Nonlinear finite element modelling of castellated steel beams lateral torsional buckling

摘要

Restrictions of space and height are often imposed to residential, commercial and industrialrnbuildings with one, or several floors, due to aspects like regional regulations, technical, economic or aestheticrnnature. In order to provide the passage of pipes and ducts with large diameter under steel girders, that normallyrnrequires great heights, sometimes leads to floors building highs with an unviable magnitude. Among others,rncastellated beams are a possible structural solution to overcome these obstacles. These beams are consideredrnstability issues, since the unbraced span lengths generally reached by them are often long enough to causerninstability effects. However, the substantial enhancement in the flexural strength of such members, due to thernextra height coming from the manufacturing process in relation with the original profile, combined with therneconomy of material and utility services, ensures to the designers the attractiveness of this solution, especiallyrnwhen applied to large spans. The present investigation aims to develop a numerical model that calibrated withrnexperimental results, enables the development of a parametric analysis centred on the finite element method.rnThis analysis aimed to determine the structural behaviour of the castellated beams and their associated failurernmechanisms, considering an elastic-plastic behaviour as well the geometric non-linearities. The results showedrncoherency and no relevant technical objections were verified, when considered the application of the castellatedrnbeams in alternative of the traditional plated beams since the advantages arising from the beams openings justifyrntheir application.