Compressive Strength Prediction of Veneer-Based Structural Products

Abstract

Veneer-based structural products, such as laminated veneer lumber (LVL) or plywood, are commonly used in timber construction. When a manufacturer wishes to use new timber species or optimize the use of its veneered stock, the nominal design values of the new products need to be determined from comprehensive and expensive experimental investigations. In an effort to cost-effectively determine these characteristics, this paper introduces a methodology to numerically predict the compressive strength of veneer-based structural products. The method combines a classical elastoplastic approach with a probabilistic strength-prediction model of the wood veneers. The veneer strength is determined from its size and characteristics which can be measured in line during manufacturing. The accuracy of the approach is verified against experimental tests performed on 24 LVL samples manufactured from two different timber species and of various sizes. Results show that the approach accurately predicts the strength of the LVL samples with an overall predicted∶experimental ratio of 1.5 and low coefficient of variation of .8. The methodology is applied to determine the compressive strength distributions of LVL columns and plywood boards manufactured from a new resource, namely early to midrotation (juvenile) hardwood plantation logs. The approach considers three different species, Gympie messmate (Eucalyptus cloeziana), spotted gum (Corymbia citriodora), and southern blue gum (Eucalyptus globulus). The modeled compressive design strength of the new products is found to be of the same order of magnitude of and up to 1.6 times greater than the strength of commercialized LVL columns and plywood boards.