Comparison of CLT Design Methods to Composite Beam Theory

Cross-laminated timber (CLT) is increasingly being used as a primary structural material. Since about 60-70% of structural material is associated with the floor system, sustainability gains are efficiently realized by use of CLT floor plates. Most floors can be modelled as 1-way slabs and idealized via beam theory; however, increasingly complicated composite beam and plate theories are being proposed for CLT design. This research compares methods from the US CLT Handbook to a composite beam design equation derived from elasticity theory. All deflection and stress results are compared to a benchmarked finite element model. Results show that CLT Handbook methods provide stresses and deflections within 5% of the FEA and composite beam theory. However, results indicate the shear analogy method over-estimates required laminate thickness for 4.6m span by up to 30% for deflection-governed design compared to the composite beam theory.