LAUSR

Abstract The efficiency of using side near-surface mounted (SNSM) carbon fiber reinforced polymer (CFRP) strips with a variable profile in strengthening reinforced concrete (RC) beams is studied. RC beams (150 × 250 × 1400 mm) were strengthened using straight, trapezoidal, and parabolic profiles of SNSM CFRP strips inserted within 25 and 35 mm of the beams' parallel side covers. The mechanical behavior of the beams is evaluated under a four-point loading test setup before the collected data is analyzed for mechanical response. This includes load-deflection diagrams and their characteristics, as well as strain in SNSM CFRP strips at the failure point. Cracking and failure modes were also monitored and characterized. The results show that strengthening RC beams with SNSM CFRP strips at variable profiles helps improve the overall mechanical performance, especially ultimate load capacity and toughness. Trapezoidal profiles of SNSM CFRP strips impart the best improvements to structural performance, followed by the parabolic profiles. Furthermore, inserting SNSM CFRP strips within the concrete side covers at the larger thickness had a limited impact on enhancing the structural performance. An analytical model for the prediction of the load capacity of the present strengthened beams is proposed and used to validate the experimentally obtained data.