Structural and dynamic response of fiber-reinforced concrete beams with low reinforcement ratios under cyclic loading

La Torre Esquivel D.; Marques Rodrigues Gaspar C.; Almeida Del Savio A.; de Andrade Silva F. · Structures (2026) · DOI: 10.1016/j.istruc.2026.111804

Resumen

Fiber-reinforced concrete (FRC) is increasingly considered for structural applications because of its ability to enhance post-cracking resistance and crack control. Nevertheless, the cyclic response of low-reinforced concrete (RC) beams with moment reversal remains insufficiently understood. This study investigates their structural response under reversed cyclic loading. An experimental program at the Structures Laboratory of the University of Lima considered loading type (monotonic and cyclic), fiber material (steel and polypropylene), and fiber volume fractions (0.5% and 1.0%). The analysis compares monotonic and cyclic load-displacement responses, stiffness degradation, ductility evolution, hysteretic parameters, and damage progression through dynamic-property changes. The novelty of the study lies in combining the direct comparison between monotonic and reversed cyclic loading with the simultaneous assessment of structural response and dynamic damage evolution in low-reinforced fiber-reinforced concrete beams. The results show that cyclic loading reduced load capacity by up to 28% and maximum drift by up to 37% compared with monotonic loading, indicating lower ductility. Steel fibers increased strength but reduced deformation capacity, while polypropylene fibers caused greater modal stiffness degradation. Conventional RC beams dissipated up to 4.1 kJ before collapse, whereas FRC beams dissipated between 0.8 and 2.3 kJ due to more localized failure mechanisms. Steel fiber-reinforced beams exhibited the highest frequency degradation, up to 33.26%, due to localized damage that more strongly affected dynamic stiffness.

Instituciones: Universidad de Lima