Behaviour of Reinforced Fibrous Concrete Beams under Reversed Cyclic Loading

When earthquakes occur, energy released by the earthquake gets induced into the structure as ground motion and this energy has to be dissipated for safety reasons. To release seismic energy, the structure should damage in such a way that on one hand, collapse of structure should not occur and on the other hand, after the earthquake, damage should be economically feasible to repair. To avoid the collapse of the structures and also to reduce the repair cost after the earthquake, most design codes focus on providing sufficient ductility to structure. Dissipation of large part of injected seismic energy is an important factor for a structure to be seismically resistant. In this contribution, use of metallic-fiber to improve the behaviour of reinforced concrete beams subjected to cyclic loading is investigated. RC beams containing metallic fibers of two different types in mono and hybrid forms were constructed and tested under reverse cyclic loading to investigate the possibility of obtaining ductile and energy dissipating RC beams to be used in seismically active area. Reverse flexural cyclic loading tests were performed on beams of cross section 150 x 200 mm with a clear span of 1 m. In all tested compositions of concrete containing fibers, metallic fibers were investigated at maximum content of 40 kg/m 3 and 80 kg/m 3 in mono and hybrid forms, respectively. Experimental results showed that metallic fibers act as energy dissipater in the concrete and significantly improve the energy dissipation capacity of RC beams. Moreover, from the results obtained in terms of energy dissipation for RC beam containing fibers in hybrid form, positive interaction between two different metallic fibers used in this study has also been underscored.