Behavior of Different Types of Bolted Timber Joints

In this paper the behavior of different types of single bolt joints for timber structures are studied considering both cases of load acting parallel to the grain and perpendicular to the grain. Experimental tests on six types of steel-to-timber joints and two types of timber-to-timber joints were carried out, considering one single diameter for the bolt (16 mm) and only one wood specie (Red-Spruce). The load-slip curve of each specimen (5 specimens for every joint type) allowed to determine the characteristic limits of each joint type that are: the proportional load, the yield load, the ultimate load, maximum slip at failure and the stiffness in service of the connection as well. Predictions of the yield load and the service stiffness were obtained using the EYM and the BEFM, respectively. The analytical predictions of the yield load are in good agreement with experimental results though experimental values for the embedding strength of wood were used in the models. Similar agreement was found for the stiffness in service. Using common empirical relationships for the embedding strength, safe predictions of the yield load were obtained only for the cases of load acting parallel to the grain