Numerical modelling of castellated beams with hexagonal openings

In this paper, a numerical model is developed to predict the behaviour of castellated beams with hexagonal. The numerical model takes into account both material and geometric non-linearity. To initiate buckling, an initial small out-of-plane geometric imperfection, obtained from an eigenvalues buckling analysis, was imposed to the model. Calibration with experimental data obtained from previous work shows that the model is able to predict, with relatively good accuracy, the ultimate load. A parametric study is then followed to determine the effect of web thickness, yielding stress and opening height on the ultimate load of the beams. Based on the parametric studies results, the accuracy of the cross-section classification for castellated beams proposed in the Annex N of Eurocode 3 is assessed.