LAUSR

The article presents numerical calculations of the variable heat flow during fire exposure based on the standard fire curve. The aim of the work was to analyse the temperature distributions in cross-sections for various methods of strengthening wooden beams using steel elements glued into the cross-section. Many historic timber elements, where reinforcement was necessary, were repaired using various steel elements. The most commonly used reinforcements were steel plates and rods glued into the cross-section in various configurations. Historic timber elements are particularly sensitive to fire. Since steel has a high thermal conductivity and timber is a flammable material, an important aspect of steel-reinforced structures is the knowledge of heat flow and, consequently, temperature distributions in the cross-section determining the cross-section combustion rate. In this work, a thermal numerical analysis was carried out in the ANSYS program for six variants of beams reinforced in different configurations with steel elements. The calculation results for the reinforced beams were compared with the unreinforced beam by analysing temperature distributions in the cross-section, charring depth, and charring rate. Based on the calculations, it can be seen that the reinforcement of wooden beams with the use of steel elements does not adversely affect the temperature distributions and charring rate. If properly performed, the reinforcement of wooden beams using steel elements should not increase the risk of faster destruction of the structure during a fire.