1 A PARAMETRIC STUDY ON THE USE OF STRAIN SOFTENING/HARDENING FRC FOR RC ELEMENTS FAILING IN BENDING

Using a design oriented model, which was recently developed for the prediction of the moment-curvature relationship of a cross section of beams made by strain softening or strain hardening fiber reinforced concrete (FRC) and that can also include a certain percentage of longitudinal steel bars, a parametric study is carried out to evidence the effect of relevant characteristics of the post-cracking behavior of these materials in the moment-curvature and force-deflection responses of this type of structural elements. The study also analyzes the influence of the reinforcement ratio of longitudinal steel bars, ρ, in order to show that for a certain content of fibers the benefits of fiber reinforcement, mainly at serviceability limit state conditions, decrease with the increase of ρ. Adopting the formulation of Model Code 2010, the moment-crack width relationship of FRC beams reinforced with steel bars are obtained and the predictive performance of this approach is assessed by comparing analytical and experimental results