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Material Input
WoodWorks Sizer typically displays the nominal width and depth of a section but, for glulam only, the actual width and depth are displayed.
A set of buttons allows you to choose whether glulam stress classes or combinations appear in the input for "grades". There are also special inputs for the existence of wane on certain southern pine combinations, and for non-edge-bonded laminations.
Glulam Beams
Sizes
Glulam beams range in thickness from 2-1/2 to 14-1/4 in. and in depth from 5-1/2 in. to 60-1/2 in.
Species and Grades
Most fabricators produce either Southern Pine or Western Species glulam. The beam thicknesses used in the WoodWorks Sizer database are industry standards, but some fabricators can produce slightly different sizes. Most fabricators use 1-1/2 in. (38mm) thick laminations of Western Species and 1-3/8 in. (35mm) thick laminations of Southern Pine.
WoodWorks Sizer implements these species and the Hardwood species, too. The program implements the stress classes and grade combinations listed in Tables 5A-5D of the NDS® supplement Design Values for Wood Construction.
Sizer also implements the relevant footnotes to the Tables 5A-5D and outputs information about the applied footnotes in the Additional Data section of the Design Check output.
Glulam Columns
A subset of the grades listed in Table 5B of the NDS® supplement Design Values for Wood Construction are supplied in a database file for members stressed primarily in axial tension or compression. Another database file contains a subset of the grades listed in Table 5A for members subjected to both axial and bending stresses. These combined stress grades have higher quality laminations on the top and bottom face so that the bending resistance is the same for negative or positive moments.
Balanced and Unbalanced Glulam
Glulam allows the manufacturer to place wood species in the lay-up to the material’s best advantage in resisting applied stresses. The whole premise of a glued laminated beam is that you are trying to put 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 would be the highest.
In an unbalanced beam lay-up, the grade and stress values for the lams on the compression side are not as high as the stress rating for the tension lams. Since wood is weaker in tension, higher strength material is placed on the tension lams than in the compression lams. This particular beam would definitely have a top and a bottom to it, and is popular in simple span applications. Thus, "Glulam Unbalanced" is used where the top is in compression.
In a balanced beam lay-up, the laminations that are used on the extreme ends of the section on either side are the same grade and stress rating. 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 moment reversals. Thus, "Glulam Balanced" is used where the top is in tension.
In a uniform beam lay-up, the grade and stress values of the laminations in the compression zone, the tension zone and the inner zone are the same throughout. "Glulam Uniform" is used mainly for resisting axial loads.
Glulam Design
For information on glulam design procedures, refer to NDS 5.3 and NDS 5.4 .