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This paper presents the outcome of an experimental study on the performance of mechanical rebar coupler (MRC) in broken reinforcement connection over the conventional technique. An in-house-made hybrid MRC is introduced to connect broken rebars ranging from 10 to 16 mm in diameter. A detailed experimental program is conducted to explore the influence of MRC with filler as a broken rebar connector. Four types of reinforced concrete (RC) beams with different reinforcement configurations are used with and without MRC at tension zone. RC beams with and without MRC are used and tested under monotonic loading. Rebar connector in different locations is used to examine the load distribution behavior of the connector. The effectiveness of rebar connector is investigated using the uni-axial tensile test of rebar with MRC, load-deflection behavior, energy dissipation, stiffness behavior, and failure pattern of RC beams and is compared with conventional specimens. The significant enhancement in post-yield behavior and energy dissipation of RC beam specimen with rebar connector authenticates the effectiveness of employed technique in structural engineering work. K E Y W O R D S damage index, RC beams, rebar connector, rebar couplers, retrofitting 1 | INTRODUCTIONRebar couplers are recent advancement in construction industry to connect two reinforcements instead of lap splice. These rebar couplers have many advantages over the existing conventional lap splice. In industry, different kinds of couplers are available but in particular parallel threaded coupler is very famous as it has short length and is quite less laborious. But these parallel threaded couplers are applicable only in new construction work. Unlike parallel threaded coupler, friction-based bolted couplers are available but they are expensive. In retrofitting of reinforced concrete (RC) structures, a new reinforcement will be introduced with the existing reinforcement to replace the damaged one. In such a case making mechanical thread in the rebar edges is critical and the connection between the new and the old reinforcement using parallel thread coupler is also not feasible. Repair and retrofitting of the RC structure requires removing of damaged concrete and thorough reinforcement to be replaced with new materials. In column or beam element, the removal of concrete in damaged region will be replaced by fresh concrete with additional additives to have better bond between the fresh and the old concrete. Also, the yielded or buckled reinforcement will be replaced by providing additional reinforcement through welding. In reinforcement replacement, welding is the major source because splicing is not possible. But welding requires adequate length to connect the broken rebar. In this case, load distribution may not be even and may require proper welding which is difficult particularly in the critical section where reinforcement detailing is very close. In RC frame structure splicing is not allowed in the joint region and in the plastic hinge region. Nowadays, in new con...

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