Progressive collapse is a structural failure phenomenon in which the local failure of a primary load-carrying element triggers a chain reaction that may lead to partial or total collapse of a structure. This study evaluates the progressive collapse behaviour of three reinforced cement concrete (RCC) framed building configurations: T-shaped, I-shaped, and Core-rectangular structures. All buildings are modelled as G+10 storey structures with identical parameters and analysed using ETABS and STAAD.Pro based on GSA (2016) guidelines. The structures are designed considering gravity and lateral loads according to IS 875 (Part 1, Part 2, Part 3) and IS 1893 (Part 1):2016. Progressive collapse is simulated by removing all columns individually, one at a time, to study the response of the remaining structural system. The structural performance is evaluated using Demand Capacity Ratio (DCR), joint displacement, and Damage percentage under variation b/w ETABS Ultimate 18.0.2 & STAAD.Pro V8i evaluated by using bending moment, shear force under wind and earthquake load combinations from both software's. Columns producing one or more member failures are identified as Critical Columns, while those causing the maximum number of failures are identified as Governing Columns. Reinforcement detailing of beams, columns, and slabs is also examined, where ETABS models are detailed using CSI Detail v18.1.1 and STAAD.Pro V8i provides direct reinforcement results for beams and columns, with slab behaviour evaluated through stress distribution. The results show that the T-shaped structure has better progressive collapse resistance, with fewer failed members and lower damage compared to the I-shaped and Core-rectangular structures. The damage is reduced by about 48% compared to the I-shaped structure and 28% compared to the Core-rectangular structure. The I-shaped structure shows the highest number of beam failures, while the Core-rectangular structure experiences higher column demand due to load concentration near the core. The results from ETABS and STAAD.Pro show similar behaviour, with a variation of about 8–14% under wind and earthquake load combinations. The results indicate that structures which efficiently redistribute loads to surrounding members after column removal exhibit better resistance to progressive collapse.
