Advancing Technology to Manufacture Trusses From Hardwood Lumber

Abstract

Low-grade hardwood lumber is abundant across the Lake States and the Northeast United States. This product has historically been used as pallet lumber, crating material, and firewood with values of $200-$300 per thousand board feet. Further, several low-valued hardwood species have become prevalent in these areas through past forestry practices. In order to actively manage the forests for historical species, new and higher value markets must be established. The purpose of this project was to evaluate the use of sugar maple (Acer saccharum) and red maple (Acer rubrum) as structural lumber in metal plate pitched and parallel chord trusses. Groups of trusses were manufactured with both chords and webs from hardwood lumber, from softwood chords and hardwood webs and from chords and webs from softwood lumber. Testing was completed according to ANSl/fPI 2-1995, Standard for Testing Metal Plate Connected Wood Trusses. Results showed that both pitched and parallel chord trusses manufactured from hardwood lumber had strength and stiffness that was equivalent to or better than softwood trusses manufactured from spruce-pine-fir (SPF) and southern yellow pine (SYP) lumber. Trusses manufactured with SPF chords and hardwood webs had properties that were equivalent to or better than complete SPF trusses. The findings indicate that the potential use of low-grade hardwood lumber as truss lumber would result in large volumes of this material being utilized in a higher value application.