Experimental Study on Influence of Material Parameters on Bond Behavior of Glued-in Rod Connection

Glued-in rod connection for timber structure has shown great potential for engineering applications because of its high strength, stiffness, and aesthetic appeal. During the past few decades, extensive research has been carried out to investigate the effects of geometrical parameters on bonding behavior of glued-in rod connection. On the other hand, comprehensive studies on the effects of material parameters are rare. This article presents an experiment program to study the effects of a number of material parameters-adhesive type, rod surface type, glued-in direction-of glued-in rod connection. Twenty-four glued-in rod specimens were tested using a universal testing machine, and the full bond-slip behaviors of specimens were collected. Test result shows that bond strength of glued-in rod connection with epoxy resin is 20 % to 30 % higher than that with polyurethane, and the effect of rod types on bond strength is negligible. Although parallel-to-grain glued-in rod connection has higher bond strength than that of perpendicular-to-grain connection, sudden brittle failure is observed for parallel-to-grain glued-in rod connection. Furthermore, a new bonding strength model is proposed to account for the effects of material parameters.