Model Uncertainties in FEM Analyses of Punching Failures of Concrete Slabs

Punching shear is a type of failure of reinforced concrete slabs subjected to localized forces. This failure has been examined by many researchers experimentally, analytically or numerically. Empirical equations based on tests observations are nowadays the basis of the existing design codes. The work described herein presents 3D Finite elements method (FEM) analysis of three slab-column connections also tested experimentally to investigate the three fundamental geometries: central, side and corner column. The sensitivity of the FEM response to input parameters such as material constitutive laws is studied. Concrete constitutive models are described in detail, including their effects on the accuracy of FEM analysis. The comparison between FEM results, experimental tests, code provisions and a new model for punching based on the compression chord capacity model is presented. As a conclusion, an estimation of the model uncertainties related to FEM analyses of punching failures without shear reinforcement is discussed