Lateral Torsional Buckling of Welded Stainless-Steel I-Profile Beams: Design and Reliability

Abstract

In this paper, a geometrically and materially nonlinear numerical model using ANSYS is validated against 13 lateral torsional buckling (LTB) experiments as well as experiments from the literature. A parametric study comprising 30 geometries with each 12 lengths in the slenderness range of 0.35–1.95 is then performed. This numerical study is repeated for the stainless steel ferritic EN 1.4016, austenitic EN 1.4404, and duplex EN 1.4462 grades to ensure a safe design for all stainless-steel families used in civil engineering structures. When compared to the numerical results, the current EN 1993-1-4 (CEN 2006) design rules are slightly unsafe for the intermediate slenderness range and increasingly conservative for stocky sections in the higher slenderness range. Based on this, the reliability assessment according to Annex D of EN 1990 (CEN 1990) leads to safety factors greater than the codified value of 1.1. However, by introducing the recent proposal of Taras and Greiner, improved predictions of the LTB strengths are achieved, especially when the adjusted imperfection factors for each stainless-steel family is used. Safe predictions are obtained in the intermediate slenderness range as well as high improvements of the prediction for stocky sections in the high slenderness range.