Proceedings

Mass Timber Research 

Workshop 2015

USDA Forest Products Laboratory

Madison, Wisconsin, USA

November 3–4, 2015

General Technical Report

FPL–GTR–241

United States Department of Agriculture

Forest 

Service

Forest Products

Laboratory

March

2016
Abstract

This report summarizes the proceedings, including key 

points and identified research needs, that evolved from the 

Mass Timber Research Workshop, which was held at the 

USDA Forest Products Laboratory (FPL), November 3–4, 

2015. The purpose of the workshop was to bring design 

professionals, researchers, and industry leaders together 

to examine the state-of-the-art in mass timber construction, with an emphasis on cross-laminated timber, and to 

identify technical barriers to the broader use of wood in 

engineered structures that need to be addressed. Following 

a plenary session on mass timber in North America, some 

120 scientists, engineers, and industry leaders heard presentations organized in four technical areas: (1) resistance to 

lateral loads, (2) building performance—durability, sound, 

vibration, and life cycle assessment, (3) fire safety, and 

(4) material resources and other research topics. Breakout 

sessions aimed at identifying future research objectives were 

then held for each of the four technical areas, followed by 

a prioritization of future research needs. Included in these 

proceedings are abstracts from each presentation, copies of 

all presentations and a summary of research needs.

Keywords: Mass timber, cross-laminated timber, wood 

construction, engineered wood structures

March 2016

Williamson, Tom; Ross, Robert J. 2016. (Eds.) Proceedings: Mass 

Timber Research Workshop 2015. General Technical Report FPLGTR-241. Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory. 364 p.

A limited number of free copies of this publication are available to the 

public from the Forest Products Laboratory, One Gifford Pinchot Drive, 

Madison, WI 53726–2398. This publication is also available online at 

www.fpl.fs.fed.us. Laboratory publications are sent to hundreds of libraries 

in the United States and elsewhere.

The Forest Products Laboratory is maintained in cooperation with the 

University of Wisconsin. 

The use of trade or firm names in this publication is for reader information 

and does not imply endorsement by the United States Department of 

Agriculture (USDA) of any product or service.

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USDA is an equal opportunity provider, employer, and lender.

2
Proceedings

Mass Timber Research Workshop 2015

USDA Forest Products Laboratory

Madison, Wisconsin

November 3–4, 2015

Edited by

Robert J. Ross, Supervisory Research General Engineer

Forest Products Laboratory, Madison, Wisconsin

Tom Williamson, Managing Partner

Timber Engineering LLC, Vancouver, Washington

3
Contents

Preface, 6 

Workshop Overview, 7

Plenary Session—Mass Timber in North America

Role of WoodWorks in the Technology Transfer of Mass Timber Research, 28

Importance of Mass Timber Research for the Softwood Lumber Industry, 36

Cross Laminated Timber in the United States: Past, Present, and Future Issues, 48

Updates/Overview of the Status of CLT R&D Activities and Tall Wood Buildings in Canada, 55

The U.S. Tall Wood Building Prize Competition and USDA’s Role with Mass Timber, 70

Session 1—Resistance to Lateral Loads

Coming Soon: Seismic Performance Factors for Cross Laminated Timber Design, 74

Performance of Mass Timber Structures under Lateral Loads: The Canadian Experience, 96

Updates and Results from NEES–CLT Planning Project, 116

The Heavy Timber Buckling Restrained Braced Frame System as a Solution for Commercial 

Construction in Regions of High Seismicity, 129 

CLT Diaphragm Research and Design in North America, 144

Session 2—Building Performance: Durability, Sound, Vibration, and Life Cycle Analysis

CLT Systems: Acoustic, Vibration and Creep Performance, 157

Hygrothermal Performance of Mass Timber Construction, 174

Acoustic Prediction Models Create Basis for Future Competitive Wooden Structures, 185

Comparative Life Cycle Assessment of a U.S. CLT Building: Planning and Challenges, 194

Session 3—Fire Safety

Fire Safe Design of Exposed Mass Timber Buildings, 204

Performance of Mass Timber Construction in Fire, 213

Forest Products Laboratory Research on the Fire Performance of Cross Laminated Timber, 226

Fire Safety of Tall Buildings—Property Protection View, 236

Session 4—Material Resources and Other Topics

CLT Supply Chain from Forest to Market, 248

Timber–Concrete Composites, 257

Mass Timber Construction in Utah: Research, Practice, and Futures, 270

Blast-Resistant Testing for Massive Timber Exterior Wall: Expanding Timber

Opportunities in North America, 295

Development of a Mass Timber Tornado Safe Room, 303

More with Less—An Overview of the First CLT Hotel in the United States, 307

Keynote Presentation—Challenges of Building with Mass Timber in the United States, 321

4
Summary of Breakout Sessions 

Breakout Session 1—Resistance to Lateral Loads, 339

Breakout Session 2—Building Performance: Durability, Sound, Vibration, and Life Cycle Analysis, 340

Breakout Session 3—Fire Safety, 341

Breakout Session 4—Material Resources and Other Topics, 343

Close-Out Session to Prioritize Future Research Needs, 344

Appendix 1—Discussion Notes for Breakout Session 1, Resistance to Lateral Loads, 347

Appendix 2—Discussion Notes for Breakout Session 2, Building Performance: Durability, Sound, 

Vibration, and Life Cycle Analysis, 350

Appendix 3—Discussion Notes for Breakout Session 3, Fire Safety, 353

Appendix 4—Discussion Notes for Breakout Session 4, Material Resources and Other Topics, 358

List of Attendees, 362

5
Preface

The use of large, solid sawn, and laminated timber members in the design and construction of structures 

has been a topic of research for over 100 years in North America. That research has resulted in many 

technical innovations that have yielded structures that have performed admirably in a wide range of 

applications, with many serving in a variety of capacities for nearly a century. Although heavy timber 

design principles and construction techniques have been in use worldwide for some time, there is a 

renewed, growing interest in the design and construction of large, multistory structures with massive 

engineered timbers, commonly referred to as “mass timber.” Cross-laminated timber (CLT) is a 

relatively new engineered mass timber building product that has sparked considerable research and 

design activity worldwide.

CLT is a multilayer wooden panel made of lumber. Each layer of boards is 

aligned perpendicular to adjacent layers and connected by adhesives for 

increased rigidity and stability. CLT—developed in Europe as an 

environmentally friendly building product—has been used successfully in 

multistory applications, such as a nine-story apartment tower in London’s East 

End and four- and seven-story buildings in Växjö, Sweden. CLT is making 

inroads in North America, but many technical questions have arisen concerning 

its use. For example, increasing density of modern 

urban population centers demands buildings that are 

taller and safer, resilient to natural hazards, and built from sustainable natural 

resources. CLT is a bio-based product that can achieve these objectives while 

utilizing low-value lumber stock such as emanating from beetle-killed trees, 

small-diameter growing stock, and other wood-based materials, rendering it 

an environmentally friendly engineered timber product. However, basic 

information needs to be developed to ensure safe designs. 

A workshop was held at the USDA Forest Products Laboratory to provide a technical forum on the topic 

of mass timber research. The objectives of the Mass Timber Research Workshop, held November 3–4, 

2015, were to (1) bring design professionals, researchers, and industry leaders together to examine the 

state-of-the-art in mass timber construction, with an emphasis on CLT, and (2) identify technical barriers 

to the broader use of mass timber in engineered structures that need to be addressed through research. 

Following a plenary session on mass timber in North America, more than 120 scientists, engineers, 

and industry leaders heard presentations organized in four technical areas: (1) resistance to lateral 

loads, (2) building performance—durability, sound, vibration, and life cycle assessment, (3) fire 

safety, and (4) material resources and other research topics. Breakout sessions aimed at identifying 

future research objectives were then held for each technical area, followed by a prioritization of future 

research needs. 

This report summarizes the proceedings, including key points and identified research needs that evolved 

from the Mass Timber Research Workshop. Included in these proceedings are abstracts from each 

presentation, copies of all presentations, and a summary of prioritized research needs. 

Tom Williamson

Robert J. Ross 

Editors 

6
Workshop Overview 

Michael Ritter, Assistant Director

USDA Forest Products Laboratory, Madison, Wisconsin 

Michael Ritter, Assistant Director 

USDA Forest Service, Forest Products Laboratory 

Madison, Wisconsin

7
y Better understand what research is currently in 

progress for mass timber

y Identify research gaps that must be filled to 

further advance mass timber structural systems

y Formulate an international network to share 

research information and compile non-refereed 

research in progress summaries

8
y Timber Engineering LLC

 Tom Williamson

y Softwood Lumber Board

 Steve Lovett, Cees de Jager

y WoodWorks

 Jennifer Cover, Jaime Krohn, Dawn Condotti, Karen Droste

y FPL Staff

 Karen Martinson, Steve Schmieding, Bruce Smith, Karen 

Nelson, Bill Ireland, Jim Godfrey, Karla Cunningham 

“...to improve people’s lives by helping to 

sustainably use our Nation’s forest natural 

resources through leading-edge science, 

technology development and information 

delivery.” 

9
• America’s forests are a major strategic asset that provide

environmental, social, and economic benefits

• The US cannot maintain healthy, diverse, productive and

sustainable forests without an equally healthy, diverse,

productive and competitive forest products industry

• Forest products contribute to the Triple Bottom Line

 Environmental Stewardship

 Social Responsibility

 Economic Prosperity (e.g. jobs and Gross Domestic

Product)

“..... A key element in maintaining 

healthy, resilient forests is our ability 

to provide value-added products 

from the full complement of forest 

biomass.”

Michael T. Rains

Director of the Forest Products Laboratory 

and Northern Research Station

10
y Contributes to healthy, sustainable forests

y Improves utilization of forest mortality

y Helps keep working forests working

y Provides economic and employment opportunities

y Contributes to greenhouse gas mitigation

y Develops the potential using the urban wood 

resources

11
12
Fire readiness and suppression has gone from 20% of the 

FS budget in 2001 to 52% in 2015. It is not uncommon to 

spend $1 million per hour fighting fires. 

13
14
y Opportunity:

Improve the health and resiliency of our 

forests and stimulate rural economies

y Challenge:

Provide a consistent, sustainable 

material supply

Acres

15
Acres

16
Acres Acres

17
Average Annual Acres Burned

Acres

9.3 million acres in 2015

y Opportunity:

Improve forest health and regeneration and 

access an abundant, low cost resource

y Challenge:

Harvest material before it deteriorates and 

economically harvest and transport logs

18
19
y Opportunity:

Family owned working forests provide 

an expanded source of material supply

y Challenge:

Educate landowners on the advantages 

of forest management and sustainable 

harvesting

0

200

400

600

800

1,000

1,200

1,400

1,600

1980 1984 1988 1992 1996 2000 2004 2008 2012

Million board feet

LVL Glulam

Engineered Wood Products Production in the U.S.

20
0

75

150

225

300

1997 1999 2001 2003 2005 2007 2009 2011 2013

Billion 2005 $ 

Wood products (NAICS 321)

Paper products (NAICS 322)

Wood furniture (parts of NAICS 337)

In 2013, the Forest Product Industries accounted for more than 5% of all 

U.S. manufacturing shipments.

Value of Forest Products Shipments by NAICS code

0

100

200

300

400

500

600

700

1997 1999 2001 2003 2005 2007 2009 2011 2013

Thousand employees

Wood products (NAICS 321)

Paper products (NAICS 322)

In 2013, the Forest Product Industries accounted for more than 

8% of all U.S. manufacturing employment.

Employment in the Forest Products Industries, by NAICS 

21
y Opportunity:

Contribute to the local and national 

economies and provide jobs for rural 

development

y Challenge:

Increase demand for mass timber

CO2 removal

The C is used to make 

wood

The C balance here 

is negative

C is 

transferred 

to products

CO2 emissions due 

to harvesting, 

manufacturing, 

transportation

Net C is NEGATIVE: more C is in the 

product than was emitted to 

atmosphere in making the product

+

-

Graphics from FPInnovations and the Athena Institute

22
y 2.4 tons of CO2 are absorbed to create 

100 ft3 of wood

y 100 ft3 of wood contains:

o 0.65 tons of carbon

o 0.55 tons of oxygen

o 0.1 tons of hydrogen

o minor amounts of other elements

From: Building with wood = Proactive climate protection

Dovetail, BSLB, SUNY

y Opportunity:

Sequester carbon to mitigate 

greenhouse gas emissions and reduce 

the potential for climate change

y Challenge:

Educate users on the environmental 

advantages of using mass timber

23
Urban and Rural Population in the United States (1790 to 2000) 

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1790 1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

In 1920, the urban 

and rural population 

were about equal

In 2000, it is about 

80% urban 

Urban

Rural

24
25
Demolition

Deconstruction

y Opportunity:

Provide an opportunity to utilize large 

quantities of urban wood that would 

otherwise be landfilled

y Challenge:

Develop an infrastructure for harvesting, 

processing and marketing urban wood.

26
The growth in demand for mass timber will 

help to foster environmental stewardship, 

social responsibility and economic 

development. To fully develop this potential, 

there must be a sustainable wood supply that 

can be harvested, transported and 

manufactured in a cost effective manner........

• Requirements for design and construction of mass

timber structures, as well as the availability of

forest resources, varies by country and can vary

within a country.

• Both research and technology transfer are critical

to overcome barriers that hinder widespread mass

timber use.

• Communicating research activities and identifying

research needs and priorities will help us all

achieve objectives in a more efficient, cost

effective manner.

27
Plenary Session—Mass Timber in North America

Role of WoodWorks in the Technology Transfer of Mass Timber Research

Jennifer Cover, Executive Director

WoodWorks, Washington, D.C.

As the only national program dedicated to educating architects and engineers on the use of wood as a 

structural building material in commercial, multifamily/midrise and taller wood construction, 

WoodWorks plays a central role related to mass timber technology transfer. As a “go-to” resource for 

designers, WoodWorks helps take innovative advancements from the research environment and place 

them in the hands of the design community so they can be applied to real-world projects, opening new 

markets and applications for wood products as quickly as possible. This presentation will cover the 

organization’s multifaceted approach to education and project support, which results in knowledgeable 

“wood champions” who are then well-positioned to make cost-effective material choices that reduce the 

carbon footprint of their projects. Examples of WoodWorks’s broad efforts related to mass timber 

market development will be highlighted, including two national tall wood symposia, efforts to open a 

market for wood use on military projects, and support for projects such as the Integrated Design 

Building at the University of Massachusetts, currently under construction. 

Technology Transfer 

Jennifer Cover, PE 

Executive Director 

WoodWorks 

Bridging the gap between 

design engineers and wood 

research advancements 

28
WoodWorks Technical Staff 

Wood Project Assistance

help@woodworks.org 

Project Support Resources 

29
Educational Outreach 

Practitioner Education Hours 

 Jan to Sept 2015 

31,000 

• 3 Wood Solution Fairs

• 17 Workshops

• 51 Lunch Seminars

• 9 Webinars

• 124 Lunch & Learns

• 1 Tour

• 48 Third Party Speaking Engagements

Waugh Thistleton Architects 

Wood Design Provides Solutions Matt Todd

Dennis Ivy Nic Lehoux

Waugh Thistleton Architects

Nic Lehoux

30
Impacting Projects – 330 YTD 

2011201220132014

Taking Wood Projects Taller 

Forté 

Melbourne, Australia 

10 stories 

105.5 ft 

Developer : Lend Lease 

Completed 2012 

How do we get there 

in the U.S.?

• Creative Architects 

• Engineering Advancements 

• Code Advancements 

• Innovative Wood Materials 

31
Mass Timber Panels 

Nail Laminated Timber (NLT) Glue Laminated Timber (GLT)

Laminated Veneer Lumber (LVL) Cross Laminated Timber (CLT)

Images Source: Structurecraft Not shown: Laminated Strand Lumber (LSL)

U.S. Tall Wood Building Prize Competition 

475 West 18th Street 

Manhattan, NY 

10 stories / 120 feet tall 

Commercial / condominiums 

Framework 

Portland, OR 

12 stories / 130 feet tall 

Retail/office/apartments 

LCT1

ARCHITECT: Hermann Kaufmann 

ENGINEER: Merz Kley Partner 

PHOTO CREDIT: CREE 

LCT1

ARCHITECT: Hermann Kaufmann

ENGINEER: Merz Kley Partner

32
WoodWorks Creating Market Demand 

18,700 hours of Tall Wood/Mass Timber education 

delivered 

WoodWorks Project Support – Mass Timber 

Team providing assistance 

on 12 projects over 7 stories 

Franklin Elementary School (45,200 sq ft) 

Franklin, WV 

Paccar Environmental Technology Building 

at Washington State University (WSU)

33
Opening New Markets for Mass Timber 

Department of Defense - Blast Testing of Mass Timber 

Redstone Hotel 

Huntsville, AL 

Photo Credit: Lend Lease 

Karagozian & Case completes a blast test of 

a curtain wall system for the government. 

2016 Education Program Plan 

150 branded events + over 200 Lunch ‘n Learns = over 38,000 education hours 

34
2016 Wood Solution Fairs 

Six Wood Solution Fairs

• Minneapolis (Q1)

• Portland (Q2)

• Oakland (Q2)

• Houston (Q3)

• Philadelphia (Q4)

• Orlando (Q4)

Program Support 

Wood Project Assistance

help@woodworks.org 

WoodWorks Website 

www.woodworks.org 

Wood Project Assistance

35
Importance of Mass Timber Research for the Softwood Lumber Industry

Steve Lovett, CEO

Softwood Lumber Board, Washington, D.C.

This presentation will cover the Softwood Lumber Board’s (SLB’s) purpose and programs emphasizing 

mass timber, SLB’s interest in the conference, why it was important for SLB to partner with FPL as a 

sponsor, and what SLB hopes to gain from the conference. Finally, it will summarize how and why the 

conference and the follow-on activities will be important to all participants.

Mass Timber

An Opportunity for 

Sustainable Growth

36
Global Climate Change

Buildings are responsible for nearly half of US CO2 

emissions. 

A Yale University-led study has found that 

using more wood and less steel and 

concrete in building and bridge 

construction would substantially reduce 

global carbon dioxide emissions and fossil 

fuel consumption. 

--Yale News, March 31, 2014

Yale School of Forestry & Environmental Studies 

University of Washington College of the Environment

Global Climate Change

37
“With a carbon footprint 

that’s 75% less than that 

of concrete or steel, is it 

any wonder that wood has 

become a top contending 

material for green 

builders?” 

US Green Building Council 

Changing Attitudes

Changing Attitudes

38
Innovation – Why Tall Wood Matters

Chicago, US 

42 stories hybrid 

Proof of concept 

Innovation – Tall Wood

• Support early adopters

• Foster innovation

• Generate broad awareness

and understanding of

wood’s value proposition.

• Budget: $3 million (includes

$1 million from USDA)

US Tall Wood Competition

39
Innovation – Tall Wood

USDA Tall Wood Competition

• Pearl district

• 12 stories – 130’

• Mixed use (retail/residential)

• Expected start: Jan ’16

• CLT plus glulam using NZ

technology to address

seismic issues.

• $1.5 million Prize

FrameWork

Portland, OR

40
USDA Tall Wood Competition

• Adjacent to Highline

• 11 stories – 120’

• Mixed use (retail/residential)

• Expected start: Dec ’16

• Team includes SHOP

architecture: “most

innovative firm in the world”

• $1.5 million Prize

West Chelsea

New York, NY

USDA Tall Wood Competition

• 8 stories – 85’

• Mixed use (retail + office)

• Expected start: Fall ’15

• $250,000 funding for 6

research projects.

Carbon 12

Portland, OR

41
USDA Tall Wood Competition

• 7 stories – 85’

• High end office space

• 220,000 square feet

• Post & beam with NLT

• Under Construction

• $0 funding

• Next project planned for

Atlanta, GA

T3 - Hines

Minneapolis, MN

Innovation – Tall Wood

42
Innovation – Cross Laminated Timber

Innovation – NLT

43
Innovation – Building Systems

Opportunity – Tall Wood 

5-6 Stories 7-10 Stories 11-15 stories 16-20 stories 21-30 stories

Residential

Non-Residential

Non-Res 2.035 bbf 1.229 bbf .425 bbf .195 bbf .113 bbf 

Residential .958 bbf .420 bbf .318 bbf .192 bbf .129 bbf 

Total 2.003 bbf 1.649 bbf .743 bbf .387 bbf .242 bbf 

Incremental Volume: 5.0 BBF/Year 

44
• Construction site fire mitigation

• Coatings: Fire performance. 

• Lateral design & noise reduction 

• Energy efficient building systems & total 

life cycle cost. 

• Market Intelligence: Industrial segment 

& construction costs 

• Data and metrics support 

Ongoing Initiatives

Research Projects

re mitigation

gs: Fire performance.

Lateral design & noise reduction

Energy efficient building systems & total

life cycle cost.

Market Intelligence: Industrial segme

construction costs

a and metric

• Database of research in wood

building products and systems

• Focus on mass timber

• Create best in-class database and

user focused interface

Database Development Project: Vision

Research Projects

45
To set up a process to create a 

continuously updating inventory of 

the current landscape of research 

in wood building products and 

wood building systems from key 

markets around the world. 

Database Project: Purpose

Research Projects

1. To compile a continuously updating inventory of 

research 

2. To display the current status of research 

3. To identify specific knowledge gaps 

4. To identify researchers best able to fill gaps 

5. To make the database public 

6. Promote database as a resource for researchers, 

design/build professionals and funders 

Database Project Goals

Research Projects

46
A Solution for the 21st Century

“If the 19th Century was the century 

of steel, and the 20th century the 

century of concrete, then the 21st

century is about timber.” 

Alex de Rijke 

dRMM Architects 

47
Cross Laminated Timber in the United States: Past, Present, and Future 

Issues

Douglas Rammer, Research General Engineer

USDA Forest Products Laboratory, Madison, Wisconsin

Cross laminated timber (CLT) is making inroads into the United States building construction market, but 

research and design needs still limit expanded use. Two of the first significant advancements were the 

development and adoption of ANSI/APA PG 320 in 2012 and the publishing of the U.S. CLT Handbook

in 2013. This talk will briefly discuss the past efforts, along with the more recent developments of 

inclusion of the CLT design specification in the National Design Specification and Oregon Building 

Code. Broad design issues using CLT in the U.S. construction market will be presented. Finally, 

ongoing USDA and Forest Service research efforts to further CLT use in the United States will be 

highlighted. 

