JP2004190404A - Reinforcing cage for cast-in-place concrete pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause no rupture of a weld part between a pile main reinforcement and a reinforcing ring even when horizontal force is applied to a cast-in-place concrete pipe in case of an earthquake or the like. <P>SOLUTION: This reinforcing cage 10 is provided with pile main reinforcements 12 passing through vertically, on the outer peripheral surfaces of first reinforcing rings 11a (11) provided at prescribed spaces along a vertical direction. Hoops 13 are provided at suitable spaces in the vertical direction around the pile main reinforcements 12. The pile main reinforcements 12 and the first reinforcing rings 11a (11) are bound with wires, and the reinforcing rings 11b-11d and the pile main reinforcements are fastened by welding. The upper end side of the pile main reinforcements 12 are provided with a pile main reinforcement restraining member 14 to suppress the curvature of the pile main reinforcement 12 in a position above the first reinforcing ring 11a (11) anchored to a foundation slab. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reinforcing cage used for a cast-in-place concrete pile method.
[0002]
[Prior art]
2. Description of the Related Art Cast-in-place concrete pile method is known as a method of providing a foundation pile for a structure such as a building. In such a construction method, a pile hole is excavated directly below the ground and in a vertical direction using a drilling machine such as an earth drill. The excavation is performed until the excavation end reaches a solid support layer capable of sufficiently supporting the load of a building or the like provided on the foundation pile.
[0003]
Into such a pile hole, a rebar cage in which a rebar or the like is combined in a substantially cylindrical shape having a length substantially equivalent to the depth of the pile hole is inserted. After that, concrete is poured into the pile hole, and a reinforced concrete foundation pile is constructed.
[0004]
The reinforcing cage used in the cast-in-place concrete pile method generally has a configuration as shown in FIGS. 6 (A) and 6 (B). That is, the reinforcing cage 1 is provided with, for example, reinforcing rings 2 formed by processing flat steel having a thickness of about 9 mm and a width of about 75 mm into a circular belt shape at predetermined intervals, and a plurality of pile main reinforcing bars around the reinforcing ring 2. The reinforcing ring 2 and the main pile 3 are welded and fixed to each other to form a cage. A ring-shaped hoop 4 is turned outside the main pile 3.
[0005]
As shown in FIG. 6, the reinforcing bar 1 is formed in a substantially circular shape and a tubular shape, and usually three or more reinforcing rings 2 are provided for each reinforcing bar.
[0006]
The first reinforcing ring 2a (2) provided at the uppermost stage among the plurality of reinforcing rings 2 provided on the reinforcing cage 1 is provided from the uppermost portion of the reinforcing bar 1, that is, from the anchoring length to the foundation slab from the uppermost end of the main reinforcing bar 3. It is provided in a slightly lowered position.
[0007]
[Problems to be solved by the invention]
The present inventor has noticed that the following technical problems exist in the reinforced cage used in the cast-in-place concrete pile method having the above configuration.
[0008]
A foundation pile supporting a building such as a building receives horizontal force during an earthquake, and a bending stress (bending moment) is generated in the pile. Such a stress is maximized at the pile head as schematically shown in FIG. 5 relating to the stress (bending moment) of the pile during an earthquake. When a bending stress acts on the pile, a tensile force is generated in the pile reinforcement buried in the concrete pile. However, since the pile reinforcement is welded and fixed to the first reinforcing ring, the pile is brittle at the weld due to the tensile force. The concrete piles break, causing a serious decrease in the strength and deformability of concrete piles.
[0009]
In the conventional reinforcing cage 1 as shown in FIG. 6, the pile main reinforcement above the first reinforcing ring 2a (2) is used for reinforcing bars when constructing the foundation slab on the pile. The pile is simply extended upward so that a certain degree of freedom can be secured for the main bars of the pile so as to facilitate the arrangement work. For this reason, the pile main bar was not easily constrained at the upper end side, and was easily bent by an external force. The present inventor has noticed that the ease of bending has a great effect on the cutting work of the excess concrete.
[0010]
In the cast-in-place concrete pile method, generally, a filling solution such as a bentonite solution or a polymer solution is injected into the excavated pile hole, and then the reinforcing cage having the above configuration is inserted and arranged. And a method of pouring concrete by using a tremy tube or the like.
