Lateral-torsional buckling of class 4 section uniform and web tapered beams at elevated temperature

An extensive numerical study of Class 4 section beams at elevated temperature is described in the paper. The study focuses on welded I-section beams of slender web and flange and covers beams of constant height as well as beams with significant web taper ratio. The numerical parametric study extends previous test results significantly in terms of various temperatures, section slenderness for flange and webs considering also combination of more stocky flanges with a slender web, various beam slenderness and moment distribution along the beam. Based on the numerically calculated resistances, a simple design rule was developed for both constant and web tapered members. The proposed model is believed to be predicting the beam capacity accurately with formulas simple enough to be used and accepted by structural engineers