Numerical analysis of the stability behaviour of castellated beams and comparison to regular hot‐rolled profiles

Castellated steel beams, characterised by their unique perforated web design, have gained significant popularity in the construction of medium‐span structures, like industrial and office buildings. These beams offer an economical solution due to their increased bending moment capacity about the major axis with relatively low weight and associated high resource efficiency. However, they are particularly susceptible to lateral‐torsional buckling as a result of their increased cross‐sectional height. Additionally, the regularly spaced openings weaken the web, leading to further local failure modes. For simplified design methods, boundary conditions are usually incorporated through the elastic critical moment, which itself is influenced by possible local failure modes, such as web distortions. This paper investigates the influence of various boundary conditions on the analytical computation of the elastic critical moment according to the draft Technichal Report CEN/TR 1993‐1‐102:2025 and the lateral‐torsional buckling design according to the 2nd Gen EN 1993‐1‐1:2022 for castellated steel beams in comparison to regular hot‐rolled profiles within a comprehensive numerical and analytical study.