CROSS LAMINATED TIMBER IN THE 

UNITED STATES: 

PAST, PRESENT, AND FUTURE 

Douglas Rammer 

USDA Forest Service 

48
Benefits of Mass Timber 

 Sustainable 

 Low Carbon Footprint 

 Rapid Construction 

 Less Waste 

 Thermal Performance/Energy Efficient 

 Fire Protection 

 Cost Effectiveness 

Waste

mal Performance/Energy Efficient

Protection

Effectiveness

Tall Wood Buildings in US 

49
Tall Wood Buildings in US 

 1,025' X 235’ footprint 

 183’ High 

Recent Developments 

50
Design Milestones 

Design Milestones 

 CLT is recognized as Type IV Construction 

 ICC Board 

51
Future of U.S. Tall Wood Buildings 

Future of U.S. Tall Wood Buildings 

52
US CLT Research 

 USDA NIFA 

 ARS 

 FPL - CAWS 

 Performance Based Design of CLT 

 NEES-Soft CLT Repair Option 

 Seismic Design Parameters for CLT 

 Rocking Shear Walls (UW-Milwaukee) 

 Mechanically Laminated CLT 

 Instrumentation of Promega Building 

 LCA of CLT 

 Supply Chain Analysis 

 Forest Service Wood Innovation Awards 

 NEEScr - CLT 

Where is the future? 

53
 Resistance to Lateral Loads 

 Building Performance: 

 Durability 

 Sound, 

 Vibration 

 LCA 

 Fire Safety 

 Material Resources and Other Research 

Topics 

Topics Areas for Workshop 

Tallest US Wood Structures 

54
Updates/Overview of the Status of CLT R&D Activities and Tall Wood 

Buildings in Canada 

Mohammad Mohammad, Research Leader/Senior Industrial Advisor 

FPInnovations, Ottawa, Ontario, Canada 

A summary of recent research activities at Canadian research institutes, including FPInnovations, 

National Research Council (NRC), and universities, on various performance attributes (e.g., structural, 

fire, acoustics, etc.) of CLT products and assemblies and status of CLT in Canadian codes and standards 

will be provided. Recent developments and initiatives related to Canadian tall wood buildings 

demonstration projects that incorporate CLT, and the specific research and development activities 

conducted in support of the proposed design concepts and regulatory approval of those tall mass timber 

projects, will be presented. 

Mass Timber (CLT) Research Workshop

Forest Products Laboratory (FPL), Madison, WI

November 3-4, 2015

M. Mohammad, P. Eng, PhD

Senior Research Advisor and Research Leader 

NRCan/FPInnovations

Overview of the Status of CLT R&D Activities 

and Tall Wood Buildings in Canada 

55
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Strong interest to re-specify wood in non-res. & mid- & highrise buildings (i.e., renaissance in wood construction)

 Key drivers:

o Availability of new generation of innovative EWP, connection systems,

design tools & advanced prefab. technologies

o Recent changes to building codes

o Environmental concerns (i.e., climatic changes)- favors wood

o Development of CLT

Recent Trends/Opportunities

© 201 3 FPI nnovations. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

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Midrise Wood Frame Construction in 

Canada: the Journey...

 2009: BC Building Code

revised to increase height limit

for wood-frame construction

from 4 to 6 storeys

 2013: Régie du Bâtiment du

Québec (RBQ)

 2015: Ontario Building Code

 2015: Alberta Building Code

 2015 National Building Code of

Canada

Expecting 1000’s of midrise buildings in Canada next few years!!

3

f

gs in Canada next few years!!

56
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Rediscovered Tall Wood Buildings

The Landing

Vancouver, 1905

Height: 30 m NBCC 1941 (7)

National Building Code

NBCC 1953 (4)

NBCC 2015 (6) 

4

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Status of CLT in Canada

o CLT introduced to Canada in 2006

o Canadian-made CLT is commercially available

( 2 manufacturers + 1 coming up soon!!)

o Over 40 projects that utilizes CLT, either

designed or built across Canada

o Extensive research conducted by FPI,

Universities (NEWBuildS), NRC and

Industry Associations (CWC)

o Mostly funded by NRCan, industry (BSLC)

and provinces (QC, FII)

o Strong interest in CLT among designers,

building officials, governments & developers

5

s

57
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CLT in NA Codes and Standards

US: CLT adopted in the 2015 editions of IBC and NDS 

Canada: Implementation process in building codes and standards 

has been generally slow..

o Designers use CLT under « Alternative Solutions»

o CLT proposal discussed at the NBCC (LLRS): Didn’t make it for the 2015

edition

o Proposals are being developed by CWC and partners (2020 NBC)

o Quebec: «Pre-approved » Alternative Solution for mass timber including

CLT for up to 12 storeys!

s. All rights reserved C edistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

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Quebec’s Guide for Mass Timber 

Construction up to 12 Storeys 

7

o Released in August, 2015

o Quebec: 1st jurisdiction in NA to officially support the

construction of tall mass timber bldgs

o “Pre-approved” Alternative Solution to facilitate the

design & approval process

o Covers CLT, hybrid and other types of mass timber

o Great interest in the Guide by other jurisdictions in

Canada and overseas

e

Bâtiments de construction massive 

en bois d’au plus 12 étages

58
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CLT in Canadian Codes and Standards

CSA O86: Canadian Timber Design Standard

o Design provisions proposed at CSA O86 (public review ended Oct. 28)

o Targetting the 2016 Supplement of CSA O86

o Comprehesive proposal that covers provisions for :

 Bending and shear resistance

 Serviceability (i.e., deflection and vibration)

 Connections

 LLRS

 Fire resistance

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Sponsored by NRCan, BSLC, AWC, USFPL, APA, WoodWorks

Developing Design Guidelines 

CLT Handbooks 

o FPI’s CLT handbooks have been instrumental in providing guidance to

designers under AS provisons & in supporting CLT code change

proposals in Canada and the US

o Need to update US CLT handbook to be in line with recently

implemented IBC and NDS provisions!

59
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R&D on Seismic Design in CLT

and logo 10

Ɣ Short and tall CLT walls & 2-storey CLT assembly tests 

at FPI & under NEWBuildS

Ɣ Evaluation of stiffness of massive wood shearwalls &

diaphragms

Ɣ Joint research between FPL, FPI & US Universities 

(WSU, CSU, etc.) on seismic perf. of CLT 

Ɣ Developing high capacity connections for CLT (i.e., 

facilitate assembly and disassembly)

© 2013 FPInnovations. All rights reserved. Copying and redis

ts

s are trademarks of FPInnovations. 10

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Gravity & Seismic Design in CLT (NEWBuildS/FPI)

 Stability of CLT wall panels under gravity loading

 In-plane stiffness and strength of CLT diaphragms

 Force transfer around openings in walls subjected to

in-plane loading

60
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Post-tensioning System Applications: 

Self-centering & Energy Dissipation

o Explore the adoption of self-centering/damage fuse concept to

CLT wall construction to resist seismic load (NEWBuildS/FPI)

o FPI acquired the IP for the NZ PT system for NA and an

implementation strategy is being developed including

supporting R&D research and design guides

Source : Deierlein et al 2005

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So

and redistribution prohibited. ® FPInnovations, it s and logos are trademarks of FPInnovations.

Deierlein et al 2005

ed. Copying

ource :

ts marks

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NEWBuildS/FPI: Structural CLT Connections

13

o Fastener Withdrawal and Embedment Strength in Timber,

Glulam and CLT

o Connections for CLT plates in hybrid steel frame structures

61
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Fire Protection: Research Areas

 Encapsulation (FPI/NRC/CWC)

 Fire Resistance Tests (FPI/NRC: TWBs)

 Surface flammability of mass timber

 Full-Scale CLT Shaft Demonstration Fire (TWBs)

 Composite mass wood-concrete floor systems

 Firestops

 Room fires (Carleton University/NEWBuildS)

14

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14

served. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

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Nailed Laminated Timber (NLT)

15

o Great interest in NLT in Canada

o Applications: floor/roof systems in mid-rise non-res & TWBs

o Used in several landmark projects in Canada & overseas

o Comes in various shapes, configurations and patterns

o Some ongoing testing at FPI including hybrid NLT with

concrete

T3 Minneapolis Office Building

ons. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its ma

http://www.structurecraft.com/projects

62
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Mass Timber Fire Research

16

 Mass timber-concrete composite floors

 2x8 laminated wood deck-concrete

Ɠ truss plates

 5-ply CLT-concrete – 3 h 34 min

Ɠ Self-tapping wood screws at 45o

 Other tests planned for 2015

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Building Envelope/Durability of CLT (NEWBuildS/FPI)

• Characterizing wind-driven rain

load on mid-rise buildings

• Developing durable building

envelope assemblies for CLT

construction

• Drying performance of CLT

63
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Source: Binder

Serviceability Research

o A challenge to designers & occupants in taller buildings (IIC,

STC, floor & building vibrations, etc.)

o Ongoing acoustic, floor & wind-induced vibrations at FPI and

NRC in support of FPI’s Mid-rise Guide & NRCan’s TWBs

o FPI’s on-site measurements and monitoring activities (WIDC)

redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations. 04/11/2015

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What is Happening in Canada 

on the TWBs Front?!! 

64
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Inspiring Modern Tall Wood Buildings 

9-Storey buildings, London, UK

1st storey concrete, 8 storeys CLT 

4 CLT residential buildings/social housing 

@ 9 storeys, Milan, Italy 

2 @ 8 storeys CLT buildings, 

Oslo, Norway

nd logos are trademarks of FPInnovations. 

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WOOD DESIGN INNOVATION 

CENTRE 

MGA

Tallest Modern Timber Building in NA!

Courtesy of Equilibrium

65
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 A request for EOI issued by CWC for design teams to

use innovative design and build high-rise wood demo

projects

 To support the initiative, a “Technical Guide for the

Design and Construction of Tall Buildings in Canada”

was developed by FPI

 Provinces & industry partnered with NRCan

 A few projects were selected and detailed design &

approval by AHJs is underway

22

NRCan’s Tall Wood Demo Buildings 

Initiative (2013) 

of FPInnovations.

detailed design

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 13-storey mass timber (12 + 1 concrete podium)

 800 m2 floor area, 40 m tall

 Incorporates a CLT core

23

 Fire, structural, acoustics, etc.

 Mainly to support the

design/approval process

Origine: Quebec City/Canada 

66
24 © 2013 FPInnovations. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations. 

o 18 Storeys: 1 concrete+ 2 concrete cores supporting 17

storeys of mass timber

o A steel connector allows for a direct load transfer

between the columns and also provides a bearing

surface for the CLT panels.

o Encapsulated CLT and glulam beams

o The floor comprised of 5-ply CLT panels that are pointsupported on glulam columns on a 2.85m x 4.0m grid.

o Mock-up built to verify constructability

UBC Residence TWB

24 © 2013 FPInnovations. All rights reserved. Copying an

UBC TWB Mock-up

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US TWB Prize Competition: 

Winning Buildings (USDA and SLB)

25

475 West 18th Street, New York

Curtsey SLB

Framework, a 12 storeys,

Portland, Oregon

Curtsey SLB

67
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Courtesy of Nordic Engineered Wood 

Use of CLT in Modern Timber Bridges in Canada

Glulam/CLT Box Girder

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Courtesy of Nordic Engineered Wood

27 © 2013 FPInnovations. All rights reserved. Copying and redistributi © 2013 FPInnovations. All rights reserved. Copying and redistribution prohibited. on prohibited. ® FPInnovations, its marks and logos are trad ® FPInnovations, its m gos are trademarks of FPInnovations. marks of FPInnovations.

Hybrid CLT- Glulam Beams

CESM Soccer Stadium in Montreal

68
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 Taller and larger buildings are demanding

more from wood products and systems

 And that is creating new opportunities for new

products and systems both in Canada and the

US

 Continue and enhance joint research ventures

between Canada and the US in support of the

design and construction of taller and larger

wood buildings

28

Final Remarks

69
The U.S. Tall Wood Building Prize Competition and USDA’s Role with Mass 

Timber

Patrick Holmes, Senior Advisor

USDA Office of the Secretary, Washington, D.C.

Through Secretary Tom Vilsack’s Leadership, USDA has launched a series of initiatives aimed at 

advancing commercialization of mass timber technologies and enhancing wood use in the commercial 

and multistory building sectors. New innovations in mass timber and other wood use can help support 

USDA’s goals for rural economic development, improving the health and resiliency of the Nation’s 

forests and enhancing the role of forests and wood products in mitigating the impacts of climate change. 

This presentation will share Secretary Vilsack’s vision; discuss key efforts such as the White House 

Rural Council Workshop: Building with Wood, Jobs and the Environment; and highlight the winning 

projects of the U.S. Tall Wood Building Prize Competition. 

70
71
72
73
Session 1—Resistance to Lateral Loads

Coming Soon: Seismic Performance Factors for Cross Laminated Timber 

Design

John W. van de Lindt, Professor 

M. Omar Amini, Ph.D. Candidate

Colorado State University, Fort Collins, Colorado 

Douglas Rammer, Research General Engineer

USDA Forest Products Laboratory, Madison, Wisconsin

Phil Line, Director, Structural Engineering

American Wood Council, Leesburg, Virginia

Shiling Pei, Assistant Professor

Colorado School of Mines, Golden, Colorado

Marjan Popovski, Principal Scientist

FPInnovations, Vancouver, British Columbia, Canada

Cross-laminated timber (CLT) based Seismic Force Resisting Systems (SFRS) are not yet recognized in 

U.S. design codes, and therefore seismic design can be performed only through alternative methods. The 

purpose of this Forest Products Laboratory funded research project currently underway at Colorado 

State University is to identify seismic performance factors for CLT as a SFRS. The study is based on the 

FEMA P-695 methodology that provides a systematic, logical, and relative approach consisting of 

nonlinear static and dynamic analyses. There are several phases to the project, including development of 

the archetypes, design methodology, testing, modeling, and the full P-695 analysis procedure itself. This 

presentation includes a brief description of the FEMA P-695 methodology along with recent progress on 

the test program. CLT archetypes developed as part of this study and nonlinear models used to simulate 

CLT behavior at the connector, wall, and system levels are presented. Some examples of several 

performance groups within the methodology will be presented in their preliminary form, and the 

procedure to determine the collapse margin ratio will be explained. The timeline to completion has been 

updated and will be provided. 

74
Department of Civil and Environmental 

Engineering

Coming Soon: Seismic Performance Factors 

For Cross Laminated Timber Design 

Oct 30, 2015

M. Omar Amini & John W. van de Lindt

Shiling Pei

Douglas Rammer

Phil Line, American Wood Council

Marjan Popovski, FPInnovations

Project Members

Charlie Kircher, Ph.D., P.E.

Principal and Owner

Charles Kircher & Associates 

J. Daniel Dolan, Ph.D., P.E.

Professor Department of Civil 

and Environmental Engineering

Washington State University

Kelly Cobeen, S.E.

Associate Principal

Wiss, Janney, and Elstner

Associates, Inc.

75
Outline

• FEMA P695 methodology

• Index buildings

– Archetypes

• Testing

• Modeling

• Illustrative example

• Next steps

FEMA P-695: Quantification of Building Seismic 

Performance Factors

• A Methodology that allows a team to identify 

seismic performance factors for a new SFRS.

• The Methodology is consistent with the 

primary “life safety” performance objective of 

seismic regulations in model building codes. 

• Peer review throughout is key

• Archetypes

• Design methodology

• Nonlinear time history analysis

• Performance evaluation 

• CMR 

76
Archetype Development

Design Space

Archetype Configurations

Archetype Designs

Archetype Models

Mathematical idealization of 

the proposed system

Index archetype 

configurations designed and 

detailed using the design 

requirements

Prototypical representation of 

a seismic-force-resisting 

system

Representative of typical 

residential and commercial 

structures in the U.S.

Configuration Design Variables Seismic Behavioral Effects

Occupancy and Use Strength

Elevation and Plan Configuration Stiffness

Building Height Inelastic-deformation Capacity

Structural Component Type Seismic Design Category

Seismic Design Category Inelastic-system Mobilization

Gravity Load

Index Buildings

Index Bldg. Type Stories

1 Single Family (SF) -

2 SF -

3 SF -

4 Multi-family (MF) 4, 6, 8

5 MF 2

6 MF 2

7 MF 3

8 MF 6, 8

9 MF 8, 10

10 MF 8, 10, 12

11 Commercial 8, 10, 12

77
Type : Single Family

Index Bldg. 1

mily

Type : Multi-family

Index Bldg. 4

Stories:4, 6, 8

4

8

78
Type : Multi-family

Index Bldg. 7

Stories: 3

Possibly mixed-use

Type : Multi-family

Index Bldg. 10

Stories: 8, 10, 12

y

10

0, 12

79
Performance groups

Basic configuration

12-15 ft

Aspect ratio

Low

Gravity

Seismic Design Category

Period Domain

High

15-30 ft

30-50 ft

50-100 ft

High

Mixed

Low

Dmax Dmin

Short Long

• Min. of 3 archetype

per performance

group

• Total= 96

performance group

that is 288

archetypes

Performance groups

Group No. 

Grouping Criteria

Archetype description

Basic Config. Design Load Level Period Domain Gravity Seismic

PG-65

30-50 ft

wall

Mixed aspect 

ratio panels

High

SDC Dmax

Short

Index building 1, 3 stories

Index building 4, 4 stories 

Index building 7, 3 stories

PG-66 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-67

SDC Dmin

Short

Index building 1, 3 stories

Index building 5, 2 stories

Index building 7, 3 stories

PG-68 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-69

Low

SDC Dmax

Short

Index building 1, 3 stories

Index building 4, 4 stories 

Index building 7, 3 stories

PG-70 Long

Index building 4, 8 stories

Index building 4, 6 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-71

SDC Dmin

Short

Index building 1, 3 stories

Index building 5, 2 stories

Index building 7, 3 stories

PG-72 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

80
• SDC Dmax only

• Based on the testing Low aspect ratio vs. High aspect

ratio vs. Mixed aspect ratio critical case will be

determined

• Calculating exact gravity loads based on architectural

plans is deemed sufficient by the peer panel and there is

no need to specifically consider low vs. high gravity

• Visual Inspection of some of the archetypes

• Only 8 performance groups are expected to be analyzed

Reducing Archetypes

Performance groups

Group No. 

Grouping Criteria

Archetype description

Basic Config. Design Load Level Period Domain Gravity Seismic

PG-65

30-50 ft

wall

Mixed aspect 

ratio panels

High

Short

Index building 1, 3 stories

Index building 4, 4 stories 

Index building 7, 3 stories

PG-66 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-67

SDC Dmin

Short

Index building 1, 3 stories

Index building 5, 2 stories

Index building 7, 3 stories

PG-68 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-69

Low

SDC Dmax

Short

Index building 1, 3 stories

Index building 4, 4 stories 

Index building 7, 3 stories

PG-70 Long

Index building 4, 8 stories

Index building 4, 6 stories

Index building 8, 8 stories

Index building 9, 10 stories

PG-71

SDC Dmin

Short

Index building 1, 3 stories

Index building 5, 2 stories

Index building 7, 3 stories

PG-72 Long

Index building 4, 6 stories

Index building 4, 8 stories

Index building 8, 8 stories

Index building 9, 10 stories

30-50 ft

wall

Critical aspect Calculated

ratio 

Reduced

Example

SDC Dmax

81
Testing Program 

Test Type Objective

Connector tests • Behavior under cyclic loading

• Interpanel connector behavior

Isolated Wall Tests • Boundary condition

• Gravity loading

• Connector thicknesses

• Connector type

• CLT panel thickness

• Connector thickness

• CLT panel aspect ratio

• Inter-panel connector (vertical joint)

• CLT grade

Box type 

configuration 

• Effect of diaphragm on wall behavior

• Diaphragm behavior

• Effect of out-of-plane loading on the connector

• Effect of bi-directional loading

• Holddowns in the corners

• Stability of the walls

Box type 

configuration with 

multiple panel 

walls

• Effect of out-of-plane loading on the connector

• Effect of bi-directional loading

• Holddowns in the corners

• Stability of the walls

• Vertical joints between perpendicular walls will also be 

investigated

3-sided wall with a 

diaphragm

• Effect of diaphragm rotation 

• Combined loading on the connectors

Testing Program 

82
Testing Program 

Testing Program 

83
• 16-parameter hysteretic model

• Developed at CSU and TAMU

• It allows more adaptive modeling of the degradation

behavior of the wood shearwall components

Modeling

Backbone curve for EPHM hysteresis Degradation of loading paths

(Pang et al, 2007; Pei and van de Lindt, 2009)

Illustrative example

Extraction of 

archetypes for PG 65

Archetype 65-1

84
Archetype 65-2

Illustrative example

Archetype 65-3

Illustrative example

85
Illustrative example

ELF Design Methodology Modeling

Nonlinear Analysis

Static pushover and dynamic 

analysis

Obtain parameters for the 

walls and model the building 

using SAPWood

Design the archetype model 

using the design methodology

Obtain shear forces for the 

archetype model

ar Analysis

using SAPWood

Performance evaluation

CMR and ACMR

p

Illustrative example

Archetype 65-1

86
Illustrative example

Archetype 65-2

Illustrative example

Archetype 65-3

87
Illustrative example

-6 -4 -2 0 2 4 6 -10

-8

-6

-4

-2

0

2

4

6

8

10

Displacement (in)

Force (kip)

Test

16 par. fit

Note: Scaled results

Illustrative example

-6 -4 -2 0 2 4 6 -20

-15

-10

-5

0

5

10

15

20

Displacement (in)

Force (kip)

Test

16 par. fit

88
Illustrative example

-6 -4 -2 0 2 4 6 -20

-15

-10

-5

0

5

10

15

20

Displacement (in)

Force (kip)

Test

16 par. fit

Illustrative example

-6 -4 -2 0 2 4 6 -25

-20

-15

-10

-5

0

5

10

15

20

25

Displacement (in)

Force (kip)

Test

16 par. fit

89
Illustrative example

-8 -6 -4 -2 0 2 4 6 8

-8

-6

-4

-2

0

2

4

6

8

Displacement (in)

Force (kip)

Test

16 par. fit

Illustrative example

ȳ = ܸ௠௔௫

ܸ = 3.03

௢ܥ = ௙௙௘,௬ߜ

ܸ௠௔௫

ܹ

݃

4ߨଶ כ max T, ܶଵ

ଶ = 4.42 ݅݊.

௥,ଵ௢ = ߶ܥ

σ ݉௫߶ଵ,௫

ே

ଵ

σ ݉௫

ே

ଵ ߶ଵ,௫

ଶ

Ɋ் = 6.6 ݅݊.

4.42 ݅݊.

= 1.5

݁ܿݏ 0.66 = ଵܶ

݁ܿݏ 0.36 = T

Archetype 65-1

0 1 2 3 4 5 6 7 8 9 10 0

5

10

15

20

25

30

35

40

45

50

Roof drift (in)

Base Shear (kip)

V=15.44 kip

0.8 Vmax

Vmax=46.8 kip

Gu= 6.6 in.

90
Illustrative example

Archetype 65-2

ȳ = ܸ௠௔௫

ܸ = 2.29

௢ܥ = ௙௙௘,௬ߜ

ܸ௠௔௫

ܹ

݃

4ߨଶ כ max T, ܶଵ

ଶ = 4.21 ݅݊.

௥,ଵ௢ = ߶ܥ

σ ݉௫߶ଵ,௫

ே

ଵ

σ ݉௫

ே

ଵ ߶ଵ,௫

ଶ

Ɋ் = 7.7 ݅݊.

4.21 ݅݊.

