Bending and shear performance of Australian Radiata pine cross-laminated timber

Cross Laminated Timber (CLT) is increasingly being used in commercial and residential construction in Australia due to its inherent strength and sustainability credentials. Until recently, infrastructure building projects using CLT have been reliant on imported products from overseas manufacturers. There is now a viable Australian grown and fabricated CLT product from Radiata pine. This paper summarises the experimental results on the mechanical behaviour of Australian Radiata pine CLT panels in out-of-plane bending and shear. Three-layer 105 mm thick panels and five-layer 145 mm panels with three different spans were tested. The results demonstrate strong correlations to existing theoretical models and were used to validate the finite element model (FEM) developed in this research. The experimental results showed that the average bending stiffness of the CLT panels were marginally greater than theoretical values. The maximum bending strength for Radiata pine exceeded the characteristic strength of 14.0 MPa for grade XLG1 external laminas, with three-layer CLT samples averaging 28.7 MPa and five-layer CLT samples averaging 26.8 MPa. The maximum observed shear stresses ranged from 1.55 MPa to 2.18 MPa, which also exceeded the rolling shear characteristic strength of 1.2 MPa for the feedstock. The results also highlighted that the shear strength decreases with an increasing thickness of the CLT panel.