JP2021025382A - Pc steel protection sheath, exhaust pipe for pc steel protection sheath and manufacturing method of pc steel protection sheath - Google Patents

Abstract

To fix an exhaust pipe for discharging air in a sheath body to the sheath body easily and reliably.SOLUTION: A hole 5 for inserting an exhaust pipe is opened in a sheath body 2 which is formed in a helical irregular shape, into which a PC steel is inserted and into which grout is injected so as to hang over at least one projecting stripe 3 of the sheath body 2, and a male screw part 11 of one end side of the exhaust pipe 10 is threaded into the hole 5 for inserting the exhaust pipe so that a flange part 12 between the male screw part 11 and the other end connected to a grout hose for discharge abuts with at least one projecting stripe 3.SELECTED DRAWING: Figure 2

Description

The present invention relates to a PC steel protective sheath that protects a PC steel material used during construction of prestressed concrete (hereinafter, also referred to as PC), an exhaust pipe for the PC steel material protective sheath, and a method for manufacturing the PC steel material protective sheath.

Conventionally, there has been known a method of applying compressive stress to concrete in advance to prevent cracks and the like from occurring in concrete as much as possible. To introduce prestress into concrete, a high-strength cable called PC steel is used. When the PC steel material is pulled and tensioned and then fixed to the concrete, a compressive force is applied to the concrete in an attempt to restore the pulled PC steel material. As a method of introducing prestress, a pre-tension method in which tension is applied before concrete placement and a post-tension method in which tension is applied after casting are known.

Then, it is known that the PC steel material is protected by a protective sheath made of a polyolefin resin material so that the PC steel material does not come into direct contact with concrete, and the sheath is filled with a curing agent (grout) such as mortar (for example). , Patent Document 1). The protective sheath is formed in a spiral concavo-convex shape to prevent the axial movement of the concrete and grout sheaths. However, in such a PC steel protective sheath, the curing agent may not be sufficiently distributed in the groove on the inner surface, and a cavity may remain.

Therefore, the sheath is connected to a connecting pipe in which the exhaust pipe is integrally formed, or a strip-shaped plate having a required width that is shaped to substantially follow the outer shape of the sheath, as in Patent Document 2, penetrates the central portion thereof. The mounting support plate with holes is penetrated through the through holes of the mounting support plate, and the sheath side of the mounting support plate and the outer side on the opposite side are projected to the required lengths and fixed to the mounting support plate. An exhaust port device including an exhaust pipe is formed, a heat-shrinkable thin film body for fixing the exhaust port device to the sheath is formed, and a hole penetrating inside is formed at a desired position on the outer peripheral surface of the sheath. , Insert the protrusion on the sheath side of the exhaust pipe into the hole of the sheath, attach the exhaust port device to the sheath, and in this state, wrap the heat-shrinkable thin film body around the exhaust port device and the sheath, and attach this heat-shrinkable thin film body. It is known that the exhaust port device is fixed to the sheath by heat shrinking by a heating means.

Japanese Unexamined Patent Publication No. 9-144210 Japanese Unexamined Patent Publication No. 11-293848

However, in the case of a connection pipe in which the exhaust pipe is integrally formed, since the exhaust pipe is fixed at a predetermined position, there is a problem that the reinforcing bar and the exhaust pipe and the hose connected to the reinforcing bar easily come into contact with each other.

On the other hand, in an exhaust port device as in Patent Document 2, after the sheath is laid in a predetermined place, a hole is made in the upper portion at a desired position on the outer peripheral surface of the sheath so as to penetrate the internal space. After sandwiching the periphery between a strip-shaped mounting support plate with an exhaust pipe integrally molded from above and below and a heat-shrinkable thin film body, heating must be performed, which is troublesome and bulky. There is.

The present invention has been made in view of this point, and an object of the present invention is to make it possible to easily and surely fix an exhaust pipe for discharging air in the sheath body to the sheath body.

In order to achieve the above object, in the present invention, the exhaust pipe is screwed directly into the sheath body having spiral irregularities.

