Experimental Analysis on the Structural Behaviour of Connections with LVL Made of Beech Wood

Despite its higher strength and stiffness properties as compared to most softwood species, beech wood is today almost entirely used for energetic purposes or non-structural applications. Benefitting from elevated mechanical properties and a reliable high degree of homogeneity, Laminated Veneer Lumber (LVL) made of beech has a great potential for applications in high performance structural elements, for instance in large span truss structures. As the performance of timber truss structures predominantly depends on the efficiency of the connections, an experimental analysis of dowel-type connections in beech LVL was performed. A series of embedment tests was carried out according to EN 383:2007, the parameters being the dowel diameter and the end distance of the connectors. The tests showed a very ductile behaviour of the material, high values of embedment strength and a low scatter in the results (CoV < 5%). These findings were confirmed in subsequent tensile tests on full dowel connections. The tested connections consisted of four dowels and two slotted-in steel plates, the examined parameters were the dowel diameter and the spacing. Provided that an adequate spacing is guaranteed, the full connections also showed a very ductile behaviour. The common problem of premature splitting failure did not occur due to the favourable effect of the cross-layers in the LVL. It was further found, that the adequate spacing has to be determined with regard to shear plug failure. The experimental analysis has confirmed the potential for efficient dowel-type connections with LVL made of beech.