Pushing
Wood
Framing
to Higher
Heights
Pushing
ClientWood
Name Framing to Higher Heights
Speakers
Nancy Ludwig FAIA LEED AP
BD&C
President, ICON architecture
Eric Montplaisir, PE
AKF Group
Rimas Veitas, PE, President
Veitas & Veitas Engineers
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Name Framing to Higher Heights
Overview
Explore the design & technical challenges of building taller wood
structures:
1 – Wood Advantages
2 – The Push for Taller Wood Structures
3 – Cost Competiveness
4 – Building Code Framework
5 – Structural Design and Detailing
6 – Questions
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Why Wood?
• Lightweight
• Readily Available
• Workable – anybody can
build with it!
Fenway Center
• Dimensional
• Affordable
June 2000
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Name Framing to Higher Heights
Material Benefits of
Wood over Steel
• Lighter than steel
• Stronger load-bearing
compared to lightness
• Good shear transfer
• Good earthquake
performance
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Name Framing to Higher Heights
Construction
Benefits of Wood
• Low material cost
• Low installation cost
• Easily panelized
• Faster construction
• Readily adaptable
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Reduced Carbon
Footprint
• Concrete & Steel production
causes 8% of Carbon dioxide
• Every cubic meter of wood
stores +¾ ton carbon
Wood Innovation Center
Michael Green, Vancouver
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Name Framing to Higher Heights
Modern Wood -Mass Timber
• Laminated Veneer Lumber
(LVL)
• Laminated Strand Lumber
(LSL)
Fenway Center
June 2000
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ClientWood
Name Framing to Higher Heights
Modern Wood -Mass Timber
• Cross Laminated Timber
(CLT)
• Compressed Mass Timber
Panels
Fenway Center
June 2000
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Name Framing to Higher Heights
UMass Integrated
Design Building
• Structure -- Heavy
Engineered Timber & Cross
laminated Shear Walls -embedded steel
connectors
Fenway Center
• Floors are cross laminated
decking with 4-inch
concrete
June 2000
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Name Framing to Higher Heights
Tall Wood:
Graphite Apartments
Andrew Waugh, London
• 9 Stories -- 8 Wood over
1 Story of Concrete
• Layers of CLT panels
joined Fenway
with Center
metal fittings
June 2000
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Name Framing to Higher Heights
Tall Wood: 30 Stories
Fenway Center
June 2000
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Name Framing to Higher Heights
Tall Wood: 34 Stories
Fenway Center
In Stockholm,
Michael Green with
Berg|CF Moller &
Dinell June
Johansson
2000
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Name Framing to Higher Heights
SOM – Making the Case for a Timber 42-story Tower
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Name Framing to Higher Heights
SOM – Making the Case for a Timber 42-story Tower
Less Volume Less than ½
Weight
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Name Framing to Higher Heights
Sustainable–
capturing carbon
– less than ¼ CO2
emissions
Wood Limits?
• 4 Story Limits – based on
last centuries’ tragedies
• Better Performance in fire
– steel buckles but wood
chars to resist flame
Fenway Center
• Modern fire resistant
“wraps”
June 2000
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Name Framing to Higher Heights
Residential--4 Stories
Fenway Center
June 2000
Commercial
1st Floor
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Name Framing to Higher Heights
Residential
4 Stories
4
3
2
1
Commercial
1 June
Story
2000
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Name Framing to Higher Heights
Fenway Center
Residential -- 5 Stories
Residential
5 Stories
5
4
3
2
1
Commercial
1 Story
June 2000
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Name Framing to Higher Heights
Fenway Center
Residential -- 6 Stories
Residential
5 Stories
6
5
4
3
2
1
Fenway Center
Residential
June 2000
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Name Framing to Higher Heights
Residential -- 6 Stories
Residential
5 Stories
25% More Units
Fenway Center
25% More Units
June 2000
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Name Framing to Higher Heights
Gatehouse 75 in Charlestown
411 D Street in South Boston
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Name Framing to Higher Heights
+$5sf Rent
$3.75-$4.75sf
Rent
$2.25-$3.75sf
Rent
$340+/SF
$230-$270/SF
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Name Framing to Higher Heights
$165-$185/SF
$5+sf Rent
$3.75-$4.75+sf
Rent
$2.25-$3.75sf
Rent
$6/sf
Type 3A
$340+/SF
$230-$270/SF
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$165-$185/SF
Podium Concept
• Urban design challenge
– R-2 fully sprinklered Type VA building
– Served by adjacent Type IA parking structure
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Name Framing to Higher Heights
Podium Concept
• “Stacking” the R-2 building on the garage
• Mixed construction types
• “Horizontal fire wall”
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History of Podium Approach
• Originally a 1970s UBC provision
• Mixed construction types for basement and/or 1 story
