Shear Strength of Cross Laminated Timber Based on Larch Lamina Combination

Cross -laminated timber (CLT) fails in the outermost tensile lamina under bending loads, or rolling shear failure occurs in the Minoir direction lamina. This study investigated the effect of lamina width (90 mm, 120 mm), modulus of elasticity (MOE), and placement of major direction lamina on the shear strength of Larix kaempferi Carr CLT. The shear test was conducted using the short span bending test. Results showed that the specimen with 90 mm width of lamina underwent rolling shear failure at the minor direction lamina. The specimen with 120 mm width of lamina had suppressed rolling shear failure and failed at the outermost tensile lamina, which resulted in 52% higher shear strength compared to the 90 mm width specimen. CLT with high MOE placed in the outermost tensile lamina had increased shear strength. The specimen with four laminas in the major direction had both the highest strength and the lowest reliability due to the high standard deviation. This suggested that the width of the larch lamina and the MOE affect the strength of CLT. The CLT strength obtained using the FEA and the theoretical analysis were compared with the measured strength values.