Predicting Collapse Mechanisms in Controlled Demolition: An Explicit Dynamics Study on Seismically Designed RC Frames with Vertical Irregularities

The increasing need for urban redevelopment in densely populated regions has elevated the importance of controlled demolition of aging high-rise structures, a high-risk operation where failure can lead to catastrophic progressive collapse. Traditional static analysis methods are fundamentally inadequate for simulating the sudden, nonlinear, and dynamic nature of such events, creating a significant gap between structural design and demolition safety planning. This research addresses this critical need by developing an integrated computational workflow utilizing ETABS for global analysis and design of a G+15 vertically irregular RC building per Indian codes, and ANSYS Explicit Dynamics for high-fidelity simulation of blast-induced progressive collapse. The study successfully identifies critical columns through pushover analysis and quantifies the dynamic response, establishing a Dynamic Amplification Factor of 1.92-2.02 and proposing a kinetic energy-based metric for robust collapse initiation detection. The results demonstrate distinct failure mechanisms for instantaneous versus blast-load removal scenarios, with the latter producing more realistic fragmentation and a 12% higher energy impulse. This work provides a validated, end-to-end methodology that bridges a crucial gap in demolition engineering, offering practical, simulation-driven insights to enhance the safety and predictability of demolishing complex irregular structures.