On the flexural behavior of fiber reinforced concrete beams

Even though a lot of research studies have demonstrated the effectiveness of fibers in improving the structural response of RC members' under different loading conditions, some concerns recently aro.se on the sectional ductility under flexure, which can be compromised under certain circumstances. In fact, fibers do no t significantly increase the ultimate moment of IUC members and, with rather tough fibers and low train- hardening ratio of the longitudinal rebars, the rotation capacity can substantially decrease owing to a cracking localization at ultimate limits. This paper will focus on this topic with a number of experimental results on full-scale fiber- reinforced concrete (PRC) beams tested under flexure. Experimental results evidence that fibers, if provided in sufficient amount, were able to move the failure from concrete crushing to steel rupture. In any case, the addition of fibers turned out to give a stiffer post-cracking behavior at service level.