JPH02274948A - Method and device for manufacturing pc concrete columnar body and main reinforcing bar for pc concrete columnar body - Google Patents

Abstract

PURPOSE:To uniformize a stretching amount of a main reinforcing bar by a method wherein an intermediate heading part situated slightly internally of the end part of the main reinforcing bar is locked to the end metal of a columnar body or embedded in end part concrete for anchoring. CONSTITUTION:An iron reinforcing cage B formed such that heading processing is applied in a 2-stage on the ends on both sides of a main reinforcing bar 1 is situated between two end part metals 8. An iron reinforcing cage B is then moved leftward, an end heading part 2 of the main reinforcing bar 1 and an intermediate heading part 3 are inserted in the insertion hole of a stretching plate 11 and the insertion hole of the metal 8, respectively, and the head part of the heading part 2 is protruded outwardly of the stretching plate 11. The iron reinforcing cage B is rotated and pulled rightwardly to lock the two heading parts 2 and 3 to each other. The metal 8 on the other side and the stretching plate 11 are pushed in leftwardly, the metal 8 and the stretching plate 11 are rotated in a state that the heading part 2 is protruded rightwardly of the stretching plate 11 and pulled rightwardly to lock the two heading parts 2 and 3 to each other. Lower forms 21 are filled with concrete C, and after the lower forms are covered with upper forms 20 for closing, the forms are fastened together at flange parts 23.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a PC concrete column such as a PC concrete pile used mainly as a foundation pile for supporting above-ground structures, a method and apparatus for manufacturing the same, and a PC concrete column. It concerns the main muscles of the body.

[Prior Art] Conventionally, when manufacturing piles, poles, etc. in which bristles are introduced into the main body, such as cylindrical PC concrete piles or PC concrete balls, the process is usually performed as follows.

As shown in Fig. 19, the core reinforcing bar cage (B) is set inside the lower formwork (21) of the cylindrical formwork (K) which is divided into upper and lower semi-cylindrical halves, and inside the lower formwork (21). After filling with a predetermined amount of ready-mixed concrete and closing it by covering it with the upper formwork (20),
It is fastened at the flange portions (23) of the upper and lower formworks (20) and (21). Both ends of this formwork (K) are sealed with fixing plates (10).

After this, the tension rod (12) set in advance on the reinforcing bar R (B) and the formwork (K) is pulled in the axial direction from the outside of the formwork (K) to apply tension to the internal reinforcing bar cage (B). In this state, the end of the tension rod (12) is locked to the end fixing plate (10) of the formwork (K) with a locking nut (13), etc., and in this state, the formwork (K) is As shown in Figure 18, the centrifugal molding device (E
) and centrifugally molded by applying high-speed rotation to the mold.

(22) is a centrifugal tire that transmits rotation to the formwork (K).

Then, when demolding after steam curing, the tension rod (
12) is loosened and tension is applied to the concrete body by the shrinking force of the reinforcing bar cage (13).
Manufactures PC concrete piles (P), balls, etc.

In the above manufacturing, when applying tension to the reinforcing bar cage (B) inside the formwork (K), the following method is used.

In Figure 19, the main reinforcement (
1) is cut to a certain length, each end is headed (or threaded) and knitted into a thin shape with hoop lines (5) and the like.

This rebar T! ! ! End fittings (40) such as piles are respectively attached to both ends of the main reinforcement (1) in (B).

As shown in FIG. 20, the conventional end fitting (40) is formed by an end plate (40a) and a side plate (40b), and the end plate (40a) has two large and small holes connected to each other. A plurality of gourd-shaped fastening holes (40c) are provided. The small hole part of the gourd-shaped fastening hole (40c) is a tapered hole (40d), into which the headed end (1a) of the main reinforcement (1) is engaged, and the large hole part is the tapered hole (40d).
A tension bolt (30), which will be described later, is engaged with a bolt screw hole (40e) having a larger diameter than 1a).

That is, at both ends of the reinforcing bar cage (B), the main bar (1)
The headed end (1a) of the end plate (40
Insert it through the bolt screw hole (40e) in a), slightly rotate the end fitting (40), and lock the heading end (1a) of the main reinforcement (1) in the tapered hole (40d). Also,
A tension bolt (30) is screwed into the bolt screw hole (40e) leaving a certain length from the head.

