Modelling deformation in nailed, thin-webbed timber box beams

Thin-web box beams made by nailing plywood or other webs to solid timber flanges are an economic form of timber construction. Their analysis presents problems because of the significant shear and nail distortions that increase deflections. This paper demonstrates how to model such members for any load distribution in any type of structure (portal frames, continuous beams) using commercially available structural analysis software. The method is approximate but slightly conservative.