JP7007691B1 - Casting method for spring spacers, reinforcing bar cages and underground piles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spring spacer, a reinforcing bar cage and an underground pile driving method capable of more accurately positioning and holding a pile of a pile reinforcing bar cage in the radial direction and preventing the pile core of the underground pile from being displaced. do. SOLUTION: This is a spring spacer bar 2 assembled to a reinforcing bar cage 1 built in an underground pile placed in the ground, and expands in the radial direction of the underground pile from a binding portion 24 with the main bar 11. It has an expanded portion 23 and a bent portion 22 that is bent and connected to the expanded portion 23. The bent portion 22 is bent so as to be parallel to the main bar 11, and its free end 21 side is bent toward the center of the underground pile. [Selection diagram] Fig. 2

Description

The present invention relates to a spring spacer, a reinforcing bar cage, and an underground pile driving method in which a reinforcing bar cage is suspended and arranged in a pile hole.

As a method of building piles in the ground, cast-in-place concrete piles in which concrete is poured after excavating a predetermined place and a reinforced concrete cage is placed in it, and ready-made reinforced concrete piles in which ready-made reinforced concrete piles are driven (or embedded) are available. be. The Building Standards Law stipulates that foundation piles such as cast-in-place concrete piles, solid foundations, and cloth foundations should be selected according to the ground bearing capacity of the site (the strength with which the ground continues to support the load of the building).

In the construction of cast-in-place piles described above, casings such as steel pipe piles and pile reinforcing bar cages to be built in pile holes drilled in the ground are required to have a position in the depth direction and installation accuracy in the radial direction of the pile. As a method for ensuring the installation accuracy in the depth direction in the construction of the cast-in-place pile, for example, the construction method disclosed in Patent Document 1 is known. In the construction method disclosed in Patent Document 1, a steel pipe having a fixing bar is suspended by a wire, and the threaded reinforcing bar is attached to the steel pipe in a state where the steel pipe is lowered to a predetermined position in a casing vertically embedded in the ground, and the casing is used. The depth of the steel pipe is finely adjusted by rotatably temporarily fixing the threaded reinforcing bar through the screwing member locked on the pedestal attached to the upper edge and rotating the threaded reinforcing bar.

Japanese Unexamined Patent Publication No. 06-167018

By the way, the position of the pile reinforcing bar cage or the like in the pile radial direction is required to be accurate because the rising position of the fixing bar at the upper part of the pile reinforcing bar cage or the like is determined by the position. On the other hand, in the upper part of the pile, the anchoring reinforcement of the upper part such as the pile reinforcing bar cage and the reinforcement of the foundation slab, the underground beam, and the column are interlaced, and the reinforcement arrangement becomes complicated. The diameter of the reinforcing bars used is also large. For this reason, it is required that the anchoring bars such as pile reinforcing bars do not interfere with the reinforcing bars such as foundation slabs and underground beams.

However, in the construction method disclosed in Patent Document 1, since there is no means for adjusting the position of the pile reinforcing bar cage in the pile radial direction and ensuring the position accuracy, the position accuracy of the fixing bar of the pile reinforcing bar cage is constant. There was a concern that the core of the underground piles that had been driven would be misaligned due to the limitations of.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and more accurately positions and holds the piles in the pile reinforcing bar cage in the radial direction to prevent the pile cores of the underground piles from being displaced. It is an object of the present invention to provide a method for placing a spring spacer, a reinforcing bar cage and an underground pile that can be formed.

In order to solve the above problems, the present invention is a spring spacer attached to a reinforcing bar cage built in an underground pile placed in the ground, and is tied along the main reinforcing bar of the reinforcing bar cage. It has a binding portion that is fixed by being bent, an expansion portion that is bent and expanded in the radial direction of the underground pile from the binding portion, and a bending portion that is bent and connected to the expansion portion. The portion has a straight portion bent with respect to the expanded portion, and the free end side of the straight portion is further bent toward the center of the underground pile, and the binding portion, the expanded portion and the bent portion are formed. It is integrally formed by bending one reinforcing bar.