enclosed parking below 3-hr horizontal separation with a
A, B, M, or R building above
• 1990s UBC allowed A < 300 (1 room), B, and M below the
3-hr assembly if podium is sprinklered
• 2000 IBC incorporated UBC podium provisions
• Subsequent versions of IBC provide greater flexibility
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• Based on UBC provisions
Stories measured above 3-hr assembly
Building “A”
Not required to be Type I
Use Group A room <300,
B, M, or R
3-hr horizontal assembly
1 story above grade
and/or basement
Building “B”
Type IA for S-2 enclosed parking
If sprinklered allows Use Group A
room <300, B, or M
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Name Framing to Higher Heights
Height in feet measured above grade
based on least construction type
2000 IBC 508.2
• Minor reformatting
• No technical changes
Stories measured above 3-hr assembly
Building “A”
Not required to be Type I
Use Group A room <300,
B, M, or R
3-hr horizontal assembly
1 story above grade
and/or basement
Building “B”
Type IA for S-2 enclosed parking
If sprinklered allows Use Group A
room <300, B, or M
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Name Framing to Higher Heights
Height in feet measured above grade
based on least construction type
2003 IBC 508.2 (780 CMR,
th
7 )
• Moves from 508.2 to 509.2
• More use group options
Stories measured above 3-hr assembly
3-hr horizontal assembly
1 story above grade
and/or basement
Building “A”
Not required to be Type I
Multiple Use Group A
rooms each <300,
B, M, R, or S
Building “B”
Height in feet measured above grade
based on least construction type
2006 IBC 509.2
Type IA for S-2 open or enclosed parking
If sprinklered allows multiple Use Group A
rooms each <300, B, or M
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Name Framing to Higher Heights
• Sprinklers below the 3-hr assembly are mandatory
• Additional flexibility
Stories measured above 3-hr assembly
3-hr horizontal assembly
1 story above grade
and/or basement
(multiple basement
levels allowed)
Building “A”
Not required to be Type I
Multiple Use Group A
rooms each <300,
B, M, R, or S
Building “B”
Height in feet measured above grade
based on least construction type
2009 IBC 509.2 (780 CMR,
th
8 )
Type IA for S-2 open or enclosed parking,
multiple Use Group A rooms each <300,
B, M, S or R
Must be sprinklered
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Type VA Example (8th Edition)
Use Group R-2 in Type VA
Fully Sprinklered
Allowable Height: 4 stories, 70 ft
Allowable Footprint Area: 36,000 sf,
up to 45,000 sf with 100% frontage
Allowable Aggregate Area: 108,000 gsf,
up to 135,000 gsf with 100% frontage
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Name Framing to Higher Heights
Type VA Example (8th Edition)
• 4 stories R-2 in Type VA over 1 story Type IA podium
70 ft max
height
above grade
4 stories
above podium
1 story
above grade
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Name Framing to Higher Heights
Type IIIA Example (8th Edition)
Use Group R-2 in Type IIIA
Fully Sprinklered
Allowable Height: 5 stories, 85 ft
Allowable Footprint Area: 72,000 sf,
up to 90,000 sf with 100% frontage
Allowable Aggregate Area: 216,000 gsf,
up to 270,000 gsf with 100% frontage
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Name Framing to Higher Heights
Type IIIA Example (8th Edition)
• 4 stories R-2 in Type IIIA over 1 story Type IA podium
85 ft max
height
above grade
5 stories
above podium
1 story
above grade
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BBRS Official Interp 2013-06
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Mezzanines within Podium
•
•
•
•
•
•
Section 505 Mezzanines
1/3 area limit
Enclosed portions don’t count
Common atmosphere
Part of floor below
Not a story
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Name Framing to Higher Heights
Mezzanines above Podium
•
•
•
•
•
•
Section 505 Mezzanines
1/3 area limit
Enclosed portions don’t count
Common atmosphere
Part of floor below
Not a story
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Name Framing to Higher Heights
What does the future have in
store for podium construction?
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Name Framing to Higher Heights
• Moves from 509.2 to 510.2
• No technical changes
Stories measured above 3-hr assembly
3-hr horizontal assembly
1 story above grade
Building “A”
Not required to be Type I
Multiple Use Group A
rooms each <300,
B, M, R, or S
Building “B”
Height in feet measured above grade
based on least construction type
2012 IBC 510.2
Type IA for S-2 open or enclosed parking,
multiple Use Group A rooms each <300,
B, M, S or R
Must be sprinklered
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ClientWood
Name Framing to Higher Heights
Stories measured above 3-hr assembly
3-hr horizontal assembly
1 story above grade
Building “A”
Not required to be Type I
Multiple Use Group A
rooms each <300,
B, M, R, or S
Building “B”
Type IA for any occupancy except H
Must be sprinklered
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Name Framing to Higher Heights
Height in feet measured above grade
based on least construction type
2015 IBC 510.2
Potential 9th Edition Project
• 4 stories R-2 in Type VA over 2 story Type IA podium?
