Effective stiffness of nailed multiple-ply timber members

Abstract

In timber roofs, multiple-ply trusses are placed next to each other and the web members are held together with nails. This paper presents various methods, among which is a simple spring model, whereby the effective stiffness of these composite web members may be calculated, based on the stiffness of the connectors and the individual web members. The spring model can be used for any number of connectors and members as long as the members are loaded within the elastic range of both the members and the connectors. Results from a limited number of finite element simulations show that this method has merit. It makes it possible to determine the bending and axial stiffness to an acceptable degree of accuracy. The paper also addresses the calculation of the stiesses in the individual members.