| The timber rivet is the only fastener within the Canadian design standard for which a set of design equations for both ductile and brittle failure modes is given. Available to the designers are two different approaches: one presented in the appendix of the standard that gives design equations for the brittle failures due to longitudinal shear and tension stresses. For the ductile failure modes, one equation is provided in the core of the standard. Also within the core of the standard, design tables are provided to determine the brittle failure resistance (by shear or tension) for a variety of possible timber rivet group configurations. The current set of design equations presented in the appendix, was developed by Foschi and Longworth (1975) and can appear overwhelming to the designers. Over the years, the introduction of new variables such as the wood species or the thickness of the steel plates has resulted into the addition of modification factors to the design equations.; Recently, with the introduction of the timber rivets on the American scene, US researchers have proposed a rational design approach to predict the resistance for both ductile and brittle failure modes. The design equations used to predict the ductile failures is a truncated set of the European Yield Model equations. The design equations for the prediction of the brittle failures in the wood are based on the material shear and tension resistances and on their corresponding areas.; Based on all of the previous work and extrapolating from work done on bolted connections, a rational approach has been developed at RMC. This new approach is presented and a comparison of the various methods is made while highlighting differences in assumptions and results. |
