Critical review of the CSA A23.3-94 punching shear strength provisions for interior columns

Abstract

The purpose of this paper is to demonstrate that the shear design of slabs according to the relevant Canadian CSA A23.3-94 (and U.S. ACI 318-95) design codes can be unsafe under certain conditions, and to propose improved design equations, some of which should be considered immediately for implementation in the Canadian CSA code. The paper deals with interior slab–column connections, with and without shear reinforcement, subjected to shear force alone or to a combination of shear force and unbalanced bending moment. Some comparisons with the British code BS 8110-85 and the CEB –FIP model code 1990 are also made. Tests reported in the literature and some experiments by the authors provide the basis for this study. Key words: flat concrete plates, slab–column connections, shear strength, punching shear, shear reinforcement, moment transfer.