= 1.83

݁ܿݏ 0.74 = ଵܶ

݁ܿݏ 0.44 = T

0 1 2 3 4 5 6 7 8 9 10 0

5

10

15

20

25

30

35

40

45

Roof drift (in)

Base Shear (kip)

Gu= 7.7 in.

0.8 Vmax

V=17.8 kip

Vmax=40.8 kip

Illustrative example

Archetype 65-3

ȳ = ܸ௠௔௫

ܸ = 2.61

௢ܥ = ௙௙௘,௬ߜ

ܸ௠௔௫

ܹ

݃

4ߨଶ כ max T, ܶଵ

ଶ = 3.49

௥,ଵ௢ = ߶ܥ

σ ݉௫߶ଵ,௫

ே

ଵ

σ ݉௫

ே

ଵ ߶ଵ,௫

ଶ

Ɋ் = 5.4 ݅݊.

3.49 ݅݊.

= 1.55

݁ܿݏ 0.67 = ଵܶ

݁ܿݏ 0.36 = ܶ

0 2 4 6 8 10 12 14 16 0

10

20

30

40

50

60

Roof drift (in)

Base Shear (kip)

0.8 Vmax

Gu= 5.4 in.

V=21.5 kip

Vmax=56.2 kip

91
0 1 2 3 4 5 6 7 0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Maximum Story Drift (%)

ST (g)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Probability

Sa (g)

Illustrative example

்஼ܵ = ܴܯܥ

ܵெ்

= 3.͸ͷ݃

1.ͷ݃ = 2.4

2.64 = 2.4 כ 1.1 = ܴܯܥ כ ܨܵܵ = ܴܯܥܣ

5

SCT=3.65 g

Archetype 65-1

SMT=1.5 g

SCT=3.6 g

0 1 2 3 4 5 6 7 0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Maximum Story Drift (%)

ST (g)

Illustrative example

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Probability

Sa (g)

்஼ܵ = ܴܯܥ

ܵெ்

= 3.ͷ݃

1.ͷ݃ = 2.33

2.57 = 2.33 כ 1.1 = ܴܯܥ כ ܨܵܵ = ܴܯܥܣ

Archetype 65-2

3.5

SCT=3.5 g

SMT=1.5 g

SCT=3.5 g

92
Illustrative example

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Probability

Sa (g)

0 1 2 3 4 5 6 7 0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Maximum Story Drift (%)

ST (g)

்஼ܵ = ܴܯܥ

ܵெ்

= 2.ͻ݃

1.ͷ݃ = 1.93

2.12 = 1.93 כ 1.1 = ܴܯܥ כ ܨܵܵ = ܴܯܥܣ

SCT=2.9 g

5

SMT=1.5 g

SCT=2.9 g

Archetype 65-3

Illustrative example

ߚ்ை் = ߚோ்ோ

ଶ + ߚ஽ோ

஽்ߚ + ଶ

ଶ + ߚெ஽௅ଶ = 0.66

0.4 ൑ ்ߤ כ 0.1 + 0.1 = ோ்ோߚ

0.26 = 1.6 כ 0.1 + 0.1 = ோ்ோߚ

On average for 

performance group

For any one 

archetype

ݏݏܲܽ ֜ 2.38 < 2.44 = ܴܯܥܣ ݃.ݒܣ

93
Illustrative example

Overstrength Factor

The value of the system overstrength factor, ȍo, for use

in design should not be taken as less than the largest average value 

of calculated archetype overstrength, ȍ, from any performance group

Deflection Amplification Factor

Inherent damping may be assumed to be 5 percent of critical, and a 

corresponding value of the damping coefficient, BI = 1.0

• Wall assembly with a diaphragm

– Low aspect ratio panels

– High aspect ratio panels

– 3 sided with an opening on one side

• Finalizing analyses

• Report submittal to the peer panel

Next Steps

ide

anel

94
Acknowledgements

This study is funded by a joint venture agreement between the United 

States Department of Agriculture Forest Products Laboratory (FPL) 

and Colorado State University. That support is gratefully

acknowledged.

Thank you!

95
Performance of Mass Timber Structures under Lateral Loads: 

The Canadian Experience

Marjan Popovski, Principal Scientist

FPInnovations, Vancouver, British Columbia, Canada

In the past 20 years, mass timber (MT) products have emerged as cost competitive, carbon efficient, 

sustainable, and reliable structural components for use in residential and nonresidential applications. 

They can complement existing light-frame and heavy-timber systems or can be used in new innovative 

construction applications that are currently dominated by concrete, masonry, and steel. MT has also 

given the opportunity to wood as a structural material to be used in tall buildings once again. To use 

these new MT-based structural systems in regions with high wind and seismic loads, a comprehensive 

investigation of their performance under lateral loads is needed. This presentation will summarize some 

of the research activities and findings related to the performance of MT-based structural systems under 

lateral loads in Canada.

Performance of Mass Timber 

Structures under Lateral Loads: 

The Canadian Experience 

Madison, WI 

November 02, 2015

Marjan Popovski, Ph.D., P.Eng.

Principal Scientist

Advanced Building Systems Department FPI

Adjunct Professor, Department of Wood Science UBC

96
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Introduction

 Mass Timber Construction (MTC) offers a wide range of

advantages compared to other types of construction

 Possibility for use of MT products in Lateral Load Resisting

Systems (LLRS) with adequate response to earthquakes or high

winds

 Presentation will cover some of the research activities in Canada

on this topic

 CLT was by far most used MT product in the research projects

2

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The Research on MT as LLRS in Canada 

 In 2007/08, FPI launched its first research program on CLT,

part of it related to performance of CLT as LLRS

 In 2010, the NSERC, FPI and NRCan have partnered to

create the NEWBuildS, a multi-disciplinary strategic research

Network for Engineered Wood-based Building Systems

Ɠ 23 Professors and 17 Researchers from FPI, NRC and CWC

Ɠ 60 graduate students and PDFs from 11 Canadian universities

Ɠ 2 out of 4 themes of the network dealt with MT

• CLT and second

• Hybrid Systems

3

97
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CLT Walls as LLRS: Configurations Tested

4

I II III IV V

VI VII VIII

IX

X

XI

V

ons, its marks and logos are trad

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Examples of Test Results

5

-120

-90

-60

-30

0

30

60

90

120

-120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120

Total Displacement [mm]

Load [kN]

CLT Wall CA-SNH-08A

2.3m x 2.3m CUREE

4 A Brackets + HTT-16( n=18; 12d nails)

18 SN 16d, D=3.9 mm, L=89 mm

-120

-90

-60

-30

0

30

60

90

120

-120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120

Total Displacement [mm]

Load [kN]

CLT Wall CS-WT-22

2.3 m x 2.3 m CUREE

18 SFS WT-T Screws D=6.5 mm 

L=130mm

98
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Examples of Test Results

6

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Tested CLT House

 6.0 m x 4.8 m in plan

 H = 4.8 m

 Platform construction with

94mm thick panels

 Symmetric in E-W direction

 Non-symmetric in N-S

 13.6 kN dead load/level

 Seismic design according

to NBCC for Vancouver, BC

(Rd = 2.0; R0 = 1.5)

7

4.8 m

99
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Plan and Elevation

8

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Objectives

 Deformability of the 3-D CLT structure

 Storey drifts that can be sustained

 Failure mechanisms

 Effects of wall openings on the response

 Performance of diaphragms

 Effects of perpendicular walls and hold-downs on resistance

and deformability

9

100
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Lateral Loading and Protocols

 Loads applied on each storey,

one direction at a time

 ISO 16670 cyclic loading

protocol

10

-150

-100

-50

0

50

100

150

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

Displacement [mm]

Time [s]

House Test 05

Loading protocol

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Testing Program

Test Type Direction Loading Rate Changes in the 

Specimen

01 Monotonic E-W (L) 5.1 mm/min until 72 mm (1.5% of 

total house height H)

02 Cyclic E-W (L) 2.5 mm/s to 60mm (1.25% H)

03 Cyclic E-W (L) 2.5 mm/s to 84 mm (1.75% H) Additional 

Hold-Downs

04 Cyclic N-S 2.5 mm/s until 108 mm (2.25% H) With Additional H-D

05 Cyclic N-S 2.5 mm/s until 108 mm (2.25% H) 64% less wall-to 

wall screws

11

101
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Global Response

12

 Combination of sliding and uplift

deformations

 Walls with openings had higher inplane deformation (some torsion in

Tests 04 and 05 N-S)

 More deformation in the first storey

(max drift 3.2%)

 Structural integrity was not

compromised at failure

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Diaphragm Behaviour

13

 Negligible slip between diaphragm

panels (max 1.7 mm)

 Rigid diaphragm behaviour (midspan deflection only 14% of that of

the walls below)

 Out-of-plane bending helped the

wall rocking at lap-joints

102
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E-W vs N-S Performance (Test 03 vs Test 04)

 Only 2.5% difference in resistance

 Higher deformability in N-S (2.2% vs 1.8% storey drift) due to:

Ɠ Wall openings

Ɠ Higher building aspect ratio (rocking component)

14

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Less screws in Perpendicular Walls

(Test 05)

15

 Did not reduce the resistance

 Increased the slip between walls (max. 6.2 mm)

 Increased the house flexibility (3.2% vs 2.3% drift)

103
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Deformability Components

16

 Total storey deformation i tot i g i r i s i w , , ,,, G GGGG 

Test 

No.

1st Storey 2nd Storey Total

Deflection 

Gtot [mm] Rocking

G1,r [%]

Sliding

G1,s [%]

In-plane

G1,w [%]

Rocking

G2,r [%]

Sliding

G2,s [%]

In-plane

G2,w [%]

03 16.0 39.5 6.9 6.3 9.9 5.4 73.7

04 26.6 21.4 14.9 2.7 5.4 2.4 86.2

05 26.8 28.3 10.8 2.2 3.3 1.8 109.6

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Failure Mechanisms

17

 Almost all damage at the bottom storey

 Yielding of screws in step-joints

 Nail withdrawal in the hold-downs

 Shear and withdrawal failure of

nails in the brackets

Withdrawal Shear

104
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Preliminary Force Modification Factors 

(Rd-factors)

 2015 NBCC has two R-factors

Ɠ Ro-factor, over-strength

Ɠ Rd-factor, ductility

 Analytical study was done with

CSU and CSM to quantify

preliminary Rd-factors for

symmetrical platform type

CLT structures

18

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Analysed Building Models

 Buildings with 3 heights

Ɠ 6 storey

Ɠ 10 storey

Ɠ 15 storey

 Designed according to NBCC

2010 ESF Procedure

Ɠ Vancouver, BC with Sa =0.743g

Ɠ Ro = 1.5

 Rd from 1.5 to 4.0 (to 6.0 for 6 storey)

 48 six-storey CLT buildings

 Six 10-storey and 15-storey buildings

 Total of 60 buildings analyzed with SAPWood

19

105
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CDF for 10 storey CLT Building

20

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Rd-factors for Different Buildings and 

Performance Targets

 Minimum Rd factor is 2.0

21

Performance Targets

Storey Drift [%] with PNE [%] 6 Storey 10 Storey 15 Storey

1.5% with 50% PNE 2.5 3.5 4.0

2.0% with 80% PNE 2.0 3.0 4.0

2.5% with 80% PNE 2.5 3.5 4.0

4.0% with 80% PNE 2.5 4.0 4.0

106
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In-plane Stiffness of CLT Panels: 

Experimental Programme

 CLT Panels Tested at FPInnovations, Quebec

 CLT beams were 1.2m high and 5-ply (175mm) thick

 6 panels from each length of 3.6m (12'), 6.1m (20'), and

8.5m (28') were tested

22 marks of FPInnovations.

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Finite Element Analyses 

 FE models of CLT panels and walls were developed in ANSYS

 UBC + FPI (Shahnewaz Md, T. Tannert, M. Popovski)

Ɠ CLT panels modelled using Solid Elements

Ɠ Glue line between lamellas modelled using Contact Elements

Ɠ Connections in CLT walls modelled using Spring Elements

23 os are trademarks of FPInnovations. 

g p g

107
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Comparison of Experimental vs 

Analytical Results

24

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Walls With Openings

 Stiffness decreased linearly with an increase in opening area

 Analytical model to calculate the in-plane stiffness of CLT

walls with opening was proposed

25 ht d C i d di t ib ti hibit d ® FPI ti it k d l t d k f FPI

(/) 1

1.15 ( / )

O P

O P

O P

A A k k

A A

a o  « » ¬ 1⁄4 

kO & kP wall stiffness with and without opening

AO & AP area of walls with and without opening

108
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Helping FFTT Concept Become Reality

 Experimental and analytical work to quantify performance of

FFTT under lateral loads (UBC + FPI)

(X. Zhang, M. Popovski, T. Tannert)

26

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Tests on Novel HSK Hold-downs

27

 Static Test

 Cyclic Test

-100

-80

-60

-40

-20

0

20

40

60

80

100

-8 -6 -4 -2 0 2 4 6 8

Force(kN)

Displacement(mm)

Cyclic-Long-Parallel(one row of duct tape)

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Force(kN)

Displacement(mm)

Long HSK test(one row of duct tape)

Static-L-perpendicular-1

Static-L-perpendicular-2

Static-L-parallel-1

Static-L-parallel-2

109
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R-factors for FFTT

 Buildings Considered with 3 , 6 , 9, 12 storeys

 Ro=1.5; Rd=1.5 to 6.0

28

Layout and first mode shape for FFTT System Option-1

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Model and Preliminary Results

29

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.5 1 1.5 2 2.5 3 3.5 4

Empirical Cumulative Distribution Function 

Inter-storey Drift (%) 

Rd=1.5

Rd=2

Rd=2.5

Rd=3

Rd=3.5

Rd=4

Rd=4.5

Rd=5

Rd=5.5

Rd=6

OpenSeas Model

110
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NEWBuildS Tall Wood Design Project

 Goal: To execute the design process of a 20-storey tall hybrid

mass timber building located in North Vancouver, BC

 Chapter 3 Lateral Load Design

(Z. Chen, Y. Chui, M. Popovski)

30

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Model and Analyses

31

Model in Abacus 3rd Mode Shape Pushover Analysis

111
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Example of LDA Results

32

0 100 200 300 400 500

0

5

10

15

20

Number of Storey

Lateral Drift, mm

Xi

XiRdRo/I

E

0 5 10 15 20 25 30

0

5

10

15

20

Number of Storey

Inter-Storey Drift, mm

xi

xiRdRo/I

E

Elastic and Non-Linear Deflection Elastic and Non-Linear Storey Drifts

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Damage Accumulation of CLT Structures

33

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500

Damage factor [-]

Time [s]

 UBC + FPI (J. Schneider, S. Tesfamariam, M. Popovski)

112
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Comparison of the Connection Tests

34

a) Spiral Nail 3.8 x 89 mm

b) Ring Shank Nail 3.4 x 76 mm

c) Ring Shank Nail 3.8 x 60 mm

d) Self tapping Screw 5 x 90 mm

e) Self tapping Screw 4 x 70 mm

Bracket A Bracket B

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Use of Innovative Connectors in CLT

 Collaboration UBC Okanagan + FPI

 (J. Schneider, S. Tesfamariam, M. Popovski)

35

113
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Steel Frame-CLT Hybrid System

 Combination of steel moment frame and infill CLT panels

connected with brackets to the frame

 Optimize the system performance, determine the R-factors

for such systems, produce design guidelines

 UBC Okanagan + FPI (M. Bezabeh, S. Tesfamariam, M. Popovski)

36

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Concluding Remarks

 Mass Timber Structures in platform-type or balloon

construction can achieve limited damage under strong

earthquake when properly designed

 The type of fasteners and connections used, selection of

"dissipative zones", aspect ratios of CLT walls and wall

segments among others influence the performance under

seismic loads

 Further research in the area is needed and will be discussed

during the Workshop

37

114
www.fpinnovations.ca

Follow us on

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Thank you

For more information contact:

marjan.popovski@fpinnovations.ca FPI Members

115
Updates and Results from NEES–CLT Planning Project

Shiling Pei, Assistant Professor

Colorado School of Mines, Golden, Colorado

As urban densification occurs in regions of high seismicity, there is a demand for tall buildings that are 

seismically resilient, economically viable, and have less negative environmental impact. In urban 

regions on the west coast of the United States, specifically the Pacific Northwest, there is significant 

interest in utilizing cross laminated timber (CLT) in 8- to 20-story residential and commercial buildings 

using locally sourced, sustainable, and economically competitive building material. This presentation 

will introduce preliminary results from the NEES-CLT Planning Project that concludes September 2015, 

which is aimed at developing and testing CLT lateral systems that may be implemented in future tall 

CLT buildings in regions with large lateral loading. A series of tests, including two types of CLT lateral 

systems, were performed at Washington State University’s Composite Materials and Engineering 

Laboratory, including a self-centering rocking wall system and a deformable floor diaphragm system. 

Numerical models for both systems were also developed to study the sensitivity of system performance 

to design parameters. The project team is in process of refining the analysis and the design approach and 

is proposing full-scale experimental validation of the tall resilient timber building concept in high 

seismic regions.

Updates and Results from NEES-CLT Planning 

Project 

Shiling Pei 

Colorado School of Mines 

John van de Lindt 

Colorado State University 

Hans-Erik Blomgren 

Michael Willford 

Arup 

Jeffrey Berman 

Ryan Ganey 

University of Washington

Richard Sause 

Lehigh University 

Douglas Rammer 

Forest Products Lab 

James D. Dolan 

Washington State University 

James Ricles 

Lehigh University 

Marjan Popovski 

FP Innovations 

116
NEES-CLT Planning Project 

• Objective: Conduct technical preparation for enabling design and 

testing of 8-20 story resilient CLT buildings 

• Website: NEESCLT.mines.edu 

Shiling Pei Dan Dolan James Ricles Richard Sauce Jeffrey Berman John van de Lindt 

Marjan Popovski Michael Willford Hans-Erik Blomgren Douglas Rammer 

Plan and Vision 

Performance Objectives Resilient CLT lateral 

elements Prep PBSD Procedure 

Full scale system level 

validation 

PBSD Procedure 

Finalized 

Enable 8-20 story resilient CLT building in high seismic regions in the U.S. 

2014-2016 2016-2019 2020 

System Level Modeling 

117
A Brief History of CLT Seismic Research 

CLT 

Invented 

in early 

1990’s 

Research in 

Slovenia 

and 

Macedonia 

Wall tests, 

Shake table test 

of wall 

assembly 

Trento 

Province, Italy 

SOFIE project 

Over strength factor, Numerical modeling 

methods, q factor 

Canada/US 

Research on 

CLT 

FPInnovations 

Forest 

Products Lab 

CLT handbook 

Estimation of R factor for 

NBCC and ASCE7 

Seismic Retrofit 

(NEESSoft) 

NEES CLT Planning 

Resilient Timber systems in NZ 

Wall tests, 

Shake table 

tests at NIED 

3-story, 7-story 

P695 on CLT shear 

wall 

Resilient CLT 

systems 

CLT 

Building 

tests 

in 

Japan 

So far, for CLT system similar to this! 

Tall CLT Building Workshop 

• January 2014, Seattle: Learn from

practitioner and end-user

communities

• About 60 Participants

• Agenda: Societal needs, Performance

expectations, Engineering challenges

• All workshop documents available

at NEESCLT website

• White paper

• All presentations

• Research progresses

NEESCLT.mines.edu 

118
Challenges for CLT in U.S. 

• First-cost still dominates decision making

for adopting CLT

• Other traits (energy, carbon sequestration)

adds to value but not as decisive

• Not cost competitive (first cost) at lower

height

• Other Challenges:

• Fire related code provisions

• Lack of experience in construction and

design

• Local jurisdiction buy-in

Performance Expectations 

• Not necessarily the higher the better. Balance of performance and cost

• A three-tiered performance expectations for tall CLT buildings

119
Try Two Resilient Systems 

• Adding ductility and energy dissipation

• Remain damage free at large deformation

CLT Rocking Wall Tests at WSU 

• Goal: Understand the behavior of

rocking CLT walls

• Wall Parameters of Interest:

– PT bar area

– PT bar initial stress

– Rocking base type

– CLT panel type

– Single vs. coupled panel

5 PLY CLT PANEL 

CLT PANEL WITH 

SCL CORE 

Vdec

Kdec

Vmax

V 

120
The Test Matrix 

- Low Vdec 

- Low Kdec

- Low Vdec 

- High Kdec

- High Vmax

- High Vdec 

- Low Kdec

- CLT Base 

- Same PT bar 

properties as 

Specimen 3 

- CLT panel with 

SCL core 

- High Vmax

- Same initial 

stress as 

Specimen 3 

- Coupled wall 

with UFPs 

- Same PT bar 

properties as 

Specimen 3 

1.58 sq in 

0.1 Fpu 

0.85 sq in 

0.2 Fpu 

1.25 sq in 

0.4 Fpu 

Test Setup 

121
Specimen 3 - High Vdec and Low Kdec

Specimen 3 - High Vdec and Low Kdec

Uplift observed at 

0.5% drift 

122
Specimen 3 - High Vdec and Low Kdec

First CLT damage 

observed at 3.8% drift 

࠱

ʍ

ʍy

E

Specimen 3 - High Vdec and Low Kdec

PT bar yielded at 

4.8% drift 

CLT damage at 

9.5% drift 

123
Spec. 2/Spec. 3 Comparison 

Vdec

Kdec

Spec. 3/Spec. 4 Comparison 

Kdec

CLT base 

post test 

124
Spec. 3/Spec. 5 Comparison 

Vmax

At 4.8% Drift: 

- Large Core split - 

PT bar yielded 

Specimen 6 – Coupled Wall 

Yielding of UFP first 

observed at 1.6% Drift 

125
• Predicts strength and

stiffness well

• Fairly good at

predicting CLT

damage

• Does not capture PT

losses due to seating

at top of wall

Experimental-Numerical Comparison 

What did we learn from rocking wall tests 

• CLT Rocking Wall Design Procedure

– The proposed seismic design procedure for tall timber buildings

resulted in CLT walls with adequate performance

• Experimental Program

– Rocking CLT panels have good ductility

– A hierarchy of desirable limit states was identified (UFP yielding, CLT

crushing, PT yielding)

– Variability in CLT materials is a concern for design

• Numerical Model

– Relatively simple nonlinear model was able to represent the test data

– Implementation of the model for tall CLT buildings showed the design

procedure can meet the performance objectives

• More research needs to be conducted for the system to be

implemented

126
Inter-story Isolation 

• Test on-going at WSU

Summary 

• Current way of CLT construction: Great for life-safety, will see

expensive damage during major earthquakes

• A road map proposed for Tall CLT in U.S. seismic region by 2020

• Two types of resilient CLT component tested during NEES-CLT

Planning, showing great potentials.

• Research Team planning for full scale system level validation of

resilient CLT design.

