Rate-dependency and hysteresis of timber connections with a single laterally-loaded dowel and a slotted-in steel plate

In timber structures, the connections are crucial for the overall behaviour of the structure and for providing plasticity. Previous research on timber connections has predominantly focused on their behaviour when subjected to quasi-static and monotonic loading. However, timber structures may also be subjected to high loading rates or cyclic loading, such as in wind or seismic loading, blast, impact, or progressive collapse. In this paper, experimental results on laterally-loaded timber connections with a single dowel and slotted-in steel plate are presented. The experiments were conducted using LVL and 10 mm S235 steel dowels in a quasi-static cyclic loading protocol and in a monotonic loading protocol with displacement rates between 0.05mm⋅s⁻¹ and 150mm⋅s⁻¹. From the cyclic experiments, severe degradation phenomena, such as pinching and strength and stiffness degradation were observed. Moreover, increasing load-to-grain angles resulted in a higher elastic stiffness and resistance and a decrease in the post-elastic stiffness. In the monotonic experiments, high loading rates led to an increase of the yield force and, at loading parallel to the grain, to a significant reduction of the ductility. The rate-dependent effects on the ductility, maximum force, and failure modes were not uniform across all load-to-grain angles.