Concrete flat plates with well-anchored shear reinforcement elements

Punching shear in reinforced concrete flat plates can cause brittle failure at a load well below its flexural strength. The present paper reports the results of a recent test series at The University of Calgary on full-size slab–column connections subjected to concentrically applied punching loads. Shear reinforcement elements in the form of vertical steel bars with square anchor plates at their ends were used. The number, cross sectional area, and distribution of the shear reinforcing elements around the column were the test variables.It is concluded that the shear strength in the concrete at a critical section outside the shear-reinforced zone decreases with the increase of the distance of the section from the column face. Provision of well-anchored shear reinforcement can increase the ultimate shear strength by 100%; equations to predict the ultimate strength are presented.