Assessment of the Reliability of Thin-Walled Steel Profiles in High-Temperature Conditions

In low-rise construction, the technology of building objects from light steel profiles is very popular. To assess the safety of objects, the temperature distribution in the fence was studied by modeling during prolonged heating from a fire source. Laboratory studies of the deformability of thin-walled profile samples at temperatures of 20 and 290 °C were conducted using a special method. A 13.4% decrease in the deformation modulus of a thin-walled steel pipe at a temperature of 290 °C was observed compared to loading at a normal temperature (20 °C). For modeling by the finite element method, a two-storey cottage with a frame made of profiled steel pipes and a fence made of foam or gas concrete blocks was adopted. In the software package “Lira”, studies of the stress-strain state of the building frame at temperatures of 20 and 290 °C were carried out. As a result of the calculations, diagrams of longitudinal and transverse forces, bending moments, and deformations of the frame elements were obtained, the values of which are significantly lower than the permissible values. It is shown that the maximum displacements in the vertical elements of the frame structure increase by 1.4 times at a temperature of 290 °C, but the calculated value of longitudinal flexibility does not exceed the maximum permissible value. Therefore, the use of thin-walled steel profiles in the frames of low-rise buildings is acceptable, taking into account the possible increase in temperature.