Embedding strength in joints of fast-growing Argentinean Eucalyptus grandis with dowel-type fasteners. Analysis according to the criterion adopted by European standards

The present paper reports on the results of an investigation regarding the determination of the embedding strength of sawn timber of Argentinean Eucalyptus grandis with dowel-type fasteners. The importance of accurately knowing this property has increased with the increasing demand for this material for structural purposes. An empirical research project with 294 specimens prepared for testing under the embedding action of rigid fasteners (nail, bolt and dowel) was carried out according to the procedures prescribed in EN 383 (2007). The results showed no significant influence of pre-drilling on the embedding strength for nailed joints, which is not in line with the European experience and the corresponding criterion adopted by the Eurocode 5 (2005). The characteristic values of the embedding strength estimated based on the timber density and by applying the corresponding equation from the Eurocode 5 (2005) for bolted joints were 45% and 176% greater than those obtained in this project for the specimens loaded parallel and perpendicular to the grain, respectively, and similar percentages were found for dowelled joints (45% and 126%). These results showed that the reliability of structural design may be strongly affected if the embedding strength of this timber species is estimated by following the procedures adopted by the Eurocode 5 (2005) for dowel-type connections.