Recorded at the Young Researchers Conference 2020.
The market for laminated timber products, such as Glued laminated timber (Glulam), Cross Laminated Timber (CLT) and Laminated Veneer Lumbar (LVL) has increased in recent years. This is because the construction industry is seeking more sustainable structural alternatives to steel and concrete.
As a result of timber’s lower stiffness, beam design is generally limited by serviceability requirements, in particular static deflection and vibration. The potential for improving the total stiffness of laminated timber beams by curing the laminations of glulam so that the timber’s grain is aligned to the line of principal stresses has been investigated.
Timber is an orthotropic material and can resist stresses 30-40 times greater in tension, and 5-10 times greater in compression, when the forces are applied parallel rather than perpendicular to the grain (Dinwoodie, 1981; Harte and Forde, 2009).
In bending a beam is generally subject to combined bending and shear stresses. The resultant principal stresses create tension and compression arches. Physical testing and development of an analytical model has been carried out to investigate how the grain angle affects the stiffness of timber beams.
Total stiffness of glulam beams with curved laminations