JP6854656B2 - Manufacturing method of SC pile with axial reinforcing bar, SC pile with axial reinforcing bar, exposure method of axial reinforcing bar of SC pile - Google Patents

Description

The present invention is a method for manufacturing an SC pile having an axial reinforcing bar, which is characteristic of the structure of a reinforcing bar cage, and an SC pile having an axial reinforcing bar, which is characteristic of assembling a reinforcing bar cage including the axial reinforcing bar, and is buried at the time of construction. Exposing the Axial Reinforcing Bars from the SC Pile The method for exposing the axial rebars of the SC piles.

Generally, for ready-made piles buried near the ground, concrete piles covered with steel pipes (so-called SC piles) have been used to enhance the horizontal strength. Since ready-made concrete piles were manufactured by centrifugal molding in order to make the concrete dense, it is important to construct a reinforcing bar cage to ensure shape retention in manufacturing.
In addition, when the building is supported by foundation piles buried in the ground, when ready-made concrete piles are used as the foundation piles, the axial reinforcements (structural reinforcements) that make up the ready-made piles and the lower end of the building (the lower end of the building) It was necessary to fix the structural reinforcement of the footing).

In this case, in one method, the axial reinforcing bar is projected upward from the upper end of the ready-made pile in advance, and after the ready-made pile is buried, the reinforcing bar is connected to the upper end of the axial reinforcing bar and connected to the structural reinforcing bar of the building. (Patent Document 3).
In another method, the upper end of the axial reinforcing bar of the ready-made pile is covered with a protective cylinder material to form the ready-made pile in a concrete non-contact state, and after the ready-made pile is buried, the outer circumference of the concrete at the upper end of the ready-made pile is formed. The upper end of the concrete was cut out together with the protective cylinder material to expose the upper end of the axial reinforcing bar of the ready-made pile (Patent Documents 1 and 2).
Further, in the case of the other method, it is necessary to fix the protective cylinder material and the axial reinforcing bar to the upper end plate, and in the case of Patent Document 1 (without a steel pipe at the upper end portion), the outer end portion of the axial reinforcing bar. A threaded portion was formed in the slab, the threaded portion was projected from the end plate, and a nut was screwed into the threaded portion to fix the axial reinforcing bar to the upper end slab. Further, in the case of Patent Document 2 (with a steel pipe at the upper end), an auxiliary plate having protrusions is attached from the outside of the upper end plate, the protrusions are inserted into the covering cylinder material, and the axial reinforcing bar and the covering cylinder material are terminated. It was inserted into the hole of the plate and fixed.

Japanese Unexamined Patent Publication No. 2010-196251 JP-A-2010-255394 Japanese Unexamined Patent Publication No. 2011-1111848

In the above one method, the axial reinforcing bar protrudes from the upper end plate of the ready-made pile, so that the axial reinforcing bar exposed from the end plate is an obstacle during the manufacturing of centrifugal molding or the construction of burying in the ground. There was a problem that it was difficult to handle. Also in other methods, the auxiliary plate protruded from the upper end plate.
Further, when the outer peripheral portion of the concrete at the upper end of the ready-made pile is cut by the above-mentioned one method, the steel plate is exposed in the remaining portion, so that there is a problem that it is difficult to fix the footing made of concrete to be constructed after that. It was.

In the present invention, in the SC pile, the upper end of the axial reinforcing bar is positioned below the upper surface of the upper end plate, and the partition plate is positioned above the planned cutting position of the steel pipe, thus solving the above-mentioned problems.

That is, the invention of this SC pile is configured as follows in the SC pile formed by fixing the upper end plate and the lower end plate if necessary above and below the steel pipe to form a concrete portion having a hollow portion in the steel pipe. It is an SC pile provided with an axial reinforcing bar.
(1) The steel pipe was divided into an upper part and a lower part at a position at a distance L0 from the upper end in the axial direction and at a planned cutting position along the outer circumference.
(2) Axial reinforcing bars are arranged in an annular shape at the upper and lower portions across the planned cutting position of the steel pipe, and a steel donut-shaped partition plate is provided above the planned cutting position in the axial direction of the steel pipe. provided, and the lower surface of the partition plate, is positioned directly above the cutting position was further passed through the respective longitudinal bars on the partition plate.
(3) A fixed portion was formed at the upper end of the axial reinforcing bar, and the upper end of the axial reinforcing bar was positioned below the upper surface of the upper end plate.
(4) The fixing portion of the axial reinforcing bar was detachably attached to the fixture detachably attached to the upper end plate.
(5) Each axial reinforcing bar was covered with a reinforcing bar covering material arranged between the partition plate and the upper end plate.
(6) The upper end plate and the partition plate were connected by a plate connecting member arranged substantially parallel to the axial reinforcing bar.
(7) The reinforcing bar cage is composed of the upper end plate, the partition plate, the axial reinforcing bar partially covered with the reinforcing bar covering material, and the plate connecting member, and the reinforcing bar cage is embedded in the concrete portion. It was.

