Fiber alignment angles effect on the tensile performance of laminated bamboo lumber

For better application of laminated bamboo lumber (LBL) in construction industry, the tensile performance of LBL was studied by conducting tension test on LBL specimens with seven different fiber alignment angles, each alignment angle containing 30 specimens. All the specimens only experienced the elastic stage before brittle failure with four failure types. With increasing alignment angle, the tensile strength, tensile modulus, and ultimate tension strain decreased rapidly from 0° to 30°, while they almost remained constant after the angle of 45°. Hankinson’s formula (n = 1.75) can be used to predict the tensile strength of LBL. An empirical equation was proposed to predict the tensile modulus of LBL. The Poisson’s ratio increased and peaked at 15° before declining. Based on the stress–strain coordinate transformation, the relation between shear properties and the alignment angle of LBL was studied; the calculated shear strength decreased with increasing alignment angle, and an empirical equation was proposed, which could be used to obtain the shear strength of LBL for engineering use.