On the evaluation of the structural redistribution factor in FRC design: a yield line approach

Fibre-reinforced concrete (FRC) is a material that can be characterized by a high standard deviation in the post-peak tensile region. As consequence, structures made of FRC show a too safe prediction of the maximum bearing capacity when derived from characteristic values identified by means of small standard specimens. The Model Code 2010 has introduced a coefficient, named structural redistribution factor, that is able to take into account a reduced variability of the structural response when compared to that of material. A simplified procedure to provide an upper bound estimation of the structural redistribution factor based on the yield line method and able to take into account the material heterogeneity is presented. As case studies, a FRC full-scale elevated flat slab, a slab on ground and a full-scale beam are considered.