Further, in the invention of the SC pile, the SC pile is provided with an axial reinforcing bar, which is characterized by being configured as follows.
(1) A threaded portion was formed at the upper end of the axial reinforcing bar, a first reinforcing bar insertion hole was formed in the upper end plate, and the upper end of the threaded portion was positioned in the first reinforcing bar insertion hole.
(2) The nut portion of the screw fixing tool locked on the upper surface side of the upper end plate was inserted into the first reinforcing bar insertion hole and screwed to the screw portion so as to be removable.
(3) A second reinforcing bar insertion hole was formed in the partition plate, and the axial reinforcing bar was passed through the partition plate.
(4) The upper end of the hollow reinforcing bar covering material was brought into contact with the upper end plate, and the lower end was brought into contact with the partition plate, so that the upper and lower parts of the covering material were substantially sealed.

Further, in the invention of the SC pile, the SC pile is provided with an axial reinforcing bar, which is characterized by being configured as follows.
(1) A guide plate is provided below the planned cutting position in parallel with the partition plate, the axial reinforcing bar is passed through the guide plate, and the guide plate is placed at a predetermined position of the steel pipe on the outer circumference of the guide plate. A spacer placed along the inner circumference of the steel pipe was attached to keep the steel pipe in place.
(2) On the upper surface of the partition plate, a covering material locking recess was formed around the second reinforcing bar insertion hole, and the lower surface of the reinforcing bar covering material was positioned.

Further, the invention of the method of exposing the reinforcing bar is to connect the lower end of the SC pile to the upper end of the lower pile made of a predetermined number of ready-made piles and expose the axial direction embedded in the SC pile as follows. This is a method of exposing axial reinforcing bars of SC piles, which is a feature.
(1) A concrete portion having a hollow portion is formed in the steel pipe, and a reinforcing bar cage in which the axial reinforcing bars arranged in an annular shape are retained by an upper end plate and a steel partition plate is embedded in the concrete portion. The structure of the SC pile was constructed as described above.
(a) The steel pipe was divided into an upper part and a lower part at a position at a distance L0 from the upper end in the axial direction and at a planned cutting position along the outer circumference.
(b) The axial reinforcing bar is arranged so as to straddle the planned cutting position of the steel pipe, the partition plate is above the planned cutting position of the steel pipe, and the lower surface of the partition plate is the planned cutting position. It was located directly above.
(c) The axial reinforcing bar is arranged at a position where the upper end thereof does not protrude upward from the upper surface of the upper end plate in the axial direction, and the outer periphery thereof is a reinforcing bar covering arranged between the upper end plate and the partition plate. The structure was covered with wood.
(2) At the construction site, the SC pile is buried by connecting to the lower pile by a usual method.
(3) With the SC pile, the outer peripheral portion of the steel pipe and the concrete portion is cut at the planned cutting position, and the upper portion of the steel pipe and the upper portion of the concrete portion are pulled out together with the upper end plate and the partition plate, and further, the said If the reinforcing bar covering material is left behind, the reinforcing bar covering material is pulled out.
(4) As described above, the upper part of the axial reinforcing bar and the upper surface of the remaining concrete part are exposed.

Further, in the invention of the method for exposing the reinforcing bar, the method for exposing the axial reinforcing bar of the SC pile is characterized in that it is configured as follows.
(1) The structure of the SC pile was constructed as follows.
(a) The axial reinforcing bar has a structure in which the upper end thereof is positioned within the thickness of the upper end plate and is not connected to the upper end plate.
(b) The upper end portion of the plate connecting member is connected to the upper end plate, and the upper end of the plate connecting member is configured so as not to protrude upward from the upper surface of the upper end plate in the axial direction.
(c) The lower end of the plate connecting reinforcing bar was connected to the partition plate, and the lower surface of the partition plate was positioned near the planned cutting position of the steel pipe.
(2) When the steel pipe is pulled out, the partition plate is pulled out at the same time together with the upper end plate and the plate connecting reinforcing bar.

In the present invention, since the upper end of the axial reinforcing bar is positioned below the upper surface of the upper end plate, there is no protrusion upward from the upper end plate, and the SC pile is formed by using ordinary pile driving means without any special device. Can be buried. Further, since there is no protrusion upward from the upper end plate, special curing for protecting the protrusion is not required when transporting the SC pile, and the transport work of the SC pile can be simplified.
In addition, since the partition plate is positioned above the planned cutting position of the steel pipe, it is easy to maintain the shape of the reinforcing bar cage with the partition plate when manufacturing the SC pile, and the cutting position is clear when the SC pile is buried. become. Further, when the SC pile is buried, the partition plate is removed, so that the concrete surface of the SC pile is exposed and the fixation with the SC pile with the footing is enhanced.

