JPS5837259A - Splicing method of screw iron wire - 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 The present invention relates to a reinforcing bar joint method using threaded reinforcing bars.

With recent efforts to save labor in civil engineering and construction work, a joint method using threaded reinforcing bars is becoming popular as a joint method for reinforcing bars.

In this construction method, a male thread is formed at the end or over the entire length of a different diameter steel bar for reinforced concrete, and the two different diameter steel bars are meshed with a coupler having a female thread that meshes with the male thread.

In threaded joints formed in this way, the strength of the joint is transmitted through the meshing of the male and female threads, and as long as the predetermined meshing length is secured, the strength of the joint is sufficient to exceed the lower limit of the standard value of the base material reinforcing bar. You can go above and beyond.

However, there is a raft between the female thread and the male thread (
The stiffness of the joint is much lower than that of the base material due to play (play).

For this reason, one method for ensuring the rigidity of threaded joints is the torque method, which applies torque to lock nuts placed at both ends to introduce axial force into the joint.

However, with the recent revision of architectural design standards, the method for evaluating the stiffness of joints has been revised, and in addition to the conventional evaluation in the elastic range, rigidity performance in the plastic range is now required.

FIG. 2 is a graph of a plastic region cyclic loading test using the above-mentioned torque method, and slippage due to cyclic loading can be seen. (The threaded reinforcing bar is D51, and the lock nut tightening torque is 500 Kp・m. Also, during roughening, σy≦40
00 Kg/al, εy = 1716x i o-
'is. ) The reason for this is that in the torque method, the contact area between the female thread and the male thread is not surface contact, but point contact or line contact.
Repeated loading under high stress causes backlash and slippage in the contact area.

As a solution to this problem, there is a method of increasing the tightening torque and introducing a louder axial force, and its effectiveness has been fully confirmed experimentally. However, increasing the tightening capacity increases the weight and size of the machine, which poses practical problems in terms of on-site workability and work space.

This invention was made in order to solve the above-mentioned problems, and involves filling and hardening a grouting agent such as cement paste or resin into the joints of the torque method to prevent the joints from slipping under high stress. There is.

The present invention will be explained below based on the drawings.

FIG. 1 shows an outline of the construction method of the present invention. First, two threaded reinforcing bars 1, 1 are connected by a coupler 2.

Next, the coupler 2 is screwed onto the threaded reinforcing bars 1, 1 in advance, and the lock nuts 3 disposed at both ends of the coupler 2 are rotated and tightened using a torque wrench or other tightening device. As a result, the threaded reinforcing bars 1, 1 are pulled in the axial direction and no longer have any looseness, and a predetermined axial force is introduced. Thereafter, a grouting material such as cement paste, cement mortar, or synthetic resin is injected through an injection hole 4 previously provided near the center of the coupler 2 and hardened.

In this case, the lock nuts 3 placed at both ends of the coupler 2
It is sufficient that the tightening torque is about 10% or more of the tightening torque required by the original torque method, and thereby the tightening machine can be made smaller and lighter.

FIG. 3 is a graph showing the results of a cyclic loading test in the plastic region for a joint obtained by the construction method of the present invention. The torque is 50, which is 10% of the conventional torque method shown in Figure 2.
Kp·m, epoxy resin was used as the grout material, and the threaded reinforcing bar was D51 as in the case of FIG. Also, σy24000 interval, εy=l 516X1,0
-'.

As is clear from the comparison between Figures 2 and 3,
In the test specimens in which the epoxy resin was cured, no slipping phenomenon observed in the torque method shown in FIG. 2 during transition from the tension side to the compression side or from the compression side to the tension side was observed.

This invention has the above-mentioned configuration, and by combining the torque method and the grout injection method, it has excellent performance particularly in the plastic region and is highly reliable. In addition, the tightening torque is about 10% of that of the conventional torque method, and sufficient reliability can be obtained, making it possible to downsize the tightening machine and save labor.

[Brief explanation of drawings]

Figure 1 shows an outline of the construction method of this invention, and is a front view of the joint part, Figure 2 is a graph of a plastic range cyclic loading test for a joint using the conventional torque method, and Figure 3 shows a joint using the construction method of this invention. It is a graph of a plastic region cyclic loading test for. 1... Threaded reinforcing bar, 2... Coupler, 3... Lock nut, 4... Injection hole. Patent applicant Sumitomo Metal Industries Co., Ltd. Procedural amendment December 14, 1980 Japan Patent Office Nagatomi Haruki Shimada 1, Indication of the case 1937 Patent application No. 1 Sang 2, Invention winter break Threaded reinforcing bar joint method 3 , It's an amendment case. Related: Patent applicant 4, Agent 5, Date of amendment order Voluntary amendment & contents of amendment Attachment O direction (1) The following sentence after “…cure” on page 4, line 10 of the specification: Insert. "This wood is preferably non-shrinkable, but it may also be expandable. If necessary, it can be fire resistant,
A material with good heat resistance, water resistance, etc. may be selected as appropriate. ”

Claims (1)

[Claims] (1) In a joint method for threaded reinforcing bars in which two threaded reinforcing bars each having a male thread at the connecting end are connected by a joint turnip or collar having a female thread on the inner surface, after the coupler is connected, the coupler is This joint method for threaded reinforcing bars is characterized in that tightening is performed by applying torque to lock nuts arranged at both ends, and further, grout is injected between the male thread and the female thread through an injection hole provided in the coupler, and then hardened.