Lateral-torsional buckling of carbon steel and stainless steel beams subjected to combined end moments and transverse loads in case of fire

This paper presents a numerical study on the behaviour of carbon steel and stainless steel I-beams subjected to lateral-torsional buckling (LTB) in case of fire. The main motivation for this work is the fact that part 1-2 of Eurocode 3 (EC3) does not take into consideration the beneficial effect, resulting from the reduction of the plastic zones connected with non-uniform bending diagrams along the beam.
Although new formulae for the LTB, that approximate better the real behaviour of steel structural elements in case of fire, have been proposed in previous works, they still do not considered the combination of end moments and transverse loads, as it is stated in part 1-1 of EC3. Therefore, in this paper numerical simulations, of steel beams with combined end moments and transverse loads, are compared with the LTB design curves of EC3, and new correction factors that improve these curves are presented.