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Canadian Wood CouncilG063

Engineered Wood Products: Current Design Topics

Jeff Olson, P.E., P.Eng.

Technical Services Manager

Boise Cascade

October 27, 2015

Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.

This course is registered with AIA CES for

continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner ofhandling, using, distributing, or dealing in any material or product.____________________________

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Questions related to specific materials, methods, and services

will be addressed at the conclusion of this presentation.

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This presentation will discuss engineered wood

products and related design topics with a

focus on specific design issues in today’s wood-framed

buildings.

CourseDescription

LearningObjectives

Key learning points:

• Discover differences between engineered wood and traditional lumber products

• Obtain information on the use of engineered wood products within diaphragms and shear walls

• Learn how engineered wood products are tested and evaluated

• Introduced to services that EWP manufacturers provide

At the end of the this course, participants will be able to:

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• Prefabricated Wood I-Joists

• BCI®, TJI®, LPI®

• Structural Composite Lumber (SCL)

• Laminated Veneer Lumber (LVL)

• VERSA-LAM®, Microllam®

• Parallel Strand Lumber (PSL)

• Laminated Strand Lumber (LSL)

• Glued Laminated Timber (Glulam)

•Other EWP Products

• Plywood

• Metal-Plate Wood Trusses

• Oriented Strand Board (OSB)

• Cross Laminated Timber (CLT)

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Knots and other defects reduce resistance

Defects dispersed in EWP

Higher strengths obtained

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• Higher Specified Strengths

• Greater Dimensional Stability

• Manufactured at low moisture content (6-8%)

• No shrinkage in the field if product kept dry

• Slight swelling to equilibrium

• Orthotropic material

• Shrink/swell ratios: Tangential, Radial, Longitudinal: 20-10-1

• Floor joist depth

• MC <= 12% for floor joists in mid-rise lower floors

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Recommended installation to account for lumber shrinkage

Not required for wood I-joists –shrinkage is typically not an issue

FPInnovations/CWC: Vertical Movement in Wood Platform Frame Structures

Majority of shrinkage in floor area

From WoodWorks

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Multiple Series & Depths for Various Applications within Residential / High Density / Light Commercial Construction

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Proprietary Factored Resistance Values

• Each manufacturer tests to establish equivalency to lumber joists

• Original APA testing of lumber joists (1950’s) – Current wood horizontal diaphragm tables in CSA O86

• Wood I-joist testing per ICC Acceptance Criteria

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Failure of sheathing

Flange thickness not limiting factor

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• Consult manufacturer for diaphragm values and limits

• Typical closest allowable nail spacing = 4”

Case 1 Diaphragm: Staggered Sheathing Perpendicular to Joist

Length

• Staggered nailing at panel edges

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• Typical Rim Board Thickness

• 1 1/8” – 1 1/4” OSB

• 1 1/4” – 3 1/2” LVL / LSL

• Vertical load and lateral nail resistance for diaphragms

• Dimension lumber should never be used as rim board with wood I-Joists

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Proprietary Factored Resistance Values

• Closest allowable nail spacing controls lateral design

• Thicker rim = tighter allowable

spacing

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Options for increased lateral load transfer

Laminated Veneer Lumber (LVL)

• Widths: 1 ¾”, 3 ½”, 5 ¼”, 7”

• Depths: Up to 24”

• Different grades possible

• High Specified Strengths• COV 10-15%

• 4800 – 6270 psi Bending, 1.7 – 2.0 x 106 psi MOE

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• Parallel Strand Lumber (PSL)

• Long strips of veneer glued together

• Developed in B.C. late 70’s – early 80’s

• Laminated Strand Lumber (LSL)

• 12” long strands

• Oriented Strand Lumber (OSL)

• 3” – 6” long strands

SCL: Specified Strengths & MOE

Product Bending Shear MOE

Doug Fir

SS Grade

2830 220 1.7 x 106

LSL 4300 575 1.3 – 1.6 x 106

24f-E DF

Glulam

4435 290 1.9 x 106

PSL 5360 540 2.0 - 2.2 x 106

LVL 4800 -6280

530 – 580 1.7 – 2.0 x 106

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• US Test Criteria: AC 202 (ICC-ES)

• Minimum nail spacing

requirements to ensure ductile failure

• Check with manufacturer for equivalent specific gravity

• EWP industry has funded a test program with cyclic

testing at FPInnovations via CCMC

• Western Canada: Douglas fir laminations• 24f-E & 24f-EX beam grades

• 16c-E column grade

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Unbalanced (24f-E) or balanced (24f-E)

