Wood as a natural and renewable material currently experiences a revival as structural building material. New technologies and a new design standard request appropriate, modern design methods for timber structures. Particularly, the design of modern timber connections is of importance since more challenging timber constructions demand ambitious connections. Most connections in timber structures are compliant in the sense that relative deformations between the connected structural elements occur during load transfer. In particular dowel connections exhibit this behavior since load transfer in dowel connections is based on the compliant embedment behavior of stiff steel dowels in wood.
The aim of this thesis is to develop a model for a consistent calculation of the load-deformation relationship of connections. Additionally, this model is applied to timber structures to study the influence of compliant connections on the structural behavior. As a basis for the modeling of dowel connections, properties of single-dowel connections are presented. Different responses of wood in case of different loading directions, as well as several models for the calculation of single-dowel slip curves are discussed. Significant differences in the predicted load-deformation behavior of single-dowels can be observed among these approaches. A sub-model is used to determine realistic single-dowel slip curves for arbitrary connection configurations. Furthermore, the state-of-the-art approach for the determination of connection slip curves of multi-dowel connections is discussed. The restriction of this approach to some specific design situations is highlighted. These limitations of the current design approach are the motivation to develop a model for the calculation of slip curves of multi-dowel connections. This model enables a straight forward determination of member forces and connection slip curves for an arbitrary set of deformations. The single calculation steps and the feasibility of application on arbitrary connection configurations are discussed. Furthermore, a modification of the model to determine the deformation and force distribution within the connection for specific member forces is presented.
Finally, the model is applied to different connections to illustrate their behavior for simple design examples. Moreover, connection slip curves have been implemented in the structural analysis of a static indetermined system in order to illustrate the necessity of considering the compliance of connections in the design of timber structures. It is shown that negligence of the connection slip may lead to uneconomic or even unsafe timber structures. Furthermore, the importance of an exact definition of the connection slip curves is discussed. Even insignificant differences from standard configurations may lead to remarkable changes in the connection behavior and, consequently, in the behavior of the structure. Moreover, a considerable influence of the used method to describe the single-dowel behavior on the behavior of the connection and, consequently, on the structural behavior has been found.