Performance evaluation and parametric optimization of advanced mechanical rebar couplers as an alternative to conventional lap splicing

Abstract

Reinforcing bar splices are an important part of reinforced concrete construction. Conventional lap splicing is widely used, but it often creates reinforcement congestion, increases steel consumption, and makes concreting and bar placement difficult. To overcome these problems, this study developed and evaluated an optimized mechanical rebar coupler as an alternative to conventional lap splices. The proposed coupler was analysed using finite element modelling in ANSYS under different tensile loading conditions. Coupler lengths of 80 mm, 100 mm, 120 mm, and 150 mm were studied for 12 mm, 16 mm, and 20 mm diameter reinforcing bars. The behaviour of the coupler was evaluated in terms of equivalent stress, elongation, elastic strain, and tensile strength based on the provisions of ACI 318, IS 16,172, IS 1786, and IS 456. The results showed that increasing the coupler length reduced stress concentration and elastic strain while keeping deformation within allowable limits. Finite element analysis under a tensile load of 10,000 N showed that the stress in the 12 mm reinforcement bar reduced from about 221 MPa for the 80 mm coupler to nearly 200 MPa for the 150 mm coupler. This shows that longer couplers helped distribute the stress more evenly. Experimental tensile testing of the developed coupler specimens gave ultimate tensile strengths of 563.48 MPa, 641.34 MPa, and 643.39 MPa for the 12 mm, 16 mm, and 20 mm reinforcement bars, respectively.These values were about 25%, 32%, and 34% higher than welded splice specimens and much higher than conventional lap splices. The developed coupler also showed better stress distribution, stable deformation behaviour, and reduced reinforcement congestion. Overall, the study shows that the proposed mechanical rebar coupler can be used as an efficient and practical alternative to conventional lap splicing in reinforced concrete construction.