According to the present invention as described above, a spring spacer bar is assembled to the reinforcing bar cage, and the spring spacer bar has an expansion portion that expands in the radial direction of the underground pile from the portion where the spring spacer reinforcement is connected to the main reinforcement, and an expansion portion. It has a bent portion that is bent and connected to the portion. The expanded portion of the spring spacer bar is brought into contact with the rebar so as to follow the hole wall due to the elasticity of the rebar, and the reaction force from the hole wall can be obtained to position the rebar cage at the center of the pile hole. Further, since the expanded portion is a bent portion whose tip side is bent, the spring spacer bar does not get caught in the hole wall, the casing, or the like, and does not hinder the smooth sinking of the reinforcing bar cage. In addition, since the free end side of the bent portion is bent toward the center of the underground pile, it is possible to more reliably prevent the spring spacer bar from being caught in the hole wall, casing, etc., and smooth laying of the reinforcing bar cage is possible. It will be possible.

In the above invention, the spring spacer is preferably expanded radially from the center of the underground pile on the outer periphery of the main bar, and the binding portion is arranged along the main bar to be arranged along the main bar. The expanded portion is bent with respect to the binding portion, and is extended diagonally upward at a predetermined angle toward the outside of the binding portion, and the bent portion is obliquely extended. It is preferably formed on the free end side of the extension portion extending upward. Further , in the above invention, it is preferable that the bent portion is bent so as to be parallel to the main bar .

Further, the present invention is a reinforcing bar cage built in an underground pile placed in the ground, and connects a plurality of main bars arranged in parallel in the vertical direction and a plurality of main bars in the horizontal direction. A hoop bar and a spring spacer bar that is fastened and fixed to the main bar are provided. It has an expanded portion that is bent in the radial direction of the underground pile to expand, and a bent portion that is bent and connected to the expanded portion, and the bent portion has a bent portion with respect to the expanded portion. It has a bent straight line portion, and the free end side of the straight line portion is further bent toward the center of the underground pile, and the binding portion, the expansion portion, and the bending portion are integrated by bending one reinforcing bar. Is formed in.

According to the present invention as described above, a spring spacer bar is assembled to the reinforcing bar cage, and the spring spacer bar has an expansion portion that expands in the radial direction of the underground pile from the portion where the spring spacer reinforcement is connected to the main reinforcement, and an expansion portion. It has a bent portion that is bent and connected to the portion. The expanded portion of the spring spacer bar is brought into contact with the rebar so as to follow the hole wall due to the elasticity of the rebar, and the reaction force from the hole wall can be obtained to position the rebar cage at the center of the pile hole. Further, since the expanded portion is a bent portion whose tip side is bent, the spring spacer bar does not get caught in the hole wall, the casing, or the like, and does not hinder the smooth sinking of the reinforcing bar cage. In addition, since the free end side of the bent portion is bent toward the center of the underground pile, it is possible to more reliably prevent the spring spacer bar from being caught in the hole wall, casing, etc., and smooth laying of the reinforcing bar cage is possible. It will be possible.

In the above invention, the spring spacer is preferably expanded radially from the center of the underground pile on the outer periphery of the main bar, and the binding portion is arranged along the main bar to be arranged along the main bar. The expanded portion is bent with respect to the binding portion, and is extended diagonally upward at a predetermined angle toward the outside of the binding portion, and the bent portion is obliquely extended. It is preferably formed on the free end side of the extension portion extending upward. Further , in the above invention, it is preferable that the bent portion is bent so as to be parallel to the main bar .

In the above invention, the method for driving an underground pile using the spring spacer according to any one of claims 1 to 3, wherein a step of excavating a pile hole in the ground and a reinforcing bar built in the pile hole are provided. An underground pile driving method characterized by including a process of assembling a spring spacer to the main bar of the cage by binding and a process of submerging the reinforcing bar cage in the pile hole.

