Shear behavior of CFRP - reinforced concrete beams using FEM

Abstract

In the current study, the finite element method using the ABAQUS program is employed to investigate the shear behavior of reinforced concrete (RC) beams strengthened by carbon fiber reinforced polymer CFRP. Load-deflection curves, modes of failure and the pattern of the cracks are studied. Also, the influence of compression strength of concrete, the configuration of CFRP (U shape and 2 side bond shape) and shear span to depth ratio (a/h ratio). The results show that the shear capacity of RC beams strengthened by CFRP increased by a maximum percentage of up to 111.7% compared to the unstrengthened beam. Also, it is found that by increasing the compressive strength of concrete from 40 MPa to 65 MPa the load-carrying capacity increases by 28% and the stiffness also increased, while the decrease of shear span to depth ratio from 1.66 to 2.33 leads to increasing the shear capacity by 23%. The maximum load of beam strengthened with U shape increased by up to11.5% when compared with the same beam strengthened with two side bond shapes of CFRP. However, the gain in the strength was reached to 22.7% for beams strengthened with CFRP laminate compare to unstrengthened beams. The strengthening of RC beams by CFRP laminates using the near surface mounted (NSM) technique is more efficient than the externally bonded reinforcement (EBR) technique for all beams in the shear behavior. The finite element models provide a good level of accuracy compared to experimental results and ACI-440.