Experimental and numerical tests on shear failure and size effect of CFRP-wrapped RC beams without stirrups: Influence of the shear-span ratio

Abstract

The target of the current works is to analyze the impact of shear-span ratio on the shear failure of Carbon Fiber Reinforced Polymers (CFRP) wrapped reinforced concrete beams having different depths. Twenty-four simply supported beams with different structure sizes (the maximum beam depth reaching 1200 mm) and distinct Shear span to effective depth ratios of 1.0, 1.5, and 2.0, under the CFRP ratioρfof 0% and 0.0835% were designed and tested. In the experiment, the shear failure process and failure pattern of beams are presented in detail. The strain distribution of the CFRP sheets is described clearly as well. In addition, the shear contribution of CFRP with different beam sizes, especially large beams, and different shear span to effective depth ratio ratios were evaluated, besides, the calculation formulas of shear capacity in design specifications were analyzed and compared. The tested results indicated that all beams with distinct shear-span ratios exhibit a visible size effect. As the shear span to effective depth ratio increases, the generalized shear strength decreases. In addition, the smaller the shear span to effective depth ratio is, the smaller the shear contribution ratio of CFRP is, manifesting the impact of CFRP in a larger shear-span ratio is not as good as that of a smaller shear-span ratio. Finally, a 3-D Meso-scale finite element model is founded to enhance the understanding of the shear failure mechanical response of CFRP shear-strengthened concrete beams without hooping under the impact of a wide range of shear-span ratio.