This paper explores methods of simulating the behaviour of building structures under progressive collapse conditions through alternative models of different levels of structural idealization. Such alternative simulation models have been applied in many previous studies of the problem, but there is insufficient information regarding the degree of reliability and appropriate representation of the actual structural behaviour as the model is simplified by reducing the level of structural idealization. To investigate the problem, the study adopts the alternative load path method through the well-established concept of notional column removal. The study focuses on the interaction of the directly affected structural members with their neighboring structural components. The results demonstrate the significant influence of this parameter on the overall structural response under progressive collapse conditions. Most importantly, it is demonstrated that this parameter depends on many factors and is difficult to quantify without explicitly analyzing the behaviour of the surrounding structure. As a conclusion, a local failure that can potentially lead to progressive collapse should be analyzed in the context of the global behaviour of the structure. Alternatively, effective methods for simulating the boundary conditions of individual structural members should be studied and developed to enable the application of reduced analysis models.
Mbah et al. (Tue,) studied this question.