Reliability of Shear Strength Models for Fibre Reinforced Concrete Members Without Shear Reinforcement

The scope and amount of fibre reinforced concrete (FRC) structural applications have seen significant increases. This means that safe and reliable ultimate limit state (ULS) models are necessary for FRC structural members. Among these, shear strength of FRC members without shear reinforcement is highly important due to the brittleness of shear failure. Because of this, the fib Model Code 2010 introduced two shear strength models: an empirical model based on Eurocode 2 and a physical model based on the Modified Compression Field Theory. However, a comprehensive reliability assessment of these models has been lacking. Therefore, in this study, the safety format of these models is assessed and the partial safety factors for FRC in shear, γ_c and γ_F are updated. As a first step, a large database of experimental results on FRC beams is used to determine model uncertainties. Following this, a comprehensive parametric probabilistic analysis is performed using the First Order Reliability Method to determine the adequate values of γ_c for different target reliability indices β. The results of this study show that in order to reach typical reliability indices used in ULS design, γ_c and γ_F values need to be increased for FRC members without shear reinforcement for both models proposed by the fib Model Code 2010.