Shear contribution of beams having different structural sizes strengthened in shear with anchored CFRP strips

Abstract

CFRP (Carbon Fiber Reinforced Plastics) debonding jeopardizes structural reinforcement in engineering projects. Anchoring CFRP paste is crucial for efficient shear strengthening. This study investigates the anchoring effect on shear resistance in nine CFRP U-wrapped concrete beams, varying shear span-to-depth ratios (1.0, 1.5, 2.0), and depths from 300 mm to 900 mm. Concurrently, nine unanchored beams and nine plain concrete beams were included in the comparison, considering the influence of beam depth and shear span ratio, referencing the prior research of Jiang et al. (2022). The evaluation of the shear contribution of CFRP with different sizes, particularly in scenarios involving large dimensions and diverse shear span ratios, was conducted. The test results revealed that the anchoring effect is most pronounced in small-scale beams with a large shear span ratio, demonstrating an improvement of over 60% compared to the CFRP shear-strengthened beam without anchoring. In contrast to beams without CFRP wrapping, the shear performance was enhanced by approximately 90%. Additionally, the study analyzed and compared the calculation formulas of shear capacity from different national specifications. Ultimately, a calculation method for CFRP shear resistance was established and its accuracy was verified.