe 31 (for example, FIG. 7A) of the structural portion joint 30 is placed on the leveled ground surface 5a. The inside of the pipe is filled with filling concrete 33 . The filling concrete 33 of the outer shell steel pipe 31 is filled so as to be integrated with the upper surface portion of the filling concrete 23 in the pile head joint pipe 20 . A predetermined number of hoop reinforcements 27 are arranged around the vertical bars 25 serving as reinforcement joints with the structural part joint 30, and the structural part joint 30 filled with filling concrete 33 and the pile positioned below it. Integration with the head joint pipe 20 is achieved.

The foundation beams 15 are joined to the sides of the structural joint 30 via joint concrete 46 . The foundation beam 15 is placed on leveled concrete 6 laid on the ground surface 5a that has been backfilled and leveled, and the beam main reinforcement 17 of the foundation beam 15 and the beam main reinforcement connection reinforcement 35 of the structural part joint 30 are mechanically connected. Joining concrete 46, which is joined via the joint 18 and connects the spaced portion 16 between the structural part joining body 30 and the end face of the foundation beam 15, is placed as cast-in-place concrete. In addition, the pile head 2 of the pile body, the structural part joint 30, and the main body of the foundation beam 15 are integrally constructed and joined by the filling concrete 33 filled in the outer shell steel pipe 31, and each member of the pile foundation structure 10 is connected. A rigid connection is achieved.

Hereinafter, the construction procedure for constructing the pile foundation structure 10 of the present invention will be described with reference to FIGS. .

A prefabricated pile such as a steel pipe pile is driven as the pile body 1, and concrete 7 is poured by leveling the ground surface 5b from which the original ground 5a is lowered so that a predetermined protrusion length can be secured. Fill concrete (not shown) for stiffening over a predetermined height in the pile of the pile head 2 to treat the pile head (Fig. 8(a)).

The pile head joint pipe 20 is placed on the leveled concrete 7 so that the pile head 2 of the pile body 1 is positioned substantially in the center of the internal space 22 of the pile head joint pipe 20 (Fig. 8(b) ).

Filling concrete 23 is filled in the gap between the internal space 22 of the pile head joint pipe 20 and the pile body 1. - 特許庁At this time, the filling concrete 23 is preferably cast to a position slightly lower than the upper end of the pile head joint pipe 20 . By filling the upper part from that position with filling concrete 33 (FIG. 10(f)) placed in the structural part joint 30, the pile head joint pipe 20 and the structural part joint 30 that are built one above the other It is preferable that the filling concrete 23, 33 should not have a pouring seam at the boundary between the two. Next, the ground 5b of the lowering part around the pile head joint pipe 20 is backfilled to the ground surface 5a of the installation level of the structural part of the pile foundation (Fig. 8(c)).

The outer shell steel pipe 31 of the structural joint 30 is placed on the backfilled ground surface 5a. Since the end of the main beam connecting bar 35 protrudes from the side surface of the outer shell steel pipe 31, the holding position of the main beam connecting bar 35 and the main beam bar 17 to which the main beam connecting bar 35 is connected (Fig. 9(e)) ), that is, the axial direction of the foundation beam 15, the structural part joint 30 is installed on the ground surface 5a. The vertical reinforcements 25 and the hoop reinforcements 27 function as reinforcement joints for integrating the structural part joint 30 and the pile head joint pipe 20 together with the filling concrete 33 to be filled in the outer shell steel pipe 31 in a later process. do. (Fig. 9(d)).

Next, as shown in FIG. 9(e), leveling concrete 6 for installing the foundation beams 15 to be connected to the structural part joint 30 is placed on the ground surface 5a, and the foundation beams 15 made of precast concrete are placed on the ground surface 5a. is placed on the concrete 6 facing the beam joint surface of the structural part joint 30 which has already been installed and separated by a predetermined separation portion 16 . Furthermore, the ends of the beam main reinforcements 17 protruding from the ends of the foundation beams 15 and the beam main reinforcement connection reinforcements 35 of the structural section joints 30 are joined by mechanical joints 18, and stirrups 45 necessary for the separated portions 16 are attached. Reinforcement is arranged and a side formwork (not shown) corresponding to the width of the beam is installed. At this time, as shown in the figure, since the beam main reinforcement connecting reinforcement 35 protrudes from the side surface of the structural part joint 30, the positioning work of the beam main reinforcement reinforcement 35 and the beam main reinforcement 17 of the foundation beam 15 is easy and high. can be done with precision.

