Comparisons on withdrawal resistance of resin and phosphate coated annular ring nails in CLT specimens

Abstract

As a fastener type, the galvanized annular ring nails are common in timber engineering. Nowadays, partially resin or fully phosphate coated annular nails are used as well. In this study, the withdrawal resistance of those nails, whose holding capacities have not been involved in the current literature, is investigated comparing with other nail types (galvanized annular and helical nails) and wood screw via experimental test results on cross-laminated timber (CLT) specimens. Each single fastener was driven perpendicularly into the surface (side face) of CLT specimen as in the wall-floor angle bracket connections. Not only the numerical values of holding capacity but also the load-displacement curves are focused in the experimental tests. Furthermore, the withdrawal energy during the pull-out of single fastener, which is not investigated so far but may have highly significant implications for metallic connections of CLT panels, was evaluated graphically. The validity of the current withdrawal models in the literature is verified by the experimental results for the nail types under consideration. Moreover, the effects of the parameters such as grain pattern, manual/gun-drive conditions are addressed in this study as well.