Install the reinforcing bar cage (B) in this state inside the lower formwork (21),
At one end of the reinforcing bar cage (B), tension bolts (3
0) into the gourd-shaped hole (
40c) through the large hole of the gourd-shaped engagement hole (10a), and by slightly rotating the reinforcing bar cage (B), it engages most of the small engagement hole (LOA). match.

In addition, at the other end of the reinforcing bar cage (B), the formwork (K
) A tension plate (11) is arranged within the lower formwork (21) at a slight distance from the end fitting (40), and this tension plate (11)
, there is a gourd-shaped engagement hole (
A plurality of tension bolts (30) screwed to the end plate (40a) of the end fitting (40) and the tension plate (11) are engaged with each other by the fixing plate (10). ).

In this state, the lower formwork (21) is filled with ready-mixed concrete (C) as described above, and the upper formwork (20) is covered and closed, and the tension openings and throats connected to the tension plate (11) are (12)
Pull it from the outside of the formwork (K) and lock it.・Grot (13)
By tightening, tension is applied to the reinforcing bar cage (B).

In addition, for demolding manufactured nozzles after centrifugal molding and steam curing, after removing the upper formwork (20), tighten the tension bolts (30) screwed to the end fittings (40). I am planning to remove it and demold it.

[Problems to be Solved by the Invention] However, in the conventional method described above, the following problems occur in the setting work of the reinforcing bar cage (B) in the formwork, especially in the setting work for tensioning and the tension state. There is.

■ Depending on the type of piles, poles, etc. to be manufactured, the number of tension bolts (30) used is the same as the number of main reinforcements in the pile, etc., and there may be as many as several dozen, which increases the number of parts used. Alternatively, it takes a lot of time and effort to tighten the tension bolt (30) to the end fitting (40) and to remove the screw when demolding.

■ Also, the tension bolt (30) for the end fitting (40)
The screw fastening is performed by attaching the main reinforcement (1) to the end fitting (40).
This can only be done after the heading end (1a) of the head is locked, which takes time, increases the number of steps, and complicates the work.

■ When tightening the tension bolt (30) to the end fitting (40), the screw-in position and screw-in amount (if the screw-in length is different, the tension force applied to each main reinforcement will change and there is a risk of breakage. ), etc., not only require precision and time, but also cannot be automated.

■ The amount of bristle stress introduced into the concrete body, that is, the tension force, varies depending on the type of pile or pole to be manufactured, and the size of the tension bolt (30) must be selected accordingly. Therefore, the number and types of tension bolts (30) required for manufacturing piles and the like increase, and these may be damaged or worn out in a short period of time due to repeated use, resulting in increased costs.

■ Furthermore, after setting the reinforcing bar cage (B) in the cylindrical formwork (K) and applying tension to the reinforcing bar cage (B), and after manufacturing the pile etc., the tension bolt (30) is attached to the end fitting (40). The process of removing the pile and demolding the pile, etc. is usually at a different location on the production line, so the number of tension bolts (30) in stock is even greater, and the need for transporting the tension bolts (30) between processes, etc. The work becomes complicated and costs money.

■ The large hole in the gourd-shaped hole (40e) of the end fitting (40) must be threaded;
0) The processing cost itself will also increase.

Conventionally, as shown in Fig. 21, the end of the main reinforcement (1) is threaded, a seated nut (32) is screwed into this threaded part (6), and this seated nut (32) is attached to the end. In the manufacturing method where the anchorage is embedded in the concrete slightly inside the section, in addition to the engagement of the main reinforcement with the tension plate,
It is necessary to screw the seated nut (32) into the main reinforcement (1), which takes time, and the seated nut (32) must be screwed into the main reinforcement (1).
32) There are also problems such as the cost involved.

Therefore, the present invention has been made for the purpose of manufacturing and providing columns such as PC concrete piles efficiently and without incurring costs by eliminating the need for the above-mentioned tightening and removing work of tension bolts. The present invention provides a new PC concrete column, a method and apparatus for manufacturing the same, and a main reinforcement for the PC concrete column.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, as the main reinforcing bars constituting the reinforcing bar cage, a two-stage heading part is provided at the end thereof, or a threaded part and a heading part are provided. By using a corresponding tensioning device, tension is applied to the concrete body such as a pile.

