A new calculation method for lateral torsional buckling of steel beams with non-uniform temperature distributions in fire

This paper describes a new calculation method for predicting the lateral torsional buckling resistance of steel beams with non-uniform temperature distributions under fire conditions with modification of the beam slenderness to account for the effects of non-uniform temperature distributions. Improvement of the new calculation method is checked against numerical simulations using the ABAQUS program. A parametric study of unprotected steel beams under the standard fire condition indicates that the new calculation method will have noticeable effect on the predicted lateral torsional buckling resistance of beams at the early stage of fire exposure, e.g. 15 or 30 minutes. At later stages of fire exposure, as the temperature distribution in the beam cross-section tends to become uniform, predictions of the beam's lateral torsional buckling resistance using both the current Eurocode 3 method and the new calculation method are almost the same.