JPH0551739B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a butt joint structure for threaded reinforcing bars using a metal reinforcing bar connector that is a hollow tubular body with open flanges at both ends. ,
The pair of joined reinforcing bars are fixed to the reinforcing bar connector by fixing one with hardened mortar and the other by tightening with nuts.

(Prior Art) Currently, most of the reinforcing bars used in reinforced concrete structures are deformed reinforcing bars. Deformed reinforcing bars are reinforcing bars whose surfaces are provided with an uneven pattern of ribs and ribs to improve adhesion to concrete, and these uneven patterns vary greatly depending on the manufacturer. Recently, threaded reinforcing bars with male threads provided as this uneven pattern have been provided. This has the advantage that various jigs (nuts, couplers, etc.) can be screwed onto the outside of the screw, but since the male screw was originally provided as a means to improve adhesion to concrete, JIS The male threads do not conform to the standard, and the patterns vary depending on the manufacturer. Therefore, the patterns of the female threads provided on the various jigs that are screwed onto these jigs differ depending on the pattern of the threaded reinforcing bars to which they are attached, and these jigs are specified for each threaded reinforcing bar manufacturer and are not compatible. .

There is a coupler method shown in FIG. 3 as a butt joining method for threaded reinforcing bars (hereinafter simply referred to as reinforcing bars). In this method, the ends of a pair of reinforcing bars 2 and 2' are screwed into a coupler 1, which is a tubular body with a female thread provided over the entire circumferential length of the inner wall. Although this method is easy to work with, it requires that the axes of the pair of reinforcing bars 2 and 2' coincide completely, and as will be described later, it is not suitable as a reinforcing bar joining method between precast concrete members. There is a sleeve coupler method shown in FIG. 3 as a reinforcing bar joining method that improves this point. (Jikko 52
-3296) This consists of a first hole 4 that has a female thread on its inner circumferential surface that can be screwed into a male thread of a reinforcing bar, and a second hole 4 that has a diameter larger than the diameter of the reinforcing bar and has an uneven inner circumferential surface. Using the reinforcing bar connector 3, which is a cylindrical member having a hole 5, one of the reinforcing bars 2 and 2' to be joined is screwed into the first hole 4, and the other reinforcing bar 2' is screwed into the first hole 4. Insert the end of into the second hole 5,
Next, the second hole 5 is filled with mortar 6 and hardened to form a bond.

This method is particularly advantageous as a method for joining reinforcing bars between precast concrete members (hereinafter referred to as PC members). That is, as shown in FIG. 5, a PC member 7 in which the reinforcing bar connector 3 with the first hole 4 screwed into one end of the member reinforcing bar 2 is buried (the second hole 5 is open at the end face of the member) The PC member 7', in which the end of the member reinforcing bar 2' is exposed and protrudes from the end face of the member, is erected by inserting the exposed end into the second hole 5. This method connects the reinforcing bars 2 and 2' between the PC members by filling the holes of 2 with mortar. In terms of design, the axes of the pair of reinforcing bars 2 and 2' to be joined should match, but the axes may deviate somewhat due to errors in the manufacturing of PC parts, errors in construction, etc. It is something. (This is called a construction error.) In the coupler method, if there is a construction error, it becomes impossible to join, but with the above method, even if the axis is slightly shifted, the reinforcing bar 2' can be inserted into the second hole 5. Since it is possible, joining is possible. (This is called absorption of construction errors.) (Problems to be solved by the invention) The reinforcing bar joining method using the reinforcing bar joining tool 3 as shown in Fig. 4 (referred to as the sleeve coupler method) is
In addition to absorbing construction errors that cannot be avoided when connecting reinforcing bars between PC members, when manufacturing PC members,
There is an advantage that the work of attaching reinforcing bar connectors to the ends of reinforcing bars of members within the formwork can be carried out simply and easily. However, the female thread pattern provided on the inner peripheral surface of the first hole 4 must be in a threaded relationship with the male thread pattern of the reinforcing bar, and the male thread pattern of this threaded reinforcing bar varies depending on the manufacturer as described above. As a result, there is a problem in that the reinforcing bar connector 3 that is compatible with one manufacturer's reinforcing bars cannot be used with another manufacturer's reinforcing bars, and is so-called incompatible.