In the SC pile of the present invention, (a) is a plan view, and (b) is a front view of the reinforcing bar cage to be used. The upper end plate used for the SC pile of the present invention, (a) is an enlarged plan view of the upper end plate, (b) is an enlarged vertical sectional view of the upper end plate, and (c) is an enlarged upper plate showing the attachment of axial reinforcing bars. Represents a vertical sectional view. The partition plate used for the SC pile of the present invention, (a) is an enlarged plan view of the partition plate, and (b) is an enlarged vertical sectional view showing the attachment of the partition plate and the axial reinforcing bar. The guide plate used for the SC pile of the present invention, (a) is an enlarged plan view of the guide plate, and (b) is a partially enlarged plan view of the guide plate. (A) to (d) and (f) are schematic vertical cross-sectional views showing a procedure for assembling the reinforcing bar cage (SC pile) of the present invention, and (e) is the state of (d) and is cut at different angles. A schematic vertical cross-sectional view showing only a PC steel bar is shown. (A) to (d) are schematic vertical cross-sectional views showing the construction procedure of the SC pile of the present invention.

Embodiments of the present invention will be described with reference to the drawings.

1. 1. Manufacture of SC pile 65

(1) The SC pile 65 is configured by burying a reinforcing bar cage 60 in a concrete portion 64 formed in the steel pipe 1 (FIG. 1 (b)). The reinforcing bar cage 60 is arranged between the upper end plate 20, the partition plate 30, and the guide plate 40, the axial reinforcing bars 10 and 10 which are arranged so as to penetrate or lock the upper end plate 20, and the partition plate 30 and the upper end plate 20. It is composed of a plate connecting material (PC steel rod 50), a coated pipe 16, and the like, and the axial reinforcing bars 10 and 10 are fixed to the upper end plate 20 by a screw fixing tool 55. Further, in the following, the SC pile 65 is generally manufactured in a state where the shaft of the steel pipe 1 is laid down substantially horizontally, but when the SC pile 65 is buried at the construction site of the building in each member, the SC pile 65 is manufactured. The lower side is the lower surface, and the upper side is the upper surface.

(2) The members used in this manufacturing method have the following configurations.

(A) The steel pipe 1 is formed with an inner diameter D01 and an outer diameter D02, and the steel pipe 1 is placed at a distance (height) L0 position from the upper end 2 (upper surface 21 of the upper end plate 20) in the axial direction (height direction). The planned cutting position 7 for cutting is set in the steel pipe 1A and the steel pipe 1B. The planned cutting position 7 may be displayed on the outer peripheral surface in advance (not shown).

(B) An axial reinforcing bar 10 (for example, a deformed reinforcing bar) having a length L1 is threaded on the upper end 11 side to form a threaded portion 13. The threaded portion 13 of the axial reinforcing bar 10 is formed with a diameter smaller than the minimum axial diameter of the axial reinforcing bar 10 via a step portion 14 whose diameter is gradually reduced from the lower side (FIG. 2C). A plurality of axial reinforcing bars 10 and 10 are arranged in a ring shape at equal intervals along a circle having a diameter of D0 in the steel pipe 1 of the SC pile 65. Although the step portion 14 has a structure in which the diameter gradually changes, it is also possible to form a step portion 14 such that a small diameter of the screw portion 13 is formed immediately from the shaft diameter (not shown).
Further, although the threaded portion 13 is formed on the upper end 11 side of the axial reinforcing bar 10, another locking structure may be adopted instead of the threaded portion 13 (not shown).

(C) Further, the reinforcing bar covering material to be used is made of a hard vinyl chloride pipe having an inner diameter larger than the maximum outer diameter of the axial reinforcing bar 10, and is referred to as a covering pipe 16. The length of the coated pipe 16 is set corresponding to the planned cutting position 7. The coated pipe 16 is a member for preventing concrete from adhering to the axial reinforcing bars 10 and 10 and fixing in the concrete portion 64 at the time of manufacturing the SC pile, and the axial reinforcing bar after the construction of the SC pile 65. Any material such as a flexible material can be used as long as it can be easily removed from 10.

