Finite element modelling of steel-timber composite beam-to-column joints with nominally pinned connections

Non-linear 3D continuum-based finite element (FE) simulations are employed to investigate the structural behaviour of steel-timber composite (STC) beam-to-column connections with shear-tabs and/or double web-angles. In the FE models developed, the material non-linearities of the steel and timber are considered using constitutive laws cast in the framework of classical plasticity and continuum-damage mechanics, respectively. Furthermore, the non-linearities associated with geometry (small strain-large displacement) and non-linear contact (interactions between different components) are considered in the models. A sensitivity analysis is performed to assess the spurious mesh sensitivity associated with softening of the timber, and the 3D FE models of the STC sub-assemblies are validated against experimental data gathered from previous studies. It is shown that the FE models proposed can predict the structural response and the complex failure modes of STC connections with reasonable accuracy. Finally, a parametric study is carried out and the influence of variables such as the depth of shear tab/web angles or the number and size of the bolts, thickness of the timber slab the and degree of composite efficiency on the failure mode, the peak load carrying capacity and moment-rotation response of the nominally pinned STC beam-to-column connections are evaluated and discussed.