ULTIMATE STRENGTH ANALYSIS OF PUNCHING SHEAR CAPACITY OF CONCRETE SLAB-COLUMN CONNECTIONS

Based on the parabolic Mohr-Coulomb failure criterion, the partial differential equation that can be applied to obtain the minimum upper-bound solution of the punching shear strength of concrete column-slab connections is derived. Based on the equation, the analytical solution corresponding to the bearing capacity of circular column-slab connections and the series solution corresponding to the bearing capacity of square column-slab connections are obtained. The relevant parameter values of plastic theory are determined by summarizing the experimental punching shear characteristics of slab-column connections, and the formulas which can be effectively used in practice are derived. For circular column-slabs connections and square column-slabs connections, the spatial distribution of stress in punching damage yield surface are analyzed comparatively. The results show that the stress at the edge of column is higher than that in the bottom of slab in both of the two connections. For square column-slabs connections, stress concentration is found at the corner of the column.