127
What’s Next? 

Testing a Full-scale Ten-story CLT Building on UCSD Shake 

Table (working on it) 

Shiling Pei spei@mines.edu 

Jeffrey W Berman jwberman@myuw.net

Dan Dolan jddolan@wsu.edu

128
The Heavy Timber Buckling Restrained Braced Frame System as a Solution 

for Commercial Construction in Regions of High Seismicity

Hans-Erik Blomgren, Structural Engineer/Associate 

Jan-Peter Koppitz, Associate 

Abel Díaz Valdés, Senior Structural Analyst

ARUP, Seattle, Washington 

Wood construction has been traditionally utilized to reduce inertial demands in high seismic regions. 

However, applications are often limited to low-rise buildings of light-wood construction. Recent 

advancements in timber technologies are pushing mass timber systems into larger commercial scale 

markets where steel and concrete systems currently dominate the landscape. In high seismic regions, 

however, timber buildings currently lack code-defined lateral force resisting systems. This paper 

presents a new concept of a seismic force resisting system known as the Heavy Timber Buckling 

Restrained Braced Frame. The system is intended, although not limited, for application for tall building 

timber construction and is inspired by the unbonded brace technology today widely spread throughout 

Japan and the United States. To prequalify the system for future implementation in building codes, this 

paper first addresses component testing of a brace consisting of a steel core and a mechanically 

laminated glulam assembly acting as the buckling restraint mechanism. Test results are discussed, and 

implementation at the system level in an archetype building is addressed, in order to assess overall 

system performance, constructability, and detailing.

Heavy Timber Buckling-Restrained 

Braced Frames

A proposed solution for buildings in regions of high seismicity

Hans-Erik Blomgren PE SE P.Eng. Struct.Eng.

Mass Timber Research Workshop, November 3, 2015

Session 1: Resistance to Lateral Loads

Forest Products Laboratory, Madison Wisconsin

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129
2

Heavy Timber Braced Frames

- Current code

- System attributes

- Precedents

The Heavy Timber BRBF concept

- BRBF primer

- Component testing

- System level evaluation

Conclusion

Outline

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3

IBC 2012 (ASCE 7-10)

BCBC 2012

Current Code Definitions

Codes

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Rd Ro Height Limits (m)

R Ωo Cd Height Limits (ft)

130
4 Load Slip Relationship of Fasteners

© Arup North America Ltd. Distribution and Reproduction By Permission Only

Dowel type fastener

Attributes of Wood in Seismic Systems

5 Hysteresis of Light Wood Framed Shear Walls (Source: FEMA)

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Attributes of Wood in Seismic Systems

131
6

Advantages

- High strength/weight ratio (low mass)

- High short term load strength

Disadvantages

- Brittle failure modes exist

- Localized damage at post-yield (pinched hysteresis)

- Concentrated locations of limited ductility (fasteners)

- Ductile connections = low stiffness

Attributes of Wood in Seismic Systems

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Heavy Timber Braced Frame Precedents

132
Braced Frames – Side Plates & Bolts (Source: Cal Poly)

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Heavy Timber Braced Frame Precedents

Braced Frames – Dowel and Flitch Plates (Source: Structurlam)

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Heavy Timber Braced Frame Precedents

133
Braced Frames – Dowel & Flitch Plates (Source: Sweco)

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Heavy Timber Braced Frame Precedents

The BRB - Primer

134
12

Buckling-Restrained Braced Frame Primer

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13

Buckling-Restrained Braced Frame Primer

© Arup North America Ltd. Distribution and Reproduction By Permission Only

135
14

Current Code:

• AISC 341-10

- Section F4 – Design

Provisions

- Capacity based philosophy

- Section K3 – Testing 

Qualifications

- Component

- Subassembly

Buckling-Restrained Braced Frame Primer

R Ωo Cd

© Arup North America Ltd. Distribution and Reproduction By Permission Only

The HTBRB

136
Heavy Timber Buckling-Restrained Brace

© Arup North America Ltd. Distribution and Reproduction By Permission Only

HTBRB Construction

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BRB Specimen Capacity = 100k

137
18

HTBRB Component Level Test Requirements

ȕ

Δbm

2.2

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HTBRBF System Level Evaluation

138
20

HTBRBF System Level Study

Archetype Building Dimensions

X

Y

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21

HTBRBF System Level Study

Archetype Building Column Sizes

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139
22

HTBRBF System Level Study

Archetype Building BRB Sizes

BRB Core Areas

(Fy = 42ksi) BRB Sizes

© Arup North America Ltd. Distribution and Reproduction By Permission Only

89kip

65kip

135kip

23

HTBRBF System Level Study

Seismic Design Parameters – Linear Response Analysis

Site Class C Ie 1.0 R 6 W 6,247k

Sds 0.66 SDC D Cd 5 Cs 0.055

S1 0.39 β 5% Ωo 2.5 V 290k

Code Period

Analysis 1st Period

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Analysis 2nd Period

1st Mode = 1.77s

Mass Part. = 73%

2nd Mode = 0.57s

Mass Part. = 18%

140
24

HTBRBF System Level Study

Story Drifts – Wind & Seismic

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H/500

25

HTBRBF System Level Study

HTBRB Forces

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141
26

HTBRBF System Level Study

HTBRBF Column Forces

24x24 GL Column 

φPn = 2570k

3.75” dia A354 Rod 

φTn = 1014k

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27

HTBRBF System Level Study

Wind Acceleration (Occupant Comfort – ISO 10137)

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ISO 10137 Wind Acceleration

142
Conclusion

• There is a need for code-defined heavy timber seismic systems

• The HTBRBF is a possible solution b/c:

• An extension of codified AISC 341 steel BRBF system

• Easy to analyze

• High strength, stiffness, & ductility (win-win-win)

• Limited irrecoverable timber damage

• Potential for rapid application near-term (PBD – ASCE 41-13)

• Sub-assembly test needed

• Economic/constructible frame details needed

• Start USA code definition

• P-695

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29

143
CLT Diaphragm Research and Design in North America

Scott Breneman, Senior Technical Director

WoodWorks, Deer Park, Washington

This presentation will discuss the state of knowledge for cross laminated timber diaphragms for the U.S. 

project design environment. Emphasis will be given to the importance of diaphragm deflections linked 

to North American research, testing planned, and in progress. 

CLT Diaphragm 

Research and Design 

in North America

Scott E. Breneman, PhD, PE, SE

Senior Technical Director

WoodWorks – Wood Products Council

Photo Ema Peter Photography

USDA Forest Products Lab

Mass Timber Workshop

November 3rd, 2015

144
Diaphragm Design 

• Diaphragm: Roof, floor transferring lateral forces to the

vertical resisting elements

• Diaphragm loads are generally uniform loads, resisted by

the diaphragm in bending, similar to a horizontal deep

beam

• Diaphragm bending results in tension/compression in

chords perpendicular to load

NIST NEHRP Wood Education Institute

New Chapter 10 covering Adjustment Factors for CLT

Formatting Similar to Wood Structural Panels

CLT in NDS 2015 – Panel Strength

145
ANSI/APA PRG 320 Product Reports

Does not include In-plane Panel Shear Strength

ICC-ES Acceptance Criteria AC 455

Defines In-plane Panel Shear Strength 

Test for use in Floor and Roof Decks

146
Connectors for CLT in NDS 2015:

Dowel Type Fasteners, e.g. Lag Screws, Bolts and Nails

CLT in NDS 2015 - Connectors

Panel + Connection = Diaphragm ? 

• WSP Diaphragms based on system testing

• WSP Diaphragms capacities listed in AWC’s

Special Design Provisions for Wind and

Seismic

Need for System Level Diaphragm Strength Verification 

147
CLT Diaphragms for Seismic

Seismic behavior is not simple question of force

demands and capacity.

Seismic design uses force as a proxy for EQ 

behavior

An European Approach

Yielding Connections

Non Yielding Connections

Designed to Overstrength

factor of 1.3 to 1.6 of 

yielding connection strength

Fragiacomo, Vasallo et al.

Typical Assumption of Rigid 

Diaphragm Behavior for CLT wall 

and floor systems

148
US CLT Handbook Approach

Yielding Connections

Non Yielding Connections

(Anchorage to Support)

• NDS Yield Modes III and IV govern.

• Strength of other (non-yielding) limit

states at connection designed to

nominal yielding connection capacity.

1/ࢥ = 1/0.65 = 1.54 overstrength factor

Design Example White Paper

149
Diaphragm Design Example

Lateral load, w

Shear Wall

CLT Panels

Design Example White Paper 

• Shows calculations for simple diaphragm

following US CLT Handbook

Recommendations with many limit states.

• Presented modification of WSP diaphragm

deflection calculation for large Panels

૜ࡸ࢜૞ = ࢇ࢏ࢊࢾ

+ ࢃ࡭ࡱૡ

ࡸ࢜

࢚࢜࢜ࡳ૝

ࢉઢ࢞ σ + ࢔ࢋࡸ࡯ +

ࢃ૛

૚ = ࡯

૛

૚

ࡸࡼ

+

૚

ࢃࡼ

PL is panel length

PW is panel width

150
FEM Modeling for Design Work

• Semi-Rigid Analysis of Diaphragm in SAP 2000

• Modelled to match design example assumptions

• Concentrated Connection Model

• 4 Springs per corner

• With No Chord Slip, 4% difference in deflections

• With Chord Slip, 11% difference in deflections

Research In Progress

University of British Columbia:

• Prof. Thomas Tannert

• Afrin Hossain, PhD Candidate

Cyclic Testing Results Available Soon?

151
Research In Progress

Colorado State University

• John van de Lindt

• Planning small full-scale

diaphragm test

Research in Progress

Oregon State University:

• Rakesh Gupta, Lech Muszinsky, Andre

Barbosa. CLT connections, etc.

University of British Columbia, Vancouver

• Terje Haukaas, Frank Lam. CLT connections,

CLT Diaphragm Modelling.

And More?

152
• Testing, Testing, Testing:

- Continue connection level testing

- Cyclical Testing of Proprietary connectors

- Diaphragm Testing paired with Analytical Studies

- Chord Design and Detailing.

• Refinement of Engineering Design Approach

• Collaboration of researchers, industry, and practitioners

• Standardization of Developed of Design Method

- Code referenceable engineered design standards for capacity 

design method

- Possibly new testing protocols for panel and connection behavior

• Education of designers for proliferation of use.

Ideas for Design Standardization

• Possible routes for near term seismic project designs under

Alternative Means and Methods include

1) Elastic Design Method

• Based on lower-bound strength of components

• Following new ASCE 7-16 alternative diaphragm method to

determine elastic seismic diaphragm force demands

2) Capacity-Based Design Method

• Using designated yielding connections with overstrength

design of non-desirable limit states.

• Based on yielding connection technologies of proven cyclic behavior

 Relatively equivalent to Wood Structural Panel diaphragm

behavior OR

 Advanced Engineering with supporting testing to justify design

Ideas for Near Term Seismic Projects

153
CLT Diaphragm Scenarios

CLT Shear 

Walls

CLT Panel

Diaphragm

Large Diaphragm Spans...

With multiple panels per span

Chords and 

Collectors

CLT Diaphragm Scenarios

CLT Shear 

Walls

CLT Panel

Diaphragm

Small Diaphragm Spans...

With full diaphragm-width panels

Chords and 

Collectors

154
CLT Diaphragm Scenarios

BRB 

Frames

CLT Panel

Diaphragm

Diaphragm spanning between

Soft Braces

Chords and 

Collectors

CLT Diaphragm Scenarios

Concrete 

Shear Wall

Core

CLT Panel

Diaphragm

Diaphragm cantilevering off

Stiff Core

Chords and 

Collectors

155
CLT Diaphragm Scenarios

Real buildings are not all 

rectangles

156
Session 2—Building Performance: Durability, Sound, 

Vibration and Life Cycle Analysis

CLT Systems: Acoustic, Vibration, and Creep Performance

Ciprian Pirvu, Senior Scientist

FPInnovations, Vancouver, British Columbia, Canada

This presentation will focus on serviceability performance of cross laminated timber systems. 

Acceptable sound insulation performance of walls and floors in buildings, as well as adequate vibration 

and time-dependent deflection (creep) of floors, are mandatory requirements specified in building codes. 

It is critical that these performance attributes are taken into account in the design to ensure that required 

safety and comfort levels of occupants are maintained during the specified service life of the structure. 

Building code requirements, research results, and practical construction solutions will be presented. 

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Ciprian Pirvu, P.Eng., Ph.D.

Senior Scientist, Advanced Building Systems

Mass Timber Workshop

November 3, 2015 – USDA FPL, Madison WI

Acoustic, Vibration, and Creep 

Performance of CLT

157
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Serviceability of CLT Systems

 Acoustic performance

 Vibration performance

 Creep performance

2

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Acoustic Performance of CLT Assemblies

 Airborne and structure-borne sound

 Noise control requirements in building codes

 Strategies for noise control

 Examples of practical solutions

3

158
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Airborne Sound

 Sound wave propagating through air

 Sound Transmission Class (STC)

• Single number rating 

• Classifies airborne sound insulation of a building element

• Laboratory measurements (ASTM E90) Æ airborne sound 

transmission loss through a wall/floor-ceiling assembly

Æ STC rating 

(based on ASTM E413) 

4

Noise Source & Human Perception STC

Loud speech or music audible, bass notes 

particularly strong 45

Loud speech faintly audible / Loud music 

barely audible, but bass notes quite noticeable 50

Loud music not generally audible, but bass 

notes still heard 55

Loud music inaudible except for very strong 

bass notes Source Table: NRC Canada 60

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Structure-Born Sound (Impact Sound)

 Sound wave propagating through a solid structure 

 Impact Insulation Class (IIC)

• Single number rating

• Classifies impact sound insulation of a floor-ceiling assembly

• Acoustical chamber without flanking (laboratory) measurements 

(ASTM E492, tapping machine) Æ impact sound transmission 

Æ IIC rating (based on ASTM E989)

5

159
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Sound Transmission Paths

 Direct Path (via partition)

• Assessed in acoustical 

chambers (labs) without flanking

 Flanking Paths (via junction)

• Suppressed in lab tests for 

STC/IIC measurements

EXAMPLES FLANKING PATHS:

• Windows and doors;

• Continuous (shared) floors/walls;

• Wall and floor/ceiling junctions;

• Plumbing chases

6

Source Figure: NRC Canada 

 

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Field Sound Transmission Classes

 FSTC / ASTC

• Field Sound Transmission Class (FSTC)

• Accounts for direct airborne sound and flanking transmission

• Field measurements (ASTM E336) Æ direct sound transmission loss 

and flanking transmission loss 

Æ FSTC rating (based on ASTM E413) 

• Same as Apparent Sound Transmission Class (ASTC)

 FIIC

• Field Impact Insulation Class (FIIC)

• Accounts for direct impact sound and flanking transmission

• Field measurements (ASTM E1007) Æ impact sound transmission 

and flanking transmission 

Æ FIIC rating (based on ASTM E989)

7

FSTC < STC

FIIC < IIC

160
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Noise Control Requirements (IBC) 

 Minimum requirements for demising walls and floor-ceiling 

assemblies 

9

Assembly

STC 50

FSTC 45 1

STC 50 IIC 50

FSTC 45 1 FIIC 45 2

1

 When tested in accordance with ASTM E336 for FSTC and ASTM E90 for STC

2

 When tested in accordance with ASTM E1007 for FIIC and ASTM E492 for IIC

Airborne Sound

Wall

Floor

Impact Sound

N/A

Source Table: 2009 IBC 

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Acoustical Performance Recommendations (ICC) 

 Acceptable & 

preferred grades 

(field tests)

 Acceptable &

preferred grades 

(lab tests)

10

Source Tables: 2010 ICC G2 

Field Sound Rating

Acceptable 

Performance 

(Grade B)

Preferred 

Performance 

(Grade A)

Airborne Noise (NNIC1) 52 57

Impact Noise (NISR2) 52 57

1

 Normalized Noise Isolation Class: When tested according to ASTM E336 2

 Normalized Impact Sound Rating: When tested according to ASTM E1007

Laboratory Sound 

Rating

Acceptable 

Performance 

(Grade B)

Preferred 

Performance 

(Grade A)

Airborne Noise (STC1) 55 60

Impact Noise (IIC2) 55 60

1

 Sound Transmission Class: When tested in accordance with ASTM E90

2

 Impact Insulation Class: When tested in accordance with ASTM E492

161
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Three Defence Approach for Noise Control

1. Control noise at the source

• Contain airborne noise in source room (use low porosity materials)

• Use resilient layer under flooring to absorb footstep impact and 

reduce (floor) vibration 

2. Control vibrations with mass and stiffness

• The greater the weight, the better the sound insulation

• The stiffer the assembly, the better the sound insulation

3. Control vibrations by decupling elements

• Prevent transmission of wall/floor vibration to adjacent element

• Use multiple layers with an air space between elements

11

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CLT Wall Design Example (STC 32 – 55)

12

Cross Section Details STC

3-layer CLT (3 3⁄4 - 4 1⁄2 in) 32 - 34

1. 5/8 in gypsum board (directly

attached to CLT on 1 side)

2. 3-layer CLT (3 3⁄4 - 4 1⁄2 in)

36 - 38

1. & 3. 3-layer CLT (3 3⁄4 - 4 1⁄2 in)

2. Sound insulation material 

(mineral wool) about 1.2 in

50

With 5/8 in gypsum board (both 

sides)

55

Source: CLT Handbook, US Ed. 

162
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CLT Wall Design Example (STC 55 & up)

13

Cross Section Details

1. 5/8 in gypsum board 

2. 3-layer CLT (3 3⁄4 - 4 1⁄2 in)

3. Sound insulation material (mineral wool) 

about 1.2 in

4. Sound insulation material (mineral wool) 

about 1.2 in

5. 3-layer CLT (3 3⁄4 - 4 1⁄2 in)

6. 5/8 in gypsum board

Source: CLT Handbook, Canadian Ed. 

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CLT Wall Design Example (FSTC 50)

14

Cross Section Details

1. 5/8 in gypsum board

2. 2x3 wood studs at 16 in o.c.

3. 2 1⁄2 in mineral wool in the wall cavity

4. 1⁄2 in air gap 

5. 3-layer CLT (4 1⁄2 in)

6. 1⁄2 in air gap 

7. 2x3 wood studs at 16 in o.c.

8. 2 1⁄2 in mineral wool in the wall cavity

9. 5/8 in gypsum board

Source: CLT Handbook, US Ed. 

163
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CLT Floor-Ceiling Assembly (FSTC >50, FIIC >50)

15

Cross Section Details

1. 2/5 laminated or engineered wood flooring

2. 1/8 in resilient underlayment (0.16 to 0.37 

lb/ft2)

3. 5-layer CLT (6 7/8 in)

4. Sound Isolation Clip (4 in high)

5. Metal hat channel at 16 in o.c.

6. Sound absorption materials (e.g. glass 

fibre) (4 in)

7. 1⁄2 in gypsum board

8. 5/8 in gypsum board

Source: CLT Handbook, US Ed. 

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CLT Floor-Ceiling Assembly (FSTC >53, FIIC >53)

16

Cross Section Details

1. Hardwood flooring attached to plywood

2. 3⁄4 in plywood

3. 2/5 in resilient underlayment (0.16 to 0.37 

lb/ft2)

4. 5-layer CLT (6 7/8 in)

5. Sound isolation clips (4 in high)

6. Metal hat channel

7. Sound insulation material (e.g. glass fibre) 

(4 in)

8. 1⁄2 in gypsum board

9. 5/8 in gypsum board

Source: CLT Handbook, US Ed. 

164
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Vibration Performance of CLT Floors

 Particular features of CLT floors

 Proposed Canadian design method for controlling floor 

vibration (FPI)

17

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Dynamic Properties of CLT Floors

18

LT Floors

Property Wood Frame CLT Concrete

Area Mass, lb/ft2 (kg/m2) 4-231 (20-110) 10-30 (50-150) > 40 ( > 200)

Damping (%) 3 1 22 - 83

Fundamental Natural Frequency (Hz) 101 - 15 > 9 < 8

Note: 1 Conventional wood joisted floors with concrete topping

2

 Bare concrete floors (Allen D.E. and Murray T.M, 1993)

3

 Full height partitions (Allen D.E. and Murray T.M, 1993)

ng

> 9

me CLT

0) 10-30 (50-150) >

1

165
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Design Methods for Floor Vibration

Æ Existing design methods do not cover CLT floors!

19

Design Method 2010 NBCC1 Not Addressed

Steel-Concrete 

(Steel Design 

Guide2

)

Floor Construction

lightweight joisted 

floor without 

topping

joisted floors with 

concrete topping 

CLT floors

steel joists 

concrete slab

Area Mass, lb/ft2

 (kg/m2) 3-6 (15-30) 6-30 (30-150) > 30 (150)

Fundamental Natural Frequency (Hz) > 15 9-15 < 9

Note: 1 NBCC recommends limits for static deflection of wood frame joisted floors 

 under concentrated loads of 225 lb (1 kN) at floor centre 2

 Murray et al, 1997. Method limits peak acceleration of a floor to control vibration.

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Proposed Canadian Design Method for Controlling 

CLT Floor Vibration

 Design criterion for CLT floors

• Applies to:

• Floors with or without topping

• Simple or continuous multi-span system

• Vibrations induced by walking

• Well-supported floors 

• Well-connected CLT panels

f, fundamental natural frequency (Hz) of a 1 ft wide CLT panel simply supported 

at both ends 

d, point load static deflection at mid-span of a simple beam (in)

20

1.125 7.0 t

d

f

166
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Verification of Proposed Method

 Vibration tests on 5-ply and 7-ply CLT floors

• Calculation of criterion parameters to predict floor vibration

• FUNDAMENTAL NATURAL FREQUENCY (f)

• POINT LOAD STATIC DEFLECTION (d)

• Subjective evaluation of floor movement (ratings given by evaluators)

21

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Results of Subjective Evaluations

22

Æ Agreement between predicted floor vibration performance and actual 

floor vibration rated by evaluators.

167
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Comparative Verification of Proposed Method

23

 CLTdesigner Software, Graz University of Technology, Austria.

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Creep Performance of CLT

 Earlier study (Austria)

 Exploratory study on creep of Canadian CLT (FPInnovations)

 Design considerations – creep factor

24

168
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Earlier Study on Creep of CLT

 Long-term behaviour of CLT 

comparable to that of plywood 

(TU Graz, Austria)

 Creep of CLT is 30-40% larger 

than that of glulam (TU Graz)

25

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Study on Creep of CLT at FPInnovations: Samples 

 Lumber: 2x SPF (B.C. & Quebec), Hem-Fir (N)

 CLT panel manufacture: 

• 5-ply CLT – 9 CLT panels – size: 13x4 ft

• 3 CLT qualities based on E-rates (MOE)

 Press limitation: 54% lower vertical pressure than specified

 Sample Preparation: 3 billets/panel – 15 in wide

26

169
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Study on Creep of CLT at FPInnovations: Tests 

 1-min ramp tests: 

• Bending tests

• Third-point loading

• Span 12 ft

• Span-to-depth ratio 27:1

 Creep tests:

• Constant loads allow max. 

deflection of L/180 (range 

3100~4800 lb)

• Test protocol (2 cycles):

• Creep (~200 days)

• Relaxation (~100 days)

27

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Study on Creep of CLT at FPInnovations: Results 

 Decreasing creep rates after 

90/120 days of loading 

 )UDFWLRQDOGHIOHFWLRQV 1.43 

after 90-day loading (2.0 

in ASTM D6815)

• LVL = 1.24-1.34

• No. 2 Douglas fir = 1.63

• Structural panels = 1.52

 Creep recovery after 

GD\VRIXQORDGLQJ

in ASTM D6815)

28

170
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Design Considerations for Creep of CLT 

 Bending members (NDS® 2015, Eq. 3.5-1)

ǻT: total deflection, in

Kcr: creep factor, Kcr = 2.0 for CLT (service MC<16%)

ǻLT: deflection due to long-term component of design load, in

ǻST: deflection due to short-term component of design load, in

29

T Kcr LT '' ' ST

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Concluding Remarks

 Noise and vibration control are associated with the 

comfort level of occupants. 

