Punching Failure of Slabs—Transfer of Moment and Shear

A theoretical method of analysis is presented for the calculation of the punching load of an internal column of a flat slab structure subjected to moment and shear transfer. The analytical procedure utilizes elastic thin plate theory and takes into consideration the complex state of stress which exists in the compression zone of the slab around the column periphery. As this prediction is based on lower bound limit analysis a safer estimate than that based on yield line analysis results. A detailed description of the steps involved in the analysis is given in a flow diagram which indicates that four different modes of failure are possible. The validity of the assumptions made is checked by comparing the predicted punching loads with those obtained from tests that are reported in the literature. This method will be of value in supplementing existing empirical procedures.