Experimental and analytical investigation on timber connections with beech, birch and laminated densified wooden dowels

The use of wooden dowels has gained renewed interest recently, primarily as a means of connecting structural components in timber construction. Serving as an alternative to metal fasteners, wooden dowels offer mechanical compatibility with timber elements and potential environmental benefits. Due to their green credentials, high compatibility with timber members, and ease of disassembly and reuse, this type of fasteners requires appropriate models to predict their mechanical properties. Due to their load-bearing capacity and lateral stiffness, wooden dowels are commonly used in composite structures, effectively enhancing the composite action between two members. There is still a lack of studies on mechanics-based models focused explicitly on wooden dowels. In fact, they exhibit a unique failure mode that can involve not only bending and/or embedment but also shear and even compression perpendicular to the grain. This study aims to evaluate predictive models for the capacity of connections with wooden dowels. The authors tested glulam-to-plywood connections with fasteners made of either birch, beech, and laminated densified wood dowels. Additionally, reference tests were performed using conventional self-tapping screw connections, and the results were compared. Additional tests were also conducted on the dowels to estimate their bending, shear, and embedment strengths. Selected predictive capacity models are compared, including that in the new Eurocode 5 proposal.