[0011]
In this concrete casting method, since mud is mixed in the concrete on the pile head side, excess concrete is poured in advance from the pile's original height to form extra concrete on the pile head, and the pile's original Mud is not mixed into the concrete part. After the pile construction is completed, the pile head extra concrete must be cut off by root cutting work in order to make the reinforcing bar appear.
[0012]
However, since the surplus concrete shaving work is performed in a narrow and cramped state surrounded by the pile main bar, there is a possibility that a breaker or an excavator will catch the reinforcing bar such as the main bar of the pile during the cutting operation. easy. In such a case, since the main bar of the pile is easily bent as described above, the main bar of the pile that is hooked is bent, causing a displacement of the main bar of the pile. Displacement of the main muscle causes troubles such as difficulty in performing the arrangement work.
[0013]
On the other hand, if the bent main reinforcement of the pile is bent back, the reinforcing steel bar may be fragile and broken in some cases, so that easy bending return cannot be performed. Therefore, in the work of shaving off the pile head excess concrete, sufficient care must be taken so as not to catch the reinforcing bar of the pile main bar.
[0014]
However, since the excess concrete is already hardened, it must be cut off with strong force, and even though it is vigorously and with sufficient caution, the pile main bar may be strongly caught. Easy to happen. It is difficult to completely eliminate hooking mistakes. From the beginning, the present inventor considered that it is desirable to keep such a pile main bar hard to bend.
[0015]
Furthermore, in the conventional reinforcing cage, when the reinforcing cage is lifted, a hook or the like is hooked on the first reinforcing ring for anchoring to the foundation slab side. In some cases, the main bars or the reinforcing ring may be deformed by strongly hitting a hook or the like. The reinforcement ring part to be anchored to such a foundation slab is also a place that maintains the position accuracy of the pile main reinforcement for arranging reinforcement with the foundation beam after foundation pile construction, and deformation of such places must be avoided as much as possible No.
[0016]
An object of the present invention is to prevent a fracture of a welded portion between a main reinforcement of a pile and a reinforcing ring even when a horizontal force acts on a cast-in-place concrete pile during an earthquake or the like.
[0017]
Another object of the present invention is to make it difficult for a pile main bar extending above a pile head to be bent in a cast-in-place concrete pile method.
[0018]
[Means for Solving the Problems]
The present invention relates to a reinforced car used in a cast-in-place concrete pile method, wherein the reinforced car has a reinforcing ring, a pile main reinforcing bar, and a hoop reinforcing bar, and the reinforced car is disposed in the pile hole. In this state, a portion of the pile main reinforcement extending upward from the first reinforcing ring is characterized in that a position change of the pile main reinforcement is restricted by a pile main reinforcement restricting member.
[0019]
The present invention relates to a reinforcing steel cage used in a cast-in-place concrete pile method, wherein the reinforcing steel cage has a pile reinforcing bar, a hoop reinforcing bar, and a reinforcing ring, and a first reinforcing ring is connected to the pile reinforcing bar and a wire. It is characterized by being united.
[0020]
In such a configuration, in a state where the reinforcing cage is arranged in the pile hole, the pile main reinforcement extending portion extending upward from the first reinforcement ring wire-bound to the pile main reinforcement is provided with the pile main reinforcement. Characterized in that a pile main bar restraint member for restraining the position variation of the pile is provided.
[0021]
In any one of the above structures, the pile main bar restraining member is formed in a ring shape, and is fixed to an upper end side of the pile main bar extension. The first reinforcing ring may be formed of a reinforcing bar.
[0022]
Here, the "first reinforcing ring" is provided at a position closest to the pile head in a state where the reinforcing steel cage is arranged in the pile hole, and is buried in the concrete after completion of the cast-in-place concrete. Means the reinforcing ring that will be used.
[0023]
In the rebar cage of the present invention having the above configuration, in the portion where the pile stress is maximum with respect to the horizontal force received during an earthquake or the like, the rebar cage of the conventional configuration is different, and the first reinforcing ring and the pile reinforcement are Since the pile main bar is not fixed by welding, brittle fracture does not occur even if the pile main bar receives a tensile force, and the pile main bar can fully exhibit its strength as a base material and function as a deformable bar.