The first aspect of the present invention is a concrete column in which the main reinforcement, which is the core material, is fixed in concrete in a tensioned state, and the intermediate heading part provided slightly inside the end of the main reinforcement is attached to the column end metal fitting. It is characterized by being anchored or fixed by being embedded in concrete at the end.

In addition, one of the manufacturing methods of the present invention for manufacturing the above-mentioned PC concrete column is to provide a two-stage heading section at the end of the main reinforcing bars constituting the reinforcing bar cage. The inner intermediate heading part is locked to the column end fitting, and the end heading part is locked to a tensioning plate of a tensioning device disposed within the cylindrical formwork or at the end, and the tensioning plate is attached to the formwork. The method is characterized in that a concrete column is manufactured by applying tension to the reinforcing bar cage in the formwork by pulling it in the axial direction.

In addition, instead of the above manufacturing method, the reinforcing bar cage is manufactured so that the intermediate heading part slightly inside the end of the two-stage heading part provided at the end of the main bar is located inside the column inside the column end fitting. is installed in the cylindrical form, and the end heading part is locked to the tension plate of the tension device disposed inside or at the end of the cylindrical form, and the tension plate is moved in the axial direction of the form in the same manner as above. A concrete column can also be manufactured by applying tension to the reinforcing bar cage in the formwork by tensioning it.

In any of the above manufacturing methods, the end heading part of the two-stage heading part of the main reinforcement end is made into a threaded part instead, and the threaded part of this end is locked to the tension plate. I can do it.

Furthermore, the apparatus for manufacturing the PC concrete column body by the manufacturing method described above includes a tension plate disposed at the end of the cylindrical formwork and provided with a gourd-shaped engagement hole that engages with the end heading portion of the main reinforcement. , a tensioning device consisting of a rod having one end connected to the tensioning plate and the other end protruding outward from the end of the formwork, and by actuating the rod from outside the formwork, the tensioning plate can be rotated or molded. It is characterized by being configured to move in the frame axis direction.

Further, the main reinforcement for the PC concrete column of the present invention is:
It is characterized in that an intermediate heading part is provided slightly inside the end of a PC steel bar cut to a certain length, and an end heading part or a threaded part is provided at the end of the steel bar.

[For production] According to the first manufacturing method of the present invention described above, a main reinforcing bar with two-stage heading parts provided at the end is used as a reinforcing bar cage, and an intermediate heading part slightly inside the end of the main reinforcing bar is used. Since the end fitting and the tension plate are respectively locked to the column end fitting and the end heading part to the tension plate, the end fitting and the tension plate are engaged and connected by the main reinforcement itself, and the end fitting is fixed as in the conventional case. There is no need to fasten multiple tension bolts to the end fittings to engage the tension plates. Furthermore, since tension is applied by engaging and pulling the tension plate in the axial direction as described above, each main reinforcement is tensioned at the same time, and the amount of tension is made uniform. Therefore, it is possible to easily manufacture a PC concrete column body in which the main reinforcement is buried in concrete with the intermediate heading part slightly inside the end part being locked to the end metal fitting, and which is in a good tension state.

In addition, the reinforcing bar cage is installed within the cylindrical form so that the intermediate heading part, which is slightly inside the end of the two-stage heading part provided at the end of the main bar, is located inside the column body, inside the column end fitting. In the case of a manufacturing method that applies tension by locking the end heading part to a tension plate, the setting work can be easily carried out without the need for tension bolts as described above, and the amount of tension in the main reinforcement can be made uniform, and the intermediate It is possible to obtain a PC concrete column body in which the heading part is embedded and fixed in the end concrete, and the main reinforcement is in a good tension state.

In addition, in the above manufacturing, if a main bar with a threaded part is used instead of the end heading part of the two-stage heading part at the end of the main bar, an internally threaded tension bolt is attached to this threaded part. By simply fastening them, a PC concrete column similar to the above can be manufactured by using the intermediate heading part slightly inside the end part as a locking part to the end metal fitting or a part fixed to the end concrete.

In particular, it includes a tensioning device comprising a tensioning plate having a gourd-shaped engagement hole through which the end heading portion of the main reinforcement can be inserted and engaged, and a rod connected to the tensioning plate and protruding outside the formwork. If a device is used in which the tensioning plate is rotated or moved in the axial direction of the formwork by externally operating a rod, the heading part of the main bar end can be inserted into the gourd-shaped engagement hole of the tensioning plate. By rotating the tension plate, the end heading portions of each main reinforcement that make up the reinforcing bar cage can be locked in the engagement holes all at once, and the tension rod is then pulled to apply tension to each main reinforcement as described above. can be given.

