Aprobation of a methodology for modeling progressive collapse using the example of a real-world accidental impact on a construction site

Abstract

In this article, the authorsexamine the issues associated with traditional approaches to determining resistance to progressive collapse, as regulated by national and international standards, which are based on the principle of independence from the type of threat. This is achieved by modeling the sudden removal of a single column or other vertical load-bearing structure from the structural model. According to statistical studies of progressive collapse cases, this approach is plausible; however, it does not fully reflect real collapse scenarios, in particular, it does not account for the nature of the cause of the structural failure and its impact on adjacent elements.

To improve the predictive accuracy and reliability of the analysis, it is proposed to expand the traditional modeling approach by considering more complex and realistic damage scenarios. Based on the results of a series of verification numerical calculations, an effective methodology for determining the resistance of buildings and structures to progressive collapse is proposed. The method is based on a dynamic approach (direct integration of the equations of motion over time) and consists of six sequential stages.

To validate the methodology, the results of modeling the progressive collapse of a steel-framed building of consequence class CC3, which sustained local damage due to a real emergency impact (UAV strike), are presented. A comparative analysis was conducted of the calculation results obtained using the traditional standard method of sudden removal of a single element and the refined approach based on reproducing the actual damage pattern. The main focus was on investigating the effect of dynamic unloading of the structural system caused by the instantaneous destruction of lightweight enclosure elements and the roof by a blast wave. The obtained data confirm the high consistency of the refined model with the actual condition of the structure and allow for an objective assessment of the remaining service life of the damaged structures to inform decisions regarding their further restoration.