Nonlinear finite element analysis of layered steel fiber reinforced concrete beams

This study investigates the effect of fiber properties and SFRC layer thickness on the flexural behavior of layered beams that undergo both compression and tension failures. Four specimens tested in a prior experimental study are modeled utilizing nonlinear finite element software ABAQUS, and numerical results are verified by comparison with experimental results. Contrary to existing nonlinear models, developed model accurately predicts damage pattern, descending portion of the load-displacement relationship, and ultimate displacement, which results in an accurate estimation of energy dissipation capacity and ductility. Moreover, a comprehensive parametric study is carried out to investigate the effect of tension reinforcement ratio, fiber volume fraction, fiber aspect ratio, and SFRC layer thickness on flexural behavior. Numerical results verify the improvement of beam flexural behavior by increasing SFRC layer thickness and indicate the significance of defining a minimum layer thickness. If the SFRC layer has a thickness lower than 40% of beam depth, there is only limited improvement in the behavior even for fibers with high aspect ratios. In contrast to SFRC beams, layered SFRC beams with up to 1.5% steel fibers exhibit a minor increase in the load carrying capacity, while ductility and energy dissipation capacity significantly improve with increasing layer thickness.