[Example] Next, embodiments of the present invention will be described based on the drawings.

Fig. 1 shows an example of a PC concrete pile (P), which is one of the PC concrete columns according to the present invention, with end fittings (8〉) attached to both ends, and reinforcement. The main reinforcement (1), which is the core material, is buried in the concrete (C), and the heading part (3) at the end of the main reinforcement (1) is fixed by being locked to the end fitting (8). There is.

FIGS. 2(a) and 2(b) each show the main reinforcement (1) used in the present invention. This main reinforcement (1) is made of a prestressed steel bar or the like cut to a certain length, and the main reinforcement (1) shown in figure (a) consists of two headings with both ends of the steel bar separated by a slight distance. Processed to provide an intermediate heading part (3) slightly inside the end part, and an end heading part (2) at the end part.
This is provided. In addition, the main reinforcement (1) shown in FIG. 6(b) has an intermediate heading part (3) slightly inside the end as described above, and a threaded part (4) at the end instead of the end heading part. It is.

The main reinforcing bars (1) processed as described above are knitted into a thin shape with hoop reinforcing bars (5) and the like to form a reinforcing bar cage (B).

(Example 1) FIG. 3 shows an example of a method for manufacturing a PC concrete pile (P) using the main reinforcement (1) shown in FIG. 2(a).

The end fitting (8), as shown in FIGS. 4 and 5,
Formed by an end plate (8d) and a side plate (8e), the end tli
2 (8d) is provided with the same number of gourd-shaped engagement holes (8a) in which two large and small holes are connected at positions corresponding to the main bars (1). The small hole portion of the gourd-shaped engagement hole (8a) is a tapered hole (8C), and a tapered seat is provided so that the intermediate heading portion (3) of the main reinforcement (1) is engaged therewith. In addition, the large hole part is the insertion hole (8) through which the heading parts (2) and (3) of the main reinforcement (1) are inserted.
b).

(11) is a tension plate with approximately the same diameter as the inner diameter of the formwork (K),
As shown in Figures 6 and 7, the same number of gourd-shaped engagement holes (lla) as above are provided at positions corresponding to the main bars (1), and the smaller holes are tapered holes (llc).
The end heading portion (2) of the main reinforcement (1) is engaged therein, and the large hole portion is formed as an insertion hole (llb) through which the heading portion (2>) of the main reinforcement (1) can be inserted.

A rod connecting portion (lid) is provided at the center of the outer surface of one (right end side in the figure) tension plate (11), and the tension rod (11) is provided with a rod connecting portion (lid).
2) is connected so as to protrude outward from a fixing plate (10) disposed at the end of the formwork (K).

(10d) is a rod hole provided at the center of the fixing plate (10), and (13) is a locking nut screwed onto the tension rod (12). A fixing rod (14) engaged with a fixing plate (10) is connected to the tension IN (11) on the other side (on the left end side in the figure), and an end (L4) that protrudes from the fixing plate (10) is connected to the tension IN (11).
a) is square.

An end metal fitting (
8) is provided with a closure part (lie) that fits into the opening in the center of the end plate. This opening part (lie) prevents the internal ready-mixed concrete (C) from leaking outward from the end fitting (8) when the cylindrical formwork (K) is filled with ready-mixed concrete (C) and centrifugally formed. In particular, the closing part (lie) of the tensioning plate (11) on the tension side (right side in the figure) by the tensioning rod (12) is connected to the reinforcing bar 7 as described later.
It also includes a locking means that moves the end fitting (8) in the direction of elongation of the main reinforcing bars (1) as the main reinforcing bars (1) elongate when tension is applied to the main reinforcing bars (B).

Rebar to formwork (K)! The setting and tension method of (+3) will be explained with reference to FIG.

First, tension plates (1) are placed near both ends of the lower formwork (21).
The end fitting (8) is installed in the lower formwork (21) so as to be close to or in close contact with 1). In this case, the end fitting (8
) and the tension plate (11) with each other's gourd-shaped engagement holes (
Install so that 8a) and (lla) are at the same position.

