An Energy-Based Partial Pushdown Analysis of Robustness Assessment of Building Structures

Vulnerability of buildings to disproportionate (or progressive) collapse has become an increasingly important performance issue in recent years. The current guidelines issued by the US Department of Defense use the alternative path method to assess the vulnerability of a structural system to disproportionate collapse. An energy-based nonlinear static pushdown analysis procedure is proposed in this paper to meet the need for a relatively simple procedure for preliminary vulnerability assessment of regular building frames subjected to local damage. This method can be used to check not only the vulnerability of the structure but also the possibility of structural instability during collapse. The predictions are found to be sufficiently close to the results of a nonlinear dynamic time history analysis (NTHA), even when failure involves more than one structural member and large displacements, that the method would be useful for collapse-resistant design of buildings with regular steel framing systems.