The method of determining the stress-strain state of metal poles of power transmission lines during the technical examination of electric grid facilities is analyzed. An example of a calculation using the automatic LIRA software package is given. The most stressed sections of structures are determined. The calculated method confirms the hypothesis that the triangular cross-section of the traverse of the portal intermediate support of the 500 kV overhead line is more economical (more efficient) than a tetrahedral (classical) cross section.

Keywords: building structures, metal structures, energy facilities, stress-strain state, technical expertise