Next, the reinforcing bars (B), which are formed by heading both ends of the main bar (1) in two stages, are installed between the end fittings (8) installed in the lower formwork (21). In this case, the end heading part (2) of the main reinforcement (1) is connected to the gourd-shaped engagement hole (8a), (
lla) so as to correspond to the insertion holes (8b) and (llb).

Then, the reinforcing steel capacity (B) is suspended by a hanging device or the like.
For example, move the end heading part (2) of the main reinforcement (1) in the direction of the left end fitting (8), that is, to the left in the figure, and insert the end heading part (2) of the main reinforcement (1) into the insertion hole (llb) of the tension plate (11), and (3) is passed through the insertion hole (8b) of the end fitting (8), and the head of the end heading part (2) is inserted into the tension plate (I).
I) Protrude slightly to the outside (to the left in the figure).

In this state, if you slightly rotate the reinforcing bar (B) or the tension plate (11) and the end fitting (8) and pull the reinforcing bar R(B) in the opposite direction, the end of the main bar (1) Heading section (
2) is the tapered hole (lie) of the tension plate (11), and the intermediate heading part (3) is the tapered hole (8c) of the end fitting (8).
respectively.

Next, push the end fitting (8) on the other side (right side in the figure) and the tension plate (11) to the left, with the end heading part (2) protruding to the right from the tension plate (11). , end fittings (
8) and the tension plate (11) slightly rotate the end fitting (8).
) and the tension plate (11) to the right, the end heading part (2) of the main reinforcement (1) will move towards the tension plate (11) in the same way as above.
), and the intermediate heading portion (3) engages with the tapered hole (8c) of the end fitting (8), respectively.

This completes the setting of reinforcing bars (B), end fittings (8), tensioning devices, and formwork (K), and then fills the lower formwork (21) with a predetermined amount of ready-mixed concrete (C). and the upper formwork (2
0) and close it, then fasten it with the flange part (23).

The fixing plate (lO) is thus placed at the end of the formwork (K).
The tension rod (12) set in is pulled from the outside of the formwork (K) in the axial direction, that is, in the right direction in the figure. In this case, the end heading part (2) at the left end of the main reinforcement (1) is locked to the tension plate (11), and the fixing plate (10) is connected to the tension plate (11) by the fixing rod (14). ), the main reinforcement (1) is stretched by the above-mentioned tensile action, and tension force is applied to the reinforcement a (B). Especially each main reinforcement (1
) is engaged with the tensioning plate (11), each main reinforcement (1) is tensioned simultaneously, and the amount of tension is made uniform.

In addition, when tensioning the tension rod (12), as shown in the schematic diagram, a tensioning device (R) (consisting of a hydraulic cylinder, etc.) provided adjacent to the right end of the formwork (K) in the figure is used. The ends of the tension rods (12) are gripped or screwed together, and the hydraulic cylinders are actuated in the axial direction to pull the reinforcing bars R(B). The tension reaction force is taken by the formwork (K).

Moreover, the end plate ( 8d) and tension plate (1
1) is engaged with the closure part (Lle) by appropriate means.

As this engagement means, for example, as shown in FIGS. 8 and 9, the inner peripheral edge (8r) of the end plate (8d) of the end fitting (8)
) is slightly protruded inward from the wall thickness (1) of the pile (P) to be manufactured, and a notch groove (8g) is provided in a part of it, and on the other hand, the opening part of the tension plate (11) is (l
ie) is provided with an engaging portion (llr) that fits into the notched groove (8g) and engages with the inner surface of the inner peripheral edge (8r) by slight rotation of the tension plate (11). can be set.

As another example of the engagement means, as illustrated in FIGS. 10 and 11, the inner peripheral edge (8r) of the end plate (8d) of the end fitting (8) has a smaller diameter on the outer surface side. The tension plate (11) is formed into a tapered shape, and on the other hand, there is a suppression part (l) that moves in and out by a spring or the like on the outer periphery of the opening part (lie) of the tension plate (11) that fits into the inner periphery of this end plate.
1g) is provided, and the end plate (8
It is also possible to press and lock the tapered inner peripheral edge (8r) of d).

Furthermore, the locking means shown in FIG. 12 can also be used. In the case of this embodiment, a tension plate (11) having a gourd-shaped engagement hole (lla) that engages with the end heading part (2) of the main reinforcement (1) is connected to a tension rod (12). A member (18) is connected to the tension rod (12) which is connected to the connecting member (18) and projects outside the formwork (K).
The push rod (
16) is installed through it.

