Upset Coupler

Category: coupler

In the Upset method, after the reinforcing bar is cut using a circular saw according to the project requirements, the bar end is subjected to hydraulic pressure by a dedicated upsetting machine.‎ This process enlarges the diameter of the threading area (oversizing), which is commonly referred to as upsetting.

The increased diameter allows the thread size to be increased by one nominal size.‎ For example, a 32 mm rebar, after the upsetting process, is threaded to 36 mm. During tensile testing, failure of this type of mechanical splice consistently occurs outside the coupler, confirming that the connection develops the full strength of the reinforcing bar.‎

It should be noted that the selected rebar must be suitable for the upsetting process.‎ Unfortunately, some locally manufactured rebars are not compatible with this method.‎ In such cases, the upsetting process significantly increases the hardness of the threaded section, making it impossible to produce threads using the cold-forming (rolling) method.‎

Because the diameter of the threaded section is increased, both the thread length and the coupler length can be reduced, resulting in a more compact and efficient mechanical splice without compromising performance.‎

Product Description

Technical Specifications

The technical specifications of the threads and couplers used in this method are shown in the table below.

It should be noted that the steel used for manufacturing these couplers conforms to DIN 1.1191.

The thread length at the end of the reinforcing bar is:

(d − P) ≤ L ≤ d

Where:

d = Nominal diameter of the reinforcing bar
P = Thread pitch
Dc = Outside diameter of the coupler
Lc = Coupler length

Installation Instructions for Connecting Threaded Reinforcing Bars Using a Standard (Right-Hand Thread) Coupler

1. After removing the plastic thread protector from the reinforcing bar, screw the standard coupler onto the reinforcing bar from the side without the plastic cap as far as possible. Then, using the special wrench (available from Sahand Mechanical Splices) or a pipe wrench, tighten the coupler securely to the end of the reinforcing bar thread.

2. The plastic cap of the coupler is provided to prevent any foreign materials from entering the coupler. Therefore, do not remove it before connecting the opposite reinforcing bar.

3. To connect the opposite reinforcing bar, after removing the plastic cap from the coupler and the thread protector from the reinforcing bar, screw the reinforcing bar into the coupler by hand as far as possible

4. Using the special wrench or a pipe wrench, completely tighten the second reinforcing bar into the coupler until the last thread. In this condition, all the threads of both reinforcing bars are engaged inside the coupler, and it is not necessary for the ends of the reinforcing bars to touch each other.

5. If, for any reason, the reinforcing bar threads have become rusty, clean them using a wire brush and apply grease or oil to the threads before tightening them.

6. To facilitate inspection and quality control of the completed connections, it is recommended that the couplers be marked with red paint after they have been fully tightened.

7. Compliance with and supervision of the requirements for the use of mechanical splices in accordance with the Iranian Concrete Code (ABA) and the National Building Regulations of Iran shall be the responsibility of the employer.

Our company’s specialists are available to assist you throughout all stages of the project and are ready to answer your questions.

You can also view the other products of Sahand Mechanical Splices on the company’s Products page.