• Subjective evaluation is important

• Control flanking sound transmission (noise) 

• Control floor stiffness and mass (vibration)

• In-situ measurements after the project is completed, and 

application of corrective measures prior to occupancy.

 Creep effects are of critical importance to timber 

engineering. A feasible test method for assessing 

creep effects of CLT is needed.

30

171
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Additional Technical Information on Acoustic, 

Vibration and Creep Performance of CLT

31

CLT Handbook, Canada

https://fpinnovations.ca

CLT Handbook, US

http://www.masstimber.com

TG Design and 

Constructions of Tall 

Wood Buildings

https://fpinnovations.ca

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Acknowledgements

 Natural Resources Canada (NRCan)

 Provincial governments in Canada

 FPInnovations’ industry members

 Softwood Lumber Board

 National Research Council of Canada

 USDA Forest Products Laboratory

32

172
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© 2015 FPInnovations. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

Thank you

Ciprian Pirvu, P.Eng, Ph.D.

FPInnovations, Wood Products Division

2665 East Mall, Vancouver BC V6T 1Z4

Phone: 1 (604) 224-3221

Email: ciprian.pirvu@fpinnovations.ca

© 2015 FPInnovations. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

INNOVATION & TECHNOLOGY 

CONFERENCE

November 25-26, 2015 | Montreal

By FPInnovations

REGISTER

at http://fpinnovates.com/ 

173
Hygrothermal Performance of Mass Timber Construction

Samuel V. Glass, Research Physical Scientist 

USDA Forest Products Laboratory, Madison, Wisconsin

This presentation provides a brief overview of research at the Forest Products Laboratory on moisture 

and thermal performance of mass timber construction. The Building Enclosure Chapter of the U.S. CLT 

Handbook is summarized, with emphasis on strategies for managing water, air, vapor, and heat in wall 

and roof assemblies. Several projects are discussed, including laboratory research on interlocking CLT, 

field monitoring of in-service moisture and temperature conditions in CLT roof panels in a commercial 

building, and computer hygrothermal simulation of CLT exterior wall systems in different U.S. climates.

Hygrothermal Performance of 

Mass Timber Construction 

Samuel V. Glass, PhD 

Building and Fire Sciences 

Forest Products Laboratory 

Mass Timber Research Workshop 

November 3, 2015 – Madison, WI 

174
an ounce of prevention is worth a pound of cure 

(Benjamin Franklin) 

2 

Building envelope is an environmental separator 

Critical functions: 

1) Prevent water intrusion

2) Manage air flow

3) Manage vapor diffusion

4) Manage heat flow

3 

175
“Perfect Wall” concept is apt for mass timber 

4 

The Perfect Wall by J. Lstiburek 

www.buildingscience.com 

Cladding Structure 

Outdoors Indoors 

Control layers 

Water management is most important 

5 

Water-shedding 

surface 

Water-resistive 

barrier (WRB) 

176
Water-resistive barrier doubles as air barrier 

6 

Vapor-open assemblies dry in both directions 

7 

Structure 

Outdoors Indoors 

Ventilated cladding 

Vapor-open WRB 

Vapor-open insulation 

177
Approaches to moisture performance research 

8 

Field 

Real buildings 

Controlled test 

huts 

Laboratory 

Full-scale 

assemblies 

Small-scale 

assemblies 

Material 

properties 

Performance 

criteria (mold, 

decay, 

corrosion) 

Computer 

Hygrothermal 

modeling 

FPL monitoring moisture in CLT roof 

9 

178
10 

11 

179
12 

13 

180
Monitoring demonstrates good moisture 

performance 

14 

0

2

4

6

8

10

12

14

16

Sep-12

Nov-12

Jan-13

Mar-13

May-13

Jul-13

Sep-13

Nov-13

Jan-14

Mar-14

May-14

Jul-14

Sep-14

Nov-14

Jan-15

Mar-15

May-15

Jul-15

Sep-15

Nov-15

Wood moisture content (%)

Sensors in upper side of CLT

Sensors in lower side of CLT

Test hut study shows CLT walls dry predictably 

15 

McClung, R.; Ge, H.; Straube, J.; Wang, J. 2014. Hygrothermal performance of cross-laminated timber wall assemblies 

with built-in moisture: field measurements and simulations. Building and Environment 71:95–110. 

181
Hygrothermal modeling identifies potential risks 

16 

Glass, S.V.; TenWolde, A.; Zelinka, S.L. 2013. Hygrothermal simulation: a tool for 

building envelope design analysis. Wood Design Focus 23(3):18–25. 

Interlocking CLT: low-rise buildings, dry climates 

17 

Cooperators: 

• University of Utah

• University of Idaho

• Brigham Young University

• Euclid Timber Frames

Rio Mesa Center Bath House 

182
How will ICLT perform in other climates? 

18 

Chamber for Analytic Research 

on Wall Assemblies exposed to 

Simulated weather (CARWASh) 

19 

183
20 

Hygrothermal performance research needs 

3⁄4 Monitor in-service performance of real buildings

3⁄4 Quantify wetting and drying during construction

3⁄4 Gauge risk of solar-driven inward diffusion from

absorptive claddings

3⁄4 Measure variability in key material properties

21 

Sam Glass | USDA FS Forest Products Laboratory | svglass@fs.fed.us 

184
Acoustic Prediction Models Create Basis for Future Competitive Wooden 

Structures 

Klas Hagberg, Head of Acoustics, Sweden

WSP, Malmö, Skåne, Sweden

The wood industry and its market shares are increasing. One important reason is raised requirements 

regarding sustainability in the building sector. However, long-term sustainability implies also that 

acoustic comfort mirrors the perception of the humans using the buildings, and in addition it requires 

that prediction models are available in order to anticipate the final acoustic and vibrational quality of 

buildings. That is not possible currently. To promote prediction model development for wooden 

construction, a new big project was started during Spring 2014 within the European WoodWisdom-Net+ 

programme. Results from the project should be integrated into the CEN and ISO standards in order to 

extend the use of these standard specifications to address wooden structures in the future. The models 

will be developed in a full frequency range (including low frequencies) adapted to future vibration 

criteria and sound insulation single numbers, developed to fit to human experience. 

Klas Hagberg

WSP Acoustics / SP wood

Acoustic prediction 

models create basis 

for future competitive 

wooden structures

185
Introduction

Æ Some ”statements:

Æ The acoustics decide the dimensions of a floor assembly

- Why is 250 mm concrete needed in a floor?

- Why is it needed 200 mm concrete in a wall?

- Why is it Hollow concrete 265 mm

- Etc etc

- Whith these dimensions, normally sound class B is fullfilled (in Sweden)

Æ Why is a wooden structure 500 mm thick?

Æ It is always the acoustics that is the design paramater for the 

structure in a building

Introduction - Where are we today?

ISO 717 ISO 717

20-50 Hz

186
Introduction

Æ New research emphasizes the importance of introducing requirements in

”very low” frequency consideration in wooden structures (AkuLite and 

AcuWood). It might require new approaches in addition to traditional

statistical methods

Æ Impact sound evaluation, correlation

50 Hz -3150 Hz, ISO 717 20-50 Hz only!

R2 = 32%

50 54 58 62 66

Lnw+CI50

0

2

4

6

8

Stegljud -ÖP

R2 = 78%

52 57 62 67 72 77 82

Ln 20-50

0

2

4

6

8

Stegljud -ÖP

Introduction

Æ At least one more project will continue after AkuLite and AcuWood to 

further develop the criteria for sound insulation, that is

- “New improved building technique-neutral criteria for sound insulation

evaluation” Luleå Technical University in Sweden, started spring 2014

Æ But it is clear –

- in order to develop high rise wooden houses, low frequencies have to be

considered in target values and also ....

- ..new prediction models.

Æ The WWN+ project ”Silent Timber Build” will develop calculation

models for wooden structures covering a ”full” frequency range

187
Material 

Characteristics is a 

challenge in 

order to

deliver

enough

accuracy

Silent Timber Build

Æ Idea is to use both FEM and SEA to cover a ”full” frequency range,

20-5000 Hz. New target values from recent research will be 

considered.

Æ The work will be carried out in five Work Packages, three ”technical”

WP:s (WP 1-3) and one WP (WP4) for dissemination and Exploitation

and one WP (WP5) for Coordination

188
Silent Timber Build

Silent Timber Build – expected results

Æ establishing basis for development of standardized engineering 

calculation methods applicable to lightweight structures 

Æ increased knowledge about calculation methods for multi storey

wooden buildings 

Æ increased knowledge about building systems that can be predicted in 

terms of sound insulation considering future requirements 

Æ possibilities for future optimization of building systems by using 

prediction tools in the design stage in order to lower the costs 

and strengthen the competitiveness of the wooden building 

sector 

189
Æ increased knowledge of sound and vibrations in the lightweight 

building industry, which is necessary for 

- beneficial development of new acoustic solutions for the industry

- innovative guidelines in the design stage

Æ further improve the “sustainability” arguments for the wooden sector. 

Wooden constructions are fully “sustainable” when sound and 

vibration properties can be 

- predicted according to modern design criteria, and then

- as the final results in a building also correspond to the predicted values

Silent Timber Build – expected results – long term 

Silent Timber Build - consortium

ÆResearch:

Æ SP Wood Technology, Borås, Sweden (Project management, WP5, 

Klas Hagberg)

Æ Lund University, Lund, Sweden (WP leader WP1, Delphine Bard)

Æ Sintef, Trondheim, Norway (WP Leader WP2, Anders Homb)

Æ Lignum, Zürich, Switzerland (WP leader WP3, Olin Bartlomé)

Æ FCBA, Bordeaux, France (WP leader WP4, Jean-Luc Kouyoumji) 

Æ CSTB, Grenoble, France (Catherine Guigou)

190
Silent Timber Build - consortium

ÆResearch:

Æ InterAC, France (Gerard Borello)

Æ Fraunhofer Institut IBP, Stuttgart, Germany (Mortitz Spaeh)

Æ TU Graz, Graz, Austria (Heinz Ferk)

Æ Tecnalia, Spain, (Mariana Pérez Abendaño)

Silent Timber Build - consortium

ÆIndustry:

Æ Building With Wood (CEI-Bois)

Æ WSP Sweden

Æ Simmons Acoustics and Development, Sweden

Æ Fristad Bygg – Building contractor in Sweden

Æ Norgeshus AS, Norway

Æ Bauer Holzbau GmbH, Germany

Æ Finland: Finish Wood Research Responsible person: Tomi Toratti, 

Confederation of Finish Construction Industries On behalf of FWR

191
Other cooperation

Æ Close cooperation with HCLTP (another WWN+ project)

Æ Cooperation with ”Höga Trähus” in Sweden (new 2015)

Æ Cooperation with one project in Luleå

Æ US and Canada Î It has started - - I hope for much more!

Æ ..... Industrial interest is big!

Silent Timber Build

Æ Started in March 2014, however due to delayed financial decisions, it 

did not really start until August 2014

Æ Expected to be finished in April 2017

Æ Visit www.silent-timber-build.com

192
Thanks for listening!

Klas Hagberg 

klas.hagberg@wspgroup.se

Klas.hagberg@sp.se 

 @klashagb

193
Comparative Life Cycle Assessment of a U.S. CLT Building: Planning and 

Challenges

Jim Bowyer, Director, Responsible Materials Program

Dovetail Partners, Minneapolis, Minnesota

As awareness of cross laminated timber (CLT) reaches the attention of more and more architects and 

engineers, additional information is needed regarding material properties and design limitations, 

environmental performance, and life cycle costs. With respect to the latter, definitive information is 

needed regarding environmental impact measures relative to typical concrete and steel construction, as 

well as projected comparative costs from construction through the life cycle of a building. This 

presentation will describe efforts to engage a U.S. partner in a comparative assessment and discuss 

challenges and issues encountered. The concept of a much more comprehensive (than initially 

envisioned) study will also be introduced. 

Assessing Comparative 

Environmental Impacts of 

CLT and More Traditional 

Construction

Jim Bowyer

Dovetail Partners, Inc.

194
Outline

• Identifying candidate projects for a

comparative LCA - Procedure

• Observations regarding project selection

- Completed projects vs. projects in

planning

- Vetting of project partners

• Conducting a comparative assessment

• Summary

Identifying Candidate 

Projects 

195
Procedure

• Contacted architects and construction firms

involved in some way in CLT building design

and/or construction.

• Contacted manufacturers and distributors

engaged in manufacturing and/or distributing

CLT products.

• Contacted companies that represent over 90

percent of hotel construction in the U.S.

• Monitored new wood building announcements

across the U.S. and Canada, and followed-up

to contact principals involved.

Procedure

• Engaged in numerous conversations and

meetings with key architectural firms

regarding potential for collaboration in

comparative LCA initiative.

196
U.S.

Project Description Remarks

Timber loft, Hines, 

Minneapolis, 

Minnesota

7-story, mixed use commercial/ 

residential. 

Final planning stage. CLT not 

selected for use in project.

Redstone hotel, 

Huntsville, Alabama

4-story CLT hotel with 93 keyed 

rooms.

Project completed 2014. 

Beneficial State 

Bank Albina 

Building

11-story office building. Extent 

of CLT use not yet determined.

Proposed. Architect not yet 

revealed.

Carbon 12 8-story mixed use building. CLT 

proposed for use for both 

decking and shear walls.

Proposed. Developed by the Kaiser 

group and PATH Architecture.

Oregon Forest 

Science Complex

$60 million project in which a 

variety of engineered wood 

products, including CLT will be 

used. Nature and extent of CLT 

application not yet determined.

Proposed. Selection of architect and 

engineering firm underway.

Building not viewed as replicable 

for comparative LCA.

Franklin School 

Project, Pendleton 

Country, West 

Virginia

1-story school building. All CLT. No apparent interest in cooperating 

in LCA.

Dropped from consideration.

S.

Summary of Candidate Projects for 

Comparative LCA

Canada

Project Description Remarks

Faction Projects, 3-

story office building, 

Kelowna, B.C.

CLT construction. Construction complete. Full set of 

information needed for comparative 

LCA has been provided by Faction 

Projects.

Gymnasium/sports 

facility, Calgary, 

Alberta

All above grade areas of a

hybrid system of wood

columns, glue-laminated

beams and trusses, SIP wall

panels, and CLT roof and floor

plates.

Complete documentation developed 

for this structure and identical 

structure built entirely of concrete 

and steel. 

Wood Innovation 

Design Centre, 

Prince George, B.C.

A 6-story 50,000 ft2 building. 

The building structure consists 

of glulam columns and beams, 

CLT floor panels, and mass 

timber walls.

Completed 2014.

Michael Green Architecture

Earth Systems 

Sciences Building, 

University of British 

Columbia, 

Vancouver, B.C.

A 5-story academic wing of 

this building is constructed of 

glue-laminated beams, 

timberstrand floor panels 

overlaid with concrete, and a 

12,400 ft2 CLT canopy that 

surrounds 3 sides of the 

building.

Completed in 2014.

Perkins+Will Architects in 

conjunction with campus architect 

Gerry McGeough.

This is an ideal candidate for a 

comparative LCA since a nearidentical lab wing of the same 

building is steel reinforced concrete 

construction.

anada

Summary of Candidate Projects for 

Comparative LCA (Cont.)

197
Canada

Project Description Remarks

Bioenergy Research 

and Demonstration 

Facility, University of 

British Columbia, 

Vancouver, B.C.

4-story 6,200 ft2 building 

constructed of glulam columns 

and beams and CLT. CLT 

panels make up the walls, 

roof deck, upper floor 

structure, and acoustic “gills”.

Completed in 2014.

Nextrerra Energy Corp. and 

McFarland Marceau Architect

Elkford Community 

Conference Centre, 

Elkford, B.C.

A 19,000 ft2 building 

constructed of CLT walls and 

shear walls.

Completed in 2012.

Douglas Sollows, Architect

North Shore Credit 

Union Environmental 

Learning Centre, 

North Vancouver, 

B.C.

This 11,000 ft2 building 

features glulam beams 

supported by steel columns, 

and CLT floors overlaid with 

concrete.

Completed in 2012.

McFarland Marceau Architects Ltd.,

Vancouver, BC. 

mchevalier@mmal.ca

Structurlam CLT 

Production Facility, 

Okanagan Falls, B.C.

A 10,000 ft2 facility

constructed of glulam and

CLT. The roof is 5-ply CLT

panels, the walls 3-ply CLT.

Completed in 2014.

Fort McMurray 

Airport Expansion, 

Fort McMurray, 

Alberta.

This 161,500 ft2, 3-story 

project uses CLT for roof 

paneling and for infill between 

curved arches and rectangular 

boundaries.

Completed in 2014.

MacFarlane Bigger Architects and 

Designers, Vancouver, B.C.

anada

Summary of Candidate Projects for 

Comparative LCA (Cont.)

Canada

Project Description Remarks

Wayne Gretzky 

Sport Centre, 

Brantford, Ontario.

This 3,000 ft2 building 

incorporates 8” x 40” CLT 

panels into the roof structure 

which is supported by glulam 

beams and columns.

Completed in 2013.

CS&P Architects, Toronto

Whistler, B.C. Fire 

Station.

The 5,000 ft2 building 

incorporates glue laminated 

columns and beams and 5-ply 

CLT walls, 7-ply CLT floor 

panels, and 7-ply CLT roof 

panels.

Completed in 2014.

Complete building plans, materials 

lists, and assembly details are 

available on-line.

anada

Summary of Candidate Projects for 

Comparative LCA (Cont.)

198
Observations Regarding 

Project Selection

Redstone 

Arsenal, 

Huntsville, 

Alabama

199
Hines T-3 Project, 

Minneapolis, 

Minnesota

Beneficial State Bank Building, 

Portland, Oregon

200
Observations RE Project Selection

• Completed projects vs. projects in planning

- Completed – no surprises

- In Planning

o Things can change (T-3)

o Beware of code issues, redundancy

(Redstone)

o Designs can become proprietary (T-3)

Observations RE Project Selection

• Vetting of project partners

- Important that developer fully understand

what an LCA is (T-3, Redstone, Beneficial 

Bank)

- Developer may seek control of

environmental assessment, publicity 

(Redstone)

201
Conducting a Comparative 

Assessment

Observations RE Conducting the 

Assessment

• Plan for costs of developing alternative designs,

material takeoffs.

• Individual comparisons of steel, concrete

alternatives needed.

• Need to conduct parallel LCCA if at all possible.

202
Conclusions

• Careful consideration is required in selecting a

project and cooperators for a comparative LCA.

• There are advantages in selecting a completed

construction project.

• All alternative designs should be assessed and

reported individually.

• Need to conduct parallel LCCA if at all possible.

203
Session 3—Fire Safety

Fire Safe Design of Exposed Mass Timber in Buildings

David Barber, Principal

ARUP, Washington, D.C.

As timber buildings are constructed taller, architects and building owners are asking for more timber to 

be exposed within compartments and asking fire engineers to develop solutions to allow more timber to 

be seen. Addressing how the exposed timber impacts a fire over its full development through to selfextinguishment is a very current fire safety issue. There is limited research available on how exposed 

timber within a compartment impacts fire peak heat release rate, temperatures, and fire duration. This 

paper brings together the available research to understand similarities, parameters, and where results can 

be directly applied to buildings. Available fire testing would indicate that where an exposed timber wall 

is in the order of 20% or less, the compartment fire is minimally impacted. This paper will assist in 

developing engineering methodology to account for the change in compartment fire dynamics, better 

define fire extinguishment, and provide a clear understanding of the impact between differing areas of 

wall and ceiling exposed.

Fire Safe Design of Exposed Timber in 

Mass Wood Buildings

David Barber, Washington D.C.

204
2

Wood Buildings

• Wood is new, again

3

Wood Buildings

• Perception of risk in model buildings codes

- Construction based on combustibility, not fire resistance

- Height and area limits wood use

205
4

Exposed Wood – What Architects Want

• Architects want exposed wood within their buildings

• Don’t we all !!!

• Limitations are based on fire safety, dealing with a new

product (CLT) and general unfamiliarity with wood

5

Exposed Wood Fire Fundamentals

• Codes permit exposed wood as an

interior finish

• Interior finish requirements are

Class C to ASTM E84 (sprinkler

protected building)

• Solid wood meets Class C (and

some meets Class B)

• Exposed wood is not a new

problem, it has just never been

accounted for.........

206
6

Exposed Wood Fire Fundamentals

• Exposed wood is now part of the loadbearing structure in mass wood

buildings

• A new issue that needs to be addressed

• Exposed floors, columns, beams, walls:

- Glulam is known, but not for high-rise

- CLT is an unfamiliar product

• Fear of the unknown

7

Exposed Wood - Key Issues

• How does the exposed wood change

the fire dynamics ?

• Impacting on:

- Fire duration ?

- Size of the fire ? (heat release rate)

- Fire temperature ?

• And hence, the fire resistance ratings

required to allow the building to

withstand a full burnout ?

• Interior wood finishes also impact on

the above items..........

• Why aren’t steel and concrete

buildings assessed for full burn out ??

207
8

Exposed Wood Compartments – Recent Research

• Osborne and Dagenais “Preliminary CLT Fire Resistance Testing Report”,

FPInnovations, 2012

• McGregor “Contribution of Cross Laminated Timber Panels to Room Fires”,

Carleton University, 2013.

• Aguanno, “Fire Resistance Tests on Cross-Laminated Timber Floor Panels: An

Experimental and Numerical Analysis”, Carleton University, 2013

• Medina Hevia “Fire Resistance Of Partially Protected Cross-Laminated

Timber Rooms”, Carleton University, 2014

• Crielaard, “Self-Extinguishment of Cross-Laminated Timber”, Delft University

of Technology, 2015.

