Factors influencing the progressive collapse resistance of RC frame structures

Progressive collapse of reinforced concrete (RC) structures has attracted much attention in the past two decades due to the devastating effects associated with it. This paper presents an overall review of the factors that influence progressive collapse resistance of RC frame structures, such as adjacent structural elements, beam dimensions, top and bottom reinforcement ratios, seismic design and detailing, column removal position, and presence of slabs and transverse beams. Through such an exercise, those factors that affect the progressive collapse resistance of RC frame structures are identified and discussed. Meanwhile, a comprehensive database of experimental results related to progressive collapse of RC beam-column and beam-slab substructures is collated and compared through a broad literature review. Dynamic behavior of RC frame structures during a progressive collapse event and numerical modelling methods used for studying progressive collapse are also reviewed. Effects of span-to-depth ratio (L/d) and longitudinal reinforcement ratio (rho) on the resistance increase factor (f(c)/f(b)) of beam-column substructures are studied as well. Furthermore, an energy absorption index (Delta(E)) is proposed for evaluating the progressive collapse resistance of RC beam-column and beam-slab substructures. Finally, knowledge gaps in the current state of the art about progressive collapse of RC frame structures are accentuated in order to promote related research in the future.