Joining concrete 46 having the same strength as the concrete of the foundation beam 15 is placed in the spaced portion 16 surrounded by the side formwork. In parallel with the concrete casting work of the joining concrete 46, the filling concrete 33 is placed in the outer shell steel pipe 31 of the structural part joining body 30 in which the vertical reinforcement 25 and the hoop reinforcement 27 are assembled. While making the pile head 2 (pile cap) into a rigid structure by this, the pile foundation structure 10 which rigidly joined the pile head 2 and the foundation beam 15 can be constructed|assembled (FIG.10(f)).

After completing the joining of each foundation beam 15 and the structural joint 30, as shown in FIG. Columns 40 are erected, and each column main reinforcement connecting reinforcement 36 and the main reinforcement 43 of the precast concrete column 40 are connected by mechanical joints 42 . The pillars 40 to be erected may be reinforced concrete pillars constructed on site. In that case, the column main reinforcement and hoop reinforcement are erected based on the column main reinforcement connection reinforcement, the formwork is assembled, and the concrete placement work is performed to construct the reinforced concrete column.

Each of the attached drawings shows a mode in which the foundation beams are joined to the structural part joint body 30 from four directions perpendicular to each other. It can be applied to peripheral piles and corner piles that are joined to the pile head 2 so as to form a letter (two directions) and a T shape (three directions). For example, when the foundation beams are joined to form an L shape, it is preferable to incorporate the beam main reinforcement reinforcements into the outer shell steel pipe so as to face two directions at right angles to the extension direction of the foundation beams.

In the above, the foundation beam was explained as an example of the structural part of the pile foundation that is joined to the structural joint, but the structural part of the pile foundation can be assumed to be a part of the foundation footing in addition to the foundation beam. . In that case, it is preferable that the beam main reinforcing bar connecting bar incorporated in the outer shell steel pipe is provided at a position where a part of the bar arrangement of the foundation footing can be securely connected to the reinforcing bar on the side of the joint of the structural part.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope indicated in each claim. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

1 Pile body 2 Pile heads 5a, 5b Ground surface 10 Pile foundation structure 15 Foundation beam (structural part)
16 Isolated portion 17 Beam main reinforcement 20 Joint steel pipe 21 Outer steel pipe 24 Inner circumference concrete 23, 33 Filling concrete 30 Structural part joint 31 Outer shell steel pipe 35 Beam main reinforcement reinforcement 36 Column main reinforcement reinforcement 40 Precast concrete column 43 Column main reinforcement 46 joint concrete

Claims (6)

A pile driven with a pile head having a predetermined protruding length from the ground surface;
a structural portion of the pile foundation joined to the pile head;
The pile is installed on the lower ground surface so that the internal space has an annular shape in plan view, the pile head is positioned substantially at the center of the internal space, and the internal space is filled with filling concrete to form the pile. a pile head joint pipe that supports the head;
The surrounding ground of the pile head joint pipe is installed on the backfilled ground surface, holds the main reinforcing bar jointed with the main reinforcing bar end of the structural part of the pile foundation, and fills the inside of the pipe with filling concrete. and a structural joint having an outer shell steel pipe,
The structural portion of the pile foundation is installed with a predetermined distance from the outer peripheral surface of the joint of the structural portion, and the main reinforcing bar ends of the structural portion of the pile foundation are joined to the connecting reinforcing bars of the main reinforcing bars. integrated with the structural part assembly through
A pile foundation structure, wherein the structural part joint is constructed by overlapping the pile head joint pipe vertically with filling concrete filled in the outer shell steel pipe and joined to the pile head. . 2. The pile foundation structure according to claim 1, wherein said pile head connection pipe is a precast concrete member of a steel pipe-concrete composite structure comprising an outer skin steel pipe and an inner peripheral concrete portion. 2. The pile foundation structure according to claim 1, wherein the pile head connecting pipe is provided with reinforcing connecting bars positioned within the outer shell steel pipe. 2. The pile foundation structure according to claim 1, wherein the outer shell steel pipe has a through hole formed in a pipe wall position opposite to a position of the main reinforcing bar of the structural portion of the pile foundation, and the connecting reinforcing bar of the main reinforcing bar is held in the through hole. 2. The pile foundation structure according to claim 1, wherein said outer shell steel pipe holds, in addition to said main reinforcing bar connecting bar, a column main reinforcing bar connecting bar which is joined to a main reinforcing bar of a column erected on the upper surface of said structure joint. The pile foundation structure according to claim 1, wherein the structural portion of the pile foundation is a reinforced concrete foundation beam or foundation footing.

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