JP7306848B2 - Branch pipe joint installation structure and construction method - Google Patents

Description

The present invention relates to a branch pipe joint installation structure and construction method, and more particularly, for example, a branch pipe joint for connecting a branch pipe to the side wall of a concrete U-shaped groove called a small box that houses and protects cables inside . It relates to an installation structure and a construction method.

An example of this type of conventional branch pipe joint is disclosed in Patent Document 1. The branch pipe joint of Patent Document 1 includes a semi-cylindrical saddle portion having an inner surface having substantially the same shape as the outer surface of the main pipe of the cable protection pipe, a branch pipe portion protruding from the outer surface of the saddle portion at an acute angle, and the saddle portion. and an opening formed in the connecting portion of the branch pipe.

JP 2012-41954 A

As a low-cost method to promote the elimination of utility poles on roads, concrete U-shaped grooves called small boxes are used instead of conduits, and cables such as communication lines and low-voltage power lines are placed in these concrete U-shaped grooves. Containment and protection schemes have been proposed. Even in such a system, it would be convenient if the cable could be taken out from the side of the concrete U-shaped groove in order to draw the cable to each home by the shortest route. However, the conventional branch pipe joint as shown in Patent Document 1 is a joint for connecting a branch pipe to a pipeline (circular pipe) and cannot be applied to the side wall of a concrete U-shaped groove.

SUMMARY OF THE INVENTION Therefore, a primary object of the present invention is to provide a novel installation structure and construction method for a branch pipe joint.

Another object of the present invention is to provide an installation structure and construction method for a branch pipe joint that can properly take out a cable from a concrete U-shaped groove.

The first invention is a branch pipe joint installation structure in which a synthetic resin branch pipe joint for connecting a branch pipe to the side wall of a concrete U-shaped groove that houses and protects cables is installed on the side wall. A branch pipe joint includes a plate-shaped base portion having a flat portion on one principal surface, a cylindrical branch pipe portion protruding from the other principal surface of the base portion at a predetermined angle, and a branch pipe portion formed on the base portion, the flat portion and the branch pipe portion. The base part and the branch pipe part are integrally molded, the flat part is not bent, and when the branch pipe joint is connected to the side wall of the concrete U-shaped groove The base end of the branch pipe portion has a flat portion on the outer surface in the width direction of the base, and the side wall is the base of the branch pipe joint. and wherein the branch fitting is fixed with the base disposed within the opening and the planar portion flush with the inner surface of the sidewall Structure .

In the first invention, a branch pipe joint is installed on the side wall of a concrete U-shaped groove called a small box. This branch pipe joint is made of synthetic resin and includes a plate-like base portion having a flat portion on one main surface and a branch pipe portion projecting from the other main surface of the base portion at a predetermined angle. The base portion and the branch pipe portion are integrally molded. In addition, a branch hole is formed in the base portion to allow communication between the flat portion and the inside of the branch pipe portion. This flat portion is not bent and consists only of a flat surface that can be flush with the inner surface of the side wall when the branch joint is connected to the side wall of the concrete U-shaped groove. In addition, a flat portion is formed on the outer surface in the width direction of the base portion at the base end portion of the branch pipe portion. On the other hand, the side wall has an opening with a larger opening area than the base of the branch joint. The base of the branch pipe joint is fitted into the opening formed in the side wall of the concrete U-shaped groove. It is fixed in a U-shaped groove.

According to the first invention, since the base has a flat portion on one main surface, the inner surface of the side wall of the concrete U-shaped groove and the one main surface of the base can be easily held flush with each other. By doing so, it is possible to appropriately prevent the branch pipe joint from being slanted and fixed. In addition, since the branch pipe part is branched at a predetermined angle with respect to the base (and the side wall of the concrete U-shaped groove), the cable can be taken out from the concrete U-shaped groove while ensuring a predetermined curvature radius. . Therefore, according to the first invention, the branch pipe joint can be properly attached to the side wall of the concrete U-shaped groove, and the cable can be properly taken out from the concrete U-shaped groove.

Moreover, according to the first invention, when the branch pipe joint is attached to the side wall of the concrete U-shaped groove, the branch pipe joint can be satisfactorily seated, and the branch pipe joint can be stably held. .

A second invention is according to the first invention, and the width of the base is set to be the same as or substantially the same as the outer diameter of the branch pipe portion.

According to the second invention, the size of the branch pipe joint can be reduced. Moreover, when the branch pipe joint is attached to the side wall, the branch pipe joint can be satisfactorily seated, and the branch pipe joint can be stably held.