According to the present invention as described above, a spring spacer bar is assembled to the reinforcing bar cage, and the spring spacer bar has an expansion portion that expands in the radial direction of the underground pile from the portion where the spring spacer reinforcement is connected to the main reinforcement, and an expansion portion. It has a bent portion that is bent and connected to the portion. The expanded portion of the spring spacer bar is brought into contact with the rebar so as to follow the hole wall due to the elasticity of the rebar, and the reaction force from the hole wall can be obtained to position the rebar cage at the center of the pile hole. Further, since the expanded portion is a bent portion whose tip side is bent, the spring spacer bar does not get caught in the hole wall, the casing, or the like, and does not hinder the smooth sinking of the reinforcing bar cage.

In the above invention, the step of excavating the pile hole includes a step of installing a casing covering the excavated wall surface near the ground surface opening of the pile hole, and in the step of submerging the reinforcing bar cage, the spring spacer after subsidence is the casing. It is preferable that the bent portion is located at the depth of the portion covered with the casing and the bent portion is in contact with the inner wall portion of the casing.

If the spring spacer bar after subsidence is located below the depth of the part covered by the casing and the spring spacer bar is positioned in the depth direction of the reinforcing bar cage so that the spring spacer bar does not touch the casing, the pile is piled up from the excavation wall surface. It is preferable that the bent portion is in contact with the excavated wall surface due to the earth pressure toward the center of the excavation. At this time, the casing suppresses the inward earth pressure from the excavated wall surface, while the earth pressure is released when the casing does not exist. The opening is smaller than the opening of the expanded portion when the spring spacer bar is applied to the casing.

As described above, in the present invention, the spring spacer bar is assembled to the reinforcing bar cage, and the spring spacer bar has an expanding portion that expands in the radial direction of the underground pile from the portion connected to the main bar and the expanding portion. It has a bent portion that is bent and connected to the portion. The expanded portion of the spring spacer bar is brought into contact with the rebar so as to follow the hole wall due to the elasticity of the rebar, and the reaction force from the hole wall can be obtained to position the rebar cage at the center of the pile hole. Further, since the expanded portion is a bent portion whose tip side is bent, the spring spacer bar does not get caught in the hole wall, the casing, or the like, and does not hinder the smooth sinking of the reinforcing bar cage. As a result, according to the present invention, the radial position of the reinforcing bar cage can be easily adjusted and held, and the pile core of the placed underground pile can be prevented from being displaced.

It is explanatory drawing which shows the procedure of the underground pile driving method which concerns on embodiment. It is a side view which shows the appearance of the spring spacer which concerns on embodiment. It is a top view which shows the appearance of the reinforcing bar cage which concerns on embodiment. It is a perspective view which shows the structure (the state which the spring spacer is expanded) of the reinforcing bar cage which concerns on embodiment. It is a perspective view which shows the structure (the state which the spring spacer is contracted) of the reinforcing bar cage which concerns on embodiment. It is sectional drawing which shows the underground pile driving method (with a casing) which concerns on embodiment. It is sectional drawing which shows the underground pile driving method (with a casing) which concerns on embodiment. It is sectional drawing which shows the underground pile driving method (without casing) which concerns on embodiment. It is sectional drawing which shows the underground pile driving method (without casing) which concerns on embodiment.

Hereinafter, embodiments of a spring spacer, a reinforcing bar cage, and an underground pile driving method using these will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments shown below exemplify an apparatus or the like for embodying the technical idea of the present invention, and the technical idea of the present invention describes the material, shape, structure, and the material of each component. The arrangement etc. is not specified to the following. The technical idea of the present invention can be modified in various ways within the scope of claims.

