Ultimate punching shear strength analysis of slab–column connections

A simple analytical model is presented to predict the ultimate punching shear strength of slab–column connections. The model is based on the physical behavior of the connections under load, and is therefore applicable to both lightweight and normal weight concrete. The model assumes that punching is a form of combined shearing and splitting, occurring without concrete crushing, but under complex three dimensional stresses. Failure is then assumed to occur when the tensile splitting strength of the concrete is exceeded. The theory is applied to predict the ultimate punching shear strength of 60 slab–column connections reported recently in literature, and designed to fail in shear, involving a large number of variables, such as type of concrete, concrete strength, tension steel ratio, compression reinforcement and loaded area. The results show very good agreement between the predicted and experimental values. The uniqueness of the model is that it incorporates many physical characteristics of the slabs and their failure behavior, and this is reflected by its ability to predict extremely well the results of tests conducted by researchers other than the authors.