A REVIEW OF PROGRESSIVE COLLAPSE ANALYSIS IN TALL STEEL STRUCTURES

Progressive collapse has become a major concern in the design and assessment of tall steel structures because local damage can propagate through the structural system and cause partial or total collapse that is disproportionate to the initiating event. This review examines the concept, causes, resistance mechanisms, analytical procedures, and current code provisions related to progressive collapse in tall steel buildings. The study highlights how factors such as column loss, transfer element failure, connection fracture, fire-induced degradation, and geometric irregularities can trigger collapse propagation. Particular emphasis is placed on the structural mechanisms that improve robustness, including alternate load path action, catenary action, Vierendeel action, diaphragm participation, continuity, and redundancy. The review also compares key design approaches, including tie-force method, alternate path method, and performance-based frameworks, while discussing the strengths and limitations of linear static, nonlinear static, linear dynamic, and nonlinear dynamic analyses. Special attention is given to modeling issues specific to tall steel structures, such as second-order effects, composite floor action, interaction between gravity and lateral systems, and realistic connection behavior. The study concludes that progressive collapse resistance in tall steel structures must be understood as a system-level property requiring integrated consideration of ductility, continuity, robustness, and realistic nonlinear response under abnormal loading scenarios.