JP2645690B2 - Forming method of split box culvert and forming tool therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a split box culvert and a tool therefor.

[0002]

2. Description of the Related Art Box culverts are used when constructing culverts and the like. In particular, when constructing a large culvert, a box culvert is formed by separately molding a block having a shape obtained by dividing the box culvert into two or three parts in the horizontal direction and assembling them on site. ing. Such a box culvert is called a split box culvert.

In the split box culvert, as shown in FIG. 4, PC steel rods c and d are inserted into a side wall a of an upper block A and a side wall b of a lower block B, respectively. d is connected to each other by a coupler e at the junction of the two blocks A and B, whereby the upper and lower blocks A and B are connected to each other;
Tension is applied to the side walls a and b to increase the strength.

In such a split box culvert, as shown in FIG. 5, a coupler receiving recess f is formed on the upper surface of the side wall b of the lower block B, and the side wall b
A PC steel rod d is embedded in the coupler steel rod, and the upper end of the PC steel rod d is projected into the coupler housing recess f. The lower end of the PC steel rod d is fixed in the block B by the anchor plate g.

In such a split box culvert, as shown in FIG. 5, when assembling the upper and lower blocks, a coupler e is first screwed into the tip of the PC steel bar d in the recess f. Next, the upper block A is placed on the lower block B, and the PC steel rod c is inserted from the upper end of the sheath hole h of the upper block A, and the lower end of the PC steel rod c is screwed to the coupler e. Then, the PC steel rod c
The upper end of the PC is pulled up with a jack or the like, and PC steel bars c and d
Is tightened, the upper end of the PC steel bar c is fastened to the upper block A by the anchor plate i and the nut j.

[0006]

By the way, the lower block B is formed so that the joint portion is located downward as shown in FIG. 6 as an example. And PC steel rod d
Has one end supported by a mold 1 or the like via a holder k, and the other end inserted into the hole n of the coupler housing concave mold m and positioned in the mold o via the coupler housing concave mold m. Is done. Then, concrete is poured into the formwork in this state, and the lower block B is formed.

[0007] The block B thus formed is released after being cured. In this demolding work, block B
Is removed from the mold while the mold m for coupler housing recess is attached, and then the mold m for coupler housing recess is taken out from the block B.

Therefore, the hole n in the coupler housing concave mold m is tapered to make it easy to come off, as is clear from FIG. Therefore, there is a possibility that the concrete may flow into the hole n when the concrete is poured, and when the concrete flows, the concrete adheres to the tip of the PC steel rod d. In that case, when screwing the coupler e, the mortar must be removed, and the work of attaching the coupler e becomes complicated.

Also, the work of mounting the coupler e must be performed in the coupler housing recess f, and the work is not easy. Furthermore, a coupler storage recess with enough space to perform the work must be formed,
Although grout is filled in the concave portion later, it is disadvantageous in strength as a box culvert.

An object of the present invention is to provide a split box culvert which facilitates the work of assembling a PC steel bar and is advantageous in strength.

[0011]

In the method of forming a split box culvert according to the present invention, an unbonded PC steel rod having an anchor plate and a nut fixed to a base end thereof is arranged at a predetermined position in a lower block formwork. A coupler is screwed into the end of the PC steel rod, and a mold for a concave portion for housing the coupler is arranged on the joint surface with the upper block so as to cover the coupler, and concrete molding is performed.

[0012]

In the method of forming a split box culvert according to the present invention, since the mold is formed while the coupler is screwed onto the tip of the PC steel rod, there is no possibility that concrete will adhere to the tip of the PC steel rod. If the concrete flows between the tip of the PC steel bar and the coupler, it has no effect on the operation because the coupler is already installed.

[0013]

1 to 3 show a split box culvert according to the present invention. This divided box culvert is divided into an upper block 1 and a lower block 2.

In forming the lower block 2, a steel coupler housing recess forming tool 10 as shown in FIG. 1 is used. The coupler housing recess forming tool 10 includes a coupler housing recess mold 11 for forming the coupler housing recess 3 and a bolt 12 for fastening the mold to the coupler. The coupler housing concave mold 11 has a truncated cone shape. A flange 1 is provided at the large-diameter end.
1a is formed. Further, a concave portion 11b is formed in the center of the small-diameter side end surface of the coupler housing concave mold 11, and a hole 1 reaching the concave portion 11b is formed in the center of the large-diameter end surface.
1c is penetrated.

On the other hand, the coupler 13 has a screw hole 13
a, and a taper 13b is formed in the screw hole opening on the end face. Further, a pin 14 is implanted at an intermediate portion of the peripheral surface of the coupler 13.

When the lower block 2 is formed, the coupler 13 is screwed into the tip 15a of the PC steel rod 15 until the tip 15a of the unbonded PC steel rod 15 contacts the pin 14. Is fitted into the coupler 13 and then the bolt 12 is inserted into the hole 11c.
Through the end of the bolt 12 and the coupler 1
3 is screwed into the screw hole 13a, and the tip portion 15a of the PC steel bar 15 supports the coupler housing concave mold 11.

As shown in FIG. 6, the PC steel rod 15 is mounted on the bottom of the mold frame 30 with the coupler accommodating recess forming tool 10 and positioned there.
Side end 15b is fixed to the upper part of the mold 30 by a holder or the like. Then, concrete is poured into the formwork 30 in this state.