A third invention is a method for constructing a synthetic resin branch pipe joint for connecting a branch pipe to a side wall of a concrete U-shaped groove for housing and protecting a cable therein, comprising: (A) one main surface; a plate-like base having a flat portion on the bottom, a cylindrical branch pipe projecting from the other main surface of the base at a predetermined angle, and a branch hole formed in the base for communicating the flat portion and the inside of the branch pipe; The base portion and the branch pipe portion are integrally molded, and the flat portion is not bent and is flush with the inner surface of the side wall when the branch pipe joint is connected to the side wall of the concrete U-shaped groove. A step of preparing a branch pipe joint that consists only of flat surfaces that can be flattened, and the base end of the branch pipe portion has a flat portion on the outer surface in the width direction of the base, (B) the concrete U-shaped groove ( C ) after step (A) and step (B) , branching to the opening formed in the side wall of the concrete U-shaped groove; fitting the base of the fitting and holding the branch fitting with the flat surface flush with the inner surface of the side wall; and ( D ) after step ( C ) between the opening and the outer surface of the branch fitting. 1. A method of installing a branch pipe fitting, comprising the steps of securing the branch pipe fitting in a concrete U-shaped groove by applying and solidifying a filler material to seal the .

According to the third invention, since the branch pipe joint is connected to the side wall of the concrete U-shaped groove, the cable can be pulled in to each household by the shortest route, and the construction cost can be reduced. In addition, since the branch pipe joint is connected to the concrete U-shaped groove with the inner surface of the side wall and the flat portion of the base flush, the cable is prevented from being damaged by the edge of the opening, and the cable can be smoothly connected. It can lead to a branch pipe section (and eventually a branch pipe). Furthermore, when connecting the branch pipe joint to the side wall of the concrete U-shaped groove, the base is fitted into the opening, so it is not affected by the shape and dimensions of the concrete U-shaped groove and the formation position of the opening. , the branch pipe joint can be connected to the concrete U-shaped groove. Also, a branch pipe joint can be connected to a concrete U-shaped groove in which a cable is accommodated. Therefore, according to the third invention, the branch pipe joint can be properly attached to the side wall of the concrete U-shaped groove, and the cable can be properly taken out from the concrete U-shaped groove.

A fourth invention is according to the third invention, in which step (A) prepares a branch pipe joint in a state in which a bent pipe member is connected to the tip of the branch pipe portion, and step ( D ) prepares the branch pipe Filling material is applied so that it is buried up to the connection part between the part and the curved pipe member.

According to the fourth aspect of the invention, since the entire branch pipe joint is protected by the filler, even if a load is applied from the ground surface, the branch pipe joint itself can be prevented from being damaged, and the branch pipe joint and the concrete U can be prevented from being damaged. It is possible to prevent damage to the connecting portion with the groove.

According to the first invention, since the branch pipe joint has a base portion having a flat portion on one main surface, the inner surface of the side wall of the concrete U-shaped groove and the one main surface of the base portion can be easily held flush with each other. By keeping them flush, it is possible to appropriately prevent the branch pipe joint from being slanted and fixed. In addition, since the branch pipe part branches at a predetermined angle with respect to the base part, the cable can be taken out from the concrete U-shaped groove while ensuring a predetermined radius of curvature. Therefore, the branch pipe joint can be properly attached to the side wall of the concrete U-shaped groove, and the cable can be properly taken out from the concrete U-shaped groove.
Moreover, when the branch pipe joint is attached to the side wall of the concrete U-shaped groove, the branch pipe joint can be satisfactorily seated, and the branch pipe joint can be stably held.

Also, according to the third invention, since the branch pipe joint is connected to the side wall of the concrete U-shaped groove, the cable can be led in to each household by the shortest route, and the construction cost can be reduced. In addition, since the branch pipe joint is connected to the concrete U-shaped groove with the inner surface of the side wall and the flat portion of the base flush, the cable is prevented from being damaged by the edge of the opening, and the cable can be smoothly connected. It can lead to a branch pipe section. Furthermore, when connecting the branch pipe joint to the side wall of the concrete U-shaped groove, the base is fitted into the opening, so it is not affected by the shape and dimensions of the concrete U-shaped groove and the formation position of the opening. , the branch pipe joint can be connected to the concrete U-shaped groove. Also, a branch pipe joint can be connected to a concrete U-shaped groove in which a cable is accommodated. Therefore, the branch pipe joint can be properly attached to the side wall of the concrete U-shaped groove, and the cable can be properly taken out from the concrete U-shaped groove.