[0024]
In addition, as described above, the main portion of the pile main bar extension is restrained and fixed by the pile main bar restraining member, so that the main bar of the pile that has been directly extended to the pile head side can be hardly bent. Therefore, for example, after completion of pile construction, when excavating soil to make reinforcing bars appear, the deformation of the main bars of the pile is less likely to occur even when the excavator or the like is slightly hooked on the reinforcing bars, and the displacement of the main bars of the pile is suppressed. Thus, the subsequent reinforcing work with the foundation beams and the like can be performed smoothly.
[0025]
Therefore, rooting work and extra concrete shaving work can be performed without using nerves for the mistake of hooking the main bar of the pile, so that such work can be performed more smoothly and more efficiently.
[0026]
Since the uppermost part of the reinforcing bar, that is, the upper end side of the pile main bar extension portion is located above the first reinforcement ring, the pile main bar restraint is performed at a position where it is not subjected to a tensile force against the horizontal force. There is no danger of brittle fracture, etc., even if the position of the extension of the main reinforcement of the pile is fixed by welding the member and the main reinforcement of the pile, etc., and there is no technical hindrance in restricting the position fluctuation of the main reinforcement of the pile in this way. .
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0028]
FIG. 1 (A) is a front view showing the reinforcing cage of the present invention in a standing state in which the reinforcing cage is disposed in a pile hole, and FIG. 1 (B) shows a state where the reinforcing cage of FIG. 1 (A) is viewed from above. It is a top view.
[0029]
As shown in FIGS. 1A and 1B, the reinforcing bar cage 10 is configured by reinforcing bars on a plurality of reinforcing rings 11 (11a, 11b, 11c, 11d) provided at predetermined intervals along the vertical direction. The pile main bars 12 are provided so as to intersect with each other.
[0030]
The reinforcing ring 11 is formed by forming a flat steel having a predetermined thickness into a ring shape, and as shown in FIG. 1B, a pile main bar 12 that passes vertically through the outer peripheral surface of the reinforcing ring 11 at a predetermined interval. Are provided.
[0031]
Of the plurality of reinforcing rings 11, the first reinforcing ring 11a provided at the top is provided on the pile head side. That is, it is provided at a position slightly lower than the uppermost end of the pile main bar 12 than the length of anchoring to the foundation slab. The other reinforcing rings 11b, 11c, and 11d may be provided at, for example, equal positions between the first reinforcing ring 11a and the bottom side of the reinforcing cage 10.
[0032]
Incidentally, in the case of the reinforcing rod cage 10 shown in FIG. 1 (A), the total length a is set to 10 m including the fixing length b used for fixing the main pile 12 to the foundation slab and the extra length c. Is exemplified.
[0033]
In order to provide the pile main reinforcement 12 on the reinforcing ring 11, the first reinforcement ring 11a and the pile main reinforcement 12 are provided by wire binding using a wire such as an iron wire. On the other hand, the pile main reinforcement 12 is fixed to the reinforcing rings 11b, 11c, and 11d by welding.
[0034]
In the conventional configuration, as shown in FIG. 6, the reinforcement ring 2 and the pile main reinforcement 3 are all welded and fixed, but in the present invention, the first reinforcement ring 11a fixed to the foundation slab and the pile reinforcement 12 are welded. It is tied by wire binding, not by fixation.
[0035]
In the conventional configuration in which welding is fixed, as described above, when horizontal force is applied during an earthquake or the like, a large bending moment generated at the pile head causes brittle fracture of the weld fixing portion between the first reinforcing ring 2a and the pile main reinforcement 3. However, according to the present invention, since the wires are bound as described above, unlike the welding fixation, no brittle fracture is caused because no defect is generated in the main pile 12 at the wire binding portion due to welding.
[0036]
As a wire used for wire binding, a metal wire such as an iron wire can be used, but any wire other than a metal wire may be used as long as the binding force is necessary to provide the main pile 12 on the first reinforcing ring 11a. Absent.
