building material

1. ENGINEERED WOOD
BUILDING MATERIAL

2. ENGINEERED WOOD
Introduction
Engineered wood, also called composite wood, man-made
wood, or processed wood includes a range of derivative wood
products which are manufactured by binding or fixing the
strands, particles, fibers, veneers or blocks of wood,
together with adhesives, to form composite material
ENGINEERED WOOD PRODUCTS
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

3. ENGINERED WOOD PRODUCT TYPES
Strands based
 Oriented Strand Board (OSB)
 Parallel strand lumber (PSL)
 Parallam
Veneer based
 Plywood
 Laminated veneer lumber
(LVL)
Lumber based
 Glued laminated timbers
(GLULAM)
 Trusses
 Edge glued products
Combinations
 I-Joists
 Structurally Insulated Panels
Fiber based
 Wood plastic composites

4. WOOD ELEMENTS
LOGS LUMBER
VENEER
STRANDS FLAKES PARTICALS FIBERS

5. EWP’S addresses some of
woods problems
 Natural variability of wood – strength
unpredictable, unreliable
 Hygrosopicity and resulting dimensional
instability
 Biodegradable – vulnerable to decay
 Combustible

6. Benifts of E.W.PRODUCTS
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. More Reliable
4. Flexible with respect to shape
5. Composite products -Take advantage of best
properties of different materials
6. Higher strength rating
7. Large dimension and length possible
8. Smaller trees are utlized
9. Waste products are utized

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. Flexible with respect to shape
and size, aesthetics

9. 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
Lengthup to 80 feet
Applications: Beams, headers, I-beam flange

10. LVL MANUFACTURING OVERVIEW
1
2
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5
6

11. LAMINATED VENEER LUMBER
 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)11
Edge
Flat

12. LVL ENDLESS DIMENSIONS
 Width 1 ½ in., 1 ¾ in., and 3 ½ in.
 Depth up to 24 in.
 Length up to 24m

13. LaminatedVeneer
Lumber
Variability is reduced
in one plane.
Solid wood
Variability is at its
greatest level.
Reduction of natural variability
 Defects in veneer can be removed or dispersed
 Variability is reduced
 Yield of veneer from logs is higher than yield of solid
lumber

14. Laminated Veneer Lumber
LVL beam
LVL in I-beam

15. LVL - headers

16. 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
Lengthup to 140 feet
Applications: Beams, columns, arches, trusses
16
Glue LaminatedTimber (Glulam)

17. GLULAM LAMINATION
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)

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

19. GLUE LAMINATION 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
19

20. GLUE LAMINATION LUMBER
(GLULAM)
 Curved members can be created
 Tighter curves require thinner laminations
 Architectural as well as structural

21. Glulam - Columns, Beams and
Rafters

22. Glulam - Curved Roof Beams

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

24. 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

25. Veneer products
Plywood
 Flat panel built up of plies of veneer through bonding
C Cross-laminated for uniform transverse strength and
 high dimensional stability

 structural panels use waterproof phenol formaldehyde r
resin glue certified for exterior use
Face
Cross-bands
Core
Back

26.  The properties of plywood depend on the quality of
the veneer plies, the order of layers, the adhesive
used, and the degree to which bonding conditions
are controlled during production
 .
 Plywood panels have significant bending strength
both along the panel and across the panel, and the
differences in strength and stiffness along the panel
length versus across the panel are much smaller than
those differences in solid wood
uses:
 Construction sheathing
 Wall, roof sheathing
 Furniture
 Cabnite boxes and panels
 Box beams

27. Strand Based EWP
1. Oriented Strand Board (OSB)
OSB is manufactured in a cross-oriented pattern to create a strong, stiff structural
panel.
OSB is composed of thin rectanglar shaped wood strands arranged in laryers at righ
angle to one another, which are laid into mats that form a panel
OSB is bonded with fully waterproof adhesives most panels are also treated with
sealent on the panel edge to guard against moisture penetration
OSB has high shear strength along the edge
Not recommended for exposed exterior application unless specialy treated

28. OSB - uses
I-Joists
Sheathing
Rim board
Structural
insulated panels

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

30. PREFABRICATED WOOD I JOISTS
 Prefabricated wood I-joists are made by gluing
solid sawn lumber or laminated veneer lumber
(LVL) flanges and oriented strand board (OSB)
panel web to produce a dimensionally stable
light-weight member with known engineering
properties.
 The uniform stiffness, strength, and light weight
of these prefabricated structural products makes
them well suited for longer span joist and rafter
applications for both residential and commercial
construction.
 The "I" shape of these products gives a high
strength to weight ratio.

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

32. sizes
 The depths of prefabricated
wood I-joists range from
241mm (9-1/2") to 508mm
(20")
 Flange depths are
commonly 38mm (1-1/2")
and common flange widths
vary from 45mm (1-3/4") to
89mm (3-1/2").
 Web thickness varies from
9.5mm (3/8") to 12.7mm
(1/2").
 Table 1 I-Joist - Standard
Depths
 Size
 mm in.
 241 9-1/2
 292 11-1/2
 302 11-7/8
 318 12-1/2
 356 14
 406 16
 457 18
 508 20

33. Trusses
Structural frame relying on a triangular
arrangement of webs and chords to
transfer loads to reaction points.
•Made from timbers or from
manufactured
wood products (i.e. glulam, PSL)
•Members connected using bolts &
plates, split rings, and special
brackets & hangars

34. Trusses - Features
•unlimited shape & size
•economy
•ease of fabrication
•fast delivery
•simplified erection procedures
•all trusses are custom designed
•flexibility in layout & longspans
•shapes and size restricted only by manufacturing
capabilities, shipping limitations & handling
considerations

35. WOOD-PLASTC COMPOSITES
Any composite that contains wood & thermoset or
thermoplastic
Thermoset : Epoxy , Phenolics
Thermoplastics: PE, PP, PVC, PS
TheWPCs are produced by mixing wood flour or fiber &
plastics to produce a material that can be processed like a
conventional plastic & has the best features of wood &
plastic”
•Wood flour : Particulate, l/d 2:1 to 4:1
•Wood fiber : Reinforcing, l/d greater than 24:1
•Commonly used species : Pine, Maple Oak
•Typical particle size : 10 to 80 mesh

36. MANUFACTURING PROCESS
Two stage Process: Compounded pellets &
shaping
Commonly Used processingTechniques
Sheets & profile extrusion
Thermoforming
Compression Molding
Injection Molding
NewTrend
In-Line Compounding & Processing

37. Extrusion of WPCs

38. ADHESIVES
Phenol-Formaldehyde
Phenol-formaldehyde (PF) resins are typically used in the
manufacture of plywood . GLULAM, oriented strandboard
where exposure to weather during construction is a
concern
Urea-Formaldehyde
Urea-formaldehyde (UF) resins are typically used in
the
manufacture of products used in interior applications,
primarily
particleboard and medium-density fiberboard (MDF),

39. ISOCYANATE
The isocyanate wood adhesive is a polymeric methylene
diisocyanate (pMDI). It is used as an alternative to PF resin,
primarily in composite products fabricated from strands.
pMDI resins are typically more costly than PF resins but
have more rapid cure rates and will tolerate higher moisture
contents
Bio-Based Adhesives
Bio-based adhesives, primarily protein glues, were widely
used prior to the early 1970s in construction plywood. In the
mid-1970s, they were supplanted by PF adhesives, on the
basis of the superior bond durability provided by phenolics.
The move toward “green” products has led to a renewed
interest in bio-based adhesives.