A Numerical Study to Investigate Shear Behavior of High-strength Concrete Beams Externally Retrofitted with Carbon Fiber Reinforced Polymer Sheets

This paper aims to numerically investigate the structural behavior of reinforced high-strength concrete (HSC) beams retrofitted by Carbon Fiber Reinforced Polymer (CFRP) sheets after cracking. Six pre-cracked HSC beams retrofitted with CFRP sheets having identical reinforcement are numerically tested by four-point loading until failure using Abaqus software, besides two others without CFRP as control beams. CFRP sheets are attached on three beam sides in the shear span after cracking under 60 % of loading. Two shear span distances, two inclinations of CFRP sheets, and the number of sheets are adopted as parameters to compare with the experimental results obtained previously. Test results are matched with the practical findings to calibrate the Abaqus parameters. The results show that retrofitting the cracked beam by CFRP raised its tolerance to the applied load by a range of (13-36) % depending on the shear span to depth ratio and the arrangement of CFRP sheets. When the beam tends to fail in shear, the effect of CFRP is more pronounced than when it tends to fracture in flexure. The inclined sheets are more effective than the vertical ones. Furthermore, two additional parameters are regarded to clarify their effects on the behavior of retrofitted beams: sheet width and concrete compressive strength. Altering the CFRP width does not affect the tolerance, whereas increasing concrete compressive strength raises the beam loading.