The vulnerability of reinforced concrete (RC) building structures to progressive collapse has become a challenging issue for professional structural engineers in order to prevent total failure resulting from local damage. Most building structures in Canada, and in general in North America, are designed as shear wall systems with flat plate components. In these buildings, the effects of natural loads, such as wind and earthquake loads, are globally resisted by the shear walls, while the slab components in these buildings are usually designed to resist only gravity loads. The objective of this paper is to enhance the understanding of such buildings' behaviour under several scenarios of lost columns at the ground level, and their potential for progressive collapse. Single storey, 5-storey and 15-storey RC shear wall buildings representing low-rise, mid-rise and high-rise building structures, respectively, designed for a high seismic zone in accordance with the 2005 edition of the National Building Code of Canada were used to achieve this objective. The buildings were analysed following the guidelines for progressive collapse analysis and design prepared by the U.S. General Services Administration. Using 3-dimensional models, a nonlinear dynamic analysis was conducted for several scenarios of removed columns, one column at a time, at the ground level of each building. The nonlinear dynamic analysis for all buildings and for all considered cases of column removal shows that the buildings could not resist progressive collapse in any of the column removal scenarios. Yet, the buildings' collapse propagates significantly when an interior column at the ground level is removed, while the buildings collapse but partially when a corner or edge column is removed.
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