Validation of the Critical Shear Crack Theory for punching of slabs without transverse reinforcement by means of a refined mechanical model

Abstract

Despite the intensive efforts dedicated in the last decades to better understanding punching shear failures, there is still no consensus on the mechanics governing this phenomenon and on how to implement it within a physical approach. In this paper, an analysis of recent detailed measurements on the kinematics and crack development associated with punching failures is presented. This allows classifying the observed cracks by their nature and to address their interaction and development on the eventual punching failure surface. On this basis, a complete mechanical model is formulated consistently with the principles of the critical shear crack theory (CSCT). This model generalizes previous approaches based on the CSCT by accounting for the various crack types and failure modes as well as for their associated kinematics. The generality of the model is verified by extensive comparisons to test data, showing accurate and consistent agreement. Its results are eventually used to investigate the role of the various potential shear-transfer actions as well as the pertinence of the assumptions adopted to simplify the CSCT by describing its failure criterion with analytical expressions.