Shear properties of composite cross-laminated bamboo panels

The inter-laminar shear behavior of cross-laminated engineered bamboo (CLB) panels is one of the governing properties determining such structural elements' overall performance; thus, it was experimentally investigated in this research. Firstly, the bond line’s shear strength between cross-laminated bamboo layers was obtained through the oblique compression shear test to validate the adhesive qualities. Then, the transverse shear modulus G and strength values f_v were evaluated by the two-plate planar shear test and short-span bending test. The shear specimens’ full-strain field was also recorded and analyzed in this study. The relative homogenous shear stress field was noticed for the two-plate planar shear test, whereas evident local stress concentrations were observed for the other two test methods. Thus, the modulus and strength values obtained through the planar shear test were suggested to be used as the reference values for future structural elements studies. Moreover, two different methods to measure the shear strain of the planar shear test were discussed in the study: dial gauges and digital image correlation (DIC) system. The direct-strain measurement method based on the DIC system is suggested for future studies as the compression deformation influence of outside bamboo layers was mitigated. Test results obtained in this study indicate that engineered bamboo panels’ shear properties can fulfil current cross-laminated timber standards' strength and modulus requirements. It has promising potential for CLB or cross-laminated bamboo and timber panels with good shear resisting ability.