Shear behavior of fibrous concrete shallow wide beams using GFRP shear reinforcement

High-strength concrete shallow wide beams (SWB) can offer sufficient shear capacity with a small depth to satisfy architectural requirements. This study investigated alternative ways to improve the shear behavior of SWB by considering the influence of different parameters, such as the steel fiber content and hybrid shear reinforcement mode. Seven experimental specimens were cast with varying parameters: spacing between stirrups (S), incorporation of steel fiber dosages into fresh concrete (SF), substitution of steel stirrups with GFRP stirrups (GST), hybrid shear reinforcement comprising outer steel stirrups and inner GFRP stirrups (GSST), and the combined utilization of GFRP stirrups and steel fibers. Using steel fibers in the concrete mix with doses of 1.5 % and 3 % from the volume fraction (VF) increased the shear loading by 9 % and 24 %, respectively. The hybrid shear reinforcement system of the outer steel stirrup and inner GFRP stirrups improved the shear strength of the SWB by 29 % compared to that of the control specimen. The fibrous concrete redistributes the strain on the stirrup branches and prevented excessive strain on the inner branches of the other tested SWB specimens without steel fibers. A Nonlinear numerical analysis using ANSYS 22 software demonstrated good agreement between the finite element simulation and experimental results. The researchers performed a theoretical expectation analysis and comparison of the codes and experimental results.