Specifically, in the first invention, the sheath body is formed into a spiral concavo-convex shape, a PC steel material is inserted inside, and grout is injected.
An exhaust pipe insertion hole opened so as to hang on at least one ridge of the sheath body, and
A male screw portion on one end side is screwed into the exhaust pipe insertion hole portion, and the other end is provided with an exhaust pipe connected to an exhaust grout hose.
A flange portion that comes into contact with at least one of the protrusions is formed on the male screw portion side of the exhaust pipe.

According to the above configuration, the male threaded portion of the exhaust pipe is screwed into the exhaust pipe insertion hole of the sheath body and fixed in a state where the flange portion is in contact with the highly rigid ridge, so that the exhaust pipe is reliable. Moreover, it is watertightly and firmly fixed to the sheath body easily.

In the second invention, in the first invention,
The flange portion is continuous with the male screw portion without a gap.

According to the above configuration, the male screw portion and the sheath body are firmly connected directly under the flange portion regardless of the positional relationship between the flange portion and the ridge.

In the third invention, in the first or second invention,
The sheath body and the exhaust pipe are resin molded products.

According to the above configuration, even if the female screw portion is not formed in the exhaust pipe insertion hole portion, the exhaust pipe insertion hole portion is appropriately deformed when the male screw portion is screwed in, and the flange portion has high rigidity. The exhaust pipe is fixed in a state of being pressed against the surface of the ridge. Therefore, it can be easily installed in any place.

In the fourth invention, a male screw portion for screwing into the exhaust pipe insertion hole portion opened in the sheath body into which the PC steel material is inserted and the grout is injected, and
A flange portion that comes into contact with the peripheral edge of the exhaust pipe insertion hole portion and
It is configured to have a hose connection portion provided at the end opposite to the male screw portion and to which an exhaust grout hose is connected.

According to the above configuration, the male threaded portion of the exhaust pipe is screwed into the exhaust pipe insertion hole of the sheath body and fixed in a state where the flange portion is in contact with the highly rigid ridge, so that the exhaust pipe is reliable. Moreover, it is watertightly and firmly fixed to the sheath body easily.

In the fifth invention, in the fourth invention,
The flange portion is continuous with the male screw portion without a gap.

According to the above configuration, the male screw portion and the sheath body are firmly connected directly under the flange portion regardless of the positional relationship between the flange portion and the ridge.

In the sixth invention, the exhaust pipe insertion hole is formed so as to be formed into a spiral concavo-convex shape, a PC steel material is inserted therein, and the sheath body into which grout is injected is hung on at least one ridge of the sheath body. And the process of opening
The male screw portion on one end side of the exhaust pipe is brought into contact with the exhaust pipe insertion hole portion, and the flange portion between the male screw portion and the other end connected to the exhaust grout hose is in contact with the at least one ridge. Including the step of screwing in.

According to the above configuration, the male threaded portion of the exhaust pipe is screwed into the exhaust pipe insertion hole of the sheath body and fixed in a state where the flange portion is in contact with the highly rigid ridge, so that the exhaust pipe is reliable. Moreover, it is watertightly and firmly fixed to the sheath body easily.

As described above, according to the present invention, an exhaust pipe insertion hole is opened in the sheath body so as to hang on at least one of the protrusions, and one end side of the exhaust pipe is opened in the exhaust pipe insertion hole. By screwing the male screw portion so that the flange portion of the exhaust pipe is in contact with the protrusion, the exhaust pipe can be easily and surely fixed to the sheath body.

It is a front view which shows the PC steel material protection sheath which concerns on embodiment of this invention. It is a vertical end view which shows the PC steel material protection sheath which concerns on embodiment of this invention. It is the end view of line III-III of FIG. It is sectional drawing which shows the state of applying the post tension using the PC steel protection sheath. It is a front view which shows the modification 1 of the exhaust pipe. It is a front view which shows the modification 2 of the exhaust pipe.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 3, the PC steel protective sheath 1 according to the embodiment of the present invention includes, for example, a sheath body 2 made of a blow-molded product of high-density polyethylene resin. In the sheath body 2, the ridges 3 and the concave grooves 4 are alternately formed in a spiral shape substantially in the entire length direction. By forming spiral irregularities on almost the entire surface in this way, the adhesive force with concrete is increased. Although the details will be described later, the PC steel material 51 is inserted into the sheath body 2 and the grout 52 is injected.

