Evaluation of finite elements for the study of the ultimate behaviour of steel-concrete composite beams

The study of the carrying load capacity of steel-concrete composite beams requires some attention, due to the non-linear interactions between the concrete slab, steel beam and shear connectors. A beam model, accounting for the weak shear interface, permits an accurate description of the global behaviour, when an appropriate solution technique is adopted. The finite element method can be used with good results; many problems occur however if an unsuitable beam element and insufficiently refined mesh are used. The authors illustrate the displacement-based and three-field mixed elements proposed in previous works. The elements are evaluated by comparison with experimental tests on continuous beams.