Characterization of the halved undersquinted scarf carpentry connection

The halved undersquinted scarf is a peculiar carpentry connection used in timber frame structures and roofs. In the classical engineering analysis, this kind of connections are usually described as hinges, able to transfer axial load but without any bending load bearing capacity. Nevertheless, from the observation and analysis of existing structures it is clear that, due to the shrinkage of the wood, wrong montage or imperfections in the structure, the connection is usually in the condition to bear eccentric forces. In the paper, a static model for the description of the behaviour of the connection is presented. Furthermore, the results of the experimental campaigns are illustrated. The work has been developed with the continuous validation of the analytic model on the base of the experimental results. Different aspects that influence the behaviour of the connection loaded in pure compression, pure bending and combined compressive and bending force are analysed. The description of carpentry connections through a static model is of importance in a scientific field for the knowledge of the mechanical behaviour of old constructional systems and many applications in the structural analysis with the aim of reinforce and restoration of old timber structures.