Collapse Test of Three-Story Half-Scale Reinforced Concrete Frame Building

Results of recent research on the dynamic response, failure mechanism, and changes in the load-transfer paths of a half-scale three-story, three-hay, and three-span reinforced concrete frame subjected to a series of sudden column removals are presented. Three phases of testing were carried out, including the removal of a corner column and a column adjacent to the corner column along the short span direction, two middle exterior columns along the long span direction, and one interior column. The column removal was enabled by using a gas cannon. The dynamic response at critical locations after the imposed failure of the respective columns was observed. The removal of the corner column followed by the adjacent column resulted in only an essentially elastic response of the structure. The removal of an interior column resulted in only small deflections. The removal of the two first-story exterior columns resulted in significant vertical deflections of the middle exterior columns and significant yielding at adjacent beams that framed into the two middle exterior columns. The vertical deflection of these two columns progressed for approximately 14 minutes, at which point the exterior frame collapsed on to preset steel shoring columns. The shift from moment-resisting mechanism to catenary mechanism was identified and the response and failure of the building are discussed using simplified analyses.