JP6782667B2 - Prestressed concrete pile - Google Patents

Description

The present invention relates to a prestressed concrete pile having a pile main body portion and a concrete portion to be removed, and a plurality of axial reinforcing bars are embedded from at least a part of the pile main body portion to the concrete removal portion.

When connecting a prestressed concrete pile (PC pile) and footing, the so-called chipping work is to expose the axial reinforcing bars by destroying the concrete (concrete part to be removed) above the pile body in the prestressed concrete pile. There is known a method of connecting with footing via those axial reinforcing bars.

However, such a method of lifting concrete requires time and labor, and since the axial reinforcing bar is attached to the concrete portion to be removed, it cannot be easily exposed.

In addition, since the lifting work is performed at the construction site of the PC pile, noise and dust are generated, which deteriorates the working environment and the surrounding environment.

Further, there is a risk of damaging the tension steel material and the axial reinforcing bar during the lifting operation.

In addition, since the prestress introduced in the concrete part to be removed is released by the lifting work, the vicinity of the concrete part to be removed has an RC structure, which requires a separate safety check by an external force and the strength is insufficient. May have to be reinforced with steel or the like.

As a means for solving these problems, a prestressed concrete pile having a structure shown in Patent Document 1 and the like is known.

Japanese Unexamined Patent Publication No. 1-125416

In the configuration of Patent Document 1 described above, in order to fix the formwork and the end plate as the partition seat plate, an anchor plate fixed to the formwork and concrete screwed to the anchor plate and subjected to unbonding treatment or the like are used. Anchor bolts or suspended PC steel materials that have been treated to prevent bonding are used. That is, tension is applied in a state where the anchor plate and the end plate which is the partition seat plate are fixed via the anchor bolt or the suspended PC steel material.

The following problems can be considered in the configuration of Patent Document 1.

First, when manufacturing a prestressed concrete pile having the configuration of Patent Document 1, an anchor bolt or a suspended PC steel material that transmits tension is separately arranged in the concrete portion to be removed, so that the pile manufacturing process is only increased. In addition, the time and effort required to process the structure for locking the anchor bolts or the suspended PC steel material into the partition seat plate (end plate) or the anchor plate also increases.

In addition, since anchor bolts or suspended PC steel materials are separately prepared and the partition seat plate (end plate) and anchor plate are processed, the manufacturing cost also increases.

Further, since the tension steel material in the pile main body and the anchor bolt or the suspended PC steel material in the concrete part to be removed are tensioned at the same time, the management of the tension force becomes complicated.

Therefore, there has been a demand for a prestressed concrete pile that can be easily manufactured by solving the problems of Patent Document 1 and can be easily constructed without the need for lifting work of axial reinforcing bars.

The present invention has been made in view of these points, and an object of the present invention is to provide a prestressed concrete pile that can be easily manufactured and that can be easily constructed without the need for lifting work of axial reinforcing bars.

The prestressed concrete pile according to claim 1 has a pile main body formed of prestressed concrete, a concrete portion to be removed provided on one side of the pile main body in the axial direction, and an outer diameter from the pile main body. A partition seat plate provided at a boundary portion between the pile main body portion and the concrete portion to be removed, and a plurality of tension steel materials embedded inside the pile main body portion and one end portion fixed to the partition seat plate. , A plurality of axial reinforcing bars embedded therein are provided from at least a part of the pile main body portion to the concrete portion to be removed.

The prestressed concrete pile according to claim 2 is the prestressed concrete pile according to claim 1, and the concrete portion to be removed has an outer diameter larger than that of the pile main body portion.

The prestressed concrete pile according to claim 3 is the prestressed concrete pile according to claim 1 or 2, in which an end plate provided at one end in the axial direction of the concrete portion to be removed and an axial reinforcing bar are attached to the end plate. It includes a first fixing means for fixing and a second fixing means for fixing the axial reinforcing bar to the partition seat plate.

The prestressed concrete pile according to claim 4 is the prestressed concrete pile according to any one of claims 1 to 3, covering a portion of the axial reinforcing bar corresponding to the concrete portion to be removed, and the axial reinforcing bar and the removal plan. It is provided with a cladding tube that prevents adhesion to the concrete portion.

According to the present invention, since the partition seat plate has a larger outer diameter than the pile main body portion, prestress can be easily introduced into the pile main body portion, can be easily manufactured, and the axial reinforcing bar does not need to be pulled out, which is easy. Can be installed in.

