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Taxonomy of Wood Products Engineered Wood Products
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Wood Products Taxonomy
Composites Solid Wood Pulp and Paper Panels Engineered Lumber Softwood Wood/Non-wood Wood Based Wood/Cement Wood/Plastic Particleboard MDF Plywood OSB LVL OSL Glulam Hardwood Treated Glued Finger joined Edge glued Pulp Paper Mechanical Chemical Boards Dimension Timber MSR Engineered Wood Products I-Beams Trusses CLT
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Solid wood products Engineered wood products
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Choice of Wood Products
Product composition ? (a) one large piece of solid wood or (b) smaller pieces wood glued together Relative strength rating ? (a) or (b)
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Engineered wood products - benefits compared to solid wood
More reliable Higher strength ratings Larger dimensions possible Smaller trees can be utilized
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Variability in wood products
frequency Solid wood strength
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Variability in wood products
mean lower 5th percentile Solid wood ÷ safety factors frequency strength allowable design stress
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Variability in wood products
mean mean lower 5th percentile ÷ safety factors Solid wood lower 5th percentile frequency Wood composite A ÷ safety factors strength allowable design stress allowable design stress
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Variability in wood products
mean mean lower 5th percentile Solid wood ÷ safety factors Wood composite B lower 5th percentile frequency ÷ safety factors strength allowable design stress allowable design stress
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Solid wood vs. Engineered lumber composite
frequency Which is “stronger”? Wood composite Solid wood strength “Stronger” = “Can accept higher design loads”
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Reduction of natural variability
Elements combined into more consistent engineered products Initial source of solid wood Strategic placement of elements Wood source reduced to designed elements
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Wood Elements Veneer sheets Strands Veneer strips Lamstock
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Wood Products Taxonomy
Composites Solid Wood Pulp and Paper Panels Engineered Lumber Softwood Wood/Non-wood Wood Based Wood/Cement Wood/Plastic Particleboard MDF Plywood OSB LVL OSL Glulam Hardwood Treated Glued Finger joined Edge glued Pulp Paper Mechanical Chemical Boards Dimension Timber MSR Engineered Wood Products I-Beams Trusses
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Laminated Veneer Lumber
Elements: Sheets of wooden veneer (1/8-1/10” thick, 2’ wide, 8’ long) Product Width 1½ - 3½ inches Dimensions: Depth up to 24 inches Length up to 80 feet Applications: Beams, headers, I-beam flange
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LVL – manufacturing overview
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Laminated Veneer Lumber (LVL)
Edge Flat Softwood veneers produced as in plywood production Veneers graded prior to assembly Higher quality veneers are placed on the outsides Veneers glued with grain running parallel to each other LVL used on flat (I-beam flanges) or on edge (beams, headers)
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LVL – end use dimensions
Width 1 ½ in., 1 ¾ in., and 3 ½ in. Depth up to 24 in. Length up to 24m
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Reduction of natural variability
Solid wood Variability is at its greatest level. Laminated Veneer Lumber Variability is reduced in one plane. Defects in veneer can be removed or dispersed Variability is reduced Yield of veneer from logs is higher than yield of solid lumber
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Laminated Veneer Lumber
LVL in I-beam LVL beam
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LVL - headers
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Glue Laminated Timber (Glulam)
Elements: “Lamstock”, high quality dimension lumber (1½” thick, up to 10” wide, up to 20’ long) Product Width 3½-14 inches Dimensions: Depth up to 8 feet Length up to 140 feet Applications: Beams, columns, arches, trusses
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Centre for Advanced Wood Processing
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Glulam - laminations Top and bottom laminations might be different species Finger joints along laminations Total dimensions = 5.25” x 17.5” (This is not a commercial sample)
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Glulam – build up of column
Mulitple pieces per width of lamination Multiple laminations
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Glue Laminated Lumber (Glulam)
Individual lamstock elements are stress-rated prior to beam fabrication Stiffer elements are placed in more critical locations in member Very large dimensions possible
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Glue Laminated Lumber (Glulam)
Curved members can be created Tighter curves require thinner laminations Architectural as well as structural
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Glulam - Columns, Beams and Rafters
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Glulam - Roof Beams
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Glulam - Curved Roof Beams
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Glulam - Curved Bridges
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Glulam – curved members
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