Evaluation of parameters influencing the load-deformation behaviour of connections with laterally loaded dowel-type fasteners

Connections made with laterally loaded dowel-type fasteners are important details in timber structures. According to Eurocode 5, their load-carrying capacity can be calculated with the so-called European Yield Model (EYM) and simplified rules for the determination of slip-moduli are given. The slip modulus is given as a mean value for the serviceability limit state and a simple reduction of slip modulus in the ultimate limit state is given in addition. Despite these simple regulations, it is well known that connections with dowel-type fasteners show a considerable non-linear load-deformation behaviour with different degrees of ductility. This ductility can enable the load redistribution in complex and statically undetermined structures and allow to achieve higher capacities compared to linear elastic design. In the paper, the deformation behaviour of connections with laterally loaded dowels dowel-type fasteners is studied based on more than 750 test results of bolted connections. The parameters influencing the slip-modulus, ductility ratio, and ultimate deformation are evaluated. It is focused on the effects of these parameters and the resulting variability in deformation behaviour. Recommendations are given on how different levels of ductility and deformation capacity can be achieved in dependency of the spacing of fasteners and other geometrical parameters.