Numerical investigation of timber log-haus walls with steel dovetail reinforcements under in-plane seismic loads

The paper investigates the structural response and vulnerability of timber log-haus wall under in-plane seismic loads. Careful consideration is given, in particular, to the structural efficiency of additional metal fasteners introduced within the thickness of traditional timber log-walls. Log-haus systems are in fact typically obtained by stacking multiple logs, and generally used for residential or commercial buildings up to two levels. Their seismic characterization, however, still requires further investigations and studies, since current standards for timber structures (i.e. Eurocode 5 and Eurocode 8) do not provide specific recommendations for their seismic design. In this regard, the so called ‘steel dovetail profiles’ investigated in this paper are aimed to improve the in-plane stiffness and ultimate resistance of traditional log-walls. In particular, taking advantage of past experiments carried out on small-scale joint specimens, as well as past 3D numerical efforts for the same structural typology (un-reinforced assemblies), full 3D solid models are described in ABAQUS, to assess the potential of steel dovetail profiles, as well as to capture possible issues. Numerical simulations are proposed both for small-scale specimens as well as full log-haus assemblies, being representative of the actual loading and boundary conditions for log-haus walls as part of a real building. As such, the effects of key input parameters and main influencing aspects are emphasized. In conclusion, it is shown that the examined reinforcing technique can offer rather stable initial stiffness and ultimate resistance increase, compared to un-reinforced assemblies. At the same time, several aspects should be taken into account to properly optimize their benefits.