Behavior of axially loaded steel short columns subjected to a localized fire

• Thermal calculation approach for steel column in localized fire is provided.
• Tb for localized fire is higher than for uniform steel temperature condition.
• Eurocode approach is conservative for short column in localized fire.

Steel short columns are used in building structures. The heating conditions in real building fires are non-uniform. The structural fire design approaches in the Eurocode are based on uniform heating conditions. This paper presents a numerical investigation on the behavior of steel short columns subjected to a localized fire. The effect of non-uniform heating condition on the failure temperature of axially loaded steel short columns is studied. Failure temperature is defined here as the maximum temperature in a steel column at failure (e.g. the onset of buckling or squashing). Simple thermal models were used to calculate the temperature of steel short columns in localized fire conditions. Sequentially coupled thermal–mechanical simulations were conducted. The study finds that the failure temperature of steel short columns in a localized fire is much higher than that of columns with a uniform temperature. The failure temperature in a localized fire might be slightly lower (within 20 °C) than that in the standard ISO 834 fire. The Eurocode design equations give conservative results of the failure temperature for steel short columns subjected to localized fires.