Global buckling of S690 transversely-stiffened plate girders with slender webs: Behaviour and design

High-strength steels (HSSs) are now used globally in different structural applications because of their constructional and environmental merits. Though, investigations on HSS elements still relatively limited. Herein, the lateral-torsional buckling (LTB) response laterally-unsupported plate girders with stiffened slender webs is explored considering steel S690, which currently under extensive testing worldwide. This done by finite element (FE) modelling to provide numerical models that well simulate actual behaviour. Accordingly, FE verified first through comparisons available tests literature. After that, parametric analyses generated examine effects geometrical characteristics cross-section (in terms effective radius gyration for LTB (rT) elastic section modulus referred compression flange (Sxc)) length behaviour strength these girders. The results show increasing value rT, computed as about minor-axis plus one-sixth web, increase more efficiently compared relative rT. On other hand, while Sxc found raise girders, has been be less than Sxc. Additionally, based current results, girder slenderness parameter 2.0 inelastic limit such built up from larger become ineffective better made conventional normal-strength steels. Furthermore, bending strengths design given AISC, EC3-1-1 AS4100. they highly conservative predictions AS4100 yielding best values. However, enhancements possible lighter same applied loads. EC3 general model (provided Clause 6.3.2.2) modified using curve “a" instead “d".