70 ft max
height
above grade
4 stories
above podium
2 stories
above grade
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Name Framing to Higher Heights
Potential 9th Edition Project
• 5 stories R-2 in Type IIIA over 2 story Type IA podium?
85 ft max
height
above grade
5 stories
above podium
2 stories
above grade
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Name Framing to Higher Heights
Structural Design of > 5 Stories
1.
Seven story structures with wood
2.
Cross laminated timber structures
3.
Review of Type IIIA materials
4.
Gravity load
5.
Wind and seismic loads
6.
Brick issues
7.
Exterior wall details
8.
Podium construction
9.
Wood technology issues
10. Additional info
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Seven Story Wood Buildings
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Seven Story Wood Structures
• Construction underway in Revere, MA with a
variance from the BBRS
• Five levels of housing over two levels of parking
completely above grade
• Two podium levels are PT - Concrete
• A “high rise wood building” > 70 feet
• The 2015 IBC will allow this type of structure
• Increased density with two levels of parking
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Name Framing to Higher Heights
Cross Laminated Timber Buildings
• For wood structures of 6 floors and beyond
• It is a work in progress
• R&D is a good thing
• There is guidance for CLT in the Canadian Code
• No Guidance for CLT in the US Code yet
• Maybe we can adapt some of the superior wood
technology into our current construction methods
• We know price point is high but we looking for an
interested owner to design CLT project
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Name Framing to Higher Heights
Type IIIA Exterior Wall Materials
•
IBC requires that walls be FRT (Fire Retardant Treated)
•
Currently FRT is available only in SP – southern pine?
•
The treatment of SPF is not able to withstand limited
exposure to the weather?
•
Sill plates need to have FRT with Borate added for PT
•
Exterior wall sheathing requires FRT for I/O Fire Rating
•
Exterior wall sheathing requires FRT and 2hour rating O/I
•
The Code guys can get creative with applying UL apps
•
For certain FRT products the nails do not need galvanizing
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Name Framing to Higher Heights
Gravity Loads
• Interior wall studs can remain 2x4’s
• Exterior studs
•
2x6 for thermal insulation
•
Treated – FRT (reduce allowable stress)
• High first floor heights may require lam studs
• Is the exterior wall bearing or non-bearing
• For large exterior wall openings - Lam beams or
LVL’s need intumescent paint or use FRT wall
trusses
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Name Framing to Higher Heights
Wind and Seismic Loads
• Flat roofs are good for IIIA
• Sloping roofs can increase the wind shear by 30%
• One layer of OSB sheathing at demising wall and a
mix of exterior walls and corridor walls is ok with
flat roofs
• With sloping roofs need additional walls at lower
two or three levels
• Need an increased level of inspection
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Name Framing to Higher Heights
Brick Issues
• The Brick/wood interface is a potential issue
• Some historical experience indicates 4 stories ok
• The literature is very conservative and rightfully so
• Value Engineering has been our friend
• Is it two or three levels of Brick before relief
• Addition of relieving angle to wood – yuk
• Consider steel posts to attach the relieving angle
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Name Framing to Higher Heights
Exterior Wall Details
It is a dynamic target and depends on the following:
• The owner
• The code consultant
• The architect
• The Building Inspector
• The General Contractor
• The Wood Component Supplier
• The framer
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Name Framing to Higher Heights
Detail at Exterior Bearing Wall
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Section – “Incidental penetration”
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Exterior Bearing Hanger Detail
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Exterior Bearing Wall
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Exterior Bearing Wall at Roof
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Exterior Bearing Wall at Roof
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Shear Wall to Exterior Wall
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Party Shear Wall at Exterior Wall
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Non-Bearing Wall to Exterior Wall
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Interior Corner at Exterior Wall
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Exterior Wall Specification on Plans
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Podium Construction Type IIIA
There are several options in New England
• Steel frame with composite deck
• Post-tensioned concrete slab
• Filigree Beam Slab system
• Concrete flat plate
• Precast concrete
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Name Framing to Higher Heights
Wood Technology
As the marketplace matures and expands
• We will have more vendors
• New products
• More innovation
Lets make sure we review the ability to implement that
“new thing” with our “wood partners”
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Name Framing to Higher Heights
Additional Information
• Who inspects your wood buildings ?
• What do they inspect ?
• As we “structurally push the to limits” we need
equally increase quality control and quality
assurance
• Detailed wood construction presentations held at
your office are offered by Veitas and Veitas
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Name Framing to Higher Heights
Copyright Materials
This presentation is protected by US and International Copyright
laws. Reproduction, distribution, display and use of the presentation
without written permission of the speaker is prohibited.
© ICON architecture, inc, 2014
© AKF Group, 2014
© Veitas and Veitas, 2014
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