Henri Ranttila: Engineering properties of used glued laminated timber

Glued laminated timbers deconstructed from buildings contain sufficient value for direct reuse. Direct reuse with minimal processing decreases reprocessing losses and preserves the value of glulam components as they are not reduced to raw material. Structural reuse of glulam necessitates that the reused components meet requirements set for structural reliability. Relying on information such as original declaration of performance or a grade stamp incurs many uncertainties.

Uncertainties complicate reliable estimation of engineering properties of used glulam components. Here a theoretical baseline is established with which to assign engineering properties for used glulam. The baseline relies on a conservative assumption about the properties of lamellas, namely that the lamellas consist of ungraded timber. In addition to estimating properties of lamellas, a methodology is presented for estimating the strength of end to end- and face to face joints within used glulam components. Properties of full components are then derived from the properties of laminations and from the joints between lamellas.