Structural Wood Corporation

4000 LABORE ROAD ST. PAUL, MINNESOTA 55110 PHONE (651) 426-8111
FAX (651) 426-6859
(800) 652-9058

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Glulam Definitions

Bending Members --- Members that are stressed principally in bending such as beams, girders and purlins.
Bond Line --- The layer of adhesive which attaches two adherents.
Bonded Assembly of Laminations --- A bonded member intended to be bonded to other assemblies or other laminations to form a completed glued laminated member.
Camber --- The small amount of curvature built into a glued laminated timber to offset anticipated deflection or to facilitate roof drainage.
Compression Members --- Members that are stressed principally in axial compression such as columns, compression chords of trusses, and arches.
Curing Time --- The period of time which an adhesive takes to attain a specified degree of cure.
Curved Members --- Members which are designed so that significant curvature remains after deflection due to service loads has taken place, such as curved beams and arches.
Custom Members --- Members that are manufactured to meet specific job specifications.
Delamination --- The separation of layers in an assembly because of failure of the adhesive, either in the adhesive itself or at the interface between the adhesive and the lamination.
Depth --- The cross-sectional dimension which is measured parallel to the direction of the principal load on the member in bending.
Dry service conditions --- Environmental exposure conditions that result in a member moisture content of less that 16% in service.
Eased Corner --- Slightly rounded surfacing of corner of member to remove sharp edge.
Equilibrium Moisture Content --- Any piece of wood will give off or take on moisture from the surrounding atmosphere until the moisture in the wood comes to equilibrium with that in the atmosphere. The moisture content of the wood at the point of balance is called the equilibrium moisture content and is expressed as a percentage of the oven-dry weight of the wood.
E-Rated Lumber --- Lumber that has been non-destructively tested to determine the modulus of elasticity.
Gap-Filling Adhesive --- An adhesive that has the capability of filling voids of up to 1/16 in between two mating surfaces and possesses the required strength and durability.
"Green" Building --- The use of renewable, environmentally friendly and sustainable products delivered from local sources to provide energy efficient and cost effective construction.
Inserts --- Wood strips inserted in the sides and faces of glued laminated timber.
Joint, Edge --- The joint formed by two or more pieces of lumber laid edge to edge to form a full width lamination.
Joint, End --- A joint formed by joining pieces of lumber end to end with adhesives.
Joint, Face --- The joint occurring between the wide faces of laminations.
Joint, Finger --- An end joint made up of several meshing fingers of wood.
Joint, Scarf --- An end joint formed by joining with adhesive the end of 2 pieces that have been tapered to form sloping plan surfaces. In some cases, a step or hook is machined into the scarf to facilitate alignment of the 2 ends, in which case, the plane is discontinuous and the joint is known as a stepped or hooked scarf joint.
Laminated Veneer Lumber --- Lumber made by laminating veneers in which the grain of all the veneers is essentially parallel to the longitudinal axis of the piece.
Laminating --- The process of bonding selected lumber or wood veneers together with adhesive.
Lamination --- A full width and full length of wood composed of one or several pieces of lumber in width or length.
Machine Stress Rated (MSR) Lumber and Machine Evaluated Lumber (MEL) --- Lumber that has been evaluated by mechanical stress-rating equipment and includes a strength test for qualification. This lumber is also required to meet certain visual requirements as set forth in the grading rules.
Manufactured Lumber --- Two or more pieces or strips of lumber structurally bonded to form a single piece of lumber. It is intended primarily for tension laminations.
Mechanically Graded Lumber --- the result of a process using mechanical or physical evaluation, combined with visual grading, to sort lumber into categories for the assignment of design properties. Mechanically graded lumber includes E-rated, machine stress rated (MSR), and machine evaluated lumber (MEL).
Moisture Content --- The amount of water contained in the wood, usually expressed as a percentage of the weight of oven-dry wood.
Multiple-Piece Lamination --- A lamination which contains 2 or more pieces of lumber across the width of the lamination. The edges may or may not be bonded. If not bonded, the edge joints in adjacent laminations must be staggered at least the net thickness of the lamination.
Non-custom Member --- Members that are not manufactured for a specific job specification. These are commonly called stock beams.
Proof Loading --- Application of a known load to a lamination, either tension or bending.
Proof Grading --- Grading of lumber by strength testing of each piece in tension to a predetermined level in order to endure single member performance.
Relative Humidity --- The ratio of actual pressure of existing water vapor to maximum possible pressure of water vapor in the atmosphere at the same temperature, expressed as a percentage.
Ripping --- The process of sawing any width lumber to develop narrower lumber.
Structural Glued Laminated Timber --- An engineered, stress rated product comprised of specially selected and prepared wood laminations securely bonded together with adhesives. The grain of all laminations is approximately parallel longitudinally. The laminations may be comprised of pieces end joined to form any length, of pieces placed or bonded edge-to-edge to make wider ones or pieces bent to curved form during bonding.
Tension Members --- Members that are stressed principally in axial tension, such as the tension chords in trusses and tension tie members.
Wet-service conditions --- Environmental exposure conditions that result in a member moisture content of 16% or greater in service.
Wet-use adhesives --- Adhesives that comply with ASTM D2559.
Width --- The cross-sectional dimension which is measured perpendicular to the direction of the principal load on the member in bending.
Wood Failure --- That portion of a bonded surface which, in cyclic delamination or strength tests, exhibits ruptured wood fiber as opposed to failure at the bond line.

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