1. Engineered Wood Products Paul Cooper Faculty of Forestry University of Toronto

2. Outline 1.What are engineered wood products? 2.What are their advantages or benefits? 3.Examples of EWP 4.Some issues with EWP

3. 1. What are Engineered Wood Products? Strands –Oriented Strand Board –Parallel strand lumber –Parallam TM Veneer based –Plywood –Laminated veneer lumber (LVL) –Veneer overlaid products Lumber based –Glued laminated timbers –Trusses –Edge glued products Combinations –I-Joists –Structurally Insulated Panels Fiber based –Fiber reinforcement Wood based products (usually composites) designed to meet application-specific performance requirements and to take best advantage of the structural properties of the different components

4. EWP’s address some of wood’s disadvantages Natural variability of wood – strength unpredictable, unreliable Hygrosopicity and resulting dimensional instability _______________________________ Biodegradable – vulnerable to decay Combustible

5. Benefits or Advantages 1.Efficient use of wood through “engineering” e.g., placing stronger and more uniform components in areas of higher stress 2.Stable, uniform & consistent 3.“Reliable” 4.Flexible with respect to shape and size 5.Value added products 6.Composite products - Take advantage of best properties of different materials

6. Efficient use of wood, Stable I-Beam is very efficient use of materials Neutral axis – Shear only Compression Tension

7. Strong and Consistent Optimize strength through Engineered design –Put strongest components where stresses are highest –Configure for efficient properties Randomization of defects to reduce variability or increase reliability

8. Reliable

9. Flexible with respect to shape and size, aesthetics

10. Value Added Benefits More employment/m 3 More value/m 3 Generates value locally Smaller enterprises Lower or no tariffs/duties

11. Take advantage of component properties Fibre Reinforced Polymer reinforced wood beams

12. A. Strand Based EWP 1.Oriented Strand Board (OSB) EWP since selected geometry of strands and orientation of layers of strands - Improvement over the original “waferboard” Special grades used for value-added engineered products such as I-joists and rim board Main deficiency is thickness swelling and Concentrated Static Load resistance

13. Reduced variability and increased reliability

14. OSB - uses I-Joists Sheathing Rim board

15. 2. Parallel strand lumber (PSL) Made from long narrow strands (from strander not veneer) E.g., Aspen Used for window joinery, headers…

16. Parallel strand products 3. Parallam ™ Strips of waste veneer (1/2” X 1-2’) Laid up in large molds Phenol Formaldehyde Resin – Microwave cure Mainly Douglas-fir and Southern pine Extremely strong and reliable

17. PARALLAM™

18. B. Veneer products 1. Plywood Flat panel built up of plies of veneer through bonding Cross-laminated for uniform transverse strength and high dimensional stability Face Cross-bands Core Back

19. Veneer

20. Plywood

21. 2. Laminated Veneer Lumber (LVL) – Poplar, Douglas-fir Southern pine etc.

23. C. Lumber-based products 1. Finger-joined lumber

24. 2. Machine stress rated lumber (MSR)

25. 3. Trusses

26. 4. Glued laminated timbers

28. AGO

30. Combination Products 1. Fibre Reinforced Polymer for Beams Failure is usually on tension face Reinforce glulam or solid timbers with small amounts (1% to 3% by volume) of FRP in tension Doubles beam bending strength or reduces beam size or allow longer span Can retrofit existing beams (e.g. in bridges)

31. 2.I-JOISTS Light Strong Long Spans Easy to put wiring, plumbing etc. through the web

32. 3. Structural Insulated Panels

33. 4. Honey-comb, Sandwich products http://www.superhoneycomb.com/characteristics.htm

34. E. Fiber Based EWP. Fillers and reinforcement such as natural fibers embedded in or bonded to a matrix (polymer, cement etc.) Enhance properties while lowering cost Both matrix and fibers maintain their identity but produce a combination of properties not achievable by one component alone.

35. Wood particle/fiber cement composites

36. Some Issues Perceived low durability (decay) Issues with fire performance of some composites Potential new applications and new developments –Design for tall wood buildings (6 story +) –“Massive components) –Earthquake stability, hurricane performance, fire, durability, dimensional stability –Nano-composites, agri-fiber composites, biomass based resins and adhesives

37. Market trend? Tough time for all construction products New home construction ↓ Renovation ↑ ↓? Commercial/residential ↑? Infrastructure ↑?

38. Thank you! “Spruce Goose” – Resin impregnated and molded Birch “Microlam”