Effect of Volume Fraction and Orientation of Steel Fiber on The Structural Performance of Normal Strength Reinforced Concrete Beams

The present study investigates the impact of steel fiber dosage and orientation on the structural performance of steel fiber-reinforced concrete (SFRC) beams through a combination of experimental testing and numerical simulation. RC beams with 0%, 0.25%, and 0.5% hooked-end steel fibers were evaluated under four-point bending. The findings indicated that the arrangement of horizontal fibers within the composite structure led to an enhancement in load-bearing capacity by up to 66% in comparison with the reference mixture. This observation was accompanied by the attainment of peak loads reaching 228.2 kN. In contrast, the alignment of vertical fibers within the composite exhibited an enhancement in stiffness, accompanied by a reduction in ductility. The random fiber distribution resulted in moderate performance outcomes. The finite element modeling (FEM) implemented in this study, utilizing the Abaqus software and the concrete damage plasticity (CDP) model, exhibited a high degree of concordance with the experimental outcomes, with prediction errors remaining within the 10% range. A comparison with ACI 318-19 revealed that conventional design models may overestimate shear strength, particularly for fiber-reinforced beams, by up to 87%. The findings emphasize the pivotal role of fiber alignment in enhancing the performance of RC beams and furnish valuable insights for formulating enhanced design strategies for seismic and high-load structural applications.