An exhaust pipe insertion hole 5 is opened at an arbitrary position of the sheath body 2 of the PC steel protective sheath 1 of the present embodiment so as to hang on at least one ridge 3. Then, the male screw portion 11 on one end side of the exhaust pipe 10 is screwed into the exhaust pipe insertion hole portion 5. The sheath body 2 and the exhaust pipe 10 are resin molded products.

The exhaust pipe 10 is provided with a flange portion 12 that is continuous with the male screw portion 11 without a gap and is in contact with the peripheral edge of the exhaust pipe insertion hole portion 5. The flange portion 12 may be formed in, for example, a hexagonal shape in a plan view so that the exhaust pipe 10 can be grasped by a tool when screwing. The flange portion 12 has a size such that the flange portion 12 abuts on at least one ridge 3 of the sheath body 2. With this configuration, the male screw portion 11 and the sheath body 2 are firmly connected directly below the flange portion 12, regardless of the positional relationship between the flange portion 12 and the ridges.

A so-called bamboo shoot-shaped hose connecting portion 13 is formed at the end opposite to the male screw portion 11 to which an exhaust grout hose 56 for exhausting air at the time of filling the grout is connected.

Since the flange portion 12 is continuous with the male screw portion 11 without a gap, the exhaust pipe insertion hole is formed when the male screw portion 11 is screwed in even if the female screw portion is not formed in the exhaust pipe insertion hole portion 5. The exhaust pipe 10 is fixed in a state where the portion 5 is appropriately deformed and the flange portion 12 is in pressure contact with the surface of the highly rigid ridge 3. Therefore, it can be easily installed in any place.

Next, an example of how to use the PC steel protective sheath 1 thus formed will be described with reference to FIG.

First, the sheath body 2 is transported to the construction site. In particular, when the exhaust pipe 10 is not fixed in advance, there is no possibility that the exhaust pipe 10 will be damaged by applying a force during transportation.

Next, at the construction site, the sheath body 2 is fixed to the reinforcing bars arranged in the formwork 54 with an iron wire, a band, or the like. At this time, since the exhaust pipe 10 does not interfere, the work is easy.

Next, in the process of opening the exhaust pipe insertion hole, the exhaust pipe insertion hole 5 is formed in the sheath body 2 so as to hang on at least one ridge 3. In the present embodiment, the exhaust pipe insertion hole 5 has an advantage that it is easy to work and can be easily formed at an arbitrary place where air is easily exhausted.

Next, in the screwing step, as shown in FIG. 2, the male screw portion 11 on one end side of the exhaust pipe 10 is screwed into the exhaust pipe insertion hole 5 so that the flange portion 12 abuts on at least one ridge 3. .. At this time, the male screw portion 11 of the exhaust pipe 10 is screwed into the exhaust pipe insertion hole portion 5 of the sheath body 2 and the flange portion 12 is fixed in contact with the highly rigid ridge 3, so that the exhaust gas is exhausted. The tube 10 is securely and watertightly and firmly fixed to the sheath body 2.

Next, the exhaust grout hose 56 for intermediate exhaust is connected to the hose connection portion 13 of the exhaust pipe 10. Since the exhaust pipe 10 is provided in a place where workability is good, it is easy to connect the exhaust grout hose 56.

Next, the concrete 53 is placed in the formwork 54 after piping and hardened. Since the PC steel protective sheath 1 is provided with a concavo-convex shape spirally continuously on substantially the entire sheath body 2, the adhesive force of the concrete 53 is increased as compared with the one having a flat outer surface.

Next, the PC steel material 51 is inserted into the PC steel material protective sheath 1 to apply tension, and both ends thereof are fixed to the mold 54 with nuts 55 or the like. Further, an exhaust grout hose 57 for exhausting the end portion is also connected to the nut 55. Further, an injection grout hose 58 is also connected to the nut 55.

