Size-scale effects and modelling issues of fibre-reinforced concrete beams

This paper compares numerical and analytical predictions for the shear capacity of fibre-reinforced concrete beams based on experimental literature tests. The authors compared the outcomes of a FE model using the DamageTC3d constitutive model, a literature formulation, and the current proposal of the Eurocode 2 draft for fibre-reinforced structures. The paper evaluates the sensitivity of the beam response to the fracture energy Gf, modified after the Model Code 2010 formulation. The investigation reveals a dependence of the estimated fracture energy on the beam size. Furthermore, the comparison between the numerical estimates and the analytical predictions using the MC2010 and the current EC2 draft proves that the error is substantially independent of the model selection but is strongly affected by the specific case study. This fact confirms the absence of weaknesses in the numerical modelling and highlights the aleatoric uncertainties of the experimental data.