Flexural behaviour of FRP reinforced concrete beams strengthened with NSM CFRP strips

This paper presents the results on an experimental programme studying the flexural behaviour of internally reinforced Glass-Fibre Reinforced Polymer (GFRP) Reinforced Concrete (RC) beams strengthened with Carbon-FRP strips using the Near-Surface Mounted (NSM) technique. Their theoretical load-carrying capacity is assessed by a cracked sectional analysis. It is seen that NSM CFRP results an effective technique to enhance the flexural capacity of RC beams internally reinforced with GFRP bars, despite the high degrees of deformability of GFRP RC. Additionally, an a analytical study to evaluate the influence of different parameters on the flexural capacity of NSM CFRP strengthened concrete beams internally reinforced with either steel or GFRP bars is performed. In general, increasing the reinforcement ratio and mechanical properties, either internal or NSM, increases the flexural capacity. However, the change in the parameters may affect in a different way the ratios of increase and cause different modes of failure.