(D) Further, the upper end plate 20 is made of a donut-shaped steel plate having an inner diameter D1 and an outer diameter D2 (D01 <D2 ≦ D02), and corresponds to the axial reinforcing bars 10 and 10 arranged in an annular shape at equal intervals of the diameter D0. The first reinforcing bar insertion holes 24, 24 are formed (FIG. 2). That is, the inner diameter D1 <D0 <outer diameter D2. Further, a washer having an inner diameter D6 (outer diameter of the threaded portion 13 of the axial reinforcing bar 10 <D6 <maximum outer diameter of the axial reinforcing bar 10) so as to cover the outer periphery of the first reinforcing bar insertion hole 24, that is, a step of the axial reinforcing bar 10. A first washer 26, which can be locked to the portion 14, is prepared (FIG. 2 (c)).
The first washer 26 can be fixed to the lower surface 22 of the upper end plate 20 in advance by welding or the like (not shown). Further, the first washer 26 can be fitted and fixed in advance on the lower surface side of the first reinforcing bar insertion hole 24 by matching the outer diameter with the diameter of the first reinforcing bar insertion hole 24 and forming the inner diameter at D6. (Not shown). Further, it is also possible to form a bottom portion on the lower surface 22 side of the upper end plate 20 without opening the first reinforcing bar insertion hole 24 downward to form a hole having a diameter D6 at the bottom portion. In this case, the first washer 26 is unnecessary (not shown).

(E) Further, the partition plate 30 has a donut shape having an inner diameter D1 and an outer diameter D3 (D3 <D01, which is smaller than the inner diameter D01 of the steel pipe 1 so that it can be inserted into the steel pipe 1 without any trouble). The second reinforcing bar insertion holes 34, 34 are formed corresponding to the axial reinforcing bars 10 and 10 which are made of steel plate and are arranged in an annular shape at equal intervals of the diameter D0 in the same manner as the upper end plate 20. The second reinforcing bar insertion hole 34 is formed to be slightly larger than the outer diameter of the coated pipe 16 to be used. A second washer 36 having an inner diameter D7 (maximum outer diameter of the axial reinforcing bar 10 <D7 <inner diameter or outer diameter of the coated pipe) is fitted and fixed to the lower surface side of the second reinforcing bar insertion hole 34 (FIG. 3 (b)). .. In this case, the second washer 36 and the partition plate 30 are fixed so that the covering pipe 16 does not move until the concrete is placed, and the partition plate 30 is easily separated when the partition plate 30 is removed during construction. It is fixed with the strength of. Further, here, the outer peripheral side of the second reinforcing bar insertion hole 34 and the upper surface of the second washer 36 (the outer peripheral side of the opening of the inner diameter D7) form a locking recess 35 of the covering pipe 16.
Further, fixing reinforcing bars 37, 37 having a predetermined length arranged in an annular shape are erected at substantially right angles on the upper surface 31 of the partition plate 30 and fixed by welding (FIG. 3). The fixing reinforcing bars 37 and 37 serve as so-called anchor reinforcing bars, and are provided to maintain the unity between the concrete portion 64 (64A) of the SC pile 65 and the partition plate 30.

(F) The guide plate 40 is made of a donut-shaped steel plate having an inner diameter D4 (inner diameter D1 <D4 of the partition plate 30 or the like) and an outer diameter D5 (D5 <outer diameter D01 of the steel pipe 1), and is the same as the upper end plate 20. A third reinforcing bar insertion hole 44 is formed corresponding to the axial reinforcing bars 10 and 10 arranged in an annular shape at equal intervals of diameter D0 (FIG. 4). The third reinforcing bar insertion hole 44 is formed with a diameter such that the axial reinforcing bar 10 can be inserted, and a communication portion 45 that opens toward the outer peripheral edge is formed so that the axial reinforcing bar 10 can be inserted from the outer peripheral side. (Fig. 4 (b)). Therefore, the guide plate 40 has a U-shaped notch shape from the donut-shaped outer peripheral edge toward the center side.

(G) A PC steel rod 50 is used as the plate connecting material, and the upper end portion 51 of the PC steel rod 50 can be fixed to the upper end plate 20 and the lower end portion 52 can be fixed to the partition plate 30. For example, an enormous portion (header processing) is formed on the upper end portion 51 of the PC steel rod 50, and a threaded portion is formed on the lower end portion 52 (not shown). Corresponding to the configuration of the PC steel rod 50, the upper end plate 20 is formed with a locking hole (header hole) for locking the huge portion within the thickness of the upper end plate 20, and the partition plate 30 is made of PC steel. A through hole into which the rod 50 can be inserted is formed (not shown). In this case, the screw portion of the lower end portion 52 and the partition plate 30 are fixed with nuts from the lower side of the lower surface 32 of the partition plate 30. Alternatively, the screw portion (lower end portion 52) of the PC steel rod 50 is fixed to the partition plate 30 so as to sandwich the partition plate 30 with two nuts from both the upper side of the upper surface 31 of the partition plate 30 and the lower side of the lower surface 32. It can also be (not shown).
As a plate connecting material, sufficient compressive strength and rigidity without bending are maintained so that the distance between the upper end plate 20 and the partition plate 30 is kept constant until the time of placing concrete, and the upper end plate 20 is maintained at the time of construction. At the same time, a material other than the PC steel rod 50 (shaped steel, resin material, etc.) can be used as long as it has a tensile strength sufficient to pull out the partition plate 30 integrally.

