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A 3D Finite Element (FE) model has been developed, which accounted the geometric nonlinearity of flange and web portions of I-beams. The nonlinear FE model was reviewed against tests on castellated timber beams having a web with hexagonal holes. Load carrying capacity, load-deflection responses and failure modes for castellated beams in flexure were predicted and compared to the experimental results. An additional parametric study involving two different web opening shapes (circular and rectangular) was performed using the presented FE model to study the effects of the change of shapes of holes in web portions on the strength and buckling behaviour of castellated beams in bending. The parametric study has shown that castellated timber beams failing due to web-post buckling modes exhibited a strong decrease in the initial load capacity.
bending test, buckling behaviour, FE model, geometric nonlinearity, parametric study, timber I-beams
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