Loss-of-Stability vs Yielding-Type Collapse Mode in 3D Steel Structures under a Column Removal Scenario

Progressive collapse of structures is the phenomenon of an initial failure mushrooming into global level, resulting in total or partial damage of the structure. This field is currently dominated by the Alternate Load Path Method, which involves the notion of a vertical key-component removal as the result of an abnormal event and the assessment of the remaining structure to bridge over the loss of that component. Previous work by the authors has shown that under a column removal scenario in a moment-resisting steel frame, the two most prominent collapse mechanisms are the loss-of-stability mode which involves the buckling of another column, and the yielding-type mode which is comprised by a series of plastic hinges at the beams ends and the eventual occurrence of a kinematic chain. The current paper expands this work in a 3D framework and develops a detailed numerical model of a 10story steel frame composite building. Interior gravity columns are removed along the height of the structure and the response of the structure in terms of the corresponding collapse mechanism is captured. The simulations are conducted using the finite element software ABAQUS and all the modeling assumptions are explicitly stated and discussed.

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