Experimental investigation on shear behavior of concrete beams with CFRP grid shear reinforcements

Abstract

Fiber Reinforced Polymer (FRP) is one of the most ideal substitutes for steel reinforcement because of its low density, high tensile strength and excellent corrosion resistance. Carbon-FRP (CFRP) grid is one type that is commonly used in engineering and has shown promising results in shear strengthening of beams. In this study, eight concrete beams, including one steel reinforced concrete (RC) beam and seven concrete beams with CFRP grids in two configurations (parallel to longitudinal axis as stirrup or perpendicular to longitudinal axis), were tested until failure. The influence of variables on shear span ratio and shear reinforcement ratio were analyzed. All the eight beams experienced shear failure as expected. As the shear span ratio increased, the shear capacity decreased while the deflection of beam increased. CFRP grids parallel to the longitudinal axis could effectively reduce the deflection and increase the cracking load of specimens. When CFRP grids were laid perpendicular to the longitudinal axis, the maximum strength of CFRP grid can reach 84% of the ultimate strength and the contribution of CFRP grid stirrups to shear capacity was higher than that of steel stirrups. Finally, experimental results of shear capacity were compared with the theoretical ones calculated by various specifications.