A rebar coupler is a technical product that is necessary when long length of bar is required. The primary work of this coupler in reinforcement is to join two TMT bars for continuous reinforcement. The rebar coupler is used in all the construction fields, such as, constructions of buildings, bridges, dams, towers, etc.

Here it is discussed about about what is rebar coupler, types of rebar couplers, threaded rebar coupler, non-threaded rebar coupler, rebar coupler size chart, rebar coupler testing procedure, rebar coupler price in India, rebar coupler installation and advantages of rebar couplers.

What is Rebar Coupler?

Rebar couplers are used in the RCC structures to replace the system of lapping and welding in reinforcement. When there is need of long length bars or when joining the additional bars to the end of existing bars, the lapping system is applied that is the bars are tied by wire next to each over. In the same way like lapping, welding is also processed where unlike tied by wire, the bars are attached by welding.

Since, there is a wastage of bar in lapping system and welding system, an alternative system is used known as rebar coupler or the coupler in reinforcement that provides an end to end connection for the continuous reinforcement of a structure. The coupler in reinforcement is used since it is economical and cost efficient unlike the lapping system, where some part of the bar is wasted due to lapping.

The rebar coupler is particularly cost efficient for large diameter bars in the big projects of construction and construction of skyscrapers. The rebar couplers are also commonly known as mechanical splices. The rebar coupler is used in all the construction fields, such as, constructions of buildings, bridges, dams, towers, etc.

Types of Rebar Couplers

There are mainly 2 types of rebar couplers in reinforcement, such as,

1. Threaded Rebar Coupler
   • Roll Thread Rebar Coupler
   • Cold Forged Rebar Coupler
2. Non-Threaded Rebar Coupler
   • Crimping Rebar Coupler
   • MBT Rebar Coupler

Roll Thread Rebar Coupler

In roll thread rebar coupler, the coupler is threaded by threading machine. To fit the bar in the roll thread coupler in reinforcement, the ends of the TMT bars are threaded in the Roll Thread Machine. After that the rebar coupler installation is done to the both ends of the TMT bar like nut and bolt, for the continuous reinforcement.

Cold Forged Rebar Coupler

Like the Roll Thread Rebar Coupler, the Cold Forged Rebar Coupler is also threaded by the threading machine. But in this coupler in reinforcement, the end of the TMT bar is forged by forging machine with the help of hydraulic pressure.

After the process of forging the end of TMT bar losses a minimal part of length and increases its thickness and then the bar end is threaded by the threading machine and fitted to the rebar coupler.

The cold forged rebar coupler is passed for the big infrastructure projects and other government projects. This system is passed by the Indian Government under the BIS code IS: 16172-2014.

Crimping Rebar Coupler

Crimping rebar coupler is known as the first coupler in reinforcement in the construction and after that threaded rebar coupler was introduced. In crimping rebar coupler there is no thread. The rebar coupler without thread is fitted in the two ends of the TMT bar and then the coupler is crimped by a crimping machine.

The crimping coupler is not economical and more material is used and also the labor cost is high. A crimping coupler in reinforcement cannot be uncrimped after installation. Because of this reasons, the crimping rebar coupler system has failed in the market.

MBT Rebar Coupler

The MBT Rebar Coupler is basically designed for the critical conditions of continuous reinforcement. This MBT coupler in reinforcement is used when there is less lap length and not much of a bar is left for the continuous reinforcement. The MBT couplers are also used in the retrofitting constructions. There are 6-8 bolts in the top one MBT coupler.

The length of MBT couplers is more than a threaded coupler. The strength of MBT couplers depends on the number of bolts present on it and with the help of this bolts the coupler in reinforcement is installed.

Rebar Coupler Size Chart

Like the size of the TMT bar, the TMT rebar coupler sizes comes in same, such as, 16, 18, 20, 22, 25, 28, 32, 36, 40 and so on.

Size (mm)	Outer Diameter (mm)	Length (mm)	Pitch (mm)	Weight (g)	One Packet Contains (nos)	Weight of One Bag (kg)	Certificate / Approval
16	24	42	2.5	92	250	23.00	CE / ISO
18	27	45	2.5	136	200	27.20	CE / ISO
20	30	50	2.5	159	132	20.98	CE / ISO
22	33	54	2.5	210	121	25.41	CE / ISO
25	38	62	3.0	340	80	27.20	CE / ISO
28	42	68	3.0	460	56	25.76	CE / ISO
32	48	76	3.0	633	42	26.58	CE / ISO
36	53	84	3.0	905	27	24.43	CE / ISO
40	59	95	3.0	1160	25	29.00	CE / ISO

Rebar Coupler Testing Procedure

A coupler in reinforcement is processed by many rebar coupler testing. Some of the test of rebar coupler are as follows:

1. Cyclic Tensile Test
2. Low Cycle Fatigue Test
3. High Cycle Fatigue Test
4. Static Tensile Test
5. Yield Strength of Steel
6. Slip Test
7. Chemical Test

Rebar Coupler Price in India

A cost analysis is discussed based on the steel saving in lapping which shows that coupler in reinforcement is and economic and effective replacement of lapping system. Here it is discussed about 4 different sizes of TMT rebar coupler.

Bar Diameter (mm)	Steel Weight per Meter (kg/m)	Development Length (mm)	Quantity of Steel Saved (kg)	Steel Saving Cost (Rs)	Rebar Coupler Cost (Rs)	Total Savings (Rs)
12	0.89	680	0.680	31.48	25	6.48
16	1.58	910	1.432	74.45	40	34.45
25	3.85	1416	5.545	285.00	60	225.00
32	6.31	1925	12.189	609.00	110	499.00

Rebar Coupler Installation

Advantages of Rebar Couplers

Some advantages of coupler in reinforcement are:

1. The rebar coupler improves the structural integrity.
2. It reduces the lapping length calculation.
3. Rebar coupler increases the bar uses by not wasting bars like the lapping.
4. The connection inspection is simple and easy.
5. It increases work speed by quick installment.
6. It is very economical amongst all the systems of joint in reinforcement.
7. The load path continuity is accurate.
8. The transferring of the load is proper.
9. It doesn’t create congestion.
10. The rebar coupler has a great quality control and easy to supervise.

So, here it is discussed about about what is rebar coupler, types of rebar couplers, threaded rebar coupler, non-threaded rebar coupler, rebar coupler size chart, rebar coupler testing procedure, rebar coupler price in India, rebar coupler installation and advantages of rebar coupler.

FAQ >

Q. How much foreign length is required for threading and coupler splicing of reinforcement length?

Ans: The length required for threading and coupler splicing depends upon the size and length of the coupler in reinforcement.

Q. Alternate name of rebar coupler which can be used in naming project.

Ans: The rebar coupler is also commonly known as mechanical splices.

Q. Both steel bars should be touched or not inside coupler?

Ans: Yes, both the steel bars should be touched inside coupler.

Q. Is rebar coupler successful in running horizontal beam?

Ans: Yes, rebar coupler is successful in running horizontal beam.

Q. Is additional stirrups required in splicing zone when we use rebar coupler?

Ans: Yes, the stirrups are required in splicing zone when coupler in reinforcement is used.

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