Innovations in Glulam Beam Design

Innovations in composite wood manufacturing continue to appear on the market. LVL and Sawn Wood Sandwich Makes Strong "Hybrid" Glulam, Journal of Light Construction, June, 2004, describes a new proprietary glue-laminated beam product combining solid lumber laminations as used in conventional glulams with higher-strength laminated veneer lumber (LVL) laminations. The result is a product suitable for wood light frame beam and girder applications that is claimed to be stronger, lighter, and more economical than alternative solutions.

Manufactured by Rosboro under the "Big Beam" trade name, the use of LVL laminations at the top and bottom of the beam (where bending stresses are highest) results in a structural member with design stress values approximately 25% higher than achievable with comparable glulams fabricated solely from solid lumber laminations.

More Info
_The Rosboro web site's Technical Reference and Specifications page has a good selection of references related to glue-laminated members and construction.
_Glue-laminated and LVL wood members are discussed on pages 90 through 92 of the textbook.