Shear Analysis of Reinforced Concrete Slabs with Effective Moment of Inertia

The effective moment of inertia concept has been used to evaluate the bending stiffnesses of reinforced concrete (RC) members in design codes. Later, it was combined with finite element (FE) methods to calculate the deflection responses of RC slabs. However, the failure of the slabs cannot be predicted by the effective moment of inertia based method. In this work, an empirical failure criterion for RC slabs under bending and shear was adopted and modified to consider the stiffness degradation of shell elements in FE analysis. In order to predict the shear failure of the slabs, a softening curve for the bending and shear stiffnesses was proposed. The model parameters in the failure criterion were calibrated according to published test results. The comparison between the numerical and the experimental results shows that the proposed method can predict the deflection response and the shear strength of the analyzed slabs with acceptable accuracy.