(Overall composition of construction equipment)
FIG. 1 is an explanatory diagram showing a procedure of an underground pile driving method according to the present embodiment. In the present embodiment, a pile hole G2 is excavated in the ground G in order to construct a pile foundation that supports the building when the building is newly constructed or rebuilt. Specifically, as shown in FIG. 1, the arm 91 of the heavy machine 9 lifts the kelly bar 92 and suspends the excavation earth drill 93. Then, the excavation earth drill 93 is lowered while rotating in one direction by the kelly bar 92 to be embedded in the ground, and the pile hole G2 is excavated. Further, the heavy machine 9 has a crane equipment that lifts the casing 8 and the reinforcing bar cage 1 and sinks them in the pile hole G2.

(Structure of rebar basket 1)
Next, the configuration of the reinforcing bar cage 1 will be described. 2 to 5 show the configuration of the reinforcing bar cage 1 according to the present embodiment. As shown in the figure, the reinforcing bar cage 1 is a reinforcing bar cage built in an underground pile placed in the ground G. Specifically, the reinforcing bar cage 1 includes a plurality of main bars 11 arranged in parallel in the vertical direction, an annular hoop bar 12 connecting the main bars 11 in the horizontal direction, and a spring that is bound and fixed to the main bars 11. It is provided with a spacer muscle 2.

A predetermined number of main bars 11 are arranged on the circumference at predetermined intervals, each main bar 11 is arranged in parallel in the vertical direction, and the plurality of main bars 11 form a tubular shape as a whole. Circular hoop bars 12 are provided around the outer circumference of the main bar 11 at predetermined intervals in the pile axis direction. The upper portion of the main bar 11 serves as a anchoring bar to the foundation and protrudes above the uppermost hoop muscle 12. Inside the main bar 11, a steel ring-shaped reinforcing material or the like for maintaining the circular arrangement of the main bar 11 is provided. The reinforcing members are attached at appropriate intervals in the pile axis direction of the reinforcing bar cage 1.

As shown in FIG. 2, the spring spacer bar 2 is fastened and fixed by a wire number 25 with the binding portion 24 along the main bar 11 of the reinforcing bar cage 1. In the present embodiment, the spring spacer bar 2 is formed of the reinforcing bar of D25, and as shown in FIG. 3, the spring spacer bar 2 is radially expanded from the center of the pile on the outer circumference of the main bar 11 arranged in a cylindrical shape.

Further, as shown in FIGS. 6 and 8, the spring spacer bar 2 is located at the uppermost position (pile head position) of the reinforcing bar cage 1 so as to be located below the top end of the pile. Is also located below. Note that FIG. 6 shows a state in which the casing 8 is buried in the ground G, and the spring spacer bar 2 is arranged within the burial depth of the casing 8 (the depth of the portion covered by the casing). FIG. 8 shows the casing. Although the state without 8 is shown, in any state, the spring spacer bar 2 is arranged below the first hoop bar 12a arranged at the uppermost position (pile head position) of the reinforcing bar cage 1. There is.

As shown in detail in FIG. 2, the spring spacer bar 2 is provided with respect to the expanding portion 23 extending in the radial direction of the underground pile from the binding portion 24 with the main reinforcing bar 11 of the reinforcing bar cage 1 and the expanding portion 23. It has a bent portion 22 connected while being bent. In the present embodiment, one reinforcing bar is bent radially from the binding portion 24 and expanded to form the expanded portion 23, and further the free end side of the expanded portion 23 is bent to form the bent portion 22. It is formed, and the binding portion 24, the expanding portion 23, and the bending portion 22 are integrally formed.

The binding portion 24 is arranged along the main bar 11 so as to be parallel to the main bar 11, and the expanding portion 23 is bent with respect to the binding portion 24 and is predetermined toward the outside of the binding portion 24. It is extended diagonally upward at the angle of. A bent portion 22 is formed on the free end side of the expanded portion 23 extending diagonally upward.

Further, in the present embodiment, the bending portion 22 is bent from the binding portion 24 via the expanding portion 23 so as to be parallel to the binding portion 24 and the main bar 11. Further, the free end 21 side of the bent portion 22 is bent toward the center side of the underground pile.

