Behavior of Slab-Column Connections of Existing Flat-Plate Structures

Experimental results of five large-scale isolated slab-column connections subjected to three types of loading histories are presented. The subassemblies represented typical flat-plate construction designed prior to the 1980s that had low slab reinforcement ratios and discontinuous bottom reinforcement at the column. The specimens failed in punching after extensive slab flexural yielding under different loading conditions. The damage induced by simulated seismic loading did not reduce the connection punching capacity under gravity loading. The post-earthquake connection stiffness was significantly reduced. The flexural reinforcement ratio had a significant effect on connection strength and stiffness.