The behavior of laterally loaded dowel-type fasteners is well established in relation to their bending deformation caused by lateral embedment stresses in wood. Modeling of the so-called “rope effect” has however attracted less attention. The rope effect in laterally loaded connections is evoked by withdrawal behavior of the shank as well as by axial resistance of the head of the fasteners. It describes the development of tensile forces along the axis of the fastener, as a consequence of its bending deformation and axial constrains. These tensile forces cause frictional forces in the shear planes of the connection, which considerably increase the strength of laterally loaded connections.

Different kind of numerical models have been proposed for the simulation of dowel-type connections, including 3D FEM with elasto-plastic material models, with damage mechanics or with so-called foundation models. In this contribution, calculations with beam-on-nonlinear foundation method will be presented. Compared to conventional foundation models, elements to account for increased lateral connection strength due to withdrawal strength and rope effect of the fasteners were added. This was implemented in terms of axial springs that encompass a withdrawal force-relative displacement relationship, similar to the lateral springs considering the embedment behavior. In addition, friction between the connected timber members was taken into account by the frictional coefficient times the force component perpendicular to the shear plane, as a result of the axial force in the fastener. 

Calculations were performed for different types of dowel-type fasteners, including screws, nails with a smooth shank, nails with an annular-ringed shank and smooth dowels. Model predictions were compared to experimental data and showed good correlation. This encourages the use of the beam model for the engineering design of dowel-type connections in timber structures based on a deeper understanding of structure-connection relationships.