Then, in the inner space of the connecting member (18) and the tension plate (11), a link mechanism (
An engaging member (19) is provided which is connected via a push rod (17) and is opened and closed by the advancing and retracting action of the push rod (17).

That is, during the setting operation, the push rod (16) is pushed against the spring (lea), and the engagement member (19)
With the end narrowed, insert the tip of the end into the end plate (8) of the end fitting (8).
By releasing the push-in after positioning the engagement member (19) inside d), the tip of the engagement member (19) engages with the inner periphery of the tapered end plate (8d). (16b
) is a dovetail groove (19a) in the longitudinal direction of the engaging member (19).
It is a guide that fits into the

In either case, in the tensioned state as described above, tighten the locking nut (13) screwed into the end of the tension rod (12), and then tighten the right side fixing plate of the formwork (K). (1
0).

After that, the formwork (K) in the above state is placed on the rotating roller (25) of the centrifugal molding device (E) as shown in FIG. 18, and the formwork (K) is given high-speed rotation. Centrifugal molding followed by steam curing.

To remove the mold after curing and curing, loosen the tension on the tension rod (Y2), that is, loosen the locking nut (Y2) fastened to the fixing plate (10).
13) and remove the upper formwork (20), the reinforcing bar R (B)
Prestress is applied to the concrete body of the pile (P) due to the shrinking force of the pile (P).

Then, rotate the tension plate (11) engaged with the end heading part (2) of the main reinforcement (1), move the tension plate (11) in the axial direction, release it from the end fitting (8), and lower the pile. Formwork (
21) The mold may be removed from the mold.

As shown in Fig. 1, the demolded pile (P) has its intermediate heading part (3) locked with the end fitting (8), and
The end heading part (2) is in a state of protruding from the pile end (dashed line in Figure 1).

The end of the main bar that protrudes outward from the pile end plate (8d) can be left as is until the pile is used and used as a locking part for hanging, but usually it is used for grinders or Cut the end plate (8d) using a rotary cutter.
) is cut along the plane.

(Example 2) Figures 13 and 14 show the side opposite to the tension side by the tensioning device in the above example, that is, the side where the main reinforcement (1) does not stretch when the main reinforcement (1) is tensioned (Fig. An embodiment is shown in which the tension plate (11) on the left side of the figure is omitted and the fixed plate (10) is also used as the tension plate.

In the case of this embodiment, the end heading part (2) of the main reinforcement (1)
) is directly engaged with the tapered hole (10c) of the fixing plate (10).

Therefore, like the tension plate (11), the fixing plate (10) includes the insertion hole (10b) of the end heading part (2) and the tapered hole (1) into which the end heading part (2) is engaged.
A gourd-shaped engagement hole (10a) consisting of 0c) is provided.

The method of inserting and locking the end heading portion (2) into the gourd-shaped engagement hole (10a) etc. is performed in the same manner as in the case of the two-tension temporary (11) above. Moreover, when removing the mold, the fixing plate (10) may be rotated and moved in the axial direction of the mold (K).

(10e) is a locking part (foe) such as a pin for stopping the fixed plate (]0) at a predetermined rotational position, and the formwork (K
) is provided so that it can be freely engaged with the end of the (24) The arcuate bone of the fixation plate (lO) is a seat.

(Example 3) In the above example, the end plate (8d) of the end fitting (8) was used with a certain degree of thickness in order to lock the heading part, but the end plate (8d) was relatively thin. In the case of the end fitting (8), it can be implemented as shown in FIG.

In other words, the reinforcing bar (B) is lowered so that the intermediate heading part (3) of the main bar (1) constituting the reinforcing bar (B) is located inside the end plate (8d) of the end fitting (8). Formwork〈21
), and the end heading part (2) is installed in the tension plate (11) or the fixing plate (lO> in Fig. 13).
The main reinforcing bars (1) are set in a locked state, and tension is applied to the main reinforcing bars (1) by the tensioning device in the same manner as described above to perform centrifugal forming.

In the case of this example, a PC concrete pile is obtained in which the main reinforcing bars (1) giving bliss stress are anchored to the concrete (C) at the intermediate heading part (3) embedded in the concrete, and each of the above-mentioned The tension amount of the main reinforcement (1) is made uniform as in the above embodiment.

