PROGRESSIVE COLLAPSE AND ROBUSTNESS OF FRAMED STRUCTURES: SIMULATION AND DESIGN

Abstract

We present a framework to investigate progressive collapse and robustness of 2D framed structures, subjected to multiple column removals. Progressive collapse is first simulated with an algorithm based on the Discrete Elements. The possible collapse mechanisms emerging from the simulations constitute the input for an analytical model. The model takes into account the dynamics of the response to the sudden initial damage and, under the hypotheses of ideally plastic or perfectly brittle ruptures, provides upper and lower bounds for the collapse loads and for the progressive collapse resistance. Closed form expressions are obtained, that can be valuable for robustness-oriented design. A novel concept of hierarchy in robustness capacity design emerges, which partly conflicts with anti-seismic capacity design. Strategies of compartmentalization and the influence of the position of the initial damage within the frame are discussed, also taking into account the impacts between falling rubble and horizontal floor slabs.

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