EXPERIMENTAL INVESTIGATION ON THE CYCLIC FLEXURAL BEHAVIOUR OF STEEL FIBRE REINFORCED CONCRETE BEAMS FOR SEISMIC APPLICATIONS

The seismic response of reinforced concrete (RC) structures largely depends on the ductility, stiffness retention, and energy dissipation capacity of their structural elements under cyclic loading conditions. In view of this, the present experimental investigation focuses on evaluating the cyclic flexural behaviour of steel fibre reinforced concrete (SFRC) beams and assessing their suitability for earthquake-resistant applications. For the study, several simply supported RC and SFRC beam specimens were cast and tested under reverse cyclic loading using a two-point loading arrangement to simulate earthquake-type actions. Steel fibres were incorporated at an optimum dosage, and the performance of SFRC beams was compared with that of conventional RC beams. Key behavioural parameters, including load–deflection characteristics, crack development, ductility factor, energy absorption capacity, and stiffness degradation, were examined using the hysteresis responses obtained experimentally. The experimental observations showed that the inclusion of steel fibres significantly delayed crack initiation, enhanced the post-cracking response, and improved the overall ductile behaviour of beams under cyclic loading. In comparison with conventional RC beams, SFRC beams exhibited substantially greater cumulative energy absorption and improved ductility, demonstrating superior resistance to seismic effects. Furthermore, the presence of steel fibres effectively controlled crack propagation through crack-bridging action and reduced the rate of stiffness deterioration. The results of the investigation establish that steel fibre reinforced concrete beams possess higher deformation capability and better energy dissipation characteristics than conventional RC beams, making them an effective alternative for earthquake-resistant structural applications. The study also highlights that the incorporation of steel fibres can considerably improve the seismic performance of flexural members without necessitating major changes in conventional reinforcement detailing.