(H) A screw fixing tool 55 is used as the fixing tool, and the screw fixing tool 55 has a nut portion 56 that can be screwed into the screw portion 13 of the axial reinforcing bar 10, and a nut portion 56 that is larger than the nut portion 56 on the upper side of the nut portion 56. It is composed of a head portion 57 having a diameter (FIG. 2 (c)). The nut portion 56 has an outer diameter that can be inserted into the first reinforcing bar insertion hole 24 of the upper end plate 20, and the head portion 57 has a flat hexagonal shape and is formed to have a larger diameter than the first reinforcing bar insertion hole 24.
When a locking structure other than the screw portion 13 is adopted on the upper end 11 side of the axial reinforcing bar 10, a fixture having a locking means instead of the nut portion 56 is adopted (not shown).

(3) Subsequently, a procedure for assembling the reinforcing bar cage 60 (configuration and manufacturing method of the reinforcing bar cage 60) will be described (FIG. 5).

(A) The partition plate 30 and the guide plate 40 are arranged in parallel at predetermined intervals, and the axial reinforcing bars 10 and 10 are inserted into the second reinforcing bar insertion holes 34 and 34 of the partition plate 30, and the lower end portion of the axial reinforcing bar 10 is inserted. Is housed in the third reinforcing bar insertion holes 44, 44 from the outer peripheral side of the guide plate 40, and the partition plate 30 and the guide plate are attached to the axial reinforcing bar 10 (FIGS. 3 (b) and 4 (b)). All the axial reinforcing bars 10 and 10 are attached to the partition plate 20 and the guide plate 30 (FIG. 5A). The position of the partition plate 30 in the axial direction of the axial reinforcing bars 10 and 10 is determined by a preset planned cutting position 7 (that is, L0).

(B) After (A) or at the same time as (A), a holding steel material (binding wire, number wire, thin reinforcing bar, etc.) is wound around the axial reinforcing bars 10 and 10 from the outer peripheral side of the guide plate 40, and the axial reinforcing bars 10, 10 is temporarily fixed so as not to move in the radial direction from the third reinforcing bar insertion holes 44, 44 (not shown).

(C) Subsequently, the covering pipe 16 is covered from the upper end 11 side of each of the axial reinforcing bars 10 and 10, and the lower end 18 of the covering pipe 16 is inserted into the second through hole 34 of the partition plate 30 to form the second washer 36. (Fig. 3 (b)). In this state, the positions of the upper ends 11 and 11 of the axial reinforcing bars 10 and 10 are substantially aligned, the first washer 26 is put on the threaded portion 13 of each axial reinforcing bar 10, and the first washer 26 is locked to the stepped portion 14. (FIG. 5 (b), FIG. 2 (c)).

(D) Subsequently, the upper end plate 30 is brought closer from the upper end 11 side of the axial reinforcing bars 10 and 10, and the threaded portion (upper end portion) 13 of each axial reinforcing bar 10 is inserted into the first reinforcing bar insertion portions 24 and 24 of the upper end plate 20. Insert and bring the first washers 26, 26 into contact with the lower surface 22 of the upper end plate 20 (FIGS. 5 (c) and 2 (c)). In this state, the threaded portion 13 of the axial reinforcing bar 10 (or the upper portion of the stepped portion 14) is in the first reinforcing bar insertion hole 24, and the upper end 11 of the axial reinforcing bar 10 (the upper end of the threaded portion 13) is. It fits in the first reinforcing bar insertion hole 24 and does not protrude from the upper surface 21 of the upper end plate 20 (FIG. 2 (c)).

(E) Subsequently, in this state, a third washer 27 is attached to the outer periphery of the nut portion 56 of the screw fixture 55 from the upper surface 21 side of the upper end plate 20, and the nut portion 56 is inserted into the first reinforcing bar insertion 24. Then, the nut portion 56 is screwed into the threaded portion 13 of the axial reinforcing bar 10 (FIG. 5 (c)). In this state, the upper end 11 side of the axial reinforcing bars 10 and 10 is fixed to the upper end plate 20.
Further, in this state, the upper end 17 of the covering pipe 16 is in contact with the lower surface of the first washer 26 (lower surface 22 of the upper end plate 20) (FIG. 2C), and the lower end 18 of the covering pipe 16 is the partition plate 30. In contact with the upper surface of the second washer 36 (FIG. 3B), the downward and vertical movement of the covering pipe 16 is restricted, and the lower end 18 of the covering pipe 16 is the second reinforcing bar insertion hole of the partition plate 30. It is located in the locking recess 35 of 36, and the movement of the covering pipe 16 in the direction orthogonal to the vertical direction is also restricted. Therefore, a constant distance can be maintained between the upper end plate 20 and the partition plate 30. Further, the upper end 17 and the lower end 18 of the coated pipe 16 are substantially sealed to prevent concrete (mortar) from entering the inside of the coated pipe 16.