In this case, as shown in Fig. 16, the end plate (8d) of the end fitting (8) has the end heading part (2) of the main reinforcement (1).
It is sufficient to provide only an insertion hole (8b) for passing the through hole.

As in the case of Example 1, the end portion protruding outward from the end plate (8d) after the pile has been removed is cut off along the end surface of the end plate (8d) using a grinder, a cutter, or the like.

(Embodiment 4) Fig. 17 shows that in the above-mentioned Embodiment 3, instead of using the main reinforcement (1) provided with the end heading part (2), Fig. 2 (
b) Main bar (1) with threaded end (4)
An example of a manufacturing method using the method is shown.

In the case of this example, the tension of the main reinforcement (1) is the threaded part (
4) by fastening an internally threaded tension bolt (31) and engaging the head of this internally threaded tension bolt (31) with the tension plate (11) or the fixing plate (10) in Fig. 13. So, the internally threaded tension bolt (3I) has the reinforcing bar capacity (B
) can be screwed into the threaded part (4) through the tension i (11) and the end fitting (8) and fastened to the lower formwork <21).

Therefore, the end plate (8d) of the end fitting (8), the tension plate (1
1), the fixing plate (10) has an insertion hole (8b) and an insertion hole (ll
b) It is only necessary to provide an insertion hole (10b).

In addition, for removing the pile after hardening, tension bolts with internal threads (3
1), and as in the case of Example 3, a pile in which the intermediate heading part (3) is embedded and fixed in the concrete (C) at the end of the pile can be obtained.

Conventionally, when using main reinforcement with threaded ends, the second
As shown in Figure 1, insert a seated nut (
32) was screwed into the concrete, but according to the method of the present invention, the intermediate heading part (3) slightly inside the end can be used as the fixing part, so the seated nut (32) can be screwed into the concrete. No need for screw-in work,
Furthermore, the seated nut (32) itself can be omitted.

[Effects of the Invention] As described above, according to the present invention, columns such as PC concrete piles and poles, in which the main reinforcement serving as the core material is buried and anchored in concrete in a tensioned state to introduce bristles into the concrete body, can be used. Can be manufactured and provided easily and efficiently.

In particular, in the case of the present invention, two ends are used as the main reinforcement serving as the core material.
By using a stepped header, the end heading part is directly locked to the tension plate for tension, so there is no need for a large number of tension bolts as in the past, and therefore it is easier to tighten the tension bolts than in the past. It is possible to save the process, time, and labor required for removing the reinforcing bars, and the precision required for setting reinforcing bars does not require the same level of precision as when tightening tension bolts. The work can be extremely simplified and streamlined, and can be easily automated. In addition, since tension bolts, which are consumable items, are not used, the storage, transportation, and other necessary costs can be reduced, and the manufacturing cost of this type of PC concrete column can be significantly reduced.

Moreover, as mentioned above, by directly locking the end heading part of the two-stage heading part to the tension plate and tensioning it, the amount of tension in each main reinforcement is equalized, and the tension state, that is, the concrete It is possible to obtain a PC concrete column with a good amount of prestress introduced into the main body.

In addition, when using a main reinforcing bar with a threaded part at the end and an intermediate heading part slightly inside the end, the intermediate heading part can be attached to the locking part of the end fitting ＼ or to the end concrete. It is not necessary to screw in a seated nand as in the conventional case, and therefore the work and cost for setting the reinforcing bar cage can be reduced.

[Brief explanation of drawings]

