Experimental investigation of steel fibers effect on the cyclic behavior of flexural members with moderate ductility

Abstract

During the past three decades, considerable research has been focused on the feasibility of utilizing fiber to obtain fiber-reinforced concrete (FRC) with better shear resistance and ductility than reinforced concrete (RC). This study aimed at identifying the benefits of using steel fiber-reinforced concrete (SFRC) in flexural members to reduce the transverse reinforcement. Hence, six full-scale geometrically identical specimens with three types of stirrup arrangements, including moderate, special and low ductility stirrups, were studied under cyclic loading. Two control specimens, both without fibers, one with moderate and the other one with special ductility stirrups were used. Two other specimens with moderate ductility stirrups and 1 and 1.5% steel fibers (SFs) and the other two specimens with low ductility stirrups and 1 and 1.5% SFs were also tested. These tests provided data on ultimate strengths, ductility, stiffness degradation, energy absorption and dissipation, damage index, and equivalent damping. The cyclic behavior of specimens containing SFs were compared with those of the two control specimens. The results showed that adding SFs to the beam reinforced with moderate ductility stirrups led to a better performance compared to the one with special ductility shear reinforcement. Therefore, instead of using crossties SFs can be used in a beam section with special shear reinforcement. Furthermore, the addition of 1 and 1.5% SFs to the beams with low ductility stirrups lead to a cyclic behavior similar to or even better than that with moderate ductility stirrups.