ANALYSIS OF FOREIGN EXPERIENCE IN RESEARCH CASES OF PROGRESSIVE COLLAPSE OF BUILDINGS AND STRUCTURES

One of the leading areas of the engineering scientific community is the research of the performance of structures and systems in general during unlikely (extreme) events, in particular, the progressive collapse of buildings and structures. A large number of cases of collapse of buildings and structures of various purposes and levels of responsibility are known, and researchers in the field of progressive collapse are interested only in cases of the highest level of responsibility because the social, political, and economic impact of the loss of such buildings and structures is the most significant. The purpose of this paper is to comprehensively analyze the phenomenon of the progressive collapse of buildings and structures based on the experience of significant foreign cases. The analysis includes the causes of progressive collapse initiation, the degree of disproportionality of progressive collapse, types of progressive collapse, and design features of progressive collapse cases. The study uses an approach that not only includes the results of the analysis of direct cases of progressive collapse, but also provides statistical characteristics depending on the cause of initiation, type of collapse, and geometric location of the initial damage. Particular attention is paid to the compliance of the accepted methods for modeling progressive collapse with real cases of progressive collapse. The study results showed that the existing estimates of progressive collapse cases take into account the so-called degree of disproportionality of the collapse. This is because it is only possible to guarantee resistance to progressive collapse if the collapse is only disproportionate. The fact that the initial failure of one or more columns occurred in about half of the progressive collapse cases indicates that modeling progressive collapse due to sudden column removal is rational. Further research can focus on finding real collapse scenarios, in particular, the choice of a column that is suddenly removed from the scheme, studying the correctness of load redistribution when a column is suddenly removed, and studying the resistance to progressive collapse of buildings with structural schemes made of wood or precast concrete.