Experimental Investigation on the Cyclic Flexural Behaviour of Steel Fibre Reinforced Concrete Beams for Seismic Applications

The seismic performance of reinforced concrete (RC) structures largely depends on the ductility, energy dissipation capacity, and stiffness retention of their structural members under cyclic loading. In this context, the present study experimentally investigates the cyclic flexural behaviour of steel fibre reinforced concrete (SFRC) beams with a focus on their suitability for seismic applications. A series of simply supported RC and SFRC beam specimens were cast and tested under reverse cyclic loading using a two-point loading arrangement to simulate earthquake-induced forces. Steel fibres were incorporated at an optimized volume fraction, and the performance of SFRC beams was compared with conventional RC beams. Key response parameters such as load–deflection behaviour, crack development, energy absorption capacity, ductility factor, and stiffness degradation were evaluated from the experimentally obtained hysteresis curves. The results demonstrate that the inclusion of steel fibres significantly delays crack initiation, enhances post-cracking behaviour, and improves the overall ductility of beams under cyclic loading. SFRC beams exhibited substantially higher cumulative energy absorption capacity and superior ductility indices compared to conventional RC beams, indicating improved seismic resistance. Furthermore, steel fibre reinforcement was found to reduce stiffness degradation and control crack propagation through effective crack-bridging action. The experimental findings confirm that steel fibre reinforced concrete beams possess enhanced deformation capacity and energy dissipation characteristics, making them a promising alternative to conventional RC beams in earthquake-resistant structures. The study highlights the potential of steel fibres in improving the seismic performance of flexural members without major changes in conventional reinforcement detailing.