ДОСЛІДЖЕННЯ ВОГНЕСТІЙКОСТІ ЕЛЕМЕНТІВ СТАЛЕВИХ КАРКАСІВ ПРОМИСЛОВИХ БУДІВЕЛЬ З ВРАХУВАННЯМ РІВНЯ МЕХАНІЧНОГО НАВАНТАЖЕННЯ

Viktor Hvozd; Olga Nekora; Stanislav Sidnei; Inna Nedilko; Svitlana Fedchenko; Eugene Tishchenko

doi:10.31731/2524-2636.2021.5.1.40.49

Viktor Hvozd Cherkassy Institute of Fire Safety Named after Chernobyl Heroes of National University of Civil Defense in Ukraine
Olga Nekora Cherkassy Institute of Fire Safety Named after Chernobyl Heroes of National University of Civil Defense in Ukraine
Stanislav Sidnei Cherkassy Institute of Fire Safety Named after Chernobyl Heroes of National University of Civil Defense in Ukraine
Inna Nedilko Cherkassy Institute of Fire Safety Named after Chernobyl Heroes of National University of Civil Defense in Ukraine
Svitlana Fedchenko Cherkassy Institute of Fire Safety Named after Chernobyl Heroes of National University of Civil Defense in Ukraine
Eugene Tishchenko Educational and Methodological Center for Civil Protection and Life Safety of the Cherkasy Region

DOI: https://doi.org/10.31731/2524-2636.2021.5.1.40.49

Keywords: fire resistance, standard fire, steel structures, mechanical load

Abstract

The article considers and analyses the methods by which it is possible to carry out research to determine the fire resistance of elements of steel frames of industrial buildings. It is determined that it is expedient to use the means of computational fluid dynamics, which has no limitations due to the high cost, complexity, environmental friendliness and complexity in comparison with real experiments. In order to conduct the most reliable computational experiments, mathematical models of temperature and mechanical reaction to the thermal effect of fire were created, taking into account the equations of thermal conductivity, systems of differential equations of stress-strain state of solids in their numerical implementation based on the finite element method. The solution of mathematical models was carried out using computational fluid dynamics, which describes the process of heat and mass transfer in test fire furnaces during the determination of fire resistance of steel structures. According to the results of computational experiments it is shown that the limiting state of loss of bearing capacity of vertical and horizontal structures occurs due to the formation of a zone of plastic deformations taking into account the associative theory of plasticity. According to the results of computational experiments, the dependence of the limit of fire resistance on the level of applied load to structures, which is close to linear, was revealed. Based on the obtained dependences and the corresponding graphs, a technique is developed based on the use of maximum deformations of the elements with the corresponding fixation of the limit state on the loss of fire resistance in terms of bearing capacity by bending this curve.