[0037]
Further, in the above description, the configuration in which the pile main bar 12 is provided on the first reinforcing ring 11a by wire binding is adopted. However, even if a large bending moment based on the horizontal force is generated by means other than the wire binding, the pile main bar is used. Any means that does not lead to brittle fracture may be employed as means for providing the first reinforcing ring 11a and the main pile 12.
[0038]
In other words, assuming that the reinforcing ring fixed to the foundation slab and the pile main reinforcement are welded and fixed, if the first reinforcing ring is attached to the pile main reinforcement, if the mounting means does not cause harmful defects in the pile main reinforcement, Means other than the wire binding means can also be employed.
[0039]
Further, in the above description, the first reinforcing ring 11a is formed by forming a flat bar into a ring shape. However, since the flat bar has a wide width, a case where wire bundling with an iron wire or the like is difficult to be performed is also assumed. Therefore, in order to facilitate such wire binding, the first reinforcing ring 11a may be made of, for example, a ring formed of a reinforcing bar instead of flat steel.
[0040]
A plurality of hoop bars 13 are provided at predetermined intervals in the vertical direction around the pile main bar 12 provided so as to cross the reinforcing ring 11 including the first reinforcing ring 11a in this manner.
[0041]
In FIG. 1, the first reinforcing ring 11a (11) is painted black so as to be easily understood.
[0042]
As shown in FIG. 2, the hoop streaks 13 are provided with spacers 13a. The spacer 13a is formed, for example, by forming a central portion of a belt-shaped flat steel into a convex shape such as a substantially trapezoidal shape, and fixing both ends to the upper and lower hoop bars 13 by welding.
[0043]
By adopting such a configuration, unlike the conventional configuration in which the spacer is attached to the pile main reinforcement by welding, even when a tensile force is applied to the pile main reinforcement, brittle fracture of the welded portion does not occur. The spacer 13a is not shown in FIG. 2 except for FIG.
[0044]
As shown in FIG. 1A, a pile main bar restraining member 14 is provided on the pile main bar 12 extending above the first reinforcing ring 11a, that is, on the pile main bar extension portion 12a. The pile main bar restraining member 14 may be formed in a ring using flat steel or a reinforcing bar, for example.
[0045]
On the outer periphery of the ring of the column main bar restraining member 14, the above-mentioned pile main bar extension 12a of the pile main bar 12 is provided by fixing means. In the case shown in FIG. 1 (A), the upper end side of the pile main bar extension portion 12a, that is, the upper end side of the pile main bar 12, is fixed to the pile main bar restraining member 14 by welding.
[0046]
Since the upper end side of the pile main reinforcement 12 is fixed to the pile main reinforcement restraining member 14, bending of the pile main reinforcement extension portion 12a is less likely to occur than in a case where such fixing is not performed. That is, even if the pile main reinforcement 12 is accidentally hooked by an excavator or the like during shaving work of the excess pile concrete after the completion of the pile construction, the pile main reinforcement 12 is hardly bent, and the foundation slab which has been a problem described above. It is hard to cause troubles when arranging reinforcement related to construction.
[0047]
In the rebar cage 1 of the conventional configuration shown in FIG. 6, the main pile 12 is simply stretched in a portion above the first reinforcing ring 2a (2). However, as shown in FIG. In 10, since the position of the pile main bar is restricted by the pile main bar restraining member 14, the pile main bar 12 is hardly deformed and hardly bent even when some external force acts.
[0048]
That is, the pile main bar restraining member 14 is fixed to the head side of the pile main bar 12 in a ring shape and restrains the pile main bar 12, so that the pile main bend 12 is bent at the time of shaving off excess concrete after completion of the pile construction. It serves to reinforce so as not to occur.
[0049]
In the case shown in FIG. 1A, the installation position of the pile main bar restraining member 14 is shown as being installed on the upper end side of the pile main bar 12, but the bending of the pile main bar 12 is effectively performed as described above. As long as it can be suppressed, it may be provided at a position slightly lower than the illustrated upper end.
[0050]
Further, in the case shown in FIG. 1 (A), a case is shown in which one pile main bar restraining member 14 is provided, but for example, a plurality of pile main bar restraining members 14 may be provided vertically separated by a predetermined distance.
