An experimental study on RC beams externally strengthened by anchored CFRP sheets monitored by Digital Image Correlation

During the past few decades, strengthening and rehabilitation of reinforced concrete (RC) structures using fiber-reinforced polymer (FRP) composites have been considered one of the most promising techniques to achieve the required strengthening and structure life span. This paper analyzes the effects of different anchorage increments using the Externally Bonded Reinforcement (EBR) strengthening technique with CFRP on the mechanical properties and deformability capacity of reinforced concrete beams subjected to bending. Axial compression, ultrasonic pulse velocity, and elastic modulus tests were carried out on cylindrical concrete specimens, and the Digital Image Correlation (DIC) technique was used to monitor the total surface deformation and track the development of cracks in the reinforced concrete beams. Strain Gauges (SGs) were used to monitor the tensile reinforcement, the compressed concrete, and the CFRP strain. Experiments on twelve beams are carried out, and the measured data from the monitoring devices are compared. The accuracy of DIC for strain and displacement monitoring matches the performance of traditional methods, with the added benefit of providing full-field monitoring. •The spike anchor method significantly augmented the ultimate load-bearing capacity.•EBROG and EBRIG techniques increased the ductility of the strengthened beams.•EBRIG with spike anchors achieved a modest increase in load capacity.•EBR techniques experienced failure due to debonding at the CFRP-concrete interface.•DIC has demonstrated its efficacy in monitoring both strain and displacement.