JP2769425B2 - Bending bolt insertion hole protection tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective tube for protecting a bent bolt insertion hole when a concrete segment is connected by using a bent bolt.

[0002]

2. Description of the Related Art A bent bolt type joint as a joint type for connecting concrete segments to each other (1) exhibits a well-balanced resistance to positive and negative moments. (2) Bolts and nuts do not rotate, so they can be easily tightened and workability is excellent. (3) There is no corroded portion in the joint part and the durability is excellent. It is trying to replace the straight bolt type joint for such reasons. However, there is a problem that the stress of the joint part concentrates on the bolt insertion hole and causes cracks in the concrete of the insertion hole wall early, and as a countermeasure, it has been proposed to reinforce the insertion hole peripheral wall with a curved pipe with a flange. ing. (No. 59-7440, No. 60-272)
No. 00)

[0003]

In the above-mentioned reinforcing method, the stress generated by the deformation of the bending bolt when tightening the bending bolt is supported only by the inner bay portion of the bending pipe.
The stress will be mainly resisted by the concrete under the inner bay. For this reason, when the stress generated at the time of connecting the concrete segments is large, only the concrete below the inner bay portion cannot sufficiently resist, and a crack may occur.

[0004]

SUMMARY OF THE INVENTION The present invention reduces the occurrence of cracks in a joint by avoiding local stress concentration by widely dispersing and transmitting the stress generated when the concrete segments are connected to the entire concrete of the joint. It is to prevent.

That is, the present invention relates to a bent bolt insertion hole protection tube formed by integrally casting a cylinder curved in an arc shape with a predetermined curvature and a plurality of studs standing upright on the outer bay side of the cylinder. .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 (a) is a longitudinal sectional view showing a state in which a concrete segment in which a bent bolt insertion hole protective tube of the present invention is embedded in a joint portion is joined at a segment joining surface, and a bent bolt is inserted into the insertion hole. , FIG.
It is an AA arrow line view of (a).

An insertion hole protection tube is buried in the joint portion of each concrete segment 1 so as to cover the entire length except for the entire length or a very small portion of the curved bolt insertion hole from the joint hole 2 to the segment joint surface 3. I have. The insertion hole protection tube is integrally cast so as to form a curved cylinder 5 and two studs 6A and 6B having different heights standing upright on the outer bay side of the cylinder 5. The inner diameter of the protection tube is made as small as possible within a range in which a bending bolt can be inserted. FIG. 1A shows a case where the insertion hole protection tube is buried so as to cover the entire length except for a very small part of the bolt insertion hole 7, but it is preferable that the protection tube is buried so as to cover the entire length. A part of the uncovered part is formed by one kind of protective tube integrally cast with a constant curvature, and has insertion holes 7 having the same curvature and the insertion holes 7 of several types of concrete segments 1 having different lengths of the insertion holes 7. This is because the protective tube is manufactured in accordance with the length of the insertion hole 7 of the concrete segment 1 having the shortest insertion hole 7 for protection. If several types of protective tubes are manufactured according to the length of each insertion hole 7, such a situation does not occur, but the cost is increased. When an uncoated part is left in a part, the uncoated part is left on the segment joining surface side as shown.

When covering the entire length of the insertion hole 7 with a protective tube, as shown in FIG. 1C, the end of the cylinder of one of the protective tubes on the segment joining surface side is a convex end 9A and the other is a convex end 9A. The end of the cylinder of the protection tube is a concave end 9B,
It is preferable to connect them by fitting. In addition, as shown in FIG. 1 (a), a protrusion 10 for supporting reinforcement may be formed on the inner bay side of the protective tube as necessary.

In the protective tube of the present invention, it is not necessary to provide a stud on the inner bay side in view of the shape of the joint portion, the thickness of the concrete, and the like, and the stud is provided on the outer bay side. As shown in FIG. 1 (a), two outer studs, 6A on the joint hole 2 side and 6B on the segment joint surface 3 side, are usually sufficient just above the outer bay side. 7 may be added in the middle corresponding to the size and length of the concrete segment 1 and the size and length of the concrete segment 1. Also, the studs are not necessarily placed just above the outer bay side, but two cylinders 6C and 6D are arranged at positions slightly inclined as shown in FIG. Or two on the joint hole 2 side, 6C and 6D,
A total of four, 6C and 6D, may be arranged on the segment joining surface 3 side. Similarly, as shown in FIG. 2B, the position in the cylindrical axis direction is shifted to a position directly above and slightly inclined, and 6E,
6F, 6G may be arranged, three 6E, 6F, 6G on the joint hole 2 side, and six on the segment joint surface 3 side.
E, 6F, and 6G, that is, three lines in total, may be arranged. Thus, the optimal number of studs is formed at a suitable position on the outer bay side. In this way, about 2 to 6 studs are provided for each protection tube, and the tip projections are dispersed in the concrete of the concrete segment 1 by changing the height of each stud.

The protection effect of the protection tube of the present invention on the insertion hole 7 will be described. The bending bolt 4A inserted into the insertion hole 7 is tightened by the nut 4B. As the bolt is tightened, a force for straightening acts on the bending bolt 4A, and a force for straightening the curved cylinder 5 of the protective tube acts. Since the gap between the bending bolt 4A and the cylinder 5 is made as small as possible, this force is transmitted to the cylinder 5 from the beginning of the tightening. The cylinder 5 is integrated with the outer bay side studs 6A, 6B, and the force transmitted to the cylinder 5 is immediately transmitted to the studs 6A, 6B. Since the studs 6A and 6B are restrained by the concrete on the outer bay side, the stress generated by the tightening is transmitted to the concrete on the outer bay side. The concrete on the outer bay side has a sufficient casting thickness, and the stress is dispersed and borne by the dispersed arrangement of the studs 6A and 6B. Therefore, even if the generated stress is large, it can sufficiently resist.

[0012]

According to the present invention, the bending bolt insertion hole is covered almost entirely with a protective tube having a plurality of studs on the outer bay side, so that the stress generated when the bending bolt is tightened passes through the protective pipe to the entire concrete on the joint outer bay side. Widely distributed transmission avoids local stress concentration.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view showing a state in which a concrete segment in which a bent bolt insertion hole protective tube of the present invention is embedded in a joint portion is joined at a segment joining surface, and a bent bolt is inserted into the insertion hole; (B) is an AA arrow view of (a). (C) is a longitudinal sectional view in which the ends of the protective tube cylinder are connected by male and female fitting at the segment joining surface.

FIG. 2 is a cross-sectional view of a protective tube in which studs are also formed in directions other than directly above the outer bay side of the protective tube cylinder, (a) having studs formed in two directions other than directly above, (b) Indicates studs formed in three directions including directly above.

[Explanation of symbols]

1 ・ ・ Concrete segment 、 2 ・ ・ Joint hall 、 3
..Segment joint surface, 4A..Bending bolt, 4B.
・ Nut, 5 ・ ・ Curved cylinder, 6A, 6B, 6C, 6D,
6E, 6F, 6G, stud, 7 ... bent bolt insertion hole, 8: unprotected portion of protective tube, 9A: cylindrical convex end, 9B: cylindrical concave end, 10: protrusion for reinforcing bar attachment.

Claims (1)

(57) [Claims] 1. A bent bolt insertion hole protection tube obtained by integrally casting a cylinder curved in an arc shape with a predetermined curvature and a plurality of studs standing upright on the outer bay side of the cylinder.