Size effects on the bending strength of Chinese larch pine laminated veneer lumber

Owing to the excellent strength-to-weight ratios, Laminated Veneer Lumber (LVL) becomes one of the favorable building materials for timber structures, especially for long-span structural beams. Attempts have been made to use high-yielding Chinese larch pine as a raw material of structural LVL, which could expand the raw material source for engineering constructions. Understanding the bending properties of Chinese larch pine LVL (CLP-LVL) is critical for promoting the development of CLP-LVL for structural applications. In this study, flatwise and edgewise bending strengths of CLP-LVL under different specimen sizes were experimentally investigated. Results showed that the CLP-LVL could provide comparable or even superior bending properties for structural applications. Subsequently, the size effects on the bending strengths of CLP-LVL were evaluated. It is suggested that the depth and width effects under a constant span-depth ratio on the bending strength should be considered when adopting strength theories to predict the bending strength of CLP-LVL. Correlations for calculating the depth and width adjustment factors related to specimen size were proposed. Results showed that the bending strengths of CLP-LVL specimens could be well predicted by the reference bending strength and proposed depth and width adjustment factors. Besides, the depth and width effect factors of flatwise bending strength for CLP-LVL determined by the slope method were 0.14 and 0.12, while that of edgewise bending strength were 0.09 and 0.05, respectively. Especially, the proposed size effect factors for CLP-LVL were further verified by the experimental results of structural-size CLP-LVL specimens.