As a result, the expanded portion 23 of the spring spacer bar 2 is expanded outward in the radial direction due to the elasticity of the reinforcing bar, and comes into contact with the hole wall so as to follow the hole wall, and the excavated wall surface (hole wall) G3 or the casing 8 is contacted. The reaction force from the inner wall surface is obtained to position the reinforcing bar cage 1 at the center of the pile hole. At this time, since the expanded portion 23 is a bent portion 22 whose tip end side is bent, the spring spacer bar 2 does not get caught in the excavation wall surface G3, the casing 8, or the like.

Here, the opening degree of the expansion portion 23 will be described in detail. As shown in FIGS. 6 and 7, the spring spacer rebar 2 after subsidence is located at the depth of the portion covered with the casing 8, and the spring spacer rebar 2 is located. When the reinforcing bar cage 1 is positioned in the depth direction so as to cover the casing 8, the expanding portion 23 is expanded outward in the radial direction due to the elasticity of the reinforcing bar, and the bent portion 22 is the casing 8. The opening degree of the expansion portion 23 is adjusted so as to be in contact with the inner wall portion of the.

Further, as shown in FIGS. 8 and 9, the spring spacer bar 2 after subsidence is located below the depth of the portion covered with the casing 8, and the depth of the reinforcing bar cage 1 is prevented so that the spring spacer bar 2 does not cover the casing 8. When the casing is positioned in the annular direction, the opening degree of the expansion portion 23 is adjusted so that the bent portion 22 comes into contact with the excavation wall surface G3 due to the earth pressure from the excavation wall surface G3 toward the center of the pile. In addition, while the casing 8 suppresses the earth pressure inward from the excavation wall surface G3, the earth pressure is released when the casing 8 does not exist, so that the spring spacer bar 2 does not cover the casing 8. The opening degree of the expanding portion 23 is smaller than the opening degree of the expanding portion 23 when the spring spacer bar 2 is applied to the casing 8.

On the other hand, the casing 8 is a hollow tubular steel member having a substantially circular cross section. The length of the casing 8 has a sufficient dimension to protect the hole wall of the ground surface layer portion of the pile hole G2. In the casing 8, the spring spacer bar 2 is arranged below the first hoop bar 12a located at the uppermost position (pile head position) of the reinforcing bar cage 1 so that the spring spacer bar 2 is located below the top end of the pile.

(Underground pile driving method)
The underground pile driving method of the present invention can be carried out by using the construction equipment and the reinforcing bar cage described above. 1 and 5 to 8 show the procedure of the underground pile driving method according to the present embodiment.

First, the process of excavating a pile hole in the ground is executed. Specifically, as shown in FIG. 1 (a), the kelly bar 92 is lifted by the arm 91 of the heavy machine 9 to suspend the excavation earth drill 93. Then, the excavation earth drill 93 is rotated and lowered by the kelly bar 92 to be embedded in the ground G, and the pile hole G2 is excavated. The excavation at this time is performed to a depth at which the casing 8 can be sunk.

After the excavation of the pile hole G2 has proceeded to a predetermined depth, as shown in FIG. 3B, a casing 8 covering the excavation wall surface G3 is sunk near the ground surface opening of the pile hole G2. The casing 8 is sunk by lifting the casing 8 using the crane equipment of the heavy machine 9. At the time of subsidence, the casing 8 is inserted into the ground G so that the upper end thereof appears on the ground. Then, as shown in FIG. 3C, excavation of the pile hole bottom surface G1 in the casing 8 is advanced, and a hole is drilled to a predetermined depth deeper than the insertion depth of the casing 8.

Then, as shown in FIG. 1 (d), the step of submerging the reinforcing bar cage 1 in the pile hole is performed. Prior to this laying, a step of assembling the spring spacer bar 2 to the main bar 11 of the reinforcing bar cage 1 by binding with the wire 25 is performed. More specifically, a predetermined number of main bars 11 are arranged on the circumference at predetermined intervals, each main bar 11 is arranged in parallel in the vertical direction, and a circular hoop bar 12 is piled around the outer circumference of the main bar 11. Reinforcing bars are arranged at predetermined intervals in the direction, and the reinforcing bar cage 1 is formed in a tubular shape as a whole. Then, as shown in FIG. 2, the spring spacer bar 2 is fastened and fixed by the number 25 with the binding portion 24 along the main bar 11 of the casing 8.

