Behavior Evaluation of Self-compacting Concrete Continuous Beams Strengthened by CFRP Using Near and Side Near Surface Mounted Technique

Abstract

In flexural strengthening of RC beams, two common techniques are adopted; externally bonded (EB) and near-surface mounted (NSM). Although extensive research exists on carbon fiber reinforced polymer CFRP-strengthened beams, most studies neglect continuous members. Adopting side near surface mounted (SNSM) method is more applicable and provide a suitable strengthening solution without having clear access to upper or lower fibers of beams. Evaluating SNSM CFRP techniques in strengthening self-compacting concrete (SCC) continuous beams is a crucial matter. Experimental and numerical approaches were used in this study to analyze the behavior of four continuous 3.0 m SCC beams designed according to ACI 440 code provisions and reinforced with CFRP using NSM and SNSM techniques. In order to study the effect of concrete compressive strength and fiber thickness on beam behavior, finite element model FEM was validated and employed. CFRP laminates in both top and bottom cover increased the ultimate load by 87% and by 81% when fixed using SNSM compared to the control beam. Increasing the concrete’s compressive strength by 200 % raised the ultimate load by about 45%. Also, raising the CFRP thickness from 0.60 mm to 2.4 mm increased the ultimate load by 20% and significantly decreased deformation at failure by 43%, indicating a decrease in ductility.