Theoretical and experimental analysis of timber-to-timber joints connected with inclined screws

The aim of this paper is to propose a method for calculating the load-bearing capacity and stiffness of screws placed in an inclined position with respect to the shear plane and subjected to shear–compression load, to shear–tension load or to a combination due to their crossed X-position. At the same time, the authors also wish to highlight how the current method indicated by Eurocode 5 is partially unsuitable for describing the experimental results of strength and stiffness for these particular configurations. To this regard, push-out tests were carried out and the analysis of the resulting load–displacement curves has led to the definition of the main parameters describing the mechanical behaviour of the connections: strength, stiffness, effective number, ductility. The experimental values of strength and stiffness were then compared with the theoretical ones obtained using the Eurocode 5 calculation method and the calculation method proposed in this paper.