JPS61294290A - Prestressed concrete bend and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bent pipe made of a prestressed concrete pipe and a method for manufacturing the same.

[Conventional technology]

For pipelines that are subject to relatively high internal pressure.

Stress was applied in advance to the hoop direction of the concrete pipe.

So-called prestressed concrete pipes are mainly used.

However, for corners where the slope or direction of the pipeline changes, as shown in Figure 8, a bent pipe 1 is used, which is made by joining multiple steel pipes together by explosion welding or the like to form a predetermined bend. be done. This bent pipe 1 is connected to other bent pipes and prestressed concrete pipes 2, 2 via joints 3.4.

[Problem that the invention seeks to solve]

However, the steel bent pipe 1 is (1
) Easily eroded, (2) Low rigidity, (3) High manufacturing costs due to high material costs and complicated manufacturing process, (4) Requires special dedicated joints for connection. The disadvantage is that construction costs are higher than concrete pipes. For these reasons, it is essentially desirable to use prestressed concrete pipes similar to straight pipes in the corner portions of pipelines.

However, in the production of prestressed concrete pipes, many processes are performed while rotating the core pipe, such as centrifugal molding of the core pipe, wrapping PCwi wire around the core pipe, and spraying a cover coat. Therefore, until now it has been difficult to manufacture bent pipes from prestressed concrete pipes, and only straight pipes have been manufactured.

The present invention has been made in view of the above-mentioned conventional problems.1 A prestressed concrete curved pipe that is durable and easy to manufacture is provided.

The purpose is to provide a manufacturing method thereof.

[Means to solve the problem]

Hereinafter, the configuration of the present invention will be explained with reference to the reference numerals in the drawings.

First, to explain the prestressed concrete curved pipe according to the first invention, it is made up of a plurality of straight core pipes.
Connecting steel pipes 12 are installed at the ends of la and llb-, respectively.
a, 12b- are fixed. These connecting steel pipes 12a, 1
2b- are joined to form a corner portion 24 at the joining location. Then, the inside and outside of the connecting steel pipes 12a and 12b are covered with concrete, mortar, or the like.

Next, to explain the method for manufacturing the prestressed concrete curved pipe according to the second invention, first, the connecting steel pipes 12 and 12- are placed in a cylindrical formwork a, the core pipe 11 is driven in, and the core pipe A connecting steel pipe 12° 12... is fixed to the middle part of 11. Next, the PC wire 14 is wrapped around the outer periphery of the core pipe 11 and fixed under tension. After that, the above connecting steel pipe 12.1
2. Divide the core pipe 11 diagonally at the section 2...... and connect one core pipe 11 to each connecting steel pipe 1.
Multiple core pipes including 2a, 12b...
, 11b-. and core pipes lla and llb
The ends of the connecting steel pipes 12a and 12b are abutted against each other by rotating relatively, and after joining them, the inside and outside are finished with concrete, mortar, etc.

[For production]

In the prestressed concrete curved pipe according to the first invention, 2. Since the corner portion 24 is reinforced with the connecting steel pipes 12a and 12b which are joined to each other,
Strength equal to or greater than other parts can be obtained. In particular, much higher joint strength can be obtained than when concrete pipes are joined together as is. Since the connecting steel pipes 12a, 12b- are covered with concrete, mortar, etc., they are not corroded and maintain stable quality over a long period of time.

In addition, all 14 PC&I lines 14 continuous steel pipes 12a, 12b
- and the steel pipes 12a, 12b... are preferably fixed to the ends of the core pipes 11a, 11b... This makes it possible to apply stress to the corner portion 24 that is generally uniform with other portions, and also allows the core pipes lla and 11 of the connecting steel pipes 12a and 12b to be applied to the corner portion 24.
Loosening of b- is prevented.

In the method for manufacturing a prestressed concrete curved pipe according to the second invention, the core pipe 11 is placed, the PC steel wire 14
The winding of the core pipes 11a, 11b, the spraying of the cover coat 21, etc.
There is no need to do it individually. That is.

Similar to manufacturing one prestressed concrete pipe, after performing these series of steps continuously, the core pipe 11 can be divided and joined to manufacture a nine-bent pipe.

