Stochastic Analysis of Wire-Connected Round Timber Trusses Edward

Abstract

Round timber, as a by-product of forest thinning, can be used for construction of innovative and attractive wooden structures. It forms an inexpensive source of construction material for agricultural structures in developing countries. Several methods of connecting round timber have been proposed and investigated world-wide. This paper considers a method that uses flitch plate and wire lacing connections to achieve stable, low-cost and durable round timber structures. For the structural designer, however, it is also necessary to have methods for structural analysis of such structures. This paper discusses a stochastic finite element analysis procedure that was developed and used to analyse round timber trusses made from eucalyptus poles. Static load versus displacement / characteristics of the trusses were investigated using full-scale trusses. In the deterministic analysis, the wire-connected joints developed for the purpose were modelled using semi-rigid connection elements. The effects of slip at the joints, and the effects of creep and joint movement over a long time were incorporated in the analysis. In the experimental set-up, only the deflection of the mid-point of the bottom chord of the truss was measured. It was observed that the results from the deterministic analysis compared well to full-scale truss tests. Keywords: Timber structures, round timber, stochastic analysis, limit states design.