CASTELLATED DUPLEX AND LEAN DUPLEX STAINLESS STEEL BEAMS NUMERICAL ASSESSMENT

Castellated beams are associated to various instability effects since their unbraced span lengths are often long enough to cause lateral buckling. However, the substantial enhancement in the flexural strength combined with the economy of material and utility services, ensures to the designers the attractiveness of this solution especially when applied to large spans. Additionally the natural transition to a sustainable development by reducing environment impacts and attitude changes in the construction market, have boosted the use of stainless steel structures although design codes are still largely based on carbon steel analogies. The present investigation aims to present a numerical model, calibrated against experiments, used in a numerical assessment centred on the finite element method. The studied castellated beam openings were made with hexagonal non-regular polygons and the analysis aimed to determine the structural behaviour of duplex castellated beams and their associated failure modes, considering an elastic-plastic response as well as geometric non-linearity. The results indicated that the use of stainless steel castellated beams are more efficiency for large length spans.