Towards predicting the buckling and crushing strength of graded SA pine with high slenderness ratios

Abstract

There is an apparent increase in failure of timber truss web members or compression chords. This paper seeks to reassess buckling of the compression chords with specific focus on web members. There are two possibilities for the seemingly lower buckling strength of web members, namely that the mean modulus of elasticity is a poor predictor of buckling strength where knots and other local changes in stiffness are concerned, and secondly that the actual crushing strength of the timber is lower than the design values. This paper will investigate both of these possibilities in order to achieve a safer approach to the design of timber compression members.