The above object, other objects, features and advantages of the present invention will become more apparent from the detailed description of embodiments given below with reference to the drawings.

1 is a cross-sectional view showing a state of use of a branch pipe joint that is an embodiment of the present invention; FIG. FIG. 2 is a front view showing the branch pipe joint of FIG. 1; FIG. 2 is a plan view showing the branch pipe joint of FIG. 1; FIG. 2 is a bottom view of the branch pipe joint of FIG. 1; FIG. 2 is a left side view showing the branch pipe joint of FIG. 1; 4 is a cross-sectional view showing a cross-section of the branch pipe joint cut along line VI-VI of FIG. 3; FIG. FIG. 4 is an illustrative view for explaining a method for installing a branch pipe joint, and shows a concrete U-shaped groove before installing the branch pipe joint; FIG. 8 is an illustrative view showing a step following FIG. 7 , showing how the base of the branch pipe joint is fitted into the opening of the side wall of the concrete U-shaped groove. FIG. 9 is an illustrative view showing the process following FIG. 8 , showing how a formwork is installed around the branch pipe joint; FIG. 10 is an illustrative view showing a step following FIG. 9 , showing a state in which a filler is applied around the branch pipe joint; FIG. 11 is an illustrative view showing the process following FIG. 10 , showing how the branch pipe joint is fixed to the side wall of the concrete U-shaped groove.

Referring to FIG. 1, a branch pipe joint 10, which is one embodiment of the present invention, includes a base portion 12 and a branch pipe portion 14. The branch pipe 104 is mounted against a side wall 102 of a concrete U-shaped groove 100 called a small box. used to connect

Concrete U-shaped groove 100 (small box) is a reinforced concrete U-shaped groove for simultaneously accommodating and protecting multiple cables 106 such as underground communication lines and power lines instead of conventional conduits. and is buried in the ground so as to connect between the hand holes 108 (special parts). The concrete U-shaped groove 100 is basically buried so that the upper end face is exposed to the ground surface, and the upper opening is provided with a lid (not shown). However, the concrete U-shaped groove 100 may be covered with soil or the like, and the concrete U-shaped groove 100 may be buried at a predetermined depth from the ground surface so that the lid is not exposed. On the other hand, the branch pipe 104 is a pipe for leading a cable 106 (mainly a communication line) housed in the concrete U-shaped groove 100 to each home, and is made of synthetic resin such as rigid vinyl chloride resin.

The configuration of the branch pipe joint 10 will be specifically described below with reference to FIGS. 2 to 6. FIG. As shown in FIGS. 2 to 6, the branch pipe joint 10 is made of a synthetic resin such as hard vinyl chloride, and has a rectangular plate-like base portion 12 having a flat portion 18 on one main surface 12a, and the other main portion of the base portion 12. and a short cylindrical branch tube portion 14 projecting at a predetermined angle from the surface 12b. A substantially elliptical branch hole 16 is formed in the base portion 12 at a connecting portion with the branch pipe portion 14 . The branch hole 16 is a hole that allows communication between the one main surface 12a (flat surface portion 18) of the base portion 12 and the inside of the branch pipe portion 14. The inner surface of 14 is smoothly connected.

One main surface 12a of the base portion 12 is entirely planar except for the portion where the branch hole 16 is formed. That is, in this embodiment, the entire one main surface 12a is the plane portion 18. As shown in FIG. However, on the one main surface 12 a side of the base portion 12 , a recessed portion or the like may be formed, and only a part of the one main surface 12 a may be the flat portion 18 . At four corners of the base 12, chamfered portions 20 are formed by chamfering the corners.

Although the size of the base portion 12 is not particularly limited, it is preferable to form the base portion 12 in a size that allows it to be fitted into the knockout portion 110 of the concrete U-shaped groove 100 described later. In this example, the longitudinal length L of the base 12 is 342 mm, the width W of the base 12 is 100 mm, and the thickness T of the base 12 is 15 mm.

The branch pipe portion 14 is formed to protrude at an acute angle (oblique direction) with respect to the longitudinal direction of the base portion 12 . It extends at an acute angle with respect to the longitudinal direction of the gutter 100 . The branching angle (take-out angle) of the branch pipe portion 14 with respect to the base portion 12 (and the side wall 102 of the concrete U-shaped groove 100) is set to an angle at which the cable 106 can be pulled in smoothly, for example, 25 to 50°. set. Further, the obtuse angle side portion (the upper portion in FIGS. 1 and 2) of the branch tube portion 14 is curved with a predetermined radius of curvature R corresponding to the allowable radius of curvature of the cable 106 to be routed. In this embodiment, the branching angle of the branch tube portion 14 with respect to the base portion 12 is 45°, and the curvature radius R of the inner surface of the obtuse side portion of the branch tube portion 14 is 300 mm.

The tip of the branch pipe portion 14 is a spigot-shaped pipe connection portion that is connected to the branch pipe 104 (bent pipe member 116). A mark 22 is provided to indicate the length.

In addition, flat portions 24 that are flush with the widthwise side surfaces of the base portion 12 are formed on both outer side surfaces in the width direction of the base portion 12 at the proximal end portion of the branch pipe portion 14 . By providing the flat portion 24 on the outer surface of the branch pipe portion 14, when the branch pipe joint 10 is attached to the side wall 102 of the concrete U-shaped groove 100 as will be described later, the branch pipe joint 10 sits well. The branch pipe joint 10 can be stably held.

Furthermore, the width W of the base portion 12 is set to be the same or substantially the same size as the outer diameter R of the distal end portion of the branch pipe portion 14 . By minimizing the size of the base portion 12 in this manner, the size of the branch pipe joint 10 can be reduced, and the opening 112 (see FIG. 8) formed in the side wall 102 of the concrete U-shaped groove 100 is also small. will be enough. In addition, since the width direction side surface (and the flat portion 24) of the base portion 12 and the outer surface of the distal end portion of the branch pipe portion 14 are formed substantially on the same plane, the branch pipe can be formed on the side wall 102 of the concrete U-shaped groove 100. When the joint 10 is attached, the seating of the branch pipe joint 10 is improved so that the branch pipe joint 10 can be stably held. In this embodiment, as described above, the width W of the base portion 12 is 100 mm, whereas the outer diameter R of the distal end portion of the branch pipe portion 14 is 96 mm. The outer diameter of the connecting portion of the tube 104 is set to be the same size as the width W of the base portion 12 .

Next, a method for constructing (mounting) the branch pipe joint 10 to the side wall 102 of the concrete U-shaped groove 100 will be described with reference to FIGS. 7 to 11. FIG.

When constructing the branch pipe joint 10, first, the periphery of the construction site is excavated to expose the concrete U-shaped groove 100, and the branch pipe joint 10 is prepared at the construction site. In this embodiment, the branch pipe joint 10 is prepared in which the bent pipe member 116 forming part of the branch pipe 104 is connected to the distal end portion of the branch pipe portion 14 . As the bent pipe member 116, for example, a 45-degree bent pipe having a radius of curvature of 300 mm on the inner surface on the inner side in the bending direction (the portion connected to the inner surface of the obtuse angle side portion of the branch pipe portion 14) is used.

Next, an opening 112 is formed in the side wall 102 of the concrete U-shaped groove 100 for connecting the branch fitting 10 and extracting the cable 106 . At this time, as shown in FIG. 7, if a thin knockout portion 110 without reinforcing bars is formed in the side wall 102 in advance, the knockout portion 110 may be removed to form the opening 112. . When constructing the branch pipe joint 10 when newly laying the concrete U-shaped groove 100, the opening 112 is formed in advance in the side wall 102 of the concrete U-shaped groove 100 at a manufacturing factory or the like. You can leave it.

After the opening 112 is formed in the side wall 102 of the concrete U-shaped groove 100 , the branch pipe joint 10 is temporarily fixed to the opening 112 . In this step, the base portion 12 of the branch pipe joint 10 is fitted into the opening 112 , and the branch pipe joint 10 is held in a state in which the planar portion 18 of the base portion 12 of the branch pipe joint 10 is flush with the inner surface 102 a of the side wall 102 . Specifically, as shown in FIG. 8, the base portion 12 is fitted into the opening portion 112 from the outside of the concrete U-shaped groove 100, and a support member 114 such as plywood fixed with a tension bar is attached to the inner surface 102a side of the side wall 102. to prevent the base 12 of the branch pipe joint 10 from protruding inside the concrete U-shaped groove 100 . Further, as shown in FIG. 9 , a formwork 118 surrounding the branch pipe joint 10 is installed outside the concrete U-shaped groove 100 .

At this time, since the base portion 12 of the branch pipe joint 10 has the flat portion 18 on the one main surface 12a, it is easy to hold (temporarily fix) the inner surface 102a of the side wall 102 and the one main surface 12a of the base portion 12 flush with each other. By keeping them flush with each other, it is possible to prevent the branch pipe joint 10 from being slanted and fixed. In addition, since the outer surface of the branch pipe portion 14 has the flat portion 24 and the width W of the base portion 12 is substantially the same as the outer diameter R of the distal end portion of the branch pipe portion 14, the branch pipe joint 10 can be easily seated. As a result, the branch pipe joint 10 can be stably held.

After the branch pipe joint 10 is temporarily fixed to the opening 112, the branch pipe joint 10 is subsequently fixed to the side wall 102 of the concrete U-shaped groove 100 with a filler 120 such as mortar. Specifically, as shown in FIG. 10 , a filling material 120 is applied in the mold 118 to seal the space between the opening 112 and the outer surface of the branch pipe joint 10 with the filling material 120 . Further, in this embodiment, the filler 120 is applied so as to fill up to the connecting portion between the branch pipe portion 14 of the branch pipe joint 10 and the bent pipe member 116 . After curing for a predetermined time, when the filler 120 is solidified, the mold 118 is removed as shown in FIG. After that, the inner surface 102a of the side wall 102 of the concrete U-shaped groove 100 is finished with a filling material 120 such as mortar so that there is no protrusion, and the construction work of the branch pipe joint 10 for the concrete U-shaped groove 100 is completed.

As described above, according to the branch pipe joint 10 of this embodiment, since the base portion 12 having the flat portion 18 on the one main surface 12a is provided, the inner surface 102a of the side wall 102 and the one main surface 12a of the base portion 12 are flush with each other. It is easy to hold in place, and it is possible to appropriately prevent the branch pipe joint 10 from being slanted and fixed.

In addition, since the branch pipe portion 14 branches at a predetermined angle with respect to the base portion 12 (and the side wall 102 of the concrete U-shaped groove 100), the cable 106 can be taken out while ensuring a predetermined radius of curvature. The load applied to the taken out cable 106 can be reduced.

Furthermore, since the branch pipe portion 14 has the flat portion 24 on the side surface of the proximal end portion, the branch pipe joint 10 can be satisfactorily satisfactorily when the branch pipe joint 10 is installed, and the branch pipe joint 10 can be held stably.

Furthermore, since the width W of the base portion 12 of the branch pipe joint 10 is set to be the same or substantially the same size as the outer diameter R of the tip portion of the branch pipe portion 14, the branch pipe joint 10 can be made smaller. Moreover, when the branch pipe joint 10 is installed, the branch pipe joint 10 can be satisfactorily satisfactorily, and the branch pipe joint 10 can be held stably.

In addition, according to the construction method of the branch pipe joint 10 of this embodiment, since the branch pipe joint 10 is connected to the side wall 102 of the concrete U-shaped groove 100, the cable 106 can be pulled in to each household by the shortest route. can reduce construction costs.

In addition, since the branch pipe joint 10 is connected to the concrete U-shaped groove 100 with the inner surface 102a of the side wall 102 and the flat portion 18 of the base portion 12 flush with each other, the cable 106 is not damaged by the edge of the opening 112. is prevented, and the cable 106 can be smoothly guided to the branch pipe portion 14 (and thus to the branch pipe 104).

Furthermore, when connecting the branch pipe joint 10 to the side wall 102 of the concrete U-shaped groove 100, the base 12 is fitted into the opening 112, so the shape and dimensions of the concrete U-shaped groove 100 and the opening 112 The branch pipe joint 10 can be connected to the concrete U-shaped groove 100 regardless of the formation position of the . Also, the branch pipe joint 10 can be connected to the concrete U-shaped groove 100 in which the cable 106 is accommodated.

Furthermore, by embedding the entire branch pipe joint 10 including the connecting portion with the bent pipe member 116 in the filling material 120 , the entire branch pipe joint 10 is protected by the filling material 120 . Therefore, even if a load is applied from the ground surface, damage to the branch pipe joint 10 itself can be prevented, and damage to the connecting portion between the branch pipe joint 10 and the side wall 102 can be prevented.

In the above-described embodiment, the base 12 of the branch pipe joint 10 was formed in a rectangular plate shape, but the specific shape of the base 12 can be changed as appropriate, and can be formed in an elliptical plate shape or the like. Further, the shape of the other principal surface 12b of the base portion 12 is not particularly limited, and the other principal surface 12b may be formed into a curved surface. Furthermore, the other main surface 12b of the base portion 12 and the outer surface of the proximal end portion of the branch pipe portion 14 can be reinforced with FRP (fiber reinforced plastic) or the like.

At least one of the end surface and the side surface of the base portion 12 may be formed with a hook portion projecting outward from the portion on the other main surface 12b side. For example, the thickness T of the base portion 12 is formed slightly larger than the thickness of the knockout portion 110, and when the base portion 12 is fitted into the opening portion 112, the hanging portion of the base portion 12 is hooked on the outer surface of the peripheral portion of the knockout portion 110. Thus, it is preferable that the flat portion 18 of the base portion 12 and the inner surface 102a of the side wall 102 are flush with each other. Alternatively, the thickness T of the base portion 12 is formed to be slightly larger than the thickness of the side wall 102, and when the base portion 12 is fitted into the opening 112, the hook portion of the base portion 12 is hooked on the outer surface of the side wall 102. 12 flat portion 18 and the inner surface 102a of the side wall 102 may be flush with each other. However, this is premised on the knockout portion 110 or the side wall 102 having a predetermined thickness.

Furthermore, in the above-described embodiment, the concrete U-shaped groove 100 is exemplified as a reinforced concrete U-shaped groove, but the concrete U-shaped groove 100 may be a resin concrete U-shaped groove.

It should be noted that the specific numerical values such as the dimensions and the specific shapes given above are merely examples, and can be appropriately changed according to the needs such as the specifications of the product.

DESCRIPTION OF SYMBOLS 10... Branch pipe joint 12... Base part 14... Branch pipe part 16... Branch hole 18... Flat part 24... Flat part 100... Concrete U-shaped groove 102... Side wall 104... Branch pipe 112... Opening part 120... Filling material

Claims (4)

A branch pipe joint installation structure in which a synthetic resin branch pipe joint for connecting a branch pipe to the side wall of a concrete U-shaped groove for housing and protecting a cable is installed on the side wall ,
The branch pipe joint is
A plate-shaped base having a flat portion on one main surface,
a cylindrical branch pipe portion projecting at a predetermined angle from the other main surface of the base portion;
The base portion and the branch pipe portion are integrally molded,
The planar portion is not bent and consists only of a planar surface that can be flush with the inner surface of the side wall when the branch pipe joint is connected to the side wall of the concrete U-shaped groove,
the proximal end of the branch pipe portion has a flat portion on the outer surface in the width direction of the base;
The side walls are
having an opening with a larger opening area than the base of the branch pipe joint,
An installation structure for a branch pipe joint, wherein the base portion of the branch pipe joint is arranged in the opening, and the flat portion is fixed in a state of being flush with the inner surface of the side wall. 2. The installation structure of a branch pipe joint according to claim 1, wherein the width of said base is set to be the same as or substantially the same as the outer diameter of the tip of said branch pipe. A method for constructing a synthetic resin branch pipe joint for connecting a branch pipe to a side wall of a concrete U-shaped groove for housing and protecting a cable therein, comprising:
(A) A plate-shaped base having a flat portion on one principal surface, a cylindrical branch pipe portion protruding from the other principal surface of the base at a predetermined angle, and the flat portion and the branch pipe formed on the base. The base portion and the branch pipe portion are integrally molded, and the flat portion is not bent and is attached to the side wall of the concrete U-shaped groove. It consists only of a flat surface that can be flush with the inner surface of the side wall when the branch pipe joint is connected, and the base end portion of the branch pipe portion has a flat portion on the outer surface in the width direction of the base portion. providing the branch fitting;
(B) forming an opening having a larger opening area than the base of the branch pipe joint in the side wall of the concrete U-shaped groove;
( C ) After the step (A) and the step (B) , the base portion of the branch pipe joint is fitted into the opening formed in the side wall of the concrete U-shaped groove, and the flat portion is aligned with the side wall. ( D ) after step ( C ), filling to seal between the opening and the outer surface of the branch fitting; A method of installing a branch fitting, comprising: securing the branch fitting to the concrete U-channel by applying and solidifying material. In step (A), the branch pipe joint is prepared in a state in which a curved pipe member is connected to the tip of the branch pipe portion,
4. The branch pipe joint construction method according to claim 3, wherein, in said step ( D ), said filler is applied so as to fill up to a connecting portion between said branch pipe portion and said bent pipe member.

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