It is a perspective view which omitted a part which shows the structure of the prestressed concrete pile which concerns on one Embodiment of this invention. It is sectional drawing which shows the state before removal of the concrete part to which the prestressed concrete pile is to be removed. It is sectional drawing which shows the state after removal of the concrete part to be removed of the prestressed concrete pile as above.

Hereinafter, the configuration of one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a prestressed concrete pile 1, and a concrete portion 3 to be removed is provided on one side in the axial direction of a prestressed concrete pile main body portion 2.

In FIG. 1, the concrete constituting the pile main body portion 2 and the concrete portion 3 to be removed is shown by a two-dot chain line so that the internal structure of the prestressed concrete pile 1 can be easily confirmed.

A partition seat plate 4 is provided at the boundary between the pile main body 2 and the concrete portion 3 to be removed, and an end plate is provided at one end of the concrete portion 3 to be removed, which is opposite to the partition seat plate 4 in the axial direction. 5 is provided.

In this prestressed concrete pile 1, the outer diameters of the concrete portion 3, the partition seat plate 4 and the end plate 5 to be removed are larger than the outer diameter of the pile main body 2, and the concrete portion 3, the partition seat plate 4 and the end plate to be removed are larger. 5 has substantially the same diameter. That is, the outer diameter of the prestressed concrete pile 1 is such that the partition seat plate 4, the concrete portion 3 to be removed, and the end plate 5 which are one side of the pile main body 2 in the axial direction of the prestressed concrete pile 1 are the pile main body. It is larger than 2. As in the prestressed concrete pile 1 shown in FIG. 1, the outer diameters of the concrete portion 3 to be removed and the partition seat plate 4 are larger than those of the pile main body portion 2, and the outer diameters of the concrete portion 3 to be removed and the partition seat plate 4 are outside. The outer diameter of the partition seat plate 4 is not limited to substantially the same, and if the outer diameter of the partition seat plate 4 is larger than that of the pile main body 2, the outer diameters of the concrete portion 3 to be removed and the partition seat plate 4 can be appropriately changed. ..

The pile main body 2 is formed of prestressed concrete into a cylindrical shape, and a partition seat plate 4 is provided at one end in the axial direction.

Further, inside the pile main body portion 2, the tension steel material 6 and the axial reinforcing bar 7 are arranged so as to be spaced apart from each other in a circumferential shape.

The concrete portion 3 to be removed is formed of concrete into a cylindrical shape, and an end plate 5 is provided at one end in the axial direction and a partition seat plate 4 is provided at the other end in the axial direction. Further, inside the concrete portion 3 to be removed, axial reinforcing bars 7 are arranged so as to be separated from each other in a circumferential shape.

The partition seat plate 4 is a ring-shaped plate member, and a plurality of through holes 11a for fixing the tension steel material 6 and a plurality of through holes 11b through which the axial reinforcing bar 7 can be inserted are separated in a circumferential shape. It is provided.

The positional relationship between the through holes 11a and the through holes 11b in the circumferential direction of the partition seat plate 4 is such that the two through holes 11a and 11a are located between the two through holes 11b and 11b at equal intervals. And are arranged.

The number and spacing of the through holes 11a and 11b are not limited to those shown in FIG. 1, and can be appropriately changed according to the number of tension steel materials 6 and axial reinforcing bars 7 required for design.

The end plate 5 is a ring-shaped plate member, and a plurality of through holes 12 through which the axial reinforcing bars 7 can be inserted are provided apart from each other in a circumferential shape.

The tension steel material 6 is arranged over the entire length of the pile body 2 in the axial direction, one end thereof is fixed to the partition seat plate 4, and the other end is the other in the axial direction of the pile body 2 in FIGS. 1 to 3. It is fixed to an end plate (not shown) provided at the lower end, which is the end.

In FIG. 2, the concrete portion 3 to be removed and the concrete portion 3 to be removed provided on one side in the axial direction from the partition seat plate 4 on the tension steel material 6 side (left side in FIG. 2) so that the mounting state of the tension steel material 6 can be easily understood. The end plate 5 is omitted.

Here, as shown in FIGS. 2 and 3, a bag nut 13 for fixing the tension steel material 6 to the partition seat plate 4 is provided in the pile main body portion 2 corresponding to the through hole 11a of the partition seat plate 4. Has been done.