As shown in FIG. 4, the connecting steel pipe 12 before cutting is a one-piece one, and after the processes from driving the core pipe 11 to spraying the cover coat 20, etc.
This may be cut diagonally, but as shown in Fig. 5, it is also possible to use a piece that has been cut diagonally in advance and temporarily fixed. Particularly in the latter case, it is preferable to arrange the core pipes 12.12 in the formwork a with partition plates interposed between the core pipes 12.12 cut in advance. In this case, the part of the partition plate is not filled with ready-mixed concrete and a discontinuous part of the core pipe 11 is formed, so after the above process, the connecting steel pipe 12.
By simply cutting the temporary fixing parts of 12 and the PC bar etc., core pipes 11 and 12 each having connecting steel pipes 12a and 12a can be created.
It can be divided into a and llb...

``Example'' Next, the present invention will be explained in detail with reference to FIGS. 1 to 5. First, a connecting steel pipe 12 is placed in the middle of a cylindrical formwork a, and the connecting steel pipe 12 is cut. Place partition plates along the surface.

For example, in the case of FIG. 4, one connecting steel pipe 12 is arranged along the inner peripheral surface of the formwork a, and a ring-shaped partition plate is arranged inside this. In the case of FIG. 5, connecting steel pipes 12, 12, which have been cut diagonally in advance, are temporarily fixed with a partition plate sandwiched between them.

This is placed inside the formwork a.

When placing the PC bar 13 in the longitudinal direction of the formwork a, place a spacer C made of foamed resin or the like along with the partition plate, and place the PC bar 13 between the spacer C and the partition plate. let Note that the PC steel wires 14 are attached to both ends of the formwork a in advance.
Anchors such as inserts for fixing 15.15-
At the same time, a through hole is made at an appropriate position in the connecting steel pipe 12, and the anchor 15.15- is also fitted therein.

Place it in formwork a.

Next, fresh concrete is poured into the formwork a while being rotated, and the fresh concrete is dehydrated and compacted by centrifugal force. Next, the fresh concrete is cured, hardened, and demolded to obtain the core pipe 11 with the connecting steel pipes 12, 12 fixed to the outer circumferential side of the intermediate portion.

The illustrated core pipe 11 has a socket 16 formed at its left end, and a spigot 17 matching the socket 16 formed at its right end.

Next, a PC5l wire 14 is wound around this core pipe 11, and the wire is tensioned to apply prestress to the core pipe 11. After that, connect this PCJI wire 14 to both ends of the core pipe 11 and the anchors 15° 15 of the connecting steel pipe 12.
Fix it with bolts 18, 18...

Next, a cover coat 20 is applied by uniformly spraying mortar or the like onto the outer peripheral surface of the core pipe 11 including the PC steel wire 14. At this time, the surface of the connecting steel pipe 12 to be cut is covered with a cover to prevent mortar etc. from adhering thereto.

After the cover coat 20 is cured, the spacer C is removed from the inside of the core pipe 11, and the spacer C is removed from the inside of the core pipe 11, and the spacer C is removed from the PC bar 13 using the gap formed in this trace as shown by the arrow opening in FIGS. 4 and 5. cut.

Next, in the case of Fig. 4, the connecting steel pipe 1 is inserted along one side of the partition plate, as indicated by the arrow A in the same figure.
2, and in the case of FIG. 5, the connecting steel pipe 12.
Cut the temporary fixing part 12. As a result, the core pipe 11 becomes two core pipes as shown in FIG.
and llb. Note that the protruding part of the PC bar 13 is as follows.

At the same time, in the case of FIG. 4, the partition plate left in one core pipe llb is removed.

Next, the two divided core pipes lla and llb are rotated 180 degrees from the state shown in FIG. 3, and as shown in FIG. Explosion weld the edges. Thereafter, resin mortar or the like is sprayed onto the outer periphery of the connecting steel pipes 12a and 12b, and a coating 21 is applied as shown by dotted lines in FIG.

Also, from the inside of the pipe, fresh concrete is filled into the joints and the gaps created by the partition plates and spacers C, and allowed to harden.

The prestressed concrete curved pipe made in this way is
, has an appearance as shown in FIG.

It has a corner portion 24 that bends at an angle twice the angle at which the connecting steel pipe 12 is cut. This corner portion 24 has a structure as shown in FIG.

In addition, in the above embodiment, two core pipes 11a, ll
We explained the case where a bent pipe is made by joining b.
As shown in FIG. 7, three or more core pipes lla, 11b, . . . can be joined to form a curved pipe. Furthermore, the connecting steel pipes 12a, 12
b- can be directly joined by means such as explosion welding, or can also be joined with another steel pipe interposed therebetween.

