This paper provides a comprehensive and critical review of the fire behaviour of steel structures to synthesise current knowledge, identifying research trends and highlighting areas requiring further investigations.
A detailed review of experimental, numerical and analytical studies has been conducted. The literature was categorised into five broad categories: behaviour of structural members, performance of connections, system-level structural response, innovative materials and advanced modelling techniques and fire-protection materials.
The review shows that the fire performance of steel structures is influenced by variables like load level, slenderness ratio, axial restraint and temperature gradients. Connection studies have shown their importance for structural survival during fire. Apart from isolated members, research has also focused on system-level response, emphasising membrane action, load redistribution, frame restraint effects and cooling-phase behaviour. Recent developments include the application of novel materials like foamed concrete and CFRP-strengthened systems and state-of-the-art computational fire simulations. They have demonstrated that fire-retardant materials can substantially increase fire resistance. However, there are still significant knowledge gaps in understanding the effects of the cooling phase, validating performance-based fire design approaches and assessing post-fire serviceability and residual structural capacity.
This review presents a combined assessment of fire behaviour at the member, connection and system level and reviews recent developments in materials, protection systems and modelling techniques. It highlights the main research gaps and suggests directions for future work to advance fire-safe and resilient steel structures.
