The diploma thesis investigates the mechanical behaviour of double-shear timber joints with beech dowels. Joints made of spruce and beech members were experimentally tested using commercially available and custom-made dowels with a diameter of 12 mm. The tests were carried out under loading both parallel and perpendicular to the grain of the outer members. Based on the force–displacement curves, the maximum load, joint stiffness and displacement at maximum load were determined. The results were supplemented by measurements of wood moisture content and density. The relationships between maximum load, stiffness and density were evaluated using Pearson’s correlation coefficient. The analytical load-carrying capacity of the joints was calculated according to the provisions of the final draft of the 2. generation of Eurocode 5 (2G EC5) using different combinations of experimentally and analytically determined values of embedment strength and dowel bending resistance. The comparison showed that 2G EC5 provides more conservative values for embedment strength and bending resistance than those obtained experimentally, resulting in analytically determined load-carrying capacities that were lower than the experimental values and therefore on the safe side. Visual inspection of a sectioned specimen revealed a failure mode characterised by the formation of four distinct fracture points in the dowel. The results confirm the applicability of beech dowels in timber joints, while also indicating the need for further research involving larger sample sizes and a more detailed evaluation of failure mechanisms.
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