Next, using the injection grout hose 58, the grout 52 is injected into the PC steel protective sheath 1 and cured. When the grout 52 is poured, the internal air is surely discharged from the exhaust grout hoses 56 and 57. Further, since the grout 52 flows in along the spiral uneven shape of the sheath main body 2, it is easier to fill the entire sheath main body 2 with the grout 52 as compared with the one having a flat pipe wall.

Therefore, according to the PC steel protection sheath 1 according to the present embodiment, the exhaust pipe 10 can be easily and surely fixed to the sheath main body 2.

-Modification example 1-
FIG. 5 shows the exhaust pipe 110 according to the first modification of the embodiment of the present invention, which is different from the above embodiment in that the shape of the exhaust pipe 110 is different. In each of the following modifications, the same parts as those in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

In this modification, the flange portion 12 and the hose connecting portion 13 are bent at a right angle as compared with the exhaust pipe 10 of the above embodiment. This configuration is suitable for use in a position where the exhaust grout hose 56 extends laterally.

-Modification example 2-
FIG. 6 shows a modification 2 of the embodiment of the present invention, which is different from the above embodiment in that the shape of the exhaust pipe 210 is different.

In this modification, the flange portion 12 and the hose connecting portion 13 are bent in a U shape as compared with the exhaust pipe 10 of the above embodiment. This configuration is suitable for use in bending the exhaust grout hose 56 toward the sheath body 2.

(Other embodiments)
The present invention may have the following configuration with respect to the above embodiment.

That is, in the above embodiment, the exhaust pipe insertion hole 5 is provided at an appropriate position after the reinforcement is arranged, but the exhaust pipe 10 may be screwed into an appropriate position of the sheath body 2 in advance.

In the above embodiment, the prestressed concrete by the post-tension method has been described, but the pre-tension method may be used in which tension is applied to the PC steel protective sheath 1 before the concrete is placed. In that case, the construction will be done in the factory.

Further, the shape of the nut 55 and the method of filling the grout are not particularly limited, and a known method may be used.

It should be noted that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications and applications.

1 PC steel protective sheath
2 Sheath body
3 Convex
4 concave groove
5 Exhaust pipe insertion hole
10 Exhaust pipe
11 Male thread part
12 Flange part
13 Hose connection
51 PC steel
52 grout
53 concrete
54 formwork
55 nuts
56 Exhaust grout hose (middle)
57 Exhaust grout hose (end)
58 Grout hose for injection

Claims (6)

A sheath body that is molded into a spiral concave-convex shape, PC steel is inserted inside, and grout is injected,
An exhaust pipe insertion hole opened so as to hang on at least one ridge of the sheath body, and
A male screw portion on one end side is screwed into the exhaust pipe insertion hole portion, and the other end is provided with an exhaust pipe connected to an exhaust grout hose.
A PC steel protective sheath characterized in that a flange portion that abuts on the at least one ridge is formed on the male screw portion side of the exhaust pipe. In the PC steel protective sheath according to claim 1,
A PC steel protective sheath characterized in that the flange portion is continuous with the male screw portion without a gap. In the PC steel protective sheath according to claim 1 or 2.
The sheath body and the exhaust pipe are PC steel protective sheaths characterized by being resin molded products. A male screw part for screwing into the exhaust pipe insertion hole opened in the sheath body where the PC steel material is inserted and the grout is injected,
A flange portion that comes into contact with the peripheral edge of the exhaust pipe insertion hole portion and
An exhaust pipe for a PC steel protective sheath, which is provided at an end opposite to the male screw portion and has a hose connection portion to which an exhaust grout hose is connected. In the exhaust pipe for the PC steel protective sheath according to claim 4.
An exhaust pipe for a PC steel protective sheath, wherein the flange portion is continuous with the male screw portion without a gap. A step of opening an exhaust pipe insertion hole so as to hang on at least one ridge of the sheath body, which is formed into a spiral concave-convex shape, a PC steel material is inserted inside, and a grout is injected into the sheath body.
The male threaded portion on one end side of the exhaust pipe is brought into contact with the exhaust pipe insertion hole, and the flange portion between the male threaded portion and the other end connected to the exhaust grout hose is in contact with the at least one ridge. A method for manufacturing a PC steel protective sheath, which comprises a step of screwing in.

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