• Li, “Modeling of Barrier Failure and Fire Spread in CUrisk”, Carleton

University, 2015

9

Exposed Wood Compartments– Recent Research

• Small ventilation controlled compartments, with

real fuel loads (natural fires)

• Testing has ranged in type of exposed wood -

walls, floors and ceilings

• Differing results provide difficulty in

comparison, but trends are apparent

From Crielaard, 2015

From Li, 2015

208
10 

Exposed Wood - Temperatures

From McGregor, 2013

11 

Exposed Wood – Fire Size (HRR)

From Medina-Hevia, 2014

209
12 

Exposed Wood – Fire Duration

From Medina-Hevia, 2014

One wall only exposed

Two adjacent walls exposed

Two opposite walls exposed

13 

Exposed Wood Compartments – Solutions

• Failure of the CLT through

delamination is an expected mode

of failure

• Delamination should not be

feared, but accepted and

engineered

• Exposed wood increases the fuel

load within the compartment –

but can be accounted for

From Medina-Hevia, 2014

From Crielaard, 2015

210
14 

Exposed Wood Compartments – Solutions

• If multiple faces are exposed wood, re-radiation leads to

continued burning after room combustibles have been

consumed (so called “second flashover”)

• Exposed wood prolongs the fire duration – can be

conservatively accounted for

• Direct impact on FRR

• How the compartment HRR decays is still yet to be fully

determined when multiple faces are exposed

• More work is needed, but some reasonable correlations can

be determined

15 

Next Steps

• More testing is needed, especially

with walls covered and ceiling

exposed

• Fire Protection Research

Foundation testing (2016 – 2017)

• Continued testing by research

consortiums, University testing

• Medium term - correlations and

basic design rules to be developed

• Longer term – detailed analytical

models

• Wood buildings will continue to

receive significant scrutiny

211
16 

Summary – Tall Wood Building & Fire Issues

• Fire risks are misunderstood and often misrepresented

• There is not enough accredited third-party fire testing

carried out in the US:

- ASTM E119 

- ASTM E84 

- Glulam connections 

• Suppliers need to invest more in fire testing

• The lack of evidential fire testing is a significant barrier to

approval

212
Performance of Mass Timber Construction in Fire

Christian Dagenais, Fire Scientist

FPInnovations, Quebec City, Quebec, Canada

Over the past 5 years, FPInnovations and National Research Council have been engaged in evaluating 

various aspects of the performance of cross laminated timber (CLT) assemblies in fire. A number of 

full-, intermediate-, and small-scale experiments have been conducted to understand the behavior of 

CLT assemblies in fire. This presentation will give some information about these experiments and will 

include fire-resistance tests, flame spread rating, service penetrations and fire stops, and large-scale 

compartment fires.

Christian Dagenais, Eng., M.Sc. – FPInnovations

Mass Timber (CLT) Research Workshop

November 3rd, 2015 – Madison (WI), USA

Performance of Mass Timber 

Construction in Fire

213
© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Outline

 Fire-Resistance

 Surface Flammability

 Fire Stops and Service Penetrations

 Compartment Fires

 Conclusion

2

© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire-Resistance of CLT

 Full-scale testing in accordance

with ULC S101 / ASTM E119

(joint FPI/NRC Test Program)

Ɠ Charring rate 

Ɠ Fire performance of adhesive (PUR) 

Ɠ Calculation procedure for US and

Canadian standards

 Additional full-scale tests were

also conducted with wood industry

partners and CLT manufacturers

3

y

214
© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire-Resistance of CLT

4

Source: Dagenais C. & Osborne L. (2015) “Recent Advances in Fire Performance of Cross-Laminated Timber”. Wood Design Focus Journal, V. 25, N. 3, pp.21-26.

© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire-Resistance of CLT

5

 Timber-Concrete Composite Floors

ons.

FRR > 31⁄2 hrs

NLT CLT

215
© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire-Resistance of CLT

 CLT can exhibit significant fire-resistance

 Charring rate similar to mass timber, but...

Ɠ 0.65 mm/min (one-dimensional)

Ɠ Stepped charring model (i.e. not constant throughout)

Ɠ Influenced by the adhesive and thickness of laminates

- More studies are required on adhesives exposed to fire

 Failure modes are different from walls to floors

Ɠ Buckling (P-' effects) vs. Integrity between panels

- Fire integrity can easily be resolved using flooring/topping

6

© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Surface Flammability

 Full-scale testing in accordance

with ULC S102 and ASTM E84

Ɠ Tests conducted with AWC and

CLT/SCL manufacturers

 Mass timber behaves as

thermally-thick solids

(vs. thermally-thin)

 Exhibit lower FSI when

compared to traditional

interior wood finish materials

7

216
© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Surface Flammability

8 © 2015 FPInnovations and NRC All rights reserved

1st Panel 2nd Panel 3rd Panel

© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Surface Flammability

9

217
© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire Stops and Service Penetrations

 INTEGRITY and CONTINUITY of fire separations

are fundamental for achieving/providing the

expected level of compartmentation

Ɠ Penetrations and junctions are to be firestopped

(tested per CAN/ULC S115 / ASTM E814)

10

© 2015 FPInnovations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from both organizations.

® FPInnovations, its marks and logos are trademarks of FPInnovations.

Fire Stops and Service Penetrations

• Junctions evaluated per CAN/ULC S115

– Floor-to-wall (sealant on unexposed side)

– Floor-to-wall (sealant on exposed side)

– Wall-to-Floor (sealant on both sides) 

– Floor-to-Floor

– Stair landings

ĺ)7-rating of 1 to 2 hours 

11 organizations.

sides)

218
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Fire Stops and Service Penetrations

 6 penetrations tested per CAN/ULC S115

ĺ)-rating of 11⁄2 hrs.

12

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Fire Stops and Service Penetrations

13

219
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Compartment Fires

 Compartment fire tests from 2011-2014

14

p

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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Compartment Fires

 Compartment fire tests from 2011-2014

Ɠ Scenarios where CLT is 100% exposed

- Contribution to fire growth

Ɠ Scenarios where CLT is partially-exposed

- Burnout of fuel content, depending on exposed face 

configurations

Ɠ Scenarios where CLT is fully protected

- Burnout of fuel content

15

Source: McGregor C., “Contribution of Cross-Laminated Timber Panels to Room Fires - Thesis”, Carleton University, 2013.

220
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Compartment Fires

 Compartment fire tests from 2011-2014

Ɠ Evaluation of combustible and noncombustible

construction subjected to natural fires

1. CLT: 2 x Type C (1⁄2 in.)

2. CLT: 2 x Type C (1⁄2 in.)

3. CLT: fully exposed

4. Wood-Frame: 1 x Type C (1⁄2 in.)

5. Wood-Frame: 2 x Type C (1⁄2 in.)

6. Cold-Formed Steel Frame: 1 x Type C (1⁄2 in.)

16

Source: Li X., Zhang X., Hadjisophocleous G., McGregor C. (2015) “Experimental study of combustible and 

non-combustible construction in a natural fire“, Fire Technology Journal, Vol. 51 (6), pp. 1447-1474.

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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Compartment Fires

 Compartment fire tests from 2011-2014

17

221
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Compartment Fires

 Mid-Rise Research Consortium (NRCC/CWC/FPI)

Ɠ 3-Storey Apartment Unit, no sprinklers

18

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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Compartment Fires

 Mid-Rise Research Consortium (NRCC/CWC/FPI)

Ɠ Duration: 185 min.

Ɠ No structural failure

Ɠ No fire spread beyond

compartment boundaries

Ɠ Fire dynamics similar

to that of a compartment

of noncombustible

construction

Ɠ CLT performed better than CFS apartment test

19

s

222
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Compartment Fires

 Fire tests in support of a TWB in Quebec City

Ɠ Exposed CLT in vertical shaft

Ɠ Encapsulated CLT in room of fire origin

Ɠ Gypsum board around fire-rated door

Ɠ 45-min fire-rated door

(vs. 20 min.)

Ɠ Tested at NRCC laboratory

Ɠ Funded by Quebec

Government (MFFP)

20

y

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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Compartment Fires

 Fire tests in support of a TWB in Quebec City

21 ations and NRC. All rights reserved. Copying and redistribution prohibited without written consent from bo

it k d l t d k f FPI ti

p

223
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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Compartment Fires

 Fire tests in support of a TWB in Quebec City

Ɠ Test conducted for 2 hours

- Per NBCC for noncombustible construction

Ɠ No fire penetration through walls/floor/ceiling

Ɠ Very little charring on exposed CLT shaft wall

Ɠ No charring/smoke inside CLT shaft

Ɠ Reports (French/English) and video (French) 

available at:

http://www.mffp.gouv.qc.ca/forets/entreprises/entreprises-transformation-resistance-feu.jsp 

22

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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Conclusion

 CLT detailing can provide for highly fire-resistance

rated compartmentation in buildings

 Test results showed the effectiveness of the

encapsulation approach in delaying contribution of

wood structural members to fires

 Inherent fire performance of CLT makes it suitable

for sound alternative solutions

 Design methods and guides are readily available

23

224
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® FPInnovations, its marks and logos are trademarks of FPInnovations.

Acknowledgements

 Natural Resources Canada (NRCan)

 Provincial governments, namely RBQ, MFFP,

OMMAH and BC FII

 Softwood Lumber Board

 FPInnovations’ industry members

 FPInnovations, NRC and USDA FPL staff

24

www.fpinnovations.ca

Follow us on

© 2015 FPInnovations. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.

Thank you!

Christian Dagenais, Eng., M.Sc.

Scientist – Serviceability & Fire Performance

Advanced Building Systems

christian.dagenais@fpinnovations.ca

225
Forest Products Laboratory Research on the Fire Performance of Cross 

Laminated Timber

Laura E. Hasburgh, Fire Protection Engineer

Keith J. Bourne, Mechanical Engineer

USDA Forest Products Laboratory, Madison, Wisconsin

Wood has been employed as a building material for thousands of years because it is readily available 

and easy to work with. Due to a recent push for sustainable construction, the use of mass timber 

elements, such as cross laminated timber (CLT), is increasing. The Fire Research Team at the USDA 

Forest Products Laboratory have developed collaborations with universities and other institutions to 

study the fire resistance properties of CLT and improve its marketability for mid- to high-rise 

construction. The goal is to find a design that maximizes the hourly fire rating so that the structural 

panels can be used in a larger variety of situations. This presentation summarizes ongoing research that 

has investigated how features such as the grade of wood, configuration of plies, adhesive types, and 

protective membranes can be optimized to reduce the charring rate and increase the hourly rating of the 

panel.

Forest Products Laboratory research on 

the fire performance of CLT 

Laura E. Hasburgh and Keith J. Bourne

226
Overall Goal 

• Increase commercialization of CLT

• Demonstrating and increasing the hourly rating

The Library on The Dock; Photograph by Diana Snape 

Collaborations 

227
Total Specimens 

• To date: 25

• By December 2015: 41

Variables 

228
Variables 

Melamine 

Formaldehyde 

Emulsion 

Polymer 

Isocyanate 

Phenol 

Resorcinol 

Formaldehyde 

Polyurethane 

Variables 

LCL 

LLC

229
Variables 

Methods 

230
Methods 

 11.5 mm 

 23 mm 

 46.5 mm 

 58 mm 

 81.5 mm 

Methods 

231
0

300

600

900

1200

0

500

1000

1500

2000

2500

0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00

Degrees F 

Time (hours) 

ASTM E 119 Time-Temperature Curve 

Degrees C 

Methods 

Methods 

232
Methods 

Methods 

233
Results 

Results 

234
Results 

Questions? 

235
Fire Safety of Tall Wood Buildings—Property Protection View

Kuma Sumathipala, Director, Fire Technology

American Wood Council, Leesburg, Virginia

The Unites States is fortunate to have a vast supply of forest biomass suitable for manufacturing into 

products that can be used to build wood buildings greater than eight stories in height. To capture this 

opportunity, stakeholders in the building construction industry must be assured these buildings are safe 

for their occupants, as well as emergency responders, and do not present an unreasonable risk for loss of 

property. Current prescriptive building codes limit combustible construction to 85 feet in height and six 

stories. To expand the market for mass timber beyond these prescriptive limits, research and testing are 

needed to evaluate and quantify the contribution of mass timber elements to room/compartment fires 

with the types of structural systems that are expected to be found in tall wood buildings. Previous 

research has shown that unprotected timber elements can contribute to the fuel load and can aid the fire 

growth rate. Fuel contribution from structural elements can potentially overwhelm fire protection 

systems, designed to mitigate and extinguish fires in noncombustible construction. As such, a 

combustible structural element’s contribution to compartment fires needs to be quantified and compared 

against noncombustible structural systems. A research program initiated by NFPA Fire Protection 

Research Foundation, and funded by Property Insurance Research Group and USDA Forest Service, 

expects to quantify the contribution of combustible structural elements to room/compartment fires for 

the full fire duration using metrics such as charring rate, visibility, temperature, etc. This will allow a 

designer to quantify the contribution, validate design equations, and develop suitable mitigating 

technologies. Findings will also provide data for the insurance industry to establish fire insurance 

premiums for this new type of construction. Additionally, test results could be used to develop and 

support new requirements for U.S. model building codes, so that these buildings can be constructed 

without undergoing time-consuming and expensive equivalency studies on a case-by-case basis.

236
Copyright © 2015 American Wood Council

American Wood Council 

www.awc.org

Fire Safety of Tall Wood Buildings 

Property Underwriting 

Madison, WI, 

November 2015 

Kuma Sumathipala 

Copyright © 2015 American Wood Council

Tall Wood Building 

U.S. 

Code allow for 5/6-stories or 85’ (grade toroof) 

Tall Wood 

 USDA/SLB Design competition for Tall Wood

• Portland, OR. 12-story mixed: Retail/Residential

• New York, NY. 10-Story:Residential

237
Copyright © 2015 American Wood Council

Property Underwriters 

Property Underwrites Initiated a Research in 

2013 

Characterize fire performance of tall wood 

Design to achieve a level of property 

protection equal to or above steel structures. 

Communicate results to serve as a guide for 

architects, engineers, and code officials. 

www.awc.org

Copyright © 2015 American Wood Council

Property Underwriters? 

Property Insurance Research Group (PIRG) 

FM Global ($5B) 

CNA ($6B) 

Liberty Mutual ($30B) 

Tokio-Marine ($19B) 

Travelers ($22B) 

XL-Group ($6B) 

Zurich ($12B) 

AIG 

www.awc.org 238
Copyright © 2015 American Wood Council

Property Insurance Research 

Property Insurance Research Group 

(PIRG) 

Fire Research of Interest to 

underwriting 

$400K per Annum 

Secretariat is the Fire Protection 

Research Foundation 

www.awc.org

Copyright © 2015 American Wood Council

FPRF Overview 

www.awc.org 239
Copyright © 2015 American Wood Council

FPRF Overview 

www.awc.org

Copyright © 2015 American Wood Council

FPRF Overview 

www.awc.org 240
Copyright © 2015 American Wood Council

FPRF Phase 1 Research 

Literature Survey and 

Gap Analysis 

 Arup chosen from 16

responses to RFP

 Arup report available at

NFPA website

www.awc.org

Copyright © 2015 American Wood Council

FPRF Phase 1: Research 

Identified Gaps 

 Interaction of structural and nonstructural components

• Connections, Adhesives, Composites,,

Penetrations, Facades & Claddings....

 Compartment Fire Dynamics

• Assume

• Sprinklers do Not activate

• Inadequate fire service response

• Growth of Content Fire Comparison

• Steel Vs. Wood Compartment

www.awc.org 241
Copyright © 2015 American Wood Council

Compartment Fire Dynamics 

Compartment Fire 

Dynamics 

 Contribution of structural

wood to a content fire

 Literature Survey of wood

compartment fires

www.awc.org

Copyright © 2015 American Wood Council

Compartment Fire Tests 

45 wood compartment fire tests 

2000-2015 

2008: Frangi 

 11’ x 11’ CLT room; window 3.3’ x 3.3’

 Hotel room contents in fire compartment

 Subject to shake table first

 Fire-rated & Regular gyp board

 Fire contained for 60 min

 Minimal damage to CLT

www.awc.org 242
Copyright © 2015 American Wood Council

Compartment Fire Tests 

Carleton University 2014 

 12’ x 8’ CLT room; door 6.5’ x 3.5’; 3-ply CLT

 Series of experiments with bedroom contents on fire

www.awc.org

Copyright © 2015 American Wood Council

Compartment Fire Tests 

National Research Council Canada 2013 

 27’ x 21’ CLT room; Two Windows 5-ply CLT

 Series of experiments with bedroom contents on fire

www.awc.org 243
Copyright © 2015 American Wood Council

National Research Council Canada 

www.awc.org

- Gypsum board protected CLT 

- Fire burned out 

 

Copyright © 2015 American Wood Council

Compartment Fire Tests 

American Wood Council (2015) 

 16’ x 12’ CLT room; door 6.5’ x 3.5’; 5-ply CLT 

 2-layers of Type X Gypsum board 

www.awc.org 244
Copyright © 2015 American Wood Council

Compartment Fire Tests 

www.awc.org

3 min 5 min 6 min 

60 min Debris Cleared 

Copyright © 2015 American Wood Council

AWC Compartment Fire Tests 

www.awc.org

Post-Fire Compartment 

245
Copyright © 2015 American Wood Council

AWC Compartment Fire Tests 

www.awc.org

Compartment Temperatures 

0

500

1000

1500

2000

2500

0 5 10 15 20 25 30

Compartment Temperatures (°F)

Time (Min)

ASTM E119 

Curve 

Copyright © 2015 American Wood Council

Conclusions-Compartment Fires 

CLT protected by 2-layers of Type X 

Gypsum board perform similar to 

Steel 

One wall unprotected –acceptable 

performance 

Two walls unprotected - exhibit CLT 

delamination (40-80 mins) 

All walls unprotected – bad actor? 

www.awc.org 246
Copyright © 2015 American Wood Council

Compare steel compartment fire performance: 

• Gypsum board protected CLT?

• One-wall unprotected CLT?

• Two-walls unprotected CLT?

www.awc.org

FPRF Compartment Fire Candidates 

Copyright © 2015 American Wood Council

Thank you! 

www.awc.org 247
Session 4—Material Resources and Other Topics

CLT Supply Chain from Forest to Market

Rusty Dramm, Forest Products Specialist

USDA Forest Products Laboratory, Madison, Wisconsin

The Forest Products Laboratory has entered into a cooperative agreement with Renewable Resource 

Solutions, LLC, to explore and assess the potential of using suitable USDA Forest Service timber 

resources and small-diameter trees as feedstock for potential siting of cross laminated timber (CLT) 

plants in the Pacific Northwest and Intermountain West. The CLT project will help provide preliminary 

due diligence for CLT and serve as a model for assessing other technologies in the future. Specific 

questions explored include (1) resource analysis—raw material characterization of CLT feedstock and 

availability of Federal timber and timber from stewardship contracting/agreements as sources of suitable 

wood supply; (2) CLT markets—CLT applications and uses—issues, barriers and opportunities 

considering both domestic and export markets; and (3) financial feasibility discussion for CLT plant 

siting.

CLT Supply Chain

“from Forest to Market”

Rusty Dramm

FPL Forest Products Marketing Unit

USDA Forest Products Laboratory

2015 CLT Research Meeting

Madison, Wisconsin

248
9 Explore potential sources of wood supply 

and markets for CLT manufacture

9 Consider CLT markets – barriers and 

opportunities

9 Provide ideas on preliminary siting a CLT 

plant in the PNW and Intermountain West 

CLT Supply Chain Project 

Overview

Western States included in the 

CLT Supply Chain Project

9 FS Region 1

• Northern Idaho

• Montana

9 FS Region 4

• Southern Idaho

• Nevada

• Utah

9 FS Region 6

• Oregon

• Washington

249
Planned Programming Approach

Consider the “forest to market”

supply chain

Raw Material Resource 

Considerations for CLT

Resource Analysis

9Raw material characterization of CLT Feedstock

9Timber availability – FS timber sales and Stewardship 

Contracting as potential sources of suitable wood supply

• Forest inventory analysis (FIA)

• Timber product output (TPO)

• Timber sales program

• Stewardship contracting

• Forestry operations capacity

• Other non-Federal sources

250
Western Regions Timber 

Performance (FY 2014)

R1 R4 R6

Timber Program Funding (all programs) $29,900,000 $11,700,000 $54,500,000 

Timber Target - million cunits 570 mccf 230 mccf 1,160 mccf 

 - million bd.ft. Scribner 285 mmbf 112 mmbf 603 mmbf 

 - million bd.ft. measure 

 lumber tally equivalent 399 mmbf 161 mmbf 812 mmbf 

Accomplished Percent (%) 99.4% 97.3% 98.6% 

American Forest Resource Council

October 31, 2014

Ecosystem Workforce Program, University of Oregon, 7/16/2014

Acres Treated

(2013)

Forest Service 

Stewardship

Contracts

251
Improving Forest Health 

and Forest Safety through 

Stewardship Contracting 

and Forest Utilization

High-Speed Mobile Sawmilling

252
Markets – CLT applications and uses; issues,

barriers and opportunities

9US Markets – structural and non-structural 

applications

• Structural load bearing housing and commercial

buildings (low-, mid-, and high-rise)

• Non-load bearing (oil well mats) and industrial

wood applications

9Export Markets – Canada, Europe, China

Market Considerations for CLT

Construction Market

Considerations for CLT

U.S. Markets – load bearing applications in 

low– and high–rise structures?

253
4 

3 

2 

1 

6 

8 

7 

CLT Building

Construction

Markets

1. SeaTac Metro

2. Portland Metro &

 Willamette Valley

3. Inland Empire

4. Boise–Nampa

5. Reno–Lake Tahoe

6. Salt Lake City Metro

7. Las Vegas Metro

8. Helena–Missoula–Great Falls

CLT Plant

Considerations

9 CLT Supply Chain – resource, markets and 

manufacturing plant 

9 Logistical – location, personnel, procurement

9 Design – site/plant layout, equipment

9 Establishment – scheduling, management 

staffing, support services, recruiting

9 Operations – operating plan, sales, QC program

9 Maintenance – maintenance plan

254
2 

1 

Current U.S. 

CLT Plants

1. SmartLam, Columbia

Falls, MT

2. D.R. Johnson,

Riddle, OR

3. Euclid Timber Frames,

LC, Heber, UT1

3 

1 Manufacturing Interlocking CLT (ICLT)

255
CLT Supply Chain Project 

Acknowledgements

Renewable Resource Solutions, LLC*

Don Peterson Terry Mace

Heather Ross Kari Divine

USDA FS – Forest Products Laboratory

Mike Ritter Melody Jones

Doug Rammer Dave Kretschmann

Brian Brashaw Delton Alderman

* FPL Cooperative Agreement

Questions?

256
Timber–Concrete Composites

Benton Johnson, Associate 

Skidmore, Owings & Merrill LLP, Chicago, Illinois

Composite construction combines different materials to satisfy the specific requirements of a given 

project. Common examples include composite metal deck slabs, composite steel beams with slabs, and 

mixed systems such as concrete cores with steel framing. This type of construction has steadily 

increased in popularity over the past decades. The rise in popularity stems from the economies gained by 

using different materials where they are most advantageous. The composite system approach can also be 

applied to mass timber structures to make them more economical and more competitive in the market. 