The lower block 2 molded and cured in this manner is, together with the coupler housing concave forming tool 10,
It is taken out of the mold 30. Then, the bolt 12 is removed from the coupler 13, and then the coupler housing concave mold 11 is taken out from the lower block 2.

FIG. 2 shows the lower block 2 formed in this manner. In the lower block 2, a coupler housing recess 3 is formed in an upper portion, and an annular cutout 4 for housing a gasket is formed in the periphery of the opening end of the recess 3.
Are formed. Then, in the coupler storage recess 3,
A coupler 13 is arranged, and the coupler 13 holds the upper end of the unbonded PC steel bar 15. This PC steel rod 1
The lower end of 5 is held by a buried anchor plate 16. Note that the upper surface 2a of the side wall of the lower block 2
, Two grooves 5 are formed at both ends of the lower block 2, and a pin hole 6 is formed between the recesses 3, 3.

In the lower block 2 thus formed, as shown in FIGS. 2 and 3, an annular gasket 17 is mounted in the notch 4 of the coupler housing recess 3, and a rod-shaped gasket 18 is inserted in the groove 5. With the pin hole 6
The pin 19 is inserted into the connector. Then, the upper block 1 is superimposed on the lower block 2, and the pins 19 are fitted into pin holes (not shown) of the upper block 1 to position the upper block 1. Next, the sheath hole 1a of the upper block 1
, A PC steel rod 20 is inserted from the recess 1b,
a is screwed into the screw hole 13 a of the coupler 13.

Next, one end 20b of the PC steel bar 20 is pulled up with a jack or the like, and the PC steel bar 20 and the PC steel bar 15 of the lower block 2 are pulled tight. Then, as shown in FIG. 3, after the anchor plate 21 is positioned on the bottom surface of the concave portion 1b, the nut 22
To settle there.

Next, grout is injected from the concave portion 1b of the upper block 1 through the injection hole 21a of the anchor plate 21 to fill the coupler housing concave portion 3 and the sheath hole 1a. At this time, the annular gasket 17 prevents the grout from flowing out from between the upper and lower blocks 1 and 2 to the outside. Thereafter, the concave portion 1b is closed with mortar or the like. In addition, the rod-shaped gasket 18 is
The seal between the two is performed to prevent the water and the like inside the box culvert from leaking to the outside after construction, and to prevent intrusion of water and the like from the outside.

[0023]

As described above, in the block molding method of the split box culvert according to the present invention, since the lower block is molded while the coupler is mounted on the tip of the PC steel bar, the concrete is formed of PC. There is no danger of sticking to the tip of the steel rod, and even if concrete flows between the tip of the PC steel rod and the coupler, the work is not affected at all since the coupler is already installed. . Therefore, the work of assembling the blocks is facilitated.

Further, since there is no need to perform the work of mounting the coupler in the coupler housing recess, the coupler housing recess does not need to be so large. Therefore, the strength of the box culvert can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a coupler housing recess forming tool for carrying out a block forming method of a split box culvert according to the present invention.

FIG. 2 is a partial perspective view showing a formed lower block in a partial cross section.

FIG. 3 is a cross-sectional view showing a state where a split box culvert is assembled.

FIG. 4 is a perspective view showing a split box culvert.

FIG. 5 is an exploded sectional view for explaining an assembling operation of a conventional split box culvert.

FIG. 6 is a cross-sectional view for explaining a forming operation of the lower block.

FIG. 7 is a cross-sectional view showing a coupler housing recess forming tool used in block forming of a conventional split box culvert.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper block 2 Lower block 3 Coupler storage recess 4 Ring-shaped notch 10 Coupler storage recess forming tool 11 Coupler storage recess mold 11a Flange 11b Recess 11c Hole 12 Bolt 13 Coupler 13a Screw hole 13b Taper 14 Pin 15 Unbonded PC steel rod 15a Tip 16 Anchor plate 17 Gasket 20 PC steel bar 21 Anchor plate 22 Nut 30 Formwork

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kojiro Yuki 2-10-22 Misonocho, Kodaira-shi, Tokyo (72) Inventor Hideki Mishima 1-36-1-830, Toganecho, Katsushika-ku, Tokyo (72) Invention Akira Honma Akira Owari, Ina-cho, Tsukuba-gun, Ibaraki Pref.

Claims (3)

(57) [Claims] 1. A box having a shape obtained by dividing a box culvert into a plurality of pieces in the horizontal direction is formed by molding, and PC steel bars inserted into respective side walls thereof are connected to each other by a coupler. ,
In a method of forming a split-type box culvert in which tension is applied to a side wall, an unbonded PC steel rod having an anchor plate and a nut fixed to a base end thereof is disposed at a predetermined position in a lower block formwork, and the PC steel rod is provided. A method of forming a split-type box culvert, characterized in that a coupler is screwed into a tip of the box, and further, the coupler is covered with the coupler, and a mold for the concave portion for housing the coupler is arranged on the joint surface with the upper block to form concrete. . 2. A coupler housing concave mold having a peripheral surface forming an inner peripheral surface of a coupler housing concave portion, a concave portion for housing a coupler at a lower end center portion, and a bolt insertion hole penetrating from the upper surface to the concave portion. 2. A bolt which is inserted into the bolt insertion hole of the coupler housing recess mold, and a tip of which is screwed to the coupler to fasten the coupler housing recess mold to the coupler. A coupler housing concave forming tool used in the block forming method of the split box culvert. 3. The coupler used in the block molding method for a split box culvert according to claim 1, wherein a pin for regulating the insertion amount of the PC steel rod is implanted in the middle.