Lateral torsional buckling of welded stainless steel I-profile beams: experimental study

In this paper, an experimental program is presented consisting of 13 experiments on welded stainless steel I-profile beams subjected to lateral torsional buckling, in which 11 specimens are made of the lean duplex stainless grades EN 1.4062 and EN 1.4162, while the last two specimens are made of the austenitic grade EN 1.4404. The beam heights are 160, 210, and 260 mm, and the beams have a constant flange width of 160 mm. This results in three different strong axis elastic section moduli but similar weak axis bending resistances. The range of beam buckling length covers slenderness values from 0.30 to 0.76. The geometrical imperfections of the specimens were measured using digital image correlation (DIC). The web was first measured along its whole length. Then, the beam was placed on its fork supports, and the imperfection was then remeasured once more to check the influence of both gravity and test setup. Traditional four-point bending tests were carried out, and during which, the displacements were measured using linear variable differential transformer (LVDTs), inclinometers, and DIC. In this paper, the measured ultimate moments, together with results of experiments collected in the literature, are compared to the design rules provided in EN 1993-1-4, for which a safe but rather conservative design is obtained, and to the recent proposal of Taras and Greiner dedicated to carbon steel beams. The latter provides better results for high slenderness values but can be further improved