Stress-Based Failure Model for Dowelled Steel-to-Timber Connections under Eccentric Loading

Dowelled steel-to-timber connections have been successfully used in timber construction for decades due to their ease of installation and high performance. The steel dowels provides some ductility to the load-bearing behaviour of the connections, where timber by itself largely fails in brittle manner. However, modelling the behaviour of dowelled connections is complex due to stress peaks, anisotropic material behaviour and the variability of mechanical properties. Current design models are based on rigid-plastic material behaviour, which simplifies calculation of ultimate load-carrying capacity but not deformation. Empirical formulae exist for linear load-displacement relationships. The non-linear load-deformation behaviour and load-carrying capacity under eccentric loading is not addressed by design models. Timber trusses with dowelled connections are therefore designed with simplified procedures. The simplified design method for trusses accounts for the load-carrying capacity of individual component but not their load-deformation behaviour or system effects of the entire structure. This thesis presents a modelling approach for simulating the load-deformation behaviour and load-carrying capacity of dowelled steel-to-timber connections under eccentric loading. The approach consists of two main components: (1) a model to simulate the load-deformation behaviour and load distribution within the connection, based on the load-deformation behaviour of individual dowels, and (2) a model to calculate the stresses within the timber part of the connection. The developed modelling framework is calibrated and validated through a comprehensive experimental test campaign on dowelled connections at the material, fastener and connection level. The model shows good agreement compared to the the experimental results and design models. The simulations show the potential of the model for the investigation of the structural behaviour and reliability of timber trusses with dowelled steel-to-timber connections.