The research of a building covering spatial truss resistance to the progressive destruction in modern CAE-systems

Abstract

Modern methods of calculating building structures for progressive collapse expect to carry out a calculation with a change in the design scheme. Change of the design scheme is carried out, for example, by excluding one or more elements from it. The calculation of the scheme remaining part for “viability” is performed after the removal of the elements. The calculation is realized in the form of an iterative process. Each subsequent result, leading to the some of the elements exclusion from the calculation scheme, increases the amount of the whole system destruction. For today there are recommendations of calculations performance on a progressing collapse in the literature. In practice, engineers have to perform a qualitative analysis of the system to remove elements from the design scheme. In this paper, we present the results for solving this problem for the metal framework of a production building with a spatial structural coverage. Solving the problem, the authors used the calculating applications Lira, SCAD, STAAD, VisualAnalysis and SAP 2000. The modeling of the fracture process was preceded by the possible damage analysis to the coating elements when the source location of ignition inside the building was changed. For the focus of the fire, the rack position for storing the finished products was taken. In order to detect the most dangerous places of fire’s origin, the authors used the graphical overlay method of the technological scheme for the construction scheme. In the fires places, areas of structural damage were identified. In this way, the elements (an element) of the construction were determined, which should be removed first from the design scheme. The conducted research of structural design showed that local emergency influence on the majority of structural elements (excluding the nodes transferring the load to the capitals) does not lead to further destruction of the spatial lattice structure elements. The authors confirmed the well-known fact that a redistribution of forces between neighboring elements occurs for statically indeterminate structures in the event of an individual element failure. The calculations showed that the cross-section of the element, selected according to the maximum values of forces, non-accidental combinations is able to withstand the load in an emergency situation.