Elastomechanical Properties of Glued Laminated Timber Made of Strength Graded Oil Palm Lumber

Abstract

The wood from oil palm trunks exhibits significant variations in distribution of structural tissue, density and elastomechanical properties across and along the trunk. Its reliable, safe, and economic usage for loadbearing purposes, such as glued laminated timber (GLT), requires a precise definition of its elastomechanical properties through appropriate strength grading procedures. Oil palm lumber is strength graded according to its density using an X-ray technique in which 50 % of the lamellas are ripped, graded, edge glued and therefore density homogenized, and 50 % are cut only according to their geometry. Lamellas are tested in tension parallel to the vascular bundles; combined GLT is produced from strength-graded lamellas and tested in bending parallel and compression parallel and perpendicular to the vascular bundles. The characteristic strength values for C10 and C14 according to EN 338 are achieved. A correlation between density and elastomechanical properties is established. GLT from density-homogenized lamellas achieve higher bending properties than from lamellas with a "natural" density gradient across the width.