Then, the bag nut 13 is locked so that one end of the tension steel material 6 is hooked, and the bolt 14 is screwed to the bag nut 13 from the through hole 11a of the partition seat plate 4, so that the bag nut 13 is attached to the partition seat plate 4. One end of the tension steel material 6 is fixed via. As a method of fixing one end of the tension steel material 6 to the partition seat plate 4, for example, a locking hole is provided in the partition seat plate 4, and a rivet head provided at one end of the tension steel material 6 is provided in the locking hole. It may be a method of locking and fixing.

The axial reinforcing bars 7 are arranged from a part of the pile main body 2 in the axial direction over the entire length of the concrete portion 3 to be removed in the axial direction. The axial reinforcing bar 7 may be provided from at least a part of the pile main body 2 in the axial direction over the entire length of the concrete portion 3 to be removed in the axial direction. For example, the axial reinforcing bar 7 may be provided on the shaft of the pile main body 2. The configuration may be arranged over the entire length in the direction.

Then, the axial reinforcing bar 7 is inserted into the through hole 11b of the partition seat plate 4, and one end thereof is inserted into the through hole 12 of the end plate 5. Further, the nut 15 as the first fixing means is screwed to the portion exposed from the end plate 5, and the pile body 2 side of the partition seat plate 4 is fixed by the nut 16 as the second fixing means. That is, a thread is formed on the outer peripheral surface of the axial reinforcing bar 7 in the range from the upper end where the nut 15 is screwed to the lower portion of the partition seat plate 4 where the nut 16 is screwed, and the axial reinforcing bar is formed. 7 is fixed to the end plate 5 by the nut 15 and fixed to the partition seat plate 4 by the nut 16.

Further, a cured steel pipe 17 as a cladding tube for preventing adhesion between the axial reinforcing bar 7 and the concrete portion 3 to be removed is provided at a portion of the axial reinforcing bar 7 corresponding to the concrete portion 3 to be removed.

That is, in the concrete portion 3 to be removed, the axial reinforcing bar 7 is covered with the cured steel pipe 17 so as not to adhere to the concrete, and one end of the axial reinforcing bar 7 exposed from the cured steel pipe 17 is end plate 5 by the nut 15. It is fixed to.

Next, the actions and effects of the above embodiment will be described.

When manufacturing the prestressed concrete pile 1, a first formwork for forming the pile main body 2 and a second formwork for forming the concrete portion 3 to be removed, which has a diameter larger than that of the pile main body 2, are used. .. That is, the first formwork and the second formwork are arranged side by side in the axial direction so that the openings at the ends in the axial direction communicate with each other with the partition seat plate 4 interposed therebetween, and are firmly assembled.

At this time, the partition seat plate 4 is fixed in contact with the peripheral edge of the opening provided at one end in the axial direction of the first formwork.

Then, a predetermined number of tension steel materials 6 are inserted into the first formwork, and one end thereof is fixed to the partition seat plate 4 by using the bag nut 13 and the bolt 14.

Further, the axial reinforcing bar 7 is inserted into the second formwork through the through hole 11b of the partition seat plate 4 from the first formwork, and the partition seat plate 4 is inserted from the first formwork side by the nut 16. At the same time, one end thereof is inserted into the through hole 12 of the end plate 5 and fixed to the end plate 5 by the nut 15.

Further, the portion (the portion of the second formwork) corresponding to the concrete portion 3 to be removed in the axial reinforcing bar 7 is covered with the cured steel pipe 17.

Next, with the partition seat plate 4 in contact with the peripheral edge of the opening provided at one end of the first formwork, the tension steel material 6 is tensioned toward the other end of the first formwork. Prestress is introduced, concrete is cast and centrifugally formed, and then the mold is removed after curing.

The introduction of prestress and the placement of concrete in the above steps may be performed in the order of the steps in which the prestress is introduced after the concrete is placed.

Further, in the above manufacturing method, the first formwork for forming the pile main body 2 and the second formwork for forming the concrete portion 3 to be removed are made into separate formwork, but the formwork is used. In order to simplify the assembling work and the demolding work, these molds may be made into an integral mold via a step portion. In this case, the partition seat plate 4 is brought into contact with the inner surface of the stepped portion to introduce prestress.

When constructing the prestressed concrete pile 1, the prestressed concrete pile 1 is buried in the construction site in a state where the concrete portion 3 to be removed is provided on one side of the pile main body portion 2 shown in FIG. 2 in the axial direction.