Fig. 1 is a partially longitudinal side view showing one example of the PC concrete pot body of the present invention, Fig. 2 (a) [:b) is a front view illustrating the main reinforcing bars used in the present invention, and Fig. 3 is FIG. 4 is a plan view before attachment of the upper formwork showing an embodiment of the manufacturing method of the present invention using the main reinforcement shown in FIG.
5 and 5 are a front view and a partially cutaway side view showing the end fitting, FIGS. 6 and 7 are a front view and a side view of the tension plate, and FIG. 8 is a front view and a partially cutaway side view of the end fitting and the tension plate. A third locking means is provided.
FIG. 9 is an enlarged plan view of a part of the figure, FIG. 9 is a front view of the end fitting portion shown in the previous figure, and FIGS. FIG. 12 is a partial longitudinal sectional plan view showing another embodiment of the locking means for the end fitting and the tension plate, and FIGS. 13 and 14 are a front view of the end fitting portion. A partial plan view and a front view showing an example in which the fixing plate also serves as a tension plate, and Figure 15 shows an example of the manufacturing method in which the intermediate heading part is embedded and fixed in the end concrete before being attached to the upper formwork. A plan view, FIGS. 16 [a] and [b) are a partially cutaway side view and a front view showing the end fitting used in the embodiment shown in the previous figure, and FIG. Figure (b)
FIG. 18 is a side view showing the entire centrifugal forming apparatus, and FIG. 19 is a plan view illustrating the conventional manufacturing method. , 20th
Figures [a] and [Cb] are a front view and a sectional view showing a conventional end fitting, and Fig. 21 is a partial side view showing the main reinforcement when the conventional end is threaded. [Explanation of symbols] (1) Main bar (2) End heading part (3) Intermediate heading part (4) Screw Cut portion (5)... Hoop line (8)... End fitting (8a)... Gourd-shaped engagement hole (8b)...
...Insertion hole (8C) ...Taber hole (8d) ...End plate (8e) ...Side plate (8r) ...Inner peripheral edge ( 10)...Fixing plate (1,0a)...Gourd-shaped engagement hole (Job)...
・Through hole (foe)...Taber hole (10d)...Rod hole (Inc)...Locking part (11)...Tension amount (lla)...Gourd-like engagement Hole (llb)...Insertion hole (l Ic)...Taber hole (tia)...Rod connecting part (lie)...Opening part (llf')...Engaging part (l1g)... ... Suppressing part (12) ... Tension rod (13) ... Locking nut (14) ... Fixed rod (15) ... With internal thread Tension bolt (20)・
... Upper formwork (21) ... Lower formwork (22) ... Centrifugal tire (23) ... Flange (24) ... The arc holder is the seat (31)...Tension bolt with internal thread (B)...
...Reinforcement capacity (C) ...Concrete (K) ...Cylindrical formwork

Claims (1)

[Scope of Claims] 1. A concrete column in which a main reinforcement serving as a core material is buried in concrete under tension, and an intermediate heading portion provided slightly inside the end of the main reinforcement is attached to a column end metal fitting. A PC concrete column characterized by being anchored to or embedded and fixed in concrete at the end. 2. A two-stage heading part is provided at the end of the main reinforcing bar that constitutes the reinforcing bar cage, and an intermediate heading part slightly inside the end of the heading part is locked to the column end fitting,
The end heading part is locked to a tensioning plate of a tensioning device installed in or at the end of the cylindrical formwork, and the tensioning plate is pulled in the axial direction of the formwork to apply tension to the reinforcing bar cage within the formwork. A method for manufacturing a PC concrete column, characterized in that the concrete column is manufactured by: 3. A two-stage heading section is provided at the end of the main reinforcement that constitutes the reinforcing bar cage, and among the heading sections, the intermediate heading section located slightly inside the end section is located within the column body inside the column end fitting. In addition to installing the reinforcing bar cage inside the cylindrical formwork,
The end heading part is locked to a tensioning plate of a tensioning device installed in or at the end of the cylindrical formwork, and the tensioning plate is pulled in the axial direction of the formwork to apply tension to the reinforcing bar cage within the formwork. A method for manufacturing a PC concrete column, characterized in that the concrete column is manufactured by: 4. According to claims 2 and 3, the end heading part of the two-stage heading part of the main reinforcement end is made into a threaded part instead, and the threaded part of this end part is locked to the tension plate. The method for manufacturing the described PC concrete column. 5. A tension plate arranged at the end of the cylindrical formwork and provided with a gourd-shaped engagement hole that engages with the end heading part of the main reinforcement, one end connected to the tension plate, and the other end connected to the end of the formwork. A PC characterized in that the PC is equipped with a tensioning device consisting of a rod that protrudes further to the outside, and is configured to rotate or move the tension plate in the axial direction of the mold by operating the rod from outside the mold. Concrete column manufacturing equipment. 6. An intermediate heading part is provided slightly inside the end of a PC steel bar cut to a certain length, and an end heading part or a threaded part is provided at the end of the steel bar. Main reinforcement for PC concrete columns.