Experimental study of dowel design in the shear plate dowel joint

The shear plate dowel joint (SPDJ) is a novel connection design for use in heavy timber structures. Load transfer between timber members is enabled using a single large diameter dowel and externally glued steel plates. The steel plates are glued to the timber using bond lines of low stiffness and high fracture energy to achieve a uniform shear stress distribution, thus maximizing the load carrying capacity. This experimental study aims at studying the global connection response for different dowel types. The SPDJ is tested for joint configurations with one or three timber structural elements using 10 and 6 different types of dowels respectively. Solid or thick-walled steel dowels are used as reference, which are compared to thin-walled metal tubes for an increased connection ductility. In addition, engineered wood products are used to investigate whether a SPDJ design made mainly of wood is possible. The results indicate that it is indeed possible to increase the ductile behaviour of the SPDJ by 30-80% using thin-walled metal dowels, generally at the expense of the load bearing capacity, with an upper limit being defined by shear plate bond line failure at 5.4 MPa in average shear. The shear plate is typically made of steel, and the study finds plywood an unsuitable replacement due to low shear strength between the veneers. Laminated densified wood is tested as dowel material with impressive results similar to those of thicker metal dowels, and such material could possibly be used also for the plates.