Experimental Study of Dynamic Progressive Collapse in Flat-Plate Buildings Subjected to Exterior Column Removal

Abstract

This paper documents the findings from a dynamic collapse experiment carried out on a single-story two-by-two bay reinforced concrete flat-plate substructure. The test specimen had a 0.4 scale, represented older flat-plate buildings designed without structural integrity reinforcement in slabs, and was subjected to an instantaneous removal of an exterior supporting column. Tests were conducted three times with different levels of gravity load until a progressive collapse occurred. The specimen survived a gravity load corresponding to 42% of the normal loading capacity defined by the direct design methods but collapsed at a load of 49% of the design loading capacity. The collapse of the specimen was initiated by the punching failure at an interior slab-column connection carrying the most redistributed load after the exterior column removal. The tests confirmed the existence of slab compressive membrane action and examined the strain rates of material under dynamic response. The tests also indicated that a slab-column connection without continuous slab bottom reinforcement through the column has limited post-punching resistance. The experiment indicated that an older flat-plate building is vulnerable to a progressive collapse when it is subjected to a sudden exterior column removal. Numerical simulations of the experiments using a macromodel were conducted and its effectiveness was confirmed.