Further, after burying, the nut 15 is removed, the boundary portion between the concrete portion 3 to be removed and the partition seat plate 4 is separated by using, for example, a crowbar, and the concrete portion 3 to be removed is pulled out by a crane and shown in FIG. In this way, the axial reinforcing bar 7 is exposed on one side (upper side) of the partition seat plate 4.

Then, the exposed portion of the axial reinforcing bar 7 and the footing are combined to integrate the pile body 2 and the footing.

According to the above embodiment, since the outer diameter of the partition seat plate 4 is larger than the outer diameter of the pile main body 2, the outer opening edge in the axial direction of the form (first form) for introducing prestress. Prestress can be introduced into the pile main body 2 by bringing the partition seat plate 4 into contact with the stepped portion of the portion or the formwork, taking a reaction force from the opening edge or the stepped portion, and tensioning the tension steel material 6. Therefore, unlike the conventional patent document 1, for example, it is not necessary to separately dispose the anchor bolt or the suspended PC steel material, or to process the partition seat plate or the anchor plate for the anchor bolt or the suspended PC steel material. With a simple structure in which the partition seat plate 4 has a diameter larger than that of the pile body 2, the tension steel material 6 in the pile body 2 can be tensioned and can be easily manufactured.

Further, since it is not necessary to separately facilitate materials such as anchor bolts and suspended PC steel materials and to separately process the partition seat plate 4, it is possible to suppress an increase in manufacturing cost and efficiently manufacture the partition seat plate 4.

Further, since the tension steel material is only the tension steel material 6 disposed in the pile main body 2, the tension force can be managed in the same manner as a normal prestressed concrete pile, and the pile can be easily manufactured.

Further, the partition seat plate 4 can be directly fixed to the formwork to accurately introduce prestress to the pile main body 2 in a more stable state.

Since the axial reinforcing bar 7 is covered with the curing steel pipe 17 in the concrete portion 3 to be removed and is prevented from adhering to the concrete portion 3 to be removed, the concrete portion to be removed is used in the work of exposing the axial reinforcing bar 7. It is not necessary to destroy the 3 and the axial reinforcing bar 7 can be revealed only by separating the boundary portion between the concrete portion 3 to be removed and the partition seat plate 4 and pulling it out with a crane or the like. That is, since the lifting work is not required, the work of exposing the axial reinforcing bar 7 is easy. It is possible to prevent the generation of noise and dust, the tension steel material 6 and the axial reinforcing bar 7 are not damaged in the lifting work, and the prestress is not released by the lifting work.

Since the concrete portion 3 to be removed is fixed to the pile main body portion 2 by screwing the axial reinforcing bar 7 to the nut 15 and the nut 16, for example, it is removed when handling the load such as when transferring the prestressed concrete pile 1. Appearance defects such as wobbling and cracking of the planned concrete portion 3 are unlikely to occur, and a decrease in commercial value can be prevented.

1 Prestressed concrete pile 2 Pile body part 3 Concrete part to be removed 4 Partition seat plate 5 End plate 6 Tension steel material 7 Axial reinforcing bar
15 Nut as first fixing means
16 Nut as a second fixing means
17 Cured steel pipe as a cladding pipe

Claims (4)

Pile body molded from prestressed concrete and
The concrete part to be removed provided on one side of the pile body in the axial direction,
A partition seat plate having a larger outer diameter than the pile main body and provided at the boundary between the pile main body and the concrete portion to be removed.
A plurality of tension steel materials embedded inside the pile body and one end fixed to the partition seat plate.
A prestressed concrete pile characterized by comprising a plurality of axial reinforcing bars embedded therein from at least a part of the pile main body portion to the concrete portion to be removed. The prestressed concrete pile according to claim 1, wherein the concrete portion to be removed has an outer diameter larger than that of the pile main body portion. An end plate provided at one end of the concrete part to be removed in the axial direction,
A first fixing means for fixing the axial reinforcing bar to the end plate, and
The prestressed concrete pile according to claim 1 or 2, further comprising a second fixing means for fixing the axial reinforcing bar to the partition seat plate. The invention according to any one of claims 1 to 3, further comprising a cladding tube that covers a portion of the axial reinforcing bar corresponding to the concrete portion to be removed and prevents the axial reinforcing bar from adhering to the concrete portion to be removed. Prestressed concrete pile.

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