Bending and shear properties of cross-laminated timber panels made of poplar (Populus alba)

Abstract With the expansion of cross-laminated timber (CLT) material throughout the global construction community, an effort is being made to explore the use of regionally produced CLT materials from Iran, including the testing of fast-grown, hand-planted poplar (Populus alba). This paper investigated the out-of-plane bending properties of CLT panels manufactured using poplar at various span-to-depth ratios (SDR). Mechanical properties of poplar CLTs investigated included the modulus of rupture, apparent modulus of elasticity, effective bending stiffness, effective shear stiffness, and maximum shear stress in both the major and minor directions. Experimental test results were compared with both the shear analogy model and finite element method (FEM) results to examine the use of predictive modeling. Bending properties were predicted using the shear analogy method and FEM compared well with experimental results, with the FEM able to predict the distribution of bending and shear stress across the beam thickness. Modulus of rupture and apparent modulus of elasticity increased with increasing SDR in both the major and minor strength directions. In the major strength direction, the effective modulus of elasticity and maximum shear strength values predicted by the shear analogy method were in good agreement with experimental results. As noted in previous studies, the effective shear stiffness predicted by the shear analogy method in the major strength direction was 510% less than that of experimental results.