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Timber Framing for Non‐Residential Construction
“Wood is universally beautiful to man, and the most humanly intimate of all [building] materials.”
Frank Lloyd Wright
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This program is registered with the 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 of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Thank you!
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Learning ObjectivesAt the end of this program, participants will be better able to:
• Compare the sustainability of heavy timber as the structural system versus steel or concrete. Focus will be on its natural renewability, sustainability, embodied energy, longevity, adaptability and reuse.
• Identify the structural soundness and integrity benefits that heavy timber brings to buildings and other structures. Focus is on the clear load paths, structural redundancy, structural flexibility, and timber’s longevity.
• Safely and responsibly incorporate heavy timber into designs and plans of non‐residential buildings. Focus will be on aesthetics, timber species, moisture content, natural resistance to bio‐agents, and fire resistance.
• Guide and evaluate the choice of heavy timber joinery style for various types of building programs, understanding the limitations of each choice. Focus will be on traditional joinery and steel assisted joinery and such factors as cost, strength, ductility, moisture content and exposure affects.
Agenda
• Introduction
• Heavy Timber context in non-residential construction
• Sustainability
• Timber Basics—From material choice through enclosure
• The best style of Heavy Timber joinery for your project
• Getting started on your Timber Frame project
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IntroductionMack Magee
• Currently:
Principal, Fire Tower Engineered Timber
Principal, FraserWood Industries
• Formerly:
General Manager, Cascade Joinery, Washington
Director of Operations, Riverbend Timber Framing, Michigan
Manager Civil Engineering, Corporate Engineering, Owens Corning
Sourcing Manager, Packaging Commodities, Owens Corning
And, many other positions, too numerous to mention…
• Education:
Masters of Science, Civil Engineering, Stanford University, 1986
Bachelors of Science, Civil Engineering, Stanford University, 1985
Ancient Non‐Residential Projects
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Older Non‐Residential Projects
Timber as Structure
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Timber brings drama and visual interest
Denver Derrick, Denver Central Library, Denver, COArchitect: Michael Graves & Associates, Princeton, NJ
North Star Trading Post at the Toledo ZooArchitect: The Collaborative Inc., Toledo, OH
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Ashton Gardens Wedding Chapel, Corinth, TXArchitect: Cisneros Design Group, Houston, TX
Gettysburg National Military Park and Museum, Gettysburg, PAArchitect: LSC Design, Inc.
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YMCA, Phoenixville, PAArchitect: Kramer/Marks P.C. Architects AIA
Alpine Orthopaedic Clinic, Franconia, NHArchitect: Samyn D’Elia
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Kituwah Immersion Language Academy, Architect: Padgett and Freeman Architects
Oak Bluffs Marina Terminal, MV, MAArchitect: Maguire Group
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West Lebanon, NH StoreArchitect: Bensonwood
Bensonwood
Administration Building and Fabrication Shop
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Structural Form in Timber Architecture
That form ever follows function…
Though that function might be aesthetic
Structural Form in Timber Architecture
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Structural Form in Timber Architecture
Structural Form in Timber Architecture
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Structural Form in Timber Architecture
Structural Form in Timber Architecture
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Structural Form in Timber Architecture
Structural Form in Timber Architecture
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Structural Form in Timber Architecture
Structural Form in Timber Architecture
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Cruck Frames
Cruck Frames
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Log Timber Framing
Knee Braces
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What is Green about Timber?