(F) After (E) or at the same time as (E), a ring reinforcing bar 46 formed in an arc shape is fixed to the outer peripheral side of the guide plate 40, and the guide plate 40 and the axial reinforcing bars 10 and 10 are attached. To fix. Further, spacers 47 and 47 for keeping the guide plate 40 (that is, the axial reinforcing bars 10 and 10) at a predetermined position (center of the steel pipe 1) are fixed to the guide plate 40 (FIGS. 5 (d) and 4 (b). )).

(G) After (E) or at the same time as (E), the lower end portion 52 side (screw portion side) of the PC steel rod 50 is inserted from the locking hole (not shown) of the upper end plate 20. Subsequently, with the enormous portion (upper end 51 side) of the PC steel rod 50 locked in the locking hole, the threaded portion on the lower end 52 side of the PC steel rod 50 protrudes from the through hole of the partition plate 30. A nut is screwed and tightened to the screw portion to fix the PC steel rods 50 and 50 to the upper end plate 20 and the partition plate 30 (FIGS. 5 (e), 2 (c), 3 (b)). Therefore, the PC steel rods 50 and 50 can firmly prevent the upper end plate 20 and the partition plate 30 from being spaced apart from each other.

(H) The reinforcing bar cage 60 is configured as described above (FIGS. 5 (f) and 1 (b)).

(I) Subsequently, the lower end side (guide plate 40 side) of the reinforcing bar cage 60 is inserted from the upper end 2 side of the steel pipe 1, and the upper end plate 20 of the reinforcing bar cage 60 is fixed to the upper end 2 of the steel pipe 1 by welding. In this state, the lower surface 32 of the partition plate 30 of the reinforcing bar cage 60 is located slightly (several mm to several cm) above the planned cutting position 7 of the steel pipe 1. It is desirable that the lower surface 32 of the partition plate 30 of the reinforcing bar cage 60 is located above the planned cutting position 7 of the steel pipe 1 and as close to the planned cutting position 7 as possible.

(J) Subsequently, a lower end plate 62 aligned with the upper end plate (not shown) of the lower pile 67 to be connected is welded and fixed to the lower end 3 of the steel pipe 1 (FIG. 5 (f)).

(K) Subsequently, concrete is injected into the steel pipe 1 by a usual method. At this time, the set distance between the upper end plate 20 and the partition plate 30 can be maintained.
Further, if the predetermined curing is performed, the SC pile 65 is formed. A concrete portion 64 having a hollow portion corresponding to the inner diameter D1 of the upper end plate 20 is formed on the inner surface 5 side of the steel pipe 1 (FIGS. 2A and 3A), and the reinforcing bar cage 60 is placed in the concrete portion 64. It is buried (Fig. 1 (b)).

2. Construction of SC pile 65 (exposing method of axial reinforcing bar 10)

(1) The SC pile 65 is shipped with the screw fixtures 55 and 55 removed from the upper end plate 20, and is transported to the construction site. Therefore, the first reinforcing bar insertion hole 24 is exposed from the upper surface 21 of the upper end plate 20 (FIGS. 1 (a) and 2 (c)), and the upper ends 11 of the axial reinforcing bars 10 and 10 are below the upper surface 21 of the upper end plate 20. Since the upper end portion 51 (enlarged portion) of the PC steel rod 50 is within the thickness of the upper end plate 20, no protrusion is generated above the upper surface 21 of the upper end plate 20 in this SC pile 65. Therefore, it is easy to handle the SC pile 65 during transportation from the factory to the construction site of the building, movement within the construction site of the building, or during construction. Therefore, at the construction site, the same construction can be performed using the same equipment as a normal SC pile.

(2) A predetermined number of lower piles 67 and SC piles 65 are constructed at the same time as the excavation of the pile holes or after the excavation of the pile holes by a normal construction method. The SC pile 65 is attached to the upper end of the lower pile 67 (FIG. 6 (a)). Further, at this time, when used in the so-called middle excavation method, since there is no protrusion from the upper surface 21 of the upper end plate 20 of the SC pile 65, a normal pile driver (FIG. While holding the SC pile 65 with (not shown), excavation can be performed with an excavation rod (not shown).
In this state, the planned cutting position 7 (partition plate 30) of the SC pile 65 is located above the ground 70 (FIG. 6A).

