A large-dimension beam used to support uniform or concentrated loads at various points along the length of a truss. Beams and girders are of solid lumber or built-up construction in which multiple pieces of nominal 2-inch-thick lumber are nailed together with the wide faces vertical.
Parallel strand lumber (PSL) is a high strength structural composite lumber product manufactured by gluing strands of wood together under pressure. It is a proprietary product marketed under the trade name ParaIlam®.
Parallel strand lumber is fabricated from slices of veneer, combined with adhesive and formed into large billets that are sawn into more useable dimensions.
Glulam is a stress-rated engineered wood product comprised of wood laminations, or "lams," that are bonded together with strong, waterproof adhesives. Glulam components can be a variety of species, and individual "lams" are typically two inches or less in thickness. ANSI/AITC A190.1 includes requirements for sizes, grade combinations, adhesives, inspection, testing, and certification of structural glued laminated timber products.
Girder Truss: Truss designed to carry heavy loads from other structural members framing into it. Usually a multiple-ply truss.