Flexural behavior of reinforced concrete beam using CFRP hybrid system

This paper presents experimental and numerical study to investigate the flexural behaviour of strengthened RC beams using three CFRP techniques. Considered main variables were CFRP technique, amount of CFRP NSM and rope and cost/increase in strength effectiveness. Results indicate that using CFRP rope and sheet increased significantly maximum load and maximum strain of RC beams. Average increase in strength and maximum strain were 76.3% to 143.5% and 206% to 246% as the control RC beam. Moreover, RC beams strengthened with CFRP rope exhibited strength approximately similar to ones strengthened with CFRP strip. The cost/increase in strength ratio of specimens strengthened by CFRP rope is 61% higher than the ratio of specimens strengthened by CFRP NSM strip. Hence, the specimens strengthened by one layer of CFRP rope is the most economic techniques based in cost/increase in strength ratio even though it exhibited maximum load less than the specimens strengthened with two layers of CFRP rope or strip. CFRP rope was 40% lower than CFRP strip when same strengthening effect was achieved. Finally, complementary to experimental work a finite element model FEM was developed to investigate the flexural behaviour of beam. The FEA model showed somehow good agreement with the experimental results.