An object of the present invention is to provide a reinforcing bar joining method that solves the above problems without impairing the above-mentioned advantages of the sleeve coupler method.

(Means for solving the problems) The present invention will be explained with reference to FIG. That is, the present invention is an essential butt joint structure of threaded reinforcing bars in which a pair of threaded reinforcing bars 2 and 2' are joined using a metal reinforcing bar connector 8, and (a) there is a narrow joint at one end. (b) One threaded reinforcing bar 2 is inserted through the opening of the narrow-mouth flange 9 into the reinforcing bar connector 8, which is a hollow tubular body provided with a mouth flange 9 and a wide-mouth flange 9' at the other end. Tighten the nut 13 so that the retainer 12 provided at the end tightly contacts the inner surface 10 of the narrow flange, and the tightening nut 13 screwed onto the threaded reinforcing bar 2 tightly contacts the outer surface 11 of the narrow flange. (c) The other threaded reinforcing bar 2' is inserted into the reinforcing bar connector 8 through the opening of the wide flange 9'. This is a threaded reinforcing bar joint structure characterized by being fixed by hardened mortar 6 filled therein.

Narrow flange 9 of reinforcing bar connector 8 in the present invention
The size of the opening is smaller than the size of the retaining body 12, and the size of the wide mouth flange 9' is larger than the size of the retaining body 12. Further, it is preferable to provide an uneven pattern on the inner circumferential surface of the reinforcing bar connector 8 in order to enhance the engagement with the hardened mortar 6. Among these uneven patterns, a particularly preferable pattern is described in JP-A No. 61-200246. It is a protrusion that looks like it is. This protrusion is an annular or spiral protrusion extending approximately perpendicularly to the axial direction of the reinforcing bar connector 8, and its height gradually decreases from the wide-mouth flange 9' toward the narrow-mouth flange 9. It is something. The shape of the main body of the reinforcing bar connector 8 is usually a straight pipe shape whose cross-sectional size is the same over the entire length in the axial direction, but it may have a shape that is not the same, and the cross-sectional shape is usually circular. Yes, but not limited to this. The shape of the narrow inner flange 9 may be such that its thickness is approximately the thickness required for strength as shown in Fig. 1, or it may be considerably thicker than the required thickness as shown in Fig. 2a. The opening may also be shaped to serve as a reinforcing bar insertion guide. In addition, as shown in Fig. 2b, a pipe section 1 for reinforcing bar insertion guide is provided.
4 may be added. Furthermore, as shown in FIG. 2c, if the opening diameter of the narrow flange 9 is tapered so as to open from the inside to the outside, it is convenient for inserting the reinforcing bars 2.

The retaining body 12 is provided at the end of the reinforcing bar 2 to prevent the reinforcing bar 2 inserted into the reinforcing bar connector from slipping out from the opening of the narrow flange. , screwing a nut, fixing a disk, etc.

The filling of the hardened mortar 6 is performed by filling unhardened mortar and then hardening it. It is preferable that the hardened mortar has high strength.
In addition, it is more preferable that the material is non-shrinkable.

In the threaded reinforcing bar joint structure of the present invention, there is a gap between the opening of the narrow inner flange 9 and the reinforcing bar 2 passing through it, and there is a risk that lateral displacement is likely to occur when shear force is applied to the joining reinforcing bar. There is. In order to prevent this, it is preferable to fill this gap with a filler (for example, cement paste, cement mortar, epoxy resin, etc.), and one method for doing so is to press-fit iron particles. This press-fit filling can be performed by tightening the tightening nut 13.

