Numerical evaluation of timber as passive fire protection for steel structural profiles

Steel is widely utilized in civil construction due to its excellent mechanical properties and durability. Nevertheless, steel remains particularly vulnerable to fire, rapidly losing mechanical strength and demonstrating high thermal conductivity under elevated temperatures. To mitigate this vulnerability, structural designers increasingly incorporate fire-resistant materials, such as timber, to delay heat propagation and prolong structural integrity. The integration of steel and timber combines the advantageous properties of each material: steel provides high load-bearing capability, while timber offers significant thermal insulation and fire-protective qualities. This research evaluates the effectiveness of timber as passive fire protection for steel profiles through advanced numerical modeling. Various configurations are examined, involving T- and I-shaped steel cross-sections combined with distinct timber species. The analyses employ SAFIR® computational software to perform transient thermal simulations, calculating temperature distributions across steel-timber composite cross-sections and assessing material degradation over time. Numerical outcomes are compared and validated with experimental results from the literature, confirming the accuracy and reliability of the methodology. Consequently, the developed numerical approach contributes to more accurate assessments of steel–timber composite elements, promoting safer, economically viable, and sustainable structural solutions.