Characterizing engineering performance of bamboo-wood composite cross-laminated timber made from bamboo mat-curtain panel and hem-fir lumber

During the global industrialization process of manufacturing cross-laminated timber (CLT), attempts have been made to use local wood species. For areas rich in bamboo resources but relatively short in timber resources, the use of bamboo- and wood-based composites to manufacture composite CLT (CCLT) has great potential. In the present work, two new types of 3-ply CCLT panel structures constituting bamboo mat-curtain panel and hem-fir lumber were investigated. In the major and minor strength directions, flatwise bending and shear tests were conducted to investigate their failure modes, maximum bending moment, bending stiffness, modulus of elasticity (MOE), bending strength, interlaminar shear strength, and specific bending and shear performance. Moreover, 3-ply hem-fir glued-laminated timber and CLT were used as controls. The effective MOE of each panel structure was calculated according to shear analogy theory and modified gamma theory and then was compared to the measured MOE. Based on the shear analogy theory, the effect of the thickness of layers on the MOE of the panels was investigated. Results showed that unlike other types of CCLT, the new CCLT exhibited distinct plate-like orthogonal strength characteristics. Its theoretical MOE agreed well with the measured MOE as the accuracy changed with the panel structure. By changing the panel structure of the new CCLT, if the MOE of one strength direction was reduced, the MOE in the other strength direction could increase accordingly based on the layer characteristics. The results presented in this paper can provide a guidance for future design and optimization of bamboo-wood CCLT.