How timber is green• Carbon sink
• Low embodied energy
• Renewable
• Recyclable
• Reusable
• Organic/Biodegradable
• Cleans air
• Cleans water
• Produces O2
• Habitat Source
Positive attributes• Avoidance of CO2
• Strong
• Lightweight
• Flexible
• Diverse
• Attractive
• Easy to fabricate
• Readily available
• Inexpensive
• Versatile
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Measure of Sustainability: Life Cycle Assessment
Life Cycle Assessment
transportation
energy use
extractioneffects
emissions to water
solidwaste
emissionsto the air
resourcedepletion
wateruse
Sustainable Measure: Life Cycle Assessment
Energy in Em
issions
Energy in Em
issions
Energy in Em
issions
Energy in Em
issions
Energy in Em
issions
Waste out
Waste out
Waste out
Waste out
Waste out
Raw materialacquisition
Materials manufacturing
Product manufacturing
Product use or
consumption
Final disposition
reuse & recycle
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Sustainability Comparison for Three Structural Systems
0
200
400
600
800
1000
1200
1400
1600
Total Energy Use
Green
house Gas Index
Air Pollution Index
Solid
Waste
Ecological Resource Im
pact
Use
Wood
Steel
Concrete
GJ x 103
KG x 103 Index Value x 108
Index Value x 104
Index Value x 104
Source: Green By Design, published by Canadian Wood Counciland developed by Athena™ Life Cycle Assessment Software
• Total Energy Use (GJ x 102):- Steel requires 2.4x the energy use that wood does- Concrete requires 1.7x the energy use of wood
• Greenhouse Gas Index (Equivalent CO2 Kg x 103): - Steel produces 1.5x the mass that wood does- Concrete produces 1.8 x the mass that wood does
• Air Pollution Index (Index Value x 108):- Steel’s impact on our environment is 1.4x that of wood- Concrete’s impact on our environment is 1.7 x the energy that of wood
• Solid Waste Index (Index Value Kg x 104): - Steel’s impact on is 1.4x that of wood- Concrete’s impact is 2x that of wood
• Ecological Resource Impact Use (Index Value x 104): - Steel’s impact on is 1.2x that of wood- Concrete’s impact is 2x that of wood
Sustainability Comparison for Three Structural Systems
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Carbon Sequestration
CO2 + H2O + SUNLIGHT ==> O2 + (C5H10O5)n (sugars)
Carbon Sequestration• Typical timber frame is +/- 12,000 bf (28 m3)
• 50% of the dry weight of wood is carbon
• 1 m3 of Douglas fir contains 0.225 tons of
carbon (not CO2)
• So, a typical timber frame contains 6.37 tons
of carbon (about as much as this tree)
• If left to decay, this carbon would generate
23.5 tons of CO2 (CO2 = 3.7 x C)
• Or, about the same emissions from 2400
gallons of gasoline
• As a result, wood has a negative carbon
footprint
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Carbon Sequestration• 3.5 billion metric tons of carbon stored in U.S. wood products
-- 670 million car-years of emissions
• Approximately 60 million metric tons are added each year
-- 11 million car-years of emissions
• Most of this wood is in the housing stock
• More of it could go into non-residential buildings
• When the wood is substituted for steel, concrete and plastic,
50% to 100% CO2 emissions can be avoided
• N.A. forestry firms obtain 65% of their energy needs from
bio-massSource: Green By Design, published by Canadian Wood Council
Carbon Sequestration Examples
ProjectVolume of wood used(cubic feet)
Time for forests to grow this fiber
(minutes)
Carbon Sequestered(metric tons)
Avoided emissions(metric tons)
Estimated carbonbenefit
(metric tons)
Cars‐yearsemissions/House –years of energy
Avalon Anaheim Stadium California
183,600 15 3,970 8,440 12,4102,369 cars 1054 houses
El Dorado HS Arkansas
153,140 13 3,660 7,780 11,4402,184 cars972 houses
New Earth Market California
2,825 0.25 70 160 23044 cars
20 houses
Source: Tackle Climate Change—Use Wood published by BC Forestry Climate Change Working Group
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Sustainable Forestry
91
90
86
82
68
66
64
63
60
40
29
26
21
16
6
0 10 20 30 40 50 60 70 80 90 100
Canada
Norway
Sweden
Finland
Russian Federation
Brazil
Indonesia
Malaysia
United States
Chile
New Zealand
Germany
China
France
United Kingdom
Per Cent of Original Forest
Sustainable Forestry• Many countries still have a large percentage of their original forests• North America not only has millions of hectares, it is largely original
Source: World Resources Institute Data Tables, 2000‐2001
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Sustainable Forestry• Rate of deforestation has fallen from 8.3M to 5.3M hectares (36%)• Heartening that two of most populous countries have largest increases
‐0.6 ‐0.4 ‐0.2 ‐1E‐15 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
CHINA
NORWAY
INDIA
SWEDEN
UNITED STATES
CANADA
RUSSIA
SUDAN
PERU
ANGOLA
COLOMBIA
MEXICO
AUSTRALIA
BRAZIL
INDONESIA
2000‐2010, Average annual change, %
Nil change
Nil change
Source: The World’s Forests Sylvan States, The Economist, 11Feb11
180
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18
18
9
8
6
4
3
2
0 20 40 60 80 100 120 140 160 180 200
N.AMERICA
FINLAND
SWEDEN
RUSSIA
AUSTRALIA
GERMANY
BRAZIL
MALAYSIA
FRANCE
CHILE
MILLIONS OF HECTARES CERTIFIED
Sustainable Forestry
• Only 10% if the world’s forest are independently certified• Over 50% of those forests are in North America (2008)
444million acres
Source: World Resources Institute Data Tables, 2000‐2001
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Certified Wood in North America
(American Forest & Paper Association)
(Canadian Standards Association)
Timber Basics: Species Choice
Commonly used for commercial projects• Douglas Fir• Southern Yellow Pine• Red Oak• White OakOther popular species• Eastern White Pine• Cypress• Hemlock• Spruce• And, many others
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Douglas Fir
White Oak
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Red Oak
Southern Pine
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Antique Timber: Reused
Industrial SalvageRecycled/Reclaimed
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Forest Salvage/Standing Dead Wood
Reclaimed Shipbuilding Timbers
SalvagedTimber
River Salvage Timbers
Glue Laminated vs
Solid Sawn
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Organic Forms are Easy with Glulams
Curved Timber
• GrainMatched™ Glulam
New Energy Works
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Elegant Curves
FraserWood
How Timber is Sawn Boxed Heart
Evergreen Specialties
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How Timber is SawnFree of Heart Center (FOHC)
Timber Basics: How Timber Dries—Boxed Heart
Evergreen Specialties
Timber Structure & ShrinkageLongitudinal: Parallel (roughly) to the direction of the cell fibers.