The required insertion length of the reinforcing bar 2' into the reinforcing bar connector 8 is:
Although it varies depending on the design value of the bond strength and the degree of adhesion between the hardened mortar and the reinforcing bars 2', it is usually about 5 to 8 times the nominal diameter of the reinforcing bars 2'.

(Function) The retaining body 12 has a function of preventing the reinforcing bars 2 from coming off, and also works together with the tightening nut 13 to prevent the reinforcing bars 2 from coming off.
It has the function of fixing the flange 9 to the narrow flange 9. The hardened mortar 6 has the function of fixing the reinforcing bars 2' in the reinforcing bar connector 8, and the wide-mouthed flange prevents the hardened mortar from slipping out by having its opening size smaller than the size of the main body of the reinforcing bar connector 8. This has the effect of increasing the strength of reinforcing steel joints. This effect will further increase if the inner peripheral surface of the reinforcing bar connector 8 is provided with an uneven pattern. The male thread shape provided on the surface of the reinforcing bar is useful for screwing the tightening nut 13 in the case of the reinforcing bar 2, and in the case of the reinforcing bar 2', it has the effect of increasing engagement with hardened mortar and increasing joint strength.
In addition, the opening of the narrow flange 9 and the reinforcing bar 2 passing through it
Filling the gap with a filler (particularly iron particles) has the effect of increasing the resistance to shearing force acting on the joint.

(Effects of the Invention) The present invention adopts a tightening and fixing means that works together with a retaining body and a tightening nut, instead of fixing the threaded reinforcing bar to the reinforcing bar connector by screwing it in the conventional sleeve coupler system. It can be applied regardless of the male thread pattern provided on the surface of the threaded reinforcing bar, and completely solves the drawback of incompatibility in the conventional sleeve coupler system. Moreover, the advantages of the conventional sleeve coupler method are that when manufacturing precast concrete members, it is easy to attach reinforcing bar connectors to the ends of the member's reinforcing bars in the formwork prior to concrete pouring, and precast concrete members The advantage of being able to easily absorb construction errors when joining the reinforcing bars between the two is not lost in any way.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a reinforcing bar joining structure of the present invention, and FIG. 2 is a longitudinal sectional view showing various embodiments of a reinforcing bar joining tool used in the invention. FIG. 3 is a longitudinal cross-sectional view showing how reinforcing bars are joined using the coupler method, and FIG. 4 is a vertical cross-sectional view showing how reinforcing bars are joined using the conventional sleeve coupler method. FIG. 5 is a diagram showing a state of joining between precast concrete members using the sleeve coupler method. The symbols in the figure are as follows. 1: Coupler, 2, 2': Threaded reinforcing bar, 3:
Rebar connector, 4: first hole, 5: second hole,
6: mortar, 7, 7': precast concrete member, 8: reinforcing bar connector, 9: narrow flange,
9': Wide mouth flange, 10: Inner side, 11: Outer side, 12: Retainer, 13: Tightening nut, 1
4: Pipe part.

Claims (1)

[Scope of Claims] 1. An essential butt joint structure of threaded reinforcing bars in which a pair of threaded reinforcing bars 2 and 2' are joined using a metal reinforcing bar connector 8, which includes: (a) one end of the threaded reinforcing bars; (b) One threaded reinforcing bar 2 is inserted through the opening of the narrow flange 9 into the reinforcing bar connector 8, which is a hollow tubular body provided with a narrow flange 9 and a wide flange 9' at the other end. Tighten the nut so that the retaining body 12 provided at the end thereof comes into close contact with the inner surface 10 of the narrow-mouthed flange, and the tightening nut 13 screwed onto the threaded reinforcing bar 2 comes into close contact with the outer surface 11 of the narrow-mouthed flange. 13 is tightened, the threaded reinforcing bar 2 is fixed to the narrow flange 9 (c) The other threaded reinforcing bar 2' is inserted into the reinforcing bar connector 8 through the opening of the wide flange 9'. A threaded reinforcing bar joint structure characterized in that the structure is fixed by hardened mortar 6 filled therein.