Ensuring the regulated reliability level of steel bar structures with increased level of responsibility on the example of the roof of the Ilyichevets sports complex in Mariupol

Introduction . The article focuses on the challenges of analyzing the susceptibility of unique bar structures and structures with increased level of responsibility to progressive collapse, as well as the methodology for analyzing the reliability of these structures. Aim . To develop an algorithm for assessing the susceptibility of unique structures with increased level of responsibility to avalanche collapse under various calculation loads. Materials and methods. The algorithm for calculating numerical indicators of structural reliability, in particular, safety characteristics, is considered. The upper numerical reliability criterion, which characterizes the failure probability of the entire group of the most responsible elements, is determined, along with the lower reliability level, i.e., the minimum value characterizing the reliability of a rod from the group of the most responsible elements of the structure. The proposed methods are implemented in the MATLAB programming language in the form of an author software. The verification of the proposed method was carried out in the design of the restoration project for the Ilyichevets sports complex in Mariupol. Results . The methods proposed provide for determining the group of the most responsible elements of the system, the failure of which will inevitably cause the onset of progressive collapse, rather than performing calculations by blind trial and error. A numerical characteristic of the susceptibility of a structure to avalanche collapse, Δβ (system survivability reserve), is proposed. Conclusions . The calculation results proved that the theoretical results obtained were nearly completely consistent with the data recorded during the inspection of the roof structures of the Ilyichivets sports complex in Mariupol, thus confirming the accuracy of the proposed algorithms for calculating the numerical reliability indicators of structural elements.