Progressive Collapse Analysis and Safety Assessment Method for Steel Truss Roof

Abstract

Progressive collapse resulting from local failures in accident events have caused many tragedies and loss of life in the past. The structural integrity and capacity to resist collapse are gradually improving as an essential requirement in structural design practice. As one of typical systems in industrial facilities and large-scale public buildings, a truss roof with low redundancy differs from a load-bearing wall and frame system. In this paper, the robustness of the truss structures is studied by both nonlinear static and dynamic analysis. The mechanism of internal force redistribution is studied and the importance of the mechanism affecting the subsequent failure process after the initial loss of the member is revealed. A method for identifying the sensitive and key element is put forth, and a Safety Assessment Method (SAM) based on linear static analysis procedure is proposed to evaluate the sensitivity index and key index of structural members. By this method, the vulnerability of a truss structure can be predicted and enhancement of the necessary countermeasures needed to prevent progressive collapse can be adopted.