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Sizes
For sawn lumber, WoodWorks Sizer displays the nominal width and depth of a section but, for glulam, the actual width and depth are displayed.
Glulam beams range in thickness from 80 to 365 mm (3-1/8 to 14-1/4 in.) and in depth from 114 mm (4-1/2") to approximately 2128 mm (84"). The beam thicknesses used in the Sizer database are industry standards, but some fabricators can produce slightly different sizes. Most fabricators use 38mm (1-1/2") thick laminations for straight beams, and this is the assumption in Sizer.
Species
Most fabricators produce either D.Fir-L or Spruce-Pine glulam. These are the species listed in CSA O86 Table 7.2 and which are included in Sizer. Sizer does not include the Hem-Fir and Douglas-Fir-Larch species combination due to its rarity.
Stress Grades
The stress grades listed in Table 7.2 are referred to as Comb'n in the Sizer user interface, meaning the combination of lumber grades making up layups that comform to the stress grades.
Beam Stress Grades
Glulam allows the manufacturer to place wood species in the lay-up to the material’s best advantage in resisting applied stresses. In a glued laminated beam fabricators try to the high strength material in the extreme zones of the cross sectional member, so when the beam is loaded, the high strength material is located where the stresses are the highest.
f-E Stress Grades
The 20f-E and 24f-E stress grades (Glulam-E materials in Sizer) are unbalanced beam lay-ups, meaning tha the bending moment strengths for the laminations on the compression side are not as high as the strengths for the tension laminations. Since wood is weaker in tension, higher strength material is placed on the tension laminations than in the compression lams. Such a beam has a top and a bottom to it, and is popular in simple span applications. Thus, Glulam-E is used where the top is in compression.
The 20f-E stress grade should be specified for applications other than long span or heavily loaded beams since fabricators do not produce large amounts of the 24f-E grade. This is due to the limited availability of the high quality laminating stock used in the 24-E lay-up.
f-EX Grade
The 20f-EX and 24f-EX stress grades (Glulam-EX materials in Sizer), are balanced beam lay-ups, meaning they have higher quality laminations on the top and bottom face so that the bending resistance is the same for negative or positive moment. This means that this beam has no designated top or bottom and could be used in either orientation. Balanced beams are popular in continuous spans and cantilevers because of bending moment moment reversals. Glulam beams are also available in the 20f-EX and 24f-EX grades.
Column Stress Grades
The 16c-E or 12c-E stress grades (Glulam-c materials in Sizer) are uniform beam lay-ups, in which the grade of the laminations in the compression zone, the tension zone and the inner zone are the same throughout to resist compression forces so Glulam-c is used mainly for resisting axial loads.
The 24-EX and 20f-EX grades are balanced layups used for members subjected to combined axial and bending loads from either direction.
Sizer does not include the 18t-E and 14t-E layups designed for tension loading due to the rarity of this application.
Proprietary Glulam
Sizer includes Nordic Lam and Nordic Lam+ proprietary glulam products.
Glulam Design
For information on glulam design procedures, refer to CSA O86 Glulam Design..