Finger Joint Strength. A Laminated Beam Strength Predictor

Abstract

SYNOPSIS The new South African Timber Design Code, SABS 0163, no longer specifies strength values for laminated products in South Africa. The onus now rests on the manufacturers to determine the strength of their laminated beams. This could lead to unnecessary costs, if every possible size of member has to be either tested or proof loaded. Proof loading at the incorrect level could lead to a large number of members being broken unnecessarily. In this paper the author illustrates that the finger joint strength is one of a number of factors that influences the strength of a laminated beam. These factors are explained and values for them are given. The author describes how, based on the strength of the finger joints, the strength of any possible beam size can be predicted. The author compares theoretical strengths with some test values and shows that there is good correlation between theoretical and test values. This method will help the manufacturers design their members correctly for strength. Costs can be...