In the present embodiment, the spring spacer bar 2 is radially expanded from the center of the pile on the outer circumference of the main bar 11 arranged in a cylindrical shape as shown in FIG. In the present embodiment, four spring spacer bars 2 are arranged at 90 degrees each at the central angle of the pile.

Then, in the step of submerging the reinforcing bar cage 1, as shown in FIGS. 6 and 7, the spring spacer reinforcing bar 2 after the subsidence is located at the depth of the portion covered with the casing 8. Positioning in the depth direction of 1 is performed. At this time, the opening degree of the expanding portion 23 is adjusted so that the bent portion 22 comes into contact with the inner wall portion of the casing 8. As shown in FIGS. 8 and 9, the depth of the reinforcing bar cage 1 is such that the spring spacer bar 2 after subsidence is located below the depth of the portion covered with the casing 8 and the spring spacer bar 2 does not cover the casing 8. When the casing is positioned in the annular direction, the bent portion 22 is brought into contact with the excavation wall surface G3 by the earth pressure from the excavation wall surface G3 toward the center of the pile. At this time, the casing 8 suppresses the inward earth pressure from the excavation wall surface G3, while the earth pressure is released when the casing 8 does not exist, so that the spring spacer bar 2 does not apply to the casing 8. The opening degree of the expanding portion 23 is smaller than the opening degree of the expanding portion 23 when the spring spacer bar 2 is applied to the casing 8.

Next, a step of placing concrete in the pile hole G2 is performed. Specifically, as shown in FIG. 1 (e), the tremie pipe 94 is inserted so as to reach the bottom surface G1 of the pile hole through the inside of the sunk reinforcing bar cage 1. Then, as shown in FIG. 1 (f), the concrete 3 is filled. At this time, the concrete 3 is filled up to the upper part of the first hoop bar 12a so that the first hoop bar 12a is located below the top end of the pile.

After that, when the casting of the concrete 3 is completed, the casing 8 is pulled out from the ground G, and the pile driving work is completed. Even when the casing 8 is pulled out from the ground G, the spring spacer bar 2 is located at the uppermost position (pile head) of the reinforcing bar cage 1 so as to be located below the top end of the pile as shown in FIGS. 8 and 9. Position), it is arranged below the first hoop muscle 12a. As a result, even if the casing 8 is pulled out and the surrounding excavated wall surface G3 is displaced before the concrete is hardened, it is possible to prevent the pile core of the underground pile placed from being displaced. Further, the portion where the casing 8 of the ground G is pulled out is filled with backfill soil.

(Action / effect)
According to the present embodiment described above, the spring spacer bar 2 is assembled to the reinforcing bar cage 1, and the spring spacer bar 2 expands in the radial direction of the underground pile from the binding portion 24 with the main bar 11. It has an open portion 23 and a bent portion 22 that is bent and connected to the expanded portion 23. The expanded portion 23 of the spring spacer bar 2 comes into contact with the rebar so as to follow the hole wall due to the elasticity of the rebar, obtains a reaction force from the excavation wall surface (hole wall) G3, and places the rebar cage 1 at the center of the pile hole. Can be positioned.

Further, since the expanded portion 23 is a bent portion 22 whose tip side is bent, the spring spacer bar 2 does not get caught in the excavation wall surface G3, the casing 8, etc., and hinders the smooth laying of the reinforcing bar cage 1. Never. As a result, according to the present embodiment, the radial position of the reinforcing bar cage 1 can be easily adjusted and held, and the pile core of the placed underground pile can be prevented from being displaced.