24f-E Design Values:Bending specified strength:

bottom edge in tension

= 4435 psi

bottom edge in

compress = 3335 psi

MOE: 1,900,000 psi

• Simple span: Tension edge on bottom – 24f-E

• Multiple spans: Bending may control on either

edge

• Larger depth 24f-E may be needed

• 24f-EX: Shallower depth but may be custom order

• Cantilevers: 24f-E fine for most applications,

24f-EX may allow shallower depth on longer

cantilevers

• Camber for Long Span Applications

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Framing – Hit-or-miss surfacing to 3-1/2" or 5-1/2" wall-framing widths – for use as headers

Architectural – S3S & with many voids filled - the most common “exposed” grade

Premium – like Architectural but with all voids filled

Rough Sawn – adds a “rough timber framing” look to either Industrial or Architectural

• ASTM - American Society For Testing and Materials, recognized in NBCC as accepted standard organization

• Members include industry, manufacturing, designers, scientists, code officials.

• Provides qualification requirements

• Mandates independent third-party inspection, in-house quality assurance, periodic re-

evaluation.

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• Evaluation Services evaluate product based on testing standards provided by ASTM

• Canada: CCMC

• US: International Code Council (ICC)

• Allows proprietary product as an alternate building material in the code

• Several product property QC checks on a daily basis

• Many process control checks

• Completed specimens taken from production line

and destructively tested to verify conformance

• Test data results in measurable trends

• QC data is reviewed and verified by an

accredited independent third party agency.

• Allows EWP manufacturers to warrant their

products

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Destructive• Web stock • Flange tension

• Full joist reaction

Non-Destructive• Veneer stress wave grading • Flange tension proof load

Tension testing of glulam

lamination

stock and

finger-joints

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In grade, full scale Glulam testing

5.5” x 28.5” x 40’ long

Approx 60,000 lb

• Flame Spread

• Surface flammability

• Typically for exposed framing

• Fire Endurance• System resistance for assemblies

• Product char rate

• CAN/ULC S-101 Fire Tests (ASTM E119)

• Higher severity of fire exposure

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Flame Spread Test – Steiner Tunnel

Fire Endurance –ULC S-101 ASTM E119

• Floor/ceiling assembly based on CAN/ULC S-

101 / ASTM E-119 fire test (45 min, 1 & 2 hour)

• Most common 1 hour assembly requires two layers of fire-rated gypsum board

• Single gypsum layer assemblies require

additional fire resistance (mineral wool

insulation, etc.)

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Most Common I-Joist Assembly2 layers of fire rated gypsum board

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Fire Assembly Testing – Floor Loading

Time – Temperature Curve

• 5:00: 550 ○C

• 10:00: 700 ○C

• 15:00: 760 ○C

• 30:00: 820 ○C

• 60:00: 930 ○C

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Failure Modes

• Structural failure of joist

• Burn through of floor sheathing

• Temperature limit exceeded on decking

• Certification defined in NBCC

• Assemblies listed by agency accredited by

Standards Council of Canada (SCC)

• Agencies included:

• ULC®

• InterTek®

• APA – The Engineered Wood Association®

• PFS® Corporation

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• SCL has the same char rate as timber & glulam

• Methodology prescribed in NBCC 2010 D-2.11.1 can

be applied to SCL

• Simple design procedure based on NRC research,

calculate endurance time of a wood member exposed

to standard fire based upon:

• the size of wood beam or column

• percent of maximum allowable design load

applied.

• More information – American Wood Council: TR10

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Sizing Software

• Manufacturers have product engineering support staff to consult

• Product Technical Notes available from manufacturers and testing agencies

• Product Warranties

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• Consult manufacturer for repairs

• Testing conducted to verify repairs for common

field conditions

Testing of common field issues & repairs

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• Individual Manufacturers

• BC WoodWorks: http://www.wood-works.org/bc

• Canadian Wood Council: www.cwc.ca• Wood I-Joist Manufacturers Association (WIJMA):

www.i-joist.org

• American Wood Council: www.awc.org• APA – Engineered Wood Association:

www.apawood.org

• US Forest Products Laboratory: www.fpl.fs.fed.us

This concludes The American Institute of Architects Continuing Education

Systems Course

Engineered Wood Products:Current Design Topics

Jeff Olson, P.E., P.Eng.jeffolson@bc.com

Canadian Wood CouncilWood WORKS! BC

www.cwc.cawww.wood-works.org