421 likes | 1.25k Views
Taxonomy of Wood Products Engineered Wood Products. WOOD. Composites. Solid Wood. Pulp and Paper. Panels. Engineered Lumber Composites. Softwood Lumber. Glued. Treated. Hardwood. Pulp. Paper. Wood/Non-wood. Wood Based. LVL. Boards. Finger joined. Mechanical. Wood/Cement.
E N D
WOOD Composites Solid Wood Pulp and Paper Panels Engineered Lumber Composites Softwood Lumber Glued Treated Hardwood Pulp Paper Wood/Non-wood Wood Based LVL Boards Finger joined Mechanical Wood/Cement Particleboard OSL Dimension Edge glued Chemical Wood/Plastic MDF Glulam Timber Plywood MSR OSB Wood Products Taxonomy Engineered Wood Products I-Beams Trusses CLT
Solid wood products Engineered wood products
Choice of Wood Products • Relative strength rating ? (a) 75-85or (b) 50-100 • Product composition ? (a) one large piece of solid woodor (b) smaller pieces wood glued together
Engineered wood products - benefits compared to solid wood • More reliable • Higher strength ratings • Larger dimensions possible • Smaller trees can be utilized
Variability in wood products frequency Solid wood strength
Variability in wood products mean lower 5th percentile Solid wood ÷ safety factors frequency strength allowable design stress
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
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
Solid wood vs. Engineered lumber composite frequency Which is “stronger”? Wood composite Solid wood strength “Stronger” = “Can accept higher design loads”
Reduction of natural variability Elements combined into more consistent engineered products Initial source ofsolid wood Strategic placement of elements Wood source reduced to designed elements
Wood Elements Veneer sheets Strands Veneer strips Lamstock
Engineered Wood Products WOOD I-Beams Composites Solid Wood Pulp and Paper Panels Trusses Engineered Lumber Composites Softwood Lumber Glued Treated Hardwood Pulp Paper Wood/Non-wood Wood Based LVL Boards Finger joined Mechanical Wood/Cement Particleboard OSL Dimension Edge glued Chemical Wood/Plastic MDF Glulam Timber Plywood MSR OSB Wood Products Taxonomy
Laminated Veneer Lumber Elements: Sheets of wooden veneer (1/8-1/10” thick, 2’ wide, 8’ long) Product Width 1½ - 3½ inchesDimensions: Depth up to 24 inches Length up to 80 feet Applications: Beams, headers, I-beam flange
LVL – manufacturing overview 2 1 3 4 5 6
Laminated Veneer Lumber (LVL) EdgeFlat • 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)
LVL – end use dimensions • Width 1 ½ in., 1 ¾ in., and 3 ½ in. • Depth up to 24 in. • Length up to 24m
Reduction of natural variability Solid woodVariability is at its greatest level. • Defects in veneer can be removed or dispersed • Variability is reduced • Yield of veneer from logs is higher than yield of solid lumber Laminated Veneer LumberVariability is reducedin one plane.
Laminated Veneer Lumber LVL in I-beam LVL beam
Glue Laminated Timber (Glulam) Elements: “Lamstock”, high quality dimension lumber (1½” thick, up to 10” wide, up to 20’ long) Product Width 3½-14 inchesDimensions: Depth up to 8 feet Length up to 140 feet Applications: Beams, columns, arches, trusses
Glulam - laminations Top and bottom laminations might be different speciesFinger joints along laminationsTotal dimensions = 5.25” x 17.5”(This is not a commercial sample)
Glulam – build up of column Mulitple pieces per width of lamination Multiple laminations
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
Glue Laminated Lumber (Glulam) • Curved members can be created • Tighter curves require thinner laminations • Architectural as well as structural