Numerical nonlinear structural analysis of a timber truss roof under fire condition

As greenhouse gases continue to rise and environmental impact reduction gains global attention, timber buildings have emerged as a vital asset in the pursuit of a sustainable future. Throughout history, timber has been linked to fire as a flammable material, and there have been numerous reports of out-of-control fires that highlight the importance of fire safety. Hence, the primary goal of this study is to assess the fire resistance of a timber truss roof. As the temperature rises, changes occur in the physical and mechanical characteristics of the timber members, causing the loss of the strength capacity and rigidity of part or the entire truss. Therefore, this research aims to explore the SAFIR computer program to carry out the following analyses: thermal analysis of the timber cross-section; and the structure’s thermo-mechanical analysis. By conducting the first analysis, it becomes possible to calculate the temperature field of timber members’ cross-section in a transient regime, while also obtaining information about the degradation of material properties. The second analysis provides the displacements, internal forces, critical time, and/or critical temperature of the timber truss during collapse. The numerical results obtained here were compared and validated with those from the literature (experimental results). The truss collapse time predicted by SAFIR’s model was quite similar to the one observed in the laboratory. The developed numerical methodology allows for more realistic studies of timber elements or systems, enabling designs based on safety, economy, and sustainability.