Experimental and Numerical Analysis for Ultra-High Performance Concrete Beams Strengthened with CFRP Sheet

Abstract This study explores the experimental work for six Specimens used to study the strengthening effect of ultra-high-performance concrete, validation and evaluation of numerical analysis methodology of ultra-high-performance concrete (UHPC) beams through the application of carbon fiber-reinforced polymer (CFRP) strips in various reinforcement configurations. The experimental program evaluated several CFRP arrangements, including full-face wrapping, U-shaped and side-bond, and strips applied at different angles, spacings, and thicknesses. These configurations were assessed to understand their influence on the beams’ shear resistance and failure modes. The control beam, unstrengthened with CFRP, experienced a typical shear failure. In contrast, the use of CFRP strips, particularly when applied at inclined angles, significantly improved the beams’ load-bearing capacity and altered the failure behaviour. Inclined strips proved more effective than perpendicular ones, and their performance closely approached that of fully wrapped configurations. Wrapping the entire effective area or using wider strips not only enhanced the shear strength but also shifted the failure mode from shear-dominated to flexure dominated in most cases. Notably, the most comprehensive reinforcement method, complete encapsulation of the beam, resulted in the highest structural improvement, although it also led to a return to a shear dominant failure mode. These results highlight the importance of reinforcement configuration and orientation in optimizing the structural performance of UHPC beams using CFRP materials.