(3) Subsequently, the outer peripheral side of the steel pipe 1 and the concrete portion 64 is cut with a cutter or the like at the height of the planned cutting position 7 of the steel pipe 1 of the SC pile 65 (FIG. 6 (b)). As described above, this cutting position (scheduled cutting position 7) is located below the lower surface 32 of the partition plate 30. The steel pipe 1 is separated into a steel pipe 1A above the planned cutting position 7 and a steel pipe 1B below.

(4) Subsequently, when the steel pipe 1A of the SC pile 65 is pulled out above the cutting position (scheduled cutting position 7) and upward, the upper part 64A of the SC pile 65 (the upper part 1A of the steel pipe 1, the upper end plate 20, the partition plate) is pulled out. 30, the covering pipe 16, the upper part 64A of the concrete part 64) is separated, and the lower part 64B of the SC pile 65 (the lower part 1B of the steel pipe 1, the guide plate 40, the lower part 64B of the concrete part 64) is left together with the lower pile 67 ( FIG. 6 (c). At this time, the coated pipes 16 and 16 are usually not included in the SC pile 65A and are left in the axial reinforcing bars 10 and 10 (FIG. 6 (c)).
At this time, since the upper end plate 20 and the partition plate 30 are connected by the PC steel rods 50 and 50 and the fixing reinforcing bar 37 is fixed to the partition plate 30, the steel pipe 1A and the upper end plate 20 are pulled up. The upper portion 64A of the concrete portion 64 and the partition plate 30 are surely separated and removed together with the SC pile 65A.

(5) Subsequently, the remaining coated pipes 16 and 16 are removed from the axial reinforcing bars 10 and 10 (FIG. 6 (d)). As a result, the axial reinforcing bars 10 and 10 are exposed above the cutting position (scheduled cutting position 7). Therefore, the exposed axial reinforcing bars are fixed to the footing reinforcing bars, concrete is cast, and the SC pile 65 is placed. A footing integrated with the lower 65B is constructed (not shown).
At this time, the partition plate 30 is removed and the upper surface 64a of the lower portion 64B of the concrete portion 64 is exposed (FIG. 6D), so that the integrity of the footing and the SC pile 65B is enhanced.

(6) In the above, when the SC pile 65A is separated (FIG. 6 (c)), all or part of the covering pipe 16 is removed from the axial reinforcing bars 10 and 10 together with the SC pile 65A. There is also.

1 Steel pipe 1A Upper part of steel pipe (removal side)
Lower part of 1B steel pipe (remaining side)
2 Upper end of steel pipe 3 Lower end of steel pipe 4 Outer surface of steel pipe 5 Inner surface of steel pipe 7 Scheduled cutting position of steel pipe 10 Axial reinforcing bar 11 Upper end of axial reinforcing bar 12 Lower end of axial reinforcing bar 13 Threaded part of axial reinforcing bar 14 Step 16 Covered pipe (reinforcing bar covering material)
16A Upper part of coated pipe 16B Lower part of coated pipe 17 Upper end of coated pipe 18 Lower end of coated pipe 20 Upper end plate 21 Upper surface of upper end plate 22 Lower surface of upper end plate 24 First reinforcing bar insertion hole of upper end plate 26 First washer of upper end plate 27 Second upper end plate washer 30 Partition plate 31 Upper end of partition plate 32 Lower end of partition plate 34 Second reinforcing bar insertion hole of partition plate 35 Locking recess of second reinforcing bar insertion hole 36 First washer of partition plate 37 Fixing reinforcing bar of partition plate 40 Guide plate 41 Upper surface of guide plate 42 Lower surface of guide plate 44 Third reinforcing bar insertion hole of guide plate 45 Communication part of third reinforcing bar insertion part 46 Ring reinforcement of guide plate 47 Spacer of guide plate 50 PC steel rod (plate connecting member) )
51 Upper end of PC steel rod 52 Lower end of PC steel rod 55 Screw fixture (fixer)
56 Nut part of screw fixture 57 Head of screw fixture 58 Third washer of upper end plate 60 Reinforcing bar cage 62 Lower end plate 64 Concrete part 64A Upper part of concrete part (removal side)
64B Lower part of concrete part (remaining side)
64Ba Upper surface of the lower part of the concrete part 65 SC pile 65A Upper part of the SC pile (removal side)
Lower part of 65B SC pile (remaining side)
67 Lower pile 70 Ground

Claims (5)

