Advances in hybrid fire simulation – A novel stiffness-update method for real-time implementation

In this paper, we present a novel computational approach for stiffness-update of fire-exposed structural member to rigorously study the thermo-mechanical coupling of a real-time hybrid fire simulation. This approach realistically considers the stiffness and strength degradation of the fire-exposed member at each instance of continuous fire evolution and its effect on the global response of the structure. A newly independent computational and experimental framework for hybrid fire procedure is implemented in this study, which applies a well-suited benchmark structure consisting of high strength steel S690QL. Various case studies with different influencing aspects such as different load ratios, heating rates and computational control parameters are presented to investigate most important temperature- and rate-induced numerical and experimental challenges. In addition, different limitations of HFS approaches in state-of-the-art studies are addressed and enhanced by the new proposed approach. This study marks a significant advancement in real-time hybrid fire simulation and proves the competence of presented methodology for rigorous and robust assessment of the fire performance of structural systems, leading to more realistic fire design of structures. • A rigorous HFS methodology deals with challenges arising in material nonlinearities and applied high heating rates. • The necessity of a method for stiffness-update of fire-exposed structural member for numerical convergence of HFS is highlighted. • The stiffness-update method enables a sound accuracy in interface errors and temperature synchronization at the interface.