Assessment of lateral–torsional buckling in steel I-beams with sinusoidal web openings

Abstract

Beams with sinusoidal web opening are alveolar beams manufactured from a single web cut, which lead to the production of higher I-sections and with a better strength-to-weight ratio when compared to the I-sections from which they originated. There are few studies in the literature about this I-section type, especially in relation to their behavior regarding global stability and Lateral Torsional Buckling (LTB) strength. Bearing in mind the importance of understanding the behavior of alveolar beams with sinusoidal openings in relation to LTB, an extensive parametric study was carried out through numerical analysis in the commercial finite element software ABAQUS. The study was performed with 10 I-sections of the IPE type, with lengths ranging from 6 m to 32 m. In addition, initial imperfections were considered, such as residual stresses and geometric imperfections. With the parametric study results, it was possible to evaluate the main existing analytical procedures, both for the determination of the LTB elastic critical moment, as well as the LTB ultimate moment. The adequacy of standard procedures (AISC; Eurocode 3 and AS4100) was evaluated, as well as analytical procedures present in the scientific literature for determining the LTB ultimate moment. Through the achieved results, it was possible to analyze the behavior of different adaptation methods for the calculation of the elastic critical moment in sinusoidal alveolar beams, as an alternative to the traditional double-T approach. Furthermore, it was found that the AISC-360 standard is unsafe in the case of actions applied to the upper flange, even though this is the most common condition in engineering projects.