Properties of 2–5 Layers Small-Sized Glued-Laminated Timber Using Lower Quality Oak (Quercus spp.) Lamellae

This study examines the mechanical performance of small-sized glued-laminated timber (GLT) produced from low-quality oak (Quercus spp.) lamellae and veneer arranged in 2–5 layers. After both non-destructive and bending tests, density, modulus of rupture, deflection and modulus of elasticity by static and dynamic methods were evaluated. Average densities ranged from 747 to 777 kg/m3. The two- and three-layer GLTs exhibited modulus of rupture values of 59.0 MPa and 63.7 MPa, while the four- and five-layer specimens reached 80.4 MPa and 80.0 MPa, respectively—up to 36% higher due to veneer reinforcement on the tension side. Static modulus of elasticity ranged between 11.2 and 12.1 GPa, and dynamic modulus of elasticity reached 13.0 GPa. The findings demonstrate that multi-layer configurations with veneer reinforcement effectively enhance bending performance and reliability, promoting the structural application potential of low-grade hardwood in accordance with EN 14080.