[0051]
The reinforcing cage 10 of the present invention configured as described above is used for the cast-in-place concrete pile method as shown in FIGS.
[0052]
As shown in FIG. 3 (A), a pile hole 20 is excavated in the ground G at the construction site of the foundation pile using a drilling machine such as an earth drill. At the time of excavation, a pipe-shaped casing 21 is inserted from the ground side to a predetermined depth to prevent collapse of the side wall at the time of excavation. Drill further with the plug inserted. Along with the excavation, a filling liquid 22 such as a bentonite solution or a polymer solution is injected so as to fill the borehole.
[0053]
In this way, excavation is advanced to the support layer G1 having sufficient hardness, and the pile hole 20 is formed. As shown in FIG. 3B, the reinforced cage 10 of the present invention is inserted into the excavated pile hole 20 while being suspended by a crane or the like, and the position of the first reinforcing ring 11a is changed to the base slab 30 (see FIG. 4). The height position is adjusted so as to match the depth of the design position.
[0054]
When suspending the rebar cage 10, in the rebar cage 10 of the present invention, the pile main bar restraining member 14 is provided above the first reinforcing ring 11a. It is sufficient to hang it. Unlike the conventional case, the first reinforcing ring 11a side is not hooked on the hook, so that there is no fear of damaging the first reinforcing ring 11a side or the pile main bar 12 around it by any chance. .
[0055]
In the state where the reinforcing cage 10 is arranged in the pile hole 20 in this way, as shown in FIG. 3C, the tremy tube 23 is inserted from the ground side to the bottom inside the pile hole, and concrete is poured. The concrete 24 is filled upward from the bottom of the pile hole while pulling the tremy tube 23 upward. At the same time, the filling liquid 22 is discharged.
[0056]
The concrete 24 is cast more than the first reinforcing ring 11a to be fixed to the foundation slab 30, thereby forming an extra concrete 24a (24) as shown in FIG. 3 (D). At this point, the casing 21 is removed. When the poured concrete 24 has hardened, that is, when the pile construction has been completed, as shown in FIG. Along with the root cutting operation, excess concrete 24a is cut off and removed.
[0057]
In the operation of shaving off the excess concrete 24a at the time of root cutting, even if the pile main reinforcement 12 is accidentally hooked by an excavator or the like, the pile main reinforcement 12 is restrained by the pile main reinforcement restraining member 14, so that it is easily bent. Etc. do not occur. Therefore, unlike the case of using the conventional configuration of the reinforcing cage 1 (see FIG. 6) that does not have a configuration corresponding to the pile main bar restraining member 14, the bending of the pile main bar 12 is not so worried and The removal and root cutting work of the embankment concrete 24a can be performed smoothly and in a shorter time than in the conventional case.
[0058]
In conjunction with the root cutting operation, though not shown, the surrounding ground G in the pile hole 20 is excavated to a position of about 300 mm above the level of the first reinforcing ring 11a to form a construction area of the foundation slab 30, and Reinforcing the foundation beam of the slab 30 with the reinforcing cage 10 is performed. In this arrangement, if the pile main bar restraining member 14 interferes with the work, the pile main bar restraining member 14 may be cut and removed as necessary.
[0059]
In this manner, the foundation pile 25 is formed, and a foundation slab 30 serving as a foundation of a building such as a building may be provided on the foundation pile 25 as shown in FIG. Such structures include not only buildings such as buildings, but also civil structures such as pier foundations.
[0060]
The present invention is not limited to the above-described embodiment, and may be changed as needed without departing from the gist thereof.
[0061]
For example, in the above description, the rebar cage 10 adopting both the configuration of the pile main bar restraining member 14 and the configuration of linearly binding the first reinforcing ring 11a and the pile main bar 12 has been described as an example. Of course, a configuration employing only one of them is also conceivable.
[0062]
That is, if it is not necessary to particularly consider the bending of the pile main bar 12 due to the hooking of the pile main bar 12 in the shaving work at the time of the extra concrete, the configuration of the wire binding between the first reinforcing ring 11a and the pile main bar 12 is adopted. It is also possible to adopt only.
