Fire Resistance Analysis of Bending Timber Structures According to Eurocode 5

Abstract

The article contains the results of the fire resistance analysis of timber bending structuresby a simplified method of reduced cross-section and an advanced method by solving the differentialequation of non-stationary thermal conductivity.The fire resistance analysis of timber floor elements was performed according to the proceduredescribed in Eurocode 5, part 1-2.The fire resistance analysis with respect to the load-bearing function and insulation function wasperformed with the reduced cross-section method.According to the results of the analysis, the failure time of the fire protection and the time of startof charring of the floor elements were determined by the method of the reduced cross-section method.The time of fire resistance of the floor with respect to insulation function was defined as the sumof the values of the times of fire resistance of individual layers and structural floor elements.The thermal analysis of the fire resistance of timber floor beams was performed by the finite elementmethod using the Ansys Mechanical 2021 R1 Academic software.Relationships between thermal properties of wood – specific heat, thermal conductivity, densityand elevated temperature were adopted in accordance with the standard DSTU-N B EN1995-1-2.The results of thermal analysis of fire resistance were obtained for three types of cross-sections, fortwo options of heating during a fire – from one and three sides for 45 and 60 minutes.