Experimental Investigation of RC Beam-Column Assemblies under Column Removal Scenario

Abstract

Progressive collapse denotes a failure of a major portion of a structure that has been initiated by failure of a relatively small part of the structure such as failure of any vertical load carrying element (typically columns). Failure of large part of any structure results in to substantial loss of human lives and natural resources. Therefore it is very important to prevent this type of progressive collapse which is also known as disproportionate collapse. Progressive collapse of a structure can be prevented by providing sufficient continuity and redundancy to redistribute additional forces through an alternate load path. In this study, experimental investigation of role of reinforcement detailing on progressive collapse resistance is carried out for 6-storey reinforced concrete structures under column removal scenario. Two 3/8th scaled specimen, which is part of structure, is designed according to IS codes with non-ductile detailing and ductile detailing. The value of response reduction factor (R) is considered as 3 and 5 during seismic design with non-ductile detailing and ductile detailing respectively. Each specimen includes two span beams and three columns with removed middle column. Removed middle column represents column removal scenario, which in turn indicates progressive collapse situation. Response of specimen in terms of vertical deflection along the span of beam is measured. From the results, it is observed that progressive collapse resistance can be significantly increased by providing continuous bottom reinforcement instead of curtailed reinforcement, closely spaced stirrups near the beam column junction and proper anchorage of reinforcement at beam column junction.