Splitting Capacity of Timber Connections with Densified Wood Dowels Loaded Perpendicular to the Grain

Dowelled connections loaded at an angle to the grain can result in splitting of the timber member. Compared to steel dowels, wooden dowels have better compatibility of stiffness with the assembled timber members, which reduces the risk of splitting of the assembled timber members. There is little research on timber connections with wooden fasteners loaded perpendicular to the grain. In this study, double shear tests loaded perpendicular to the grain were conducted on timber connections with densified wood (DW) dowels, which show higher mechanical properties than hardwood dowels. The effects of hygroscopic swelling of dried DW dowels and connection geometries on the splitting capacity of timber connections were explored, with the studied parameters being relative connection height, timber member width, and connection width. Tests on timber connections with steel dowels were also performed. The splitting capacities of timber connections with DW dowels and steel dowels showed a statistically significant difference. The splitting capacities of timber connections with DW dowels were higher than those of timber connections with steel dowels. Design formulae for splitting capacity of timber connections with DW dowels loaded perpendicular to the grain were proposed on the basis of design approaches given in German National standard for design of timber structures DIN 1052 and proposed by Ballerini and Rizzi.