[0063]
Further, when it is not necessary to particularly consider the brittle rupture of the pile main bar 12 described above relating to a large bending moment based on a horizontal force such as at the time of an earthquake, a configuration in which only the pile main bar restraining member 14 is provided is adopted. It does not matter.
[0064]
【The invention's effect】
In the reinforced cage of the present invention, the portion where the stress of the pile is maximized against the horizontal force at the time of an earthquake or the like is employed so that the pile main bar is not welded and fixed, so that the brittle fracture of the pile main bar does not occur. In addition, the strength of the base material can be ensured sufficiently.
[0065]
In the rebar cage of the present invention, since the pile main bar restraint member for restricting the position of the pile main bar is provided in the pile main bar portion above the first reinforcing ring, deformation such as bending of the pile main bar can be suppressed.
[0066]
For this reason, for example, in the removal of excess concrete at the time of root cutting after the completion of pile construction, etc., the pile main reinforcement is difficult to bend even if the pile main reinforcement is accidentally hooked. The work can be carried out without much inconvenience, and the root cutting work and the extra concrete removal work after the completion of the pile work can be performed efficiently in a shorter time.
[Brief description of the drawings]
FIG. 1A is a front view showing a reinforcing cage of the present invention in an upright state in which the reinforcing cage is disposed in a pile hole, and FIG. 1B shows a state in which the reinforcing cage of FIG. It is a top view.
FIG. 2 is a partial front view showing a mounting state of a spacer in the reinforcing cage of the present invention.
3 (A) to 3 (E) are cross-sectional explanatory views showing main working steps of a cast-in-place concrete pile method using a reinforcing cage of the present invention.
FIG. 4 is an explanatory diagram showing a state in which a foundation slab is provided on a foundation pile formed by a cast-in-place concrete pile method.
FIG. 5 is an explanatory diagram showing the state of action of stress on a foundation pile during an earthquake.
FIG. 6 (A) is a front view showing a reinforced cage having a conventional configuration in an upright state in which the reinforced cage is disposed in a pile hole, and FIG. 6 (B) shows a state where the reinforced cage of FIG. It is a top view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reinforcing cage 2 Reinforcing ring 3 Pile main bar 4 Hoop bar 10 Reinforcing cage 11 Reinforcing ring 11a 1st reinforcing ring 12 Pile main bar 13 Hoop bar 14 Pile main bar restraining member 20 Pile hole 21 Casing 22 Filling liquid 23 Tremy tube 24 Concrete 24a Extra filling Concrete 25 Foundation pile 30 Foundation slab a Total length b Anchoring length c Extra length G Ground G1 Support layer

Claims (6)

A reinforced basket used for the cast-in-place concrete pile method,
The rebar cage has a reinforcing ring, a pile main bar, and a hoop bar,
In the state where the rebar cage is disposed in the pile hole, a portion of the pile main bar extending upward from the first reinforcing ring is restrained by a pile main bar restraint member from a positional change of the pile main bar. Reinforced basket for cast-in-place concrete piles. A reinforced basket used for the cast-in-place concrete pile method,
The reinforcing bar has a pile main bar, a hoop bar, and a reinforcing ring,
The first reinforcing ring is wire-tied with the pile main reinforcing bar, wherein the reinforcing steel cage for cast-in-place concrete piles is provided. The reinforced car for cast-in-place concrete pile according to claim 2,
In a state where the rebar cage is arranged in the pile hole, a position change of the pile main bar is provided at a pile main bar extension portion extending upward from the first reinforcing ring which is linearly bound to the pile main bar. A reinforcing steel cage for cast-in-place concrete piles, comprising a pile main bar restraining member for restraining the pile. The steel cage for cast-in-place concrete pile according to claim 2 or 3,
The pile reinforcing bar restraining member is formed in a ring shape, and is fixed to an upper end side of the pile reinforcing bar extending portion. The reinforced car for cast-in-place concrete pile according to any one of claims 2 to 4,
The first reinforcing ring is formed of a reinforcing bar, wherein the reinforcing cage for a cast-in-place concrete pile is provided. The cast-in-place concrete pile reinforcing steel cage according to any one of claims 1 to 5,
A spacer for a cast-in-place concrete pile, wherein the spacer is provided on the hoop.

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