Experimental Study on Thermal Response of Thin‐Walled Uprights Subjected to Radiative Heat Flux

Thin‐walled steel members are used extensively in the industry. However, due to their low massivity, thin‐walled members are particularly prone to fire. The time for fire exposure to have a critical impact on the structure is thus short. In industrial applications, vertical elements (uprights) serve as main structural elements for complex systems such as storage racks, catwalks, or even self‐supporting warehouses. Most uprights are, at the initial phase of the fire, exposed mainly to the radiative heat flux. This type of thermal attack induces a non‐uniform temperature field in the cross‐section that can lead to additional bending moment affecting compressive members. The study quantified the temperature gradient in thin‐walled uprights exposed to the heat flux imposed by a gas‐fired radiant panel. The results show that even at relatively low exposure (12.5‐25.0 kW/m 2 ), there is a significant temperature gradient observed (locally >20°C/mm). It can lead to the severe bending moments induced in the member. A premature failure of the uprights may then be expected in members that are not engulfed in flames. Further research, however, is required to assess the exact mechanical behaviour of CFS uprights exposed to the non‐uniform thermal exposure.