Shrinkage ranges between 0.1% to 0.2% from green to oven dry.
Radial: Perpendicular (roughly) to the growth rings.
Shrinkage ranges between 2.1% to 7.7%.
Tangential: Coincident (roughly) with the growth rings.
Shrinkage ranges between 4.4% to 12.7%.
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FraserWood
Shrinkage
Quartersawn
Flatsawn
Boxed Heart
Bastard SawnFree of Heart Center
From Wood Handbook by FPL
FraserWood
Note that the shrinkage is not linear from a FSP of 30% to 24%
From 24% to oven dry, the shrinkage is mostly linear.
Roughly, a timber will shrink from green at 24% to 8% in WY environments. At 19%, it has seen only 1/3 of its shrinkage.
Shrinkage
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Evergreen Specialties
Shrinkage
Boxed Heart Free of Heart Center
Evergreen Specialties
Conventional Kiln DryingIndirect steam heat‐‐convection
• Humidity is removed via a system of vents
• Cool dry air is introduced at one end
• Warm moist air is expelled at the other
• Use of steam increases heat transfer
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Radio Frequency Kiln Drying
FraserWood
• Capacitance heating (volumetric)—whole volume at once
• Lower temperature
• Faster timber drying—5 to 8 days for timber
• Designed for timber—it will dry timber
Radio Frequency Kiln Drying
FraserWood
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Timber Basics: Rate of Growth
Fabrication
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Power Tools on Steroids
Precision Hand Tools
Precision not typical in commercial work
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Handcrafted Joinery
CNC Fabrication
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CNC Joints
Crane Raising
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Structural Insulated Panels
(SIPs)
Timber Frame Basics: Enclosure
Foam Core
• Expanded Polystyrene (EPS)
• Extruded Polystyrene (XPS)
• Polyurethane & Polyisocyanurate
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SIP Thickness R-Value Perm
4.5” 15 0.61
6.5” 23 0.43
8.25” 30 0.35
10.25” 37 0.28
10.5” 38 0.27
12.25” 45 0.24
12.875” 48 0.19
15” 56 0.19
17” 63 0.17
25” 94 0.12
SIP Size & Thickness
• Jumbo Panels 8’ x 24’
Frame Embellishments
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Frame Embellishments
Frame Embellishments
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Frame Embellishments
Finial
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Chamfered Edges
Surface Treatment
• Planed
• Rough Sawn
• Hewn
• Adzed
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Planed
Adzed
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Hewn
Rough Sawn
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RoughSurface
Treatment
Determining the style of joinery
• All wood
• Wood with hidden metal connections
• Wood with exposed metal connections
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Joinery Style: All Wood
Bensonwood
Any structure is a collection of connections held together with members.
Hammerbeam Trusses
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Joinery: Steel Gussetts
Fink Truss
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Cast Steel ConnectionHardware
Getting Started
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How do you find a qualified, experienced Timber Frame Company?
• Searchable database on www.timberframe.org,
Structural Engineer of Record (SER)vs
Specialty Structural Engineer (SSE)
• Structural Engineer of Record – responsible for the entire structural frame and foundation
• Specialty Structural Engineer – responsible for the timber frame only
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Where to Find a Qualified Engineer
The Timber Frame Business Council Website Has a “Find a Timber Frame Engineer” Map at http://www.timberframe.org/timber-frame-engineer.html
Includes engineers licensed in each state/province.
• Questions?
• Comments
• Complaints?
Thank You
Wood is the most humanly sympathetic of all building materials because it affects so many of our senses…it may even be that our appreciation of proportion comes from the natural dimensions of trees.
Peter Davey, Editor, The Architectural Review