Behaviour of reinforced concrete buildings subjected to progressive collapse

Progressive collapse is a severe structural problem initiating from local damage and leading to total building collapse, significantly increasing life safety risks. This thesis investigates the potential for seismic progressive collapse in reinforced concrete buildings. The study examines the effects of parameters such as column location and quantity, slab thickness, and beam capacity under column removal scenarios, along with various structural irregularities. Nonlinear Time History Analysis was used to capture structural behavior during progressive collapse, utilizing suitably selected and scaled ground motions. A prototype model with a three-story regular plan was used as the main model to enable comparison of results across various scenarios. Analysis revealed that edge-middle and interior column removal scenarios are riskier than corner column removal. Increasing slab thickness adversely affected structural performance, while increasing beam capacity did not help control progressive collapse risk. The most significant increases in neighboring columns following a column removal were in axial force and torsional moments. Load transfer to adjacent columns improved with greater slab thickness, but beam capacity increases were ineffective on this mechanism. However, increased slab and beam capacity enhanced beam resistance to additional loads from column loss. Models with soft-story (Model C) and combined soft-/weak-story (Model E) irregularities exhibited higher progressive collapse potential compared to other irregularities. Ultimately, this thesis identifies key parameters and their interactions in assessing progressive collapse potential in RC buildings.