Engineered Wood Product

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Engineered Wood Product

• They are the result of new technology and the
  economic need to make use of different species
  and smaller trees that can not be used to produce
  solid sawn lumber. Glued Laminated Timbers
  (Glulams), Wood I Joists, Structural Composite
  Lumber (laminated veneer lumber, LVL and parallel
  strand lumber).

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Structural Glued Laminated Timber (glulam)

• Cross sectional and lengths of sawn lumber
  members are limited by the size of the trees
  available. For long spans or large loads, glulam
  members can be used.

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Structural Glued Laminated Timber

• Glulam members are fabricated from relatively
  thin laminations (nominal 1 and 2 in) of wood.
  These laminations can be end-jointed and glued
  together to produce wood members of any size and
  length.

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Structural Glued Laminated Timber
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Structural Glued Laminated Timber
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Structural Glued Laminated Timber

• The structural properties of glulam members
  exceed the structural properties of sawn lumbers
  because
• Lamination optimizes material by dispersing the
  strength reducing defects throughout the member.
• High-quality laminations are located in the
  portions of the cross section, which are more
  highly stressed (outer tension lamination).

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Structural Glued Laminated Timber
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Structural Glued Laminated Timber

• Effective end splices must be developed in a
  glulam lamination (butt joint, finger joint or
  scarf joint).

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Structural Glued Laminated Timber
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Structural Glued Laminated Timber

• Laminations are selected and dried to a MClt16
  before gluing (glulams are more dimensionally
  stable).

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Structural Glued Laminated Timber

• Adjustment Factors
• CD Load Duration Factor (the same as sawn
  lumber)
• CM Wet service Factor for MCgt 16 use values
  given on page 47 of NDS Supplement
• CV Volume Factor (similar to size factor for
  sawn lumber). Applies only to bending stress. CV
  1 for standard size (b5 1/8 in, d12 in, L21
  ft), otherwise use the formula on p. 47.

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Structural Glued Laminated Timber

• Structural Use
• B Bending (simple span)
• CB Bending (continuous or cantilever)
• C Compression
• T Tension
• Combination Symbol
• 24F-V3 Visually graded (allowable bending stress
  in hundreds of psi)
• 22F - ES graded for stiffness (such as MSR)