Side Near Surface Mounted (SNSM) technique for flexural enhancement of RC beams

The rehabilitation of existing Reinforced Concrete (RC) structures constitutes one of the leading challenges in civil engineering. The crucial reasons for the strengthening of RC structures comprise frequent increases in design loads, engineering errors in design or workmanship issues during construction, changes in code and functional requirements. This paper introduces an innovative approach comprising the Side-Near-Surface-Mounted (SNSM) technique, which incorporates Carbon Fiber Reinforced Polymer (CFRP) and steel bars as strengthening reinforcement. Experimental and analytical investigation was adopted to explore flexural strengthening of RC beams with them. Analytical models are presented to predict the ultimate load, crack spacing and deflection. Four-point bending tests were performed up to failure on the rectangular RC beams strengthened with different ratios of SNSM reinforcement. The failure characteristics, yield and ultimate capacities, deflection, cracking behavior, ductility and energy absorption capacities were evaluated. The SNSM technique significantly enhanced the flexural behavior of the beams. The yield and ultimate load carrying capacities of the beams increased by a factor of 2 and 2.38 times, respectively. The cracking loads improved more notably (3.17 times). Predicted results from the analytical models showed good agreement with the experimental results, which confirmed proficient implementation of the proposed SNSM technique.