Enhancing shear strength of RC beams through externally bonded reinforcement with stainless-steel strips and FRCM jacket to mitigate the failure risk

This study aims to assess the efficacy of innovative and sustainable methods in improving the shear performance of Reinforced Concrete (RC) beams lacking shear stirrups. Eleven specimens, including two control specimens and nine strengthened ones, underwent monotonic loading through three-point testing. Various strengthening configurations were investigated, involving the application of Stainless-Steel Strips (SSSs) affixed to the beam surface in the defective zone, along with a Fiber-Reinforced Cementitious Matrix (FRCM) jacket. In the first set of beams, SSSs were vertically applied, while the second set featured beams with SSSs inclined at 60°, and the third set had SSSs inclined at 45°. Each set comprised three beams, allowing for the examination of the impact of SSS thicknesses, set at 1 mm, 1.25 mm, and 1.50 mm. After the installation of SSSs, all strengthened beams received an FRCM jacket, including a 5 mm Engineered Cementitious Composites (ECC) layer with embedded Glass Fiber Reinforced Polymer (GFRP) textile. The study concludes that incorporating SSS strips with an FRCM jacket delays the initiation of the first crack in defective beams. Increasing SSSs thickness contributes to a more favorable crack distribution. The 60° inclined SSSs proves to be the most effective, rectifying the deficiency from the absence of shear stirrups and surpassing the original beam's performance. Additionally, finite element analysis was conducted, and the results supported the accurateness of the developed model in simulating responses and crack patterns throughout all loading stages.