In particular, in the present embodiment, the bent portion 22 is bent so as to be parallel to the main bar 11, and further, the free end 21 side of the bent portion 22 is bent toward the center of the underground pile, so that the spring spacer bar 2 is bent. Can be more reliably prevented from being caught in the excavated wall surface G3, the casing 8, or the like, and the reinforcing bar cage 1 can be smoothly sunk.

The above description of the embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and various changes can be made according to the design and the like as long as it does not deviate from the technical idea of the present invention.

G ... Ground G1 ... Pile hole bottom G2 ... Pile hole G3 ... Excavation wall surface 1 ... Reinforcing bar cage 2 ... Spring spacer bar 3 ... Concrete 8 ... Casing 9 ... Heavy equipment 11 ... Main bar 12 ... Hoop bar 21 ... Free end 22 ... Bending part 23 … Expansion part 24… Tightening part 25… Track 91… Arm 92… Kelly bar 93… Earth drill for excavation 94… Tremy pipe

Claims (8)

It is a spring spacer that can be attached to a reinforcing bar cage built in an underground pile that is driven underground.
The binding part that is tied and fixed along the main bar of the reinforcing bar cage,
An expansion portion that is bent and expanded in the radial direction of the underground pile from the binding portion, and an expansion portion.
It has a bent portion that is bent and connected to the expanded portion, and has a bent portion.
The bent portion has a straight portion bent with respect to the expanded portion, and the free end side of the straight portion is further bent toward the center of the underground pile.
A spring spacer characterized in that the binding portion, the expanding portion, and the bending portion are integrally formed by bending a single reinforcing bar. The spring spacer according to claim 1, wherein the spring spacer is radially expanded from the center of the underground pile on the outer periphery of the main bar. The binding portion is arranged along the main bar so as to be parallel to the main bar.
The expanded portion is bent with respect to the tightening portion, and extends diagonally upward at a predetermined angle toward the outside of the binding portion.
The spring spacer according to claim 1, wherein the bent portion is formed on the free end side of the expanded portion extending diagonally upward. It is a rebar cage built in an underground pile that is placed underground.
With multiple main bars arranged in parallel in the vertical direction,
A hoop bar that connects the plurality of main bars in the horizontal direction,
It is equipped with a spring spacer bar that is fastened and fixed to the main bar.
The spring spacer muscle
With respect to the tightening portion that is fastened and fixed along the main bar of the reinforcing bar cage, the expansion portion that is bent from the binding portion in the radial direction of the underground pile and expands, and the expansion portion. It has a bent part that is connected while being bent.
The bent portion has a straight portion bent with respect to the expanded portion, and the free end side of the straight portion is further bent toward the center of the underground pile.
A reinforcing bar cage characterized in that the binding portion, the expanding portion, and the bending portion are integrally formed by bending a single reinforcing bar. The reinforcing bar cage according to claim 4, wherein the spring spacer bar is radially expanded from the center of the underground pile on the outer periphery of the main bar. The binding portion is arranged along the main bar so as to be parallel to the main bar.
The expanded portion is bent with respect to the tightening portion, and extends diagonally upward at a predetermined angle toward the outside of the binding portion.
The reinforcing bar cage according to claim 4, wherein the bent portion is formed on the free end side of the expanded portion extending diagonally upward. A method for placing underground piles using the spring spacer according to any one of claims 1 to 3.
The process of excavating a pile hole in the ground and
The process of assembling the spring spacer to the main bar of the reinforcing bar cage built in the pile hole by binding, and
The process of submerging the reinforcing bar cage in the pile hole and
A method for placing underground piles, which comprises a step of placing concrete in the pile holes. The step of excavating the pile hole includes a step of installing a casing covering the excavated wall surface near the ground surface opening of the pile hole.
The step of submerging the reinforcing bar cage is characterized in that the spring spacer after subsidence is located at the depth of the portion covered with the casing, and the bent portion is in contact with the inner wall portion of the casing. The method for placing underground piles according to claim 7.

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