The structural applications of Steel Fiber Reinforced Concrete (SFRC) have recently been increasing due to the improvement of material properties, such as in the material toughness under tension and durability. However, because the behavior of such structures is fairly different from conventional Reinforced Concrete (RC) structures the classic design method should be critically reviewed considering the post-cracking resistant mechanism.

This work focuses on the application of SFRC in tunnel lining segments, as an alternative to conventional RC segments. Based on an accurate experimental investigation on full scale specimens, a smeared crack model, which implements the Hilleborg’s criteria was used. In order to assess the SFRC  reliability, a wide population of tensile tests on cylinders drilled out from a reference full scale specimen was carried out. The tensile constitutive relation, which is the fundamental property for SFRC materials, was chosen on a probabilistic fashion accounting for the actual dispersions of fiber in the tunnel segment due to the casting procedure. According to the finite element analysis, the structural response of such structures was found to be very sensitive to the fiber dispersion. Finally, the AFREM recommendation for SFRC materials and the simplified ‘struts and ties’ model were evaluated by means of a parametric analysis.