〔Effect of the invention〕

As described above, by using the prestressed concrete curved pipe according to the first invention.

It will now be possible to construct the corners of the pipeline with curved pipes of the same quality as the prestressed concrete pipes before and after. This has caused a problem when steel bent pipes were conventionally used in the corner portions. Compared to concrete pipes, they are (1) more susceptible to corrosion, (2) less rigid, and (3) more expensive. (4) Construction is expensive. All such shortcomings will be eliminated.

Further, according to the method for manufacturing a prestressed concrete pipe of the second invention, steps such as driving the core pipe 11, wrapping the PC@ wire 14, and spraying the cover coat 20 are performed to manufacture one prestressed concrete pipe. As well as.

Can be performed continuously. Therefore, the process is simpler than the case where the above process is performed individually for each of the plurality of core pipes lla, llb, . . . to be joined. Moreover, when joining steel pipes for connection.

The edges of the tube fit together reliably, and a curved tube with uniform inner and outer diameters on both sides of the corner can be obtained.

[Brief explanation of drawings]

Fig. 1 is a feeding surface view of a prestressed concrete curved pipe showing an embodiment of the first invention, Fig. 2 is a sectional view showing part A in Fig. 1, and Fig. 3 is a feeding surface view of a prestressed concrete curved pipe showing an embodiment of the second invention. A partially cutaway side view showing a prestressed concrete curved pipe in the manufacturing process. Figure 4 is a longitudinal sectional side view of the embodiment showing the arrangement within the formwork corresponding to section B in Figure 3. Figure 5 is a view inside the same formwork. Fig. 6 is a side view showing a prestressed concrete curved pipe in the manufacturing process in the same embodiment, and Fig. 7 shows another embodiment of the first invention. FIG. 8 is a partially cutaway side view of a pressed and trestled concrete curved pipe, and is a construction drawing showing an example of construction of a pipeline using a conventional curved pipe. 11- Core pipe before splitting

Claims (1)

[Claims] 1. PC steel wire 1 in the core pipes 11a, 11b...
In the prestressed concrete pipe, the outer periphery of the core pipes 11a, 11b, etc. containing the PC steel wire 14 is covered with a cover coat 20, and a plurality of straight core pipes 11a, 11b... Connecting steel pipes 12a, 12b, respectively, are installed at the ends of the
In addition to fixing these connecting steel pipes 12a, 12b,
Prestressed concrete is characterized by joining... to form a corner portion 24 at the joint location, and covering the inside and outside of the connecting steel pipes 12a, 12b... with concrete, mortar, etc. curved pipe. 2. The PC steel wire 14 is connected to the connecting steel pipes 12a, 12b...
. . . The bent pipe according to claim 1, wherein the steel pipes 12a, 12b, . . . are fixed to the ends of the core pipes 11a, 11b, . 3. In a method of manufacturing a prestressed concrete pipe by wrapping a PC steel wire 14 around a formed core pipe 11 and fixing it under tension, a cover coat 20 is applied to the outer periphery of the core pipe 11 including the PC steel wire 14, After arranging the connecting steel pipes 12, 12, etc. in a cylindrical formwork a, driving the core pipe 11, wrapping the PC wire 14 around the outer circumference of the core pipe 11, and fixing it under tension. , in the above-mentioned connecting steel pipes 12, 12...,
One core pipe 11 is connected to a connecting steel pipe 12a,
A plurality of core pipes 11a, 11 including 12b...
Divided diagonally into b... core pipes 11a, 11
By relatively rotating the connection steel pipe 12a,
A prestressed concrete curved pipe characterized in that the ends of the connecting steel pipes 12a, 12b, etc. are butted and joined, and then the inside and outside of the connecting steel pipes 12a, 12b, etc. are finished with concrete, mortar, etc. Production method. 4. After tensioning the PC steel wire 14, connect it to the connecting steel pipe 12
, 12... and the anchors 15, 15... fixed to the core pipe 11.
2. Method for manufacturing a bent pipe as described in Section 1. 5. Connecting steel pipes 12, 12, before splitting the core pipe 11.
. . . are cut obliquely with respect to the central axis of the core pipe 11 in advance and temporarily fixed. 6. The method for manufacturing a curved pipe according to claim 5, wherein the partition plate b is sandwiched between the connecting steel pipes 12, 12, etc., which have been cut in advance.