Axial reinforcing bars characterized as follows in an SC pile formed by fixing an upper end plate and, if necessary, a lower end plate above and below the steel pipe to form a concrete portion having a hollow portion in the steel pipe. SC pile with.
(1) The steel pipe was divided into an upper part and a lower part at a position at a distance L0 from the upper end in the axial direction and at a planned cutting position along the outer circumference.
(2) Axial reinforcing bars are arranged in an annular shape at the upper and lower portions across the planned cutting position of the steel pipe, and a steel donut-shaped partition plate is provided above the planned cutting position in the axial direction of the steel pipe. provided, and the lower surface of the partition plate, is positioned directly above the cutting position was further passed through the respective longitudinal bars on the partition plate.
(3) A fixed portion was formed at the upper end of the axial reinforcing bar, and the upper end of the axial reinforcing bar was positioned below the upper surface of the upper end plate.
(4) The fixing portion of the axial reinforcing bar was detachably attached to the fixture detachably attached to the upper end plate.
(5) Each axial reinforcing bar was covered with a reinforcing bar covering material arranged between the partition plate and the upper end plate.
(6) The upper end plate and the partition plate were connected by a plate connecting member arranged substantially parallel to the axial reinforcing bar.
(7) The reinforcing bar cage is composed of the upper end plate, the partition plate, the axial reinforcing bar partially covered with the reinforcing bar covering material, and the plate connecting member, and the reinforcing bar cage is embedded in the concrete portion. It was. The SC pile provided with the axial reinforcing bar according to claim 1, which is characterized by being configured as follows.
(1) A threaded portion was formed at the upper end of the axial reinforcing bar, a first reinforcing bar insertion hole was formed in the upper end plate, and the upper end of the threaded portion was positioned in the first reinforcing bar insertion hole.
(2) The nut portion of the screw fixing tool locked on the upper surface side of the upper end plate was inserted into the first reinforcing bar insertion hole and screwed to the screw portion so as to be removable.
(3) A second reinforcing bar insertion hole was formed in the partition plate, and the axial reinforcing bar was passed through the partition plate.
(4) The upper end of the hollow reinforcing bar covering material was brought into contact with the upper end plate, and the lower end was brought into contact with the partition plate, so that the upper and lower parts of the covering material were substantially sealed. The SC pile provided with the axial reinforcing bar according to claim 1, which is characterized by being configured as follows.
(1) A guide plate is provided below the planned cutting position in parallel with the partition plate, the axial reinforcing bar is passed through the guide plate, and the guide plate is placed at a predetermined position of the steel pipe on the outer circumference of the guide plate. A spacer placed along the inner circumference of the steel pipe was attached to keep the steel pipe in place.
(2) On the upper surface of the partition plate, a covering material locking recess was formed around the second reinforcing bar insertion hole, and the lower surface of the reinforcing bar covering material was positioned. The axial reinforcing bar of the SC pile, which is characterized in that the lower end of the SC pile is connected to the upper end of the lower pile made of a predetermined number of ready-made piles to expose the axial direction embedded in the SC pile as follows. Exposure method.
(1) A concrete portion having a hollow portion is formed in the steel pipe, and a reinforcing bar cage in which the axial reinforcing bars arranged in an annular shape are retained by an upper end plate and a steel partition plate is embedded in the concrete portion. The structure of the SC pile was constructed as described above.
(a) The steel pipe was divided into an upper part and a lower part at a position at a distance L0 from the upper end in the axial direction and at a planned cutting position along the outer circumference.
(b) The axial reinforcing bar is arranged so as to straddle the planned cutting position of the steel pipe, the partition plate is above the planned cutting position of the steel pipe, and the lower surface of the partition plate is the planned cutting position. It was located directly above.
(c) The axial reinforcing bar is arranged at a position where the upper end thereof does not protrude upward from the upper surface of the upper end plate in the axial direction, and the outer periphery thereof is a reinforcing bar covering arranged between the upper end plate and the partition plate. The structure was covered with wood.
(2) At the construction site, the SC pile is buried by connecting to the lower pile by a usual method.
(3) With the SC pile, the outer peripheral portion of the steel pipe and the concrete portion is cut at the planned cutting position, and the upper portion of the steel pipe and the upper portion of the concrete portion are pulled out together with the upper end plate and the partition plate, and further, the said If the reinforcing bar covering material is left behind, the reinforcing bar covering material is pulled out.
(4) As described above, the upper part of the axial reinforcing bar and the upper surface of the remaining concrete part are exposed. The method for exposing axial reinforcing bars of an SC pile according to claim 6, wherein the SC pile is configured as follows.
(1) The structure of the SC pile was constructed as follows.
(a) The axial reinforcing bar has a structure in which the upper end thereof is positioned within the thickness of the upper end plate and is not connected to the upper end plate.
(b) The upper end portion of the plate connecting member is connected to the upper end plate, and the upper end of the plate connecting member is configured so as not to protrude upward from the upper surface of the upper end plate in the axial direction.
(c) The lower end of the plate connecting reinforcing bar was connected to the partition plate, and the lower surface of the partition plate was positioned near the planned cutting position of the steel pipe.
(2) When the steel pipe is pulled out, the partition plate is pulled out at the same time together with the upper end plate and the plate connecting reinforcing bar.

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