Pre- and post-punching failure performances of flat slab-column joints with drop panels and shear studs

Abstract

To investigate the pre- and post-punching failure performances of flat slab-column joints with drop panels and shear studs, static loading tests were conducted on three joint specimens subjected to in-plane restraints. The pre- and post-punching failure modes and load capacities of the joints were analysed. The tests identified successive punching failures at two critical regions (column perimeter and slab-drop panel interface) in all three joints. Compared with the specimen with a drop panel only, installing shear studs within the drop panels contributed to improving the punching shear strength. Although the post-punching capacity was not significantly improved, utilisation of shear studs effectively increased the ductility of the joints, rendering the punching failure around the column area more ductile. Punching shear strength validation against the international design codes reveals that they were conservative for the specimen with a drop panel only but overestimated for specimens with drop panels and shear studs.