This presentation will discuss how composite timber–concrete systems can be used in a variety of 

building types. Current composite timber–concrete research will also be discussed as it relates to real 

building applications. 

Timber-Concrete Composites 

Mass Timber Research Workshop 

November 3RD, 2015 

Forest Products Laboratory 

Presenter: 

Benton Johnson, PE SE 

Skidmore, Owings & Merrill LLP 

257
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Elements 

STEEL CONCRETE 

TIMBER 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Elements 

Composite Metal Deck 

258
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Elements 

Composite Steel Beams Composite Steel Trusses 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Elements 

Concrete Encased Steel Column Concrete Filled Steel Tube 

259
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Buildings 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Buildings 

Photo © McShane Fleming Studios 

Photo © Ezra Stoller | Esto 

CTBUH Tallest Steel Building Rankings 

***Willis Tower consists of 75,000 tons of steel and 100,000 tons of concrete 

260
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Why Composite? 

Strength Stiffness Mass Acoustics Fire

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Why Composite? 

Strength Stiffness Mass Acoustics Fire

COST 

261
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Learning from Other Industries 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Timber vs. Concrete 

Select Structural SPF 

• Density = 30pcf +/-

• Combustible

• Shrink & swell

• Prefabricated

• Regular load paths

5,000 psi Concrete 

• Density = 145pcf +/-

• Non-combustible

• Shrink

• Cast-in-place

• Complex load paths

C=2,600psi 

T=1,300psi 

C = 800psi 

200psi 

T = 0psi 

= Side Face 

C = 2,500psi – 3,400psi 

140-710psi 

T = 500psi – 2,150 psi 

= Cut 

Face 

= Cut Face 

262
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

SOM Research – Initial Project 

COST 

• Strength

• Stiffness

• Mass

• Acoustics

• Fire Resistance

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

SOM Research – Gravity Framing Report 

COST 

• Strength

• Stiffness

• Mass

• Acoustics

• Fire Resistance

263
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Fire Resistance of Composite Timber Floors 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Timber Floors 

KLH System 

CREE System 

HSK / HBV Mesh Plates 

264
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Composite Timber Floors 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Model Composite Timber Building 

Model Building Diagram 

COST 

• Strength

• Stiffness

• Mass

• Acoustics

• Fire Resistance

265
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Model Composite Timber Building 

Concrete 

Residential 

Tower 

Parking 

Foundations 

R/C Shear 

Wall Core 

Concrete Jointed 

Timber Frame 

System for Tower 

R/C Shear Wall 

System 

Concrete Structure 

at Parking & Retail 

Foundations 

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Model Composite Timber Building 

Concrete 

Residential 

Tower 

Parking 

Foundations 

R/C Shear 

Wall Core 

Concrete Jointed 

Timber Frame 

System for Tower 

R/C Shear Wall 

System 

Concrete Structure 

at Parking & Retail 

Foundations 

Less Concrete 

& Rebar 

Foundation 

Savings 

Faster 

Schedule 

Higher Quality 

Finishes 

Energy Savings 

266
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Strategic Plan for ICC 2021 

ICC Recognition of Composite Timber Floors / Structures 

• Structural testing

• Acoustic testing

• Fire testing

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

SOM Research – Testing at Oregon State Univ. 

267
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Strategic Plan for ICC 2021 

ICC Recognition of Composite Timber Floors / Structures 

• Structural testing

• Acoustic testing

• Fire testing

Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Strategic Plan beyond ICC 2021 

ICC Recognition of Composite Timber Floors / Structures 

• Structural testing

• Acoustic testing

• Fire testing

• Precedents

268
Timber-Concrete Composites 

November 3rd, 2015 

© 2015 Skidmore, Owings & Merrill LLP 

Conclusions 

STEEL CONCRETE 

TIMBER 

Timber-Concrete Composites 

Mass Timber Research Workshop 

November 3RD, 2015 

Forest Products Laboratory 

Thank You 

Contact: 

benton.johnson@som.com 

269
Mass Timber Construction in Utah: Research, Practice, and Futures

Ben Hagenhoffer-Daniel, Assistant Research Professor 

University of Utah, Salt Lake City, Utah 

This presentation is an overview of mass timber research, development, and commercial work, using 

beetle-killed pine from the intermountain forests. This work is performed by an industry–university 

partnership between the University of Utah, Brigham Young University, and Euclid Timber LLC, a 

timber fabricator and general contractor in Heber, Utah. The presentation will include the following: (1) 

Explorations into non-glued solutions to mass timber construction through a product commercially 

available from Euclid Timber LLC called Interlocking Cross-Laminated Timber (ICLT). The 

presentation will explain research on optimizing and testing ICLT for structural and hygrothermal 

performance, case studies of built works utilizing ICLT, and studies into digital interoperability, 

dimensional stability, and economic impacts of drying for alternative non-glued mass timber products. 

(2) The research team has more recently been exploring transverse post-tensioned timber planar 

elements and the potential of cellulose fiber. (3) Finally, the presentation will reveal results of a recently 

released report, “Solid Timber: Process Practice Performance,” sponsored by USDA Forest Products 

Laboratory, FPInnovations, and the AIA that documents 17 case study mass timber projects for their 

cost, schedule, quality, and risk key performance indicators in comparison to traditional site-built 

construction. 

MASS TIMBER CONSTRUCTION IN UTAH

research, practice and futures

Ben Hagenhofer-Daniell, Assistant Research Professor

Integrated Technology in Architecture Center, University of Utah

USDA Forest Products Laboratory - Mass Timber Workshop

November 2, 2015

Partners:

Euclid Timber LLC

Fernando Fonseca, Brigham Young University

Paul Thorley, Acute Engineering

David Kretschmann, USDA FPL

Sam Glass, USDA FPL

270
NO-GLUE 

OPTIMIZATION 

PERFORMANCE

INTERLOCKING CLT

POST-TENSIONED 

TIMBER

DIGITAL WORKFLOW

COST/SCHEDULE

NO-GLUE

271
Source: U.S. Census Data 2000 – 2010 

EXTENT OF COMPLETION EXTENT OF COMPLETION

GLT SCL CLT

DLT CNLT ICLT

GLUED NON-GLUED

Credit: COCIS Edinburgh Napier University & ITAC UofU 

NLT

272
= 

2 million acres

2006 2007 2008 

1.0

1.5

2.0

Source: Colorado State University Report No. 5.528 

44%

Area = 1,000,000 acres

Trees (50 / acre) = 50,000,000 trees

Board feet = 1695 B.F. / tree

Board feet total = 84,750,000,000 B.F.

B.F. / House = 40,000 B.F.

# of potential houses = 2,118,750 Homes

80’

3’

Adapted from DOA U.S. Forest Service Data 

273
2 Ply: 5.5”

3 Ply: 8.25”

4 Ply: 11”

5 Ply: 13.75”

Credit: Euclid Timber 

274
Credit: Euclid Timber 

Credit: Brigham Young University & Acute Engineering 

275
3-PLY ICLT WITH EXTERIOR INSULATION

Exterior to interior:

• Composite wood

siding

• Drainage

cavity/ventilated air 

space

• R-10 insulation

• Vapor-permeable air

barrier membrane

• 3-ply ICLT with no

interior finish

Vapor-open

Mineral wool

Vapor-tight

Extruded polystyrene

Credit: Sam Glass, 

USDA Forest 

Products Laboratory 

276
Credit: Euclid Timber 

277
Credit: Euclid Timber 

Credit: Euclid Timber 

278
Credit: Euclid Timber & ITAC UofU 

Credit: Euclid Timber & ITAC UofU 

279
Credit: Euclid Timber & ITAC UofU 

Credit: Euclid Timber & ITAC UofU 

280
Credit: Girl Scouts of Utah & ITAC UofU 

Credit: Girl Scouts of Utah & ITAC UofU 

281
Credit: Euclid Timber & ITAC UofU 

Credit: Girl Scouts of Utah, ITAC UofU, & AJR Altier 

282
Credit: Euclid Timber, Girl Scouts of Utah, ITAC UofU 

Credit: Euclid Timber, Girl Scouts of Utah, ITAC UofU 

283
Credit: Euclid Timber, Girl Scouts of Utah, ITAC UofU 

Credit: Euclid Timber, Girl Scouts of Utah, ITAC UofU 

284
Credit: Euclid Timber, Girl Scouts of Utah, ITAC UofU 

Credit: ITAC UofU 

285
Credit: ITAC UofU 

Credit: ITAC UofU 

286
Credit: ITAC UofU 

Credit: ITAC UofU 

287
External Post-tension Cable 

Internal Post- tension 

 Cable 

Connection Piece 

Credit: ITAC UofU 

External Post-tension Cable 

Credit: ITAC UofU 

288
Credit: ITAC UofU 

OPTIMIZATION

289
Source: ITAC UofU 

Source: ITAC UofU 

290
Source: ITAC UofU 

PERFORMANCE

291
ELEMENTS USED IN LAST 12 MO?

Source: NIBS OSCC 

NEXT 12 MO?

BARRIERS TO UPTAKE

Credit: COCIS Edinburgh Napier University & ITAC UofU 

BENEFIT OF SOLID-TIMBER

292
293
EXTRINSIC RESEARCH

CONSTRUCTION PERFORMANCE

• COST AND SCHEDULE PERFORMANCE

• WORKER SAFETY

• CHANGE ORDER REDUCTION

SOCIAL BENEFITS

• ENVIRONMENTAL IMPACT

• ALTERNATIVE MASS TIMBER WITH LOCAL SUPPLY CHAIN

• TAX INCENTIVES

MARKETS 

• REGIONS AND BUILDING TYPE COMPATABILITY

• DECISION MAKING / DEMAND MANAGEMENT

• REGULATORY PATHWAYS

PROJECT DELIVERY TOOLS

• DETAILS AND SPECIFICATION INFORMATION

• SOFTWARE TOOL DEVELOPMENT

• CONTRACTS AND PROJECT MANAGEMENT TOOLS

SUPPLY CHAIN DEVELOPMENT

• SALVAGE WOOD SUPPLY

• DRYING INFRASTRUCTURE

294
Blast-Resistant Testing for Massive Timber Exterior Wall: Expanding 

Timber Opportunities in North America

Lisa Podesto, Senior Technical Director

WoodWorks, Aptos, California

This presentation will share the research plan with regard to performance of mass timber walls under 

blast loading. The project goal is to characterize the response of cross laminated timber (CLT) panels 

under blast loading and establish inelastic and ultimate response limits of CLT structural systems to gain 

repeatable approval for CLT construction on United States military bases where there is currently little 

room for wood structural solutions. As a project that recently received funding from the USDA Wood 

Innovation Grant program, the research is intended to support expansion of the U.S. wood products 

market.

Blast-Resistant Testing for 

Massive Timber Exterior Wall: 

Expanding Timber 

Opportunities In North America

November 2015 – Mass Timber Workshop

B-15-91.1

© 2015

Karagozian & Case, Inc.

Karagozian & Case, Inc.

700 N. Brand Blvd.

Glendale, CA 91203

818-240-1919

www.kcse.com

WoodWorks – Wood 

Products Council

www.woodworks.org

University of Maine

Orono, ME 04469

www.umaine.edu

By:

Lisa Podesto, P.E. (WW)

Dr. Edwin Nagy, Ph.D., P.E., S.E. (UMaine)

Mark Weaver, P.E., S.E. (K&C)

Leonardo Torres, P.E., S.E. (K&C)

Garry D. Myers, P.E., S.E. (K&C)

295
B-15-91 Project Objectives pg 2

 Expand market opportunities for wood construction

in Department of Defense and growing civilian

markets requiring blast resistant structures.

 Work with the Army Corps of Engineers Protective

Design Center to develop an acceptable mass timber

blast resistant alternative to steel and masonry.

 Create a basis for inclusion of mass timber

solution(s) in the Unified Facilities Criteria’s

conventional construction provisions.

B-15-91 Project Deliverables pg 3

 Develop analytical methodologies to analyze CLT for blast

loads. Both SDOF and high-fidelity physics-based (HFPB) FE

methods will be developed.

 Conduct static and dynamic CLT testing that tests / improves

developed analytical methodologies.

 Document analytical methodologies and test data in a form that

could be used in blast analysis by structural engineers and

potentially incorporated into SBEDS.

 Establish a foundation for characterizing material dynamic

response of Nail Laminated Timber walls.

296
B-15-91

pg 4

 Conduct literature review.

 Develop preliminary SDOF

analysis methodology.

 Define target conventional CLT

construction.

 Create HFPB FE CLT model.

 Perform static CLT testing.

 Refine SDOF and HFPB FE

analysis methodologies.

 Perform dynamic CLT testing.

 Document literature review,

analysis methodologies, and

testing results in report form.

 Publicize findings of effort.

Project Overview

Approach & Organizational Chart

 Conduct literature review.

 Develop preliminary SDOF

analysis methodology.

 Define target conventional CLT

construction.

B-15-91

pg 5

Literature Review

Overview

 Sources Sought

 Published testing results that document out-of-plane response of 

CLT.

 Case studies that document the usage of CLT in practice.

 CLT standards and design aids.

 Conclusion

 Limited published test results that documents out-of-plane 

response of laminated timber exposed to high-strain rates.

297
B-15-91

pg 6

Preliminary Scoping Analyses

Single Degree-of-Freedom

 Preliminary Assumptions

 Ultimate resistance, ru, and equivalent stiffness, k, derived 

using “shear analogy” method (Kreuzinger, 1999).

 Both flexural and shear stiffness were used to derive equivalent 

stiffness.

 Residual resistance, rr, derived assuming innermost ply(s) 

provides flexural strength.

 Assume immediate softening stiffness is equivalent to 

initial stiffness.

 Static increase factor (from ANSI/APA PRG 320-2012)

 2.1 for out-of-plane flexure.

 3.15 for out-of-plane shear.

 Dynamic increase factor set equal to one and CD = 1

 Response limit: Ductility, P = 1 (i.e., elastic response only).

 All of the above assumptions will be investigated

via the UMaine static testing and ideally refined

based on uOttawa and PDC CLT testing.

k k

ru

rr

'e 'r

Outermost CLT 

ply ruptures

Innermost CLT 

ply ruptures

Schematic SDOF Flexural 

Resistance Function for 3-Ply CLT

B-15-91

pg 7

Preliminary Scoping Analyses

Typical Grade Information

298
B-15-91

pg 8

Preliminary Scoping Analyses

Supported Weight: Wood Panel (i.e., 10 psf)

EWII

EWI

32’

75’

43’

60’

81’ 104’

146’

200’

B-15-91

pg 9

Preliminary Scoping Analyses

Supported Weight: Brick Veneer (i.e., 44 psf)

EWII

EWI

23’

28’

42’

53’

53’

67’

100’

127’

299
B-15-91

pg 10

Preliminary Scoping Analyses

Proposed Conventional Construction Options

Wall Type Sections Span

Min. 

Static 

Material 

Strength

EWI

Standoff 

Distance

EWII 

Standoff

Distance

Reinforced Concrete ൒ 6” 12’ – 20’ 3,000 psi 66 16

CLT – Brick Veneer (44 psf) 5-ply 10’ – 14’ Grade E1 53 23

CLT – Brick Veneer (44 psf) 3-ply 10’ – 14’ Grade E1 67 28

Reinforced Masonry 8” – 12” 10’ – 14’ 1,500 psi 86 30

CLT – Wood Panel (10 psf) 5-ply 10’ – 14’ Grade E1 75 32

Wood Studs – Brick Veneer 2x4 & 2x6 8’ – 10’ 875 psi 105 36

CLT – Brick Veneer (44 psf) 5-ply 10’ – 14’ Grade V2 100 42

CLT – Wood Panel (10 psf) 3-ply 10’ – 14’ Grade E1 104 43

CLT – Brick Veneer (44 psf) 3-ply 10’ – 14’ Grade V2 127 53

CLT – Wood Panel (10 psf) 5-ply 10’ – 14’ Grade V2 146 60

Steel Studs – Brick Veneer 600S162-43; 600S162-54; 600S162-68 8’ – 12’ 50,000 psi 187 75

CLT – Wood Panel (10 psf) 3-ply 10’ – 14’ Grade V2 200 81

Wood Studs – EIFS 2x4 & 2x6 8’ – 10’ 875 psi 207 86

Steel Studs – EIFS 600S162-43; 600S162-54; 600S162-68 8’ – 12’ 50,000 psi 361 151

B-15-91

pg 11

Proposed Static CLT Testing

Overview

 Objective: Investigate out-of-plane behavior of CLT for different

conventional connection configurations.

 Tests will be used to develop resistance functions for SDOF analysis.

 5 to 7 days of testing at University of Maine.

 Proposed panel: 3-ply (and/or 5-ply), two different grades, 4’x8’ specimen

size.

 Two connection configurations to be tested (likely self-tapping screws &

brackets).

 Baseline (i.e., roller supports)

 Brackets (weaker)

 Brackets (stronger)

300
B-15-91

pg 12

Proposed Static CLT Testing

Test Jig Concept

Panels w/o Connections

water bladder

water bladder

Deflection gage

Panels w/ Connections

Reaction floor

Reaction floor

B-15-91

pg 13

 Objective

 To demonstrate the blast resistance capability of cross-laminated timber (CLT) via a live blast 

field full-scale test.

 To validate SDOF and HFPB FE analysis methodologies. 

 Peak Blast Load

 EWII at 30-ft

 Test Configuration Options

 Option 1: One (or two) 1- to 2-story, 30’x15’ two bay CLT structures.

 Option 2: (24) 4’x10’ panels supported by previously constructed reaction structures. For 

purposes of cost, assume 3 panels are tested at a time.

Proposed CLT Dynamic Testing

Overview

Opening

CLT Partition

1st Shot

2nd Shot

OPTION 1

CONFIGURATION

301
B-15-91 Live Blast Testing pg 14

302
Development of a Mass Timber Tornado Safe Room

Bob Falk, Research Engineer

USDA Forest Products Laboratory, Madison, Wisconsin

This presentation will overview the development and impact testing of a tornado safe room built from 

mechanically laminated commodity wood products. Various wall designs were tested and indicate the 

effect of wood product type, fastening, adhesives, and sheathing type on impact resistance. Results of 

testing to develop a wood tornado safe room door will also be presented. 

Development of a Mass Timber 

Tornado Safe Room 

Bob Falk 

Research Engineer 

Forest Products Laboratory 

303
Objectives 

• Design a residential tornado safe room from

commodity wood products

– Feasible for existing housing

– Buildable by a DIY’er

– Most materials available at a big box store

– Low cost compared to existing steel and concrete

safe rooms

– Sized to serve another function and optimize

material usage

Objectives (cont.) 

• Perform wall and door testing to verify design

for EF-5 tornado

– Debris impact testing (2x4 @ 100mph)

– Wind pressure testing (225 psf – 340 psf)

• Build full size room and wind load test

• Develop standard plans and guidelines for

construction

• Develop a dynamic impact model to simulate

wall behavior

304
Cooperative Effort 

• FPL 

– Bob Falk, John Hermanson, Adam Senalik 

• PFS Corporation (Cottage Grove, WI) 

– Deepak Shrestha 

Video Overview of Project 

305
Status 

• Impact test of walls panels and doors completed 

• Research report on wall testing completed 

• Research report on door testing in preparation 

• Pressure testing initiated (in cooperation with PFS 

Corporation) 

• Room built and wind load test setup under 

development 

• Plans and construction guidelines to be 

developed 

• Dynamic impact model developed and verified 

For More Information 

 Bob Falk 

 rfalk@wisc.edu 

 (608) 231-9255 

306
More with Less—An Overview of the First CLT Hotel in the United States

Jeff Morrow, Program Manager

Lendlease, Nashville, Tennessee

This presentation will provide an overview of the construction of the Redstone Arsenal Candlewood 

Suites Hotel built from cross laminated timber.

More with Less –

An Overview of the 1st CLT 

Hotel in the U.S.

Timber Innovations Group

2016 Mass Timber Research Workshop

November 3, 2016

307
2

Cross Laminated 

Timber in the US

Positively disrupting 

traditional construction 

of mid rise structures

REDSTONE ARSENAL CLT PERFORMANCE COMPARISON VS. PREVIOUS METAL STUD NEW BUILD HOTELS IN PAL PORTFOLIO 3

PAL PORTFOLIO 

TYPICAL NEW 

PAL HOTEL 

(ACTUAL*) 

REDSTONE 

ARSENAL 

(ACTUAL) 

DIFFERENCE 

Gross SF 54,891 62,688 +14%

Average # of 

Employees 18 (Peak 26) 10 (Peak 11) -43% 

Structural 

Duration 

(Days) 

123 78 -37%

Structural 

Man Hours 14,735 8,203 -44%

Structural 

Production 

Rate/Day (SF) 

460 SF/day 803 SF/day +75% 

Overall 

Schedule 15 months 11 months** -27%** 

The Case for CLT / Modular Construction 

* PAL New Build Hotel Historical Average 

**Forecasted completion 10/26/15 

308
MARKET SECTOR STRATEGIES 4

The Sweet Spot

CLT should be strongly 

considered when a 

project experiences 

3 of these 4 

conditions.

y

5

309
6

7

310
1 8 ST FLOOR CONSTRUCTION FLOOR CONSTRUCTION

9

311
10

11

312
1213

313
14

15

314
16

17

17

315
18

19

316
20

TRIPLE BOTTOM LINE SUSTAINABILITY HIGHLIGHTS 21

Economic 

• 27% Faster than Traditional Metal Stud Construction 

• Cost Neutral to Metal Stud Framing

Environmental 

• 27% more energy efficient than previous PAL New Hotels of similar size per current energy model 

• 1,656 tons carbon sequestered (1 m3 of timber = 1 ton CO2) 

Social 

• Unemployed Veterans were upskilled in the construction trades.

• Eliminated exposure to falls for workers from elevated heights.

317
22

Smart Design Cannot Eliminate 

Human Error

LESSONS LEARNED

23

R&D Priorities

• Testing

• Fire (UL)

• Force Protection / Blast Resistance

• Seismic

• What is the correct R-value?

• Acoustical

• Thermal Envelope

• Vibration

• Regulatory/Political

• AHJ Acceptance for taller buildings

• Union Acceptance

• DoL Recognition – CLT Installer

GOING FORWARD

318
24

Cross Laminated 

Timber in the US

Positively disrupting 

traditional construction 

of mid rise structures

25

319
26

320
Keynote Presentation

Challenges of Building with Mass Timber in the United States

Robert Malczyk, Principal

Equilibrium Consulting, Vancouver, British Columbia, Canada

Equilibrium Consulting has been recently commissioned to work on two large U.S. based university 

projects: Integrated Design Center at UMass in Amherst Massachusetts and Peavy and AWP Research 

and Testing Building at Oregon State University. The purpose of this presentation is to present the wide 

variety of issues that we are confronted with by the design team when a project uses a mass timber 

solution. This presentation will list major challenges and elaborate more on the ones that can be 

addressed by research and development and code authorities. 

Challenges List:

1. Find appropriate CLIENT.

a. Educate the client.

b. Develop trust.

2. Identify available GRANT – if possible.

3. Develop political support: federal, state or local

4. Find an open minded LOCAL CONSULTANT TEAM.

a. Timber Engineer and EOR relationship – one or more structural consultants.

b. Mechanical and Electrical

c. Code – Fire

5. Educate client and consultant team about not code based parameters:

a. Vibration criteria and limits.

b. Deflections including creep and visual effects.

c. Sound transfers.

6. Know what is currently in and what is coming up in local design CODES

7. Find appropriate PROJECT DELIVERY METHOD and scope of contracts: fabrication with or

without erection.

a. Construction Manager with open mind and willingness to change.

b. Try DESIGN ASSIST to lower costs and get Mass Timber fabricator on design team.

8. Identify and pre-qualify SUPPLIERS and ERECTORS of Mass Timber.

a. U.S. based

b. Canadian

c. EU based

9. Shop drawing coordination.

a. Cadwork, Dietrich and AutoCad.

b. Viewers and software education.

c. Use of Revitt 3D by architect – liability.

10. Negotiate a CONTRACT at the right time when scope becomes clear during design assist.

a. Develop a system to deal with extra costs and savings resulting from design assist.

i. Volume CLT pricing

321
ii. Steel connection pricing for:

1. Simple plates and bars

2. Simple connectors – hangers

3. Complicated geometry connectors.

4. Patented systems.

11. Use of PATENTED SYSTEMS.

a. Appropriate approvals and testing for:

i. Composite Floor Systems.

ii. Hold down systems and large capacity shear transfer systems.

12. Education and coordination with other trades on construction site.

a. Concrete – accuracy and fit

b. Mechanical/Electrical

c. Finishes: steel studs and drywall.

13. Coordination with erection contractor

a. Experience with working with wood.

b. Shoring: timing and coordination with other trades.

c. Erection plan.

d. Temporary stresses – lifting points

14. INSPECTIONS;

a. Local engineer for day to day inspections.

b. Use of photographs.

c. Final inspections

15. As built drawings to accommodate fabricators changes.

a. Shop drawings versus structural drawings.

b. 3D model as as-built

16. Maintenance plan:

a. Inspection after one heating season.

b. Client education when new systems introduced – Passive House.

322
CLT ?

EU TRAVEL

PUBLICATIONS

CONSULTANTS

SEMINARS

323
SOURCES

RELIABLITY

PRELIM & FINAL

COMPARISSON

PRICE

ESTABLISHED:

CONCRETE

MASONRY

STEEL

UN-RELIABLE:

WOOD

PRICING

324
COMPETITION

NLT

BRISCO

CONCRETE

FRAMING

LVL/LSL

PUBLIC

PRIVATE

DEVELOPER

RENTER

CLIENT

325
FIRST TO BE SECOND

GRANTS

PILOT PROJECTS

GOVERNMENT

INDUSTRY

FEDERAL

STATE

326
ARCHITECT

CONTRACTOR

CM

GENERAL 

DESIGN ASSIST 

PAYMENTS

SCHEDULE

327
FABRICATOR

SPECIALTY 

STEEL

GC

ERECTION

SPEED

PREFAB

EASY TRADES

FIT

328
PATENTED SYSTEMS

FABRICATOR

CANADA

EUROPE

USA

329
BUILDING CODE

UPCOMING EDITIONS

TECHNICAL APPROVALS

FOREIGN CODES

GUIDELINES

TESTING

LATERAL

R FACTORS

CONNECTIONS

BRACING + SW

WIND DRIFT

330
SYSTEMS

TESTING

APPROVALS

ALTERNATIVES

KNOWHOW

CODES

PRICE

REPORTS

APPROVALS

SYSTEMS

CODES

TESTING

331
RESEARCH

IDEAS

NEW SYSTEMS

DESIGN INFO

REPORTS

CODES

HOLD-DOWN

RIVETS

SCREWS

HSK

??

332
NAILS

R

US

VIBRATION

PERCEPTION

DEFLECIONS

LIMITS 8 HERZ?

TOPPING

CODE

333
DEFLECTION

LIMITS

ACCURACY

OVERHANGS

CREEP

ACCOUSTICS

PERCEPTION

EU SYSTEMS

TOPPINGS

PRICE

CODE

334
CODES

IBC 2015

O-860-16

FPINNOVATIONS

EU REPORTS

FABRICATORS

IDB AMHERST, MA

335
UBC ESB

DESIGN

ASSIST

CONCEPT

60% DRAWINGS

INCENTIVES

RESULTS

336
SUCCESS?

CLIENT

PRICING 

CONSULTANTS

FABRICATOR

ERECTOR

CHALLENGES

337
CHAMPION

338
Summary of Breakout Sessions

Breakout Session 1—Resistance to Lateral Loads 

Doug Rammer, FPL (session moderator) and Adam Senalik, FPL (session assistant), led discussions 

with attendees for this session. Detailed notes recording discussion points are provided in Appendix 1. 

Rammer and Senalik summarized key findings of this session as follows: 

Seismic Design Parameters Research 

Completion of the FEMA P-695 research at Colorado State University (CSU) to develop R-factors for 

seismic design needs to be a high priority. Aspects of this study that are important to the future use of 

CLT include comparative performance of long/short walls with various aspect ratios and an analysis of 

the performance of connections. Is a FEMA P-795 study for connections needed, or can the results of 

the CSU study be extrapolated to other connection systems? 

Full scale validation (3 stories to 10 stories) tests are needed to gain a better understanding of building 

height limitations for CLT construction. The effect of openings in CLT shear walls is another design 

aspect that needs to be evaluated through testing. 

While most of the research focus to date has been on CLT, similar research is needed to determine 

design parameters for nail laminated systems. 

Diaphragms

In addition to the performance of CLT as shear walls, it is critical to complete research that will quantify 

the diaphragm behavior of CLT systems. Full-scale diaphragm testing is needed to validate finite 

element models that have been developed to establish a reliable design approach. The effects of 

openings in CLT diaphragms needs to be studied 

Also, research is needed to determine how balloon versus platform framing influences CLT diaphragm 

performance. Research efforts need to be expanded to other systems, such as nail laminated decks. 

Resilient Seismic Systems

The rocking wall system research needs to be continued, and the effect of deformation (soft story) is 

important to understand. Post-tensioning could be highly beneficial, but how this will work needs to be 

better understood. Subassembly validation is required, plus large-scale validation followed by a fire test. 

Connections

Research is needed on high-capacity connections for overturning and shear forces because these forces 

can be quite high in a multi-story mass timber building. Is the failure mode of pullout of nails at the base 

of shear walls a correct design approach, or do we need to evaluate alternative failure modes? 

Deformation compatibility between lateral and gravity systems is an important consideration that needs 

further study.

339
Are glued connection systems viable, and if so, what research is needed? 

Connection innovations for fire protection to achieve 1- and 2-hour fire ratings is very important and 

needs to be a high-priority research item to advance CLT into “tall” buildings.

More testing is needed at both connections and component levels. 

Other Design Topics 

A better understanding of the 3D behavior of mass timber (CLT) buildings is needed. 

Advances in numerical/structural modeling of mass timber framing systems are needed. But are such 

models adequate for the design community? Do designers need a commercial software package, and 

how can this all interface with Revit/BIM? 

Information availability and coordination for structural design is needed (i.e., there is a critical need for 

a clearing house for CLT design information). 

The development of a simplified design guide needs to be considered. Related to this is the need to 

update the CLT Handbook to reflect the latest information available.

Breakout Session 2—Building Performance: Durability, Sound, Vibration, 

Life-Cycle Assessment (LCA) 

Jim Bowyer, Dovetail Partners (session moderator), and Sam Glass, FPL (session assistant), led 

discussions with attendees for this session. Detailed notes recording discussion points are provided in 

Appendix 2. Bower and Glass summarized key findings of this session as follows: 

Acoustics

Because many CLT projects to date have been multifamily apartments or condos, acoustics is a major 

concern and research is needed to provide designers with guidance on how to best achieve good acoustic 

performance using CLT assemblies. The research needs to cover a wide range of sound frequencies and 

construction systems. 

Life-Cycle Assessment (LCA)

It was agreed that an LCA study comparing a CLT-framed building with competitive materials is needed 

to demonstrate the environmental benefits of using CLT. The project or projects need to be carefully 

selected based on reproducibility of results, having willing partners providing data sharing, and 

publishability. 

Vibration/Creep

Vibration is a key design consideration for CLT-framed floors. Additional research is needed to better 

quantify floor vibrations, especially for CLT systems that span continuously from one building area to 

340
another, such as between apartments and corridors. Many variables can impact vibration performance, 

such as spans, boundary conditions, and floor weight, and the impact of each of these needs to be 

assessed through research. 

Another vibration issue that needs research is the effect of vibrations induced by wind forces on the 

performance of tall wood buildings. Very little is known about this phenomenon, and designers need 

guidance as the heights of mass timber buildings increase.

Creep in horizontal floor and roof systems due to long-term applied loads is well understood for many 

wood products. But little is known about creep performance of CLT panels, and research is needed to 

better understand this design parameter. 

Durability

In accordance with PRG-320 and the IBC, CLT is limited to dry use conditions. However, it is 

recognized that CLT panels may be subjected to bulk water, such as during transport, on site 

construction delays, the possible breach of the building envelope, fire sprinkler activation, or internal 

plumbing leaks. Research is needed to evaluate the performance of CLT panels when subjected to 

exposure to bulk water. 

General Building Performance

Overlap of all performance areas on a set of typical details for multiple archetypes, including fire, 

vibration, creep, acoustics, and the moisture/building envelope, need to be better understood. 

Breakout Session 3—Fire Safety 

Kuma Sumathipala, American Wood Council (session moderator), and Sam Zelinka Glass, FPL (session 

assistant), led discussions with attendees for this session. Detailed notes recording discussion points are 

provided in Appendix 3. Sumathipala and Zelinka summarized key findings of this session as follows: 

ICC Height and Area Limitations

Existing ICC limitations for Type IV (Heavy Timber) come from a historical basis with numerous 

assumptions, and new state-of-the-art firefighting capabilities have not been accounted for. It is 

essentially a political issue, and the wood products industry needs to develop fire performance data that 

can be used to address/revise these limitations in light of new information. As a first step, the ICC has 

issued a public comment request to create a committee to look at Tall Wood Buildings; an ad hoc 

committee will be formed in early 2016 to begin discussing this. Fire performance research is needed to 

substantiate industry claims in support of this effort. 

Alternative Means and Methods

Engineering design firms want third-party accredited test report data on assembly and component fire 

resistant characteristics. Preference is for manufacturers to be the source of these reports, but this is very 

expensive and probably not feasible. Plus, most North American labs cannot fully load a CLT wall 

during an E119 wall fire test. What are the alternatives for developing and providing this information? 

341
Fire performance of mass timber structures with different degrees of exposed timber needs further study.

Adhesives

The type of adhesive used in CLT will affect performance levels due to delamination and hence multiple 

flashovers. Most CLT fire test data in North America is based on PUR adhesives, which is also the 

adhesive used in Europe. Research is needed on fire performance of CLT using a broader range of 

adhesives, such as the work begin done at FPL, and this effort needs to be expanded. It is desirable if 

this research can evaluate adhesives that are similar in manufacturing time/ease and also are 

formaldehyde free. 

Education of Fire Service and Code Officials

Communication and education of fires service and code officials regarding fire performance of mass 

timber structures is a major barrier restricting growth of these building systems. How can we educate 

these groups efficiently about how CLT assemblies perform in fire? Would 1- or 2-hour seminars for 

fire service and code officials in the United States work, and if so, how would they be funded? 

In Canada, demonstration projects for fire performance of elevator shafts were conducted and fire 

service representatives were invited to observe the tests. Two-day workshops for fire chiefs also 

were held. 

Extensive documentation is needed to demonstrate that mass timber can offer not just “equal to” but 

“better than” fire performance of other competitive construction systems. 

Risk Analysis

Considerations of property protection (sprinkler efficiency, redundancy), life safety, water damage, and 

occupant modifications to passive fire protection must be analyzed and provided to the insurance 

industry and fire services and code officials to bring them up to speed and favorable to mass timber 

construction. 

Need to understand and calculate entire risk scenario and how to compare mass timber to traditional 

construction 

Fire Resistance of Connections

There is no fire test standard for screw or bolted connections such as used with mass timber, but 

designer’s need 1- and 2-hour fire-rated connection information. There are some recommended 1-hour 

rated connections for glulam, but none have been fire tested and there are no 2-hour rated glulam 

connections. Does every potential connection system need to be tested, or can typical connections be 

tested and models be developed to expand to other systems? This can be very expensive—is it the 

responsibility of connector suppliers, CLT manufacturers, or others? Not having this information has the 

potential to limit the broader application of mass timber to tall buildings and is a high-priority research 

area.

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Need to document existing field data that demonstrate the performance of connectors in fire situations. 

When failures occur at connections, what is the nature of the failure and how can we learn from it? 

Breakout Session 4—Material Resources and Other Topics 

Brian Brashaw, FPL (session moderator), and Xiping Wang, FPL (session assistant), led discussions for 

this session with attendees. Detailed notes recording discussion points are provided in Appendix 4. 

Brashaw and Wang summarized key findings of this session as follows: 

Materials—Resources

A recurrent topic of discussion was the importance of research that will lead to optimizing the available 

timber resources for mass timber. Questions were posed regarding the certainty of supply to support a 

growing industry. The importance of evaluating use of beetle-killed timber and forest restoration 

materials was emphasized as well as a need to evaluate use of hardwoods and other underutilized 

softwood species. 

Strategies are needed to bring wood resources to market and to further develop the supply chain. 

Certification opportunities need to be better understood as they impact the expansion of available 

resources, and more information is needed regarding properties of hybrid/composite systems. 

Manufacturing Issues

A “tension” seems to exist between standardization of CLT products and promotion of custom products. 

PRG 320 provides seven standard grades (layups) but clearly supports the development of custom 

products by individual manufactures that support their specific available resources. As this industry 

evolves, this issue should become less of a point of controversy, much like the glulam industry promotes 

both standard and custom grades. 

Optimization of manufacturing to reduce costs is important.

• The use of a wider range of lumber species and grades is needed.

• Adhesives and press cycles need to be better understood.

• Manufacturing process needs to be studied with an emphasis on issues such as workforce training,

labor considerations, and optimum crew size.

Need exists to determine what is the best business model for CLT to attract additional manufacturers, 

(i.e., capitalization costs, inventory control, and labor force considerations). 

It is important to understand what technical assistance and manufacturing support is available to current 

and potential new manufacturers. 

Durability and Preservation

Minimal information exists related to the preservation side, such as the need for water protection and 

what environmentally friendly preservative treatments are available. Treatment options and their effect 

on material properties need to be studied. 

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A myriad of durability issues related to the use of composite and hybrid systems exist and need to be 

better understood to advance the use of these emerging technologies. Of particular interest is what 

happens at the interface between concrete and CLT, and studies are needed to make sure there are no 

concerns on long-term durability. 

Moisture and Stability

Wood–moisture relationship is important for CLT, such as dimensional stability and the impact of 

system and manufacturing modifications.

Need to know how important it is for the materials to be kept dry during the construction process. What 

problems will occur if it gets wet? Needs to be addressed and solution identified. 

Other Topics

More extensive marketing information is needed to expand the industry, such as green building markets, 

blast-resistant structures markets, and niche non-building markets. 

Policy incentives, such as those associated with GSA purchasing vs. public buildings vs. private 

construction, all impact future markets and need to be better understood. 

Deconstruction and reparability of CLT buildings need to be understood. 

What trade association can best represent CLT? APA is currently certifying all N.A. production, and 

AWC is heavily involved with codes and standards related to CLT.

Research database is needed for mass timber. A vast amount of research has been published, and a 

significant need exists to have a central source of this information

Close-Out Session to Prioritize Future Research Needs

Tom Williamson, Workshop Facilitator, led a discussion with attendees to try to prioritize future mass 

timber research needs. Key observations were reported as follows:

Resistance to Lateral Loads

The development of CLT shear wall system R factors and design guidelines and examples for seismic 

performance were identified as a high priority. Current testing at Colorado State University (CSU) 

needs to be completed with the understanding that whatever comes of the current FEMA P-695 

project will be limited based on the scope of what was able to be modeled and validated by testing and 

those limits will become the future barriers to CLT use. 

Diaphragm testing and design guideline

a. The testing of connections and full-scale experimental diaphragm testing are needed to quantify the

behavior and failure modes of CLT systems.

b. Design and modeling guidelines are needed to enable designers to use CLT and lead to the eventual

standardization of design methodologies. 

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Whether the lateral force resisting system is a wall or a Heavy Timber Buckling Restrained Braced 

Frame, the diaphragm comes into play for seismic load transfer and becomes an important design 

consideration that needs further study. A concern exists that details of panelized CLT diaphragms may 

produce brittle behavior and loss of structural function in seismic overload situations and this needs to 

be evaluated.

The deformation compatibility between gravity framing and lateral deflections needs further evaluation. 

The Heavy Timber Buckling Restrained Braced Frame (BRB) seems very promising, but a FEMA P695 evaluation will probably be needed to prove that surrounding wood elements and construction 

details developing the strength of the BRB can indeed function as intended prior to a broadly 

accepted code/standards recognition. 

Connections 

a. A FEMA P-795 research study is very expensive for product manufacturers to pursue and thus may

not be a viable option. Preference is for the FEMA P-695 testing at CSU to identify the 

establishment of performance criteria/parameters that connectors must meet so that additional costly 

testing does not need to be repeated. 

b. Higher capacity connections and construction details for mass timber framing are needed such as for

overturning and shear forces. 

Building Performance

Moisture research is needed to demonstrate moisture performance of CLT and tall wood buildings 

during transport, construction, and operation cycles. Little is known about the effect of exposure of CLT 

to bulk water, and this needs further study. 

Vibration research

a. Need exists for performance-based vibration design guidelines for mass-timber floors because this is

a key design consideration. 

b. Many variables impact vibration performance, such as spans, boundary conditions, and floor weight,

and all these need to be assessed through future research. 

c. Coupling vibration research with acoustics research could be beneficial.

Wind-induced vibration in tall wood buildings is another design consideration that needs evaluation 

from both occupant comfort and structural performance perspectives. 

Overlaps of all performance areas on a set of typical details for multiple archetypes, including fire, 

vibration, acoustics, and moisture/building envelope, need to be better understood. 

Fire Safety 

Connection performance—Fire resistance ratings of connections used in HT/mass timber applications 

are needed, whether concealed or otherwise. It was noted that there may not be standardized testing for 

this, so perhaps research should help determine what that standard should look like. 

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Adhesives 

a. It was observed that adhesive performance is a concern due to delamination and hence multiple

flashover, and further study of this is needed. 

b. A need exists to establish which adhesives are at least similar in manufacturing time/ease and also

are formaldehyde free—from there further fire performance testing would be useful. 

Communication and education regarding fire performance of mass timber structures is a major barrier 

restricting market growth of these building systems. How do we best share this information with fire 

service and code officials and the insurance industry? 

Need exists to develop documented fire performance data to convince the ICC to increase heights and 

area limitations for Heavy Timber/mass timber construction (Type IV). 

Fire performance of structures with different degrees of exposed mass timber needs further 

documentation. 

Risk analysis/risk modeling is needed. Is there an additional fire risk associated with mass timber 

buildings? Probably not, but how do we prove it to the insurance industry? 

Need proof that CLT/mass timber performs in a superior way from other framing systems when 

exposed to fire—perhaps through full-scale fire demonstration projects.

Material Resources and Other Research Topics

More information on the costing aspects of CLT is needed. Is it cost competitive, and if not, what 

research needs to be done to address this? As first steps, we need to do the following: 

a. Develop a series of case studies with detailed cost information

b. Complete economic impact studies

c. Undertake general market research associated with costs

Better understanding of sourcing for mass timber products is needed. Gap appears to exist between the 

wood fiber that we “need” to use, such as beetle-killed and forest fire thinning materials, and what is 

accessible/economical to use. 

General

A lot of time and effort goes into finding information regarding mass timber research, and a wellmaintained and easy-to-access industry database is needed.

A concern was expressed as to how the wood products industry is going to train future leaders to carry 

these efforts forward at both the university level and the practicing professional level.

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Appendix 1—Discussion Notes for Breakout Session 1, Resistance to 

Lateral Loads 

Doug Rammer and Adam Senalik reported discussion points from attendees for this session as follows: 

R-Factors for high-aspect-ratio CLT panels—how much reduction in R is based on aspect ratio, or is it 

something with the specific system evaluated reducing the R values. CSU test program limited aspect 

ratio during testing to 1:1. What will happen with aspect ratios less than one? Response is currently 

beyond the scope and reduction unknown. 

Displacement capacity is important and is driving the R-Factor. Difficult to drive results in one 

direction. Results expected in December. Design provisions were present before starting, and the current 

study now designed to those provisions. If those provisions are changed, the project would need to be 

started over from scratch. 

Trying to get the panel activated rather than just connections. End of first quarter, 2016, will have more 

results. Wind rather than R-factor will likely guide construction on East coast. Need to move away from 

statics and think deformed shapes as it yields better design. 

How do we determine the proper design parameters to plug and chug to design a building in CLT? Do 

we have the R factors to design them? Seismic design is a blank area. It is not out for public release yet. 

Reports will be reviewed and out within the next 6 months. It will probably come out as a FPL 

publication and will be in public domain. Then it has to go to the building seismic safety council 

(BSSC) then to ASCE 7 and ultimately the I-codes for adoption and general use by designers. 

National building code of Canada—is there any methodology to recommend an R value based upon 

height? 

Is there anything available right now for R factor? CLT Handbook hints at R value and gives preliminary 

values. State of Oregon has pulled in values from ASCE 7. You can go to a municipality and show that a 

high seismic area has made a decision regarding R values.

How are the CSU numbers comparing to the Oregon numbers? Group in Canada said an R of 3 would 

be a good number. There was talk about two R’s at one time. Everyone thinks it will be greater than 2. 

R = 1.5 for long panels. Long brittle system. It’s a business decision of best product for least cost. 

Low seismic performance factors probably won’t have much effect. 

CLT shear walls with openings are an area of interest that needs to be researched.

What do we need to know to design the connection systems? The R value testing will help guide the 

connection system to achieve those R values.

Balloon type framing different than mounted to slab. Platform framing—if you have ductile layers you 

will have large R.

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Most test results show the failure mode is pullout of nails at the base of shear walls. Is there another 

system where we find that acceptable? Systems with axial loads on the walls; should we be providing 

greater support at the base of those walls? 

On the Canadian projects, when will that information be made available? We need to be knowledge 

sharing, but when you are in the middle of the research there is nothing to yet share. As practitioners we 

have to protect our intellectual property. How do we get around that? 

What can be shared and when depends upon the nature of the research. There is a commitment that 

information that is publically funded will be made available to the public. When something is 100% 

publically funded that information will be made available. When a private firