Abstract
An experimental investigation on steel-to-timber joints arranged with multiple bolts was carried out, both in the case of load parallel and perpendicular to the timber grain. The joints were made with timber side members and steel main member; high strength bolts were used for fasteners. The experimental results allowed determining the stiffness in service, the slip at failure and the reference loads (proportional limit, yielding, ultimate). A descreasing ductility of joints was observed at the increase of the number of bolts. With the above characteristic loads the bolt effectiveness of multiple joint loaded parallel to grain was evaluated and compared with that obtained from some analytical predictions found in the literature. It was evidenced that the provisions of Eurocode N.5 provide values for the bolt effectiveness quite closer to experimental reslts. The results of joints loaded perpendicular to the grain were compared with some analytical predictions; significant differences were noted with all analytical predictions considered.
Résumé
Une investigation expérimentale a été conduite pour étudier les joints entre le bois et l'acier, réalisés avec des boulons multiples soumis à une traction aussi bien parallèle que perpendiculaire aux fibres de bois. Les joints ont été construits avec l'élément central en acier et les éléments latéraux en bois; des boulons à haute résistance ont été utilisés. Les résultats des essais ont permis de déterminer la rigidité en service, le glissement à la rupture et les valeurs de résistance caractéristiques (limite de proportionnalité, évervement, limite ultime). En augmentant le nombre de boulons, on a constaté une diminution de ductilité du joint. Avec les valeurs de résistance caractéristiques, on a évalué l'efficacité de boulons des joints chargés parallèlement aux fibres du bois et la valeur a été comparée avec celles obtenues par quelques relations analytiques trouvées en littérature. Le travail de recherche a mis en évidence que la relation proposée par l'Eurocode No. 5 donne des valeurs très proches des résultats expérimentaux. Les résultats des essais sur les joints soumis à une traction perpendiculaire aux fibres de bois, comparés avec quelques relations analytiques, mettent toujours en évidence beaucoup de différences.
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Gattesco, N., Toffolo, I. Experimental study on multiple-bolt steel-to-timber tension joints. Mat. Struct. 37, 129–138 (2004). https://doi.org/10.1007/BF02486609
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DOI: https://doi.org/10.1007/BF02486609