The influence of nail ductility on the load capacity of a glulam truss structure

When considering the design of load-carrying structures, brittle behaviour at failure should be avoided in order to attain a higher level of safety. In wood structures, the way to achieve high ductility is to take advantage of the plasticity of mechanical connectors (nails, dowels, bolts, etc.). In this paper the influence of ductile connections, slotted-in nailed wood to steel joints, on the total load-carrying capacity and deformability of a glulam truss is investigated. Experimental and finite element parametric studies are carried out to observe how different shapes of the nail load–displacement curve affect the load-carrying capacity. The results clearly show that consideration of the true elasto-plastic load–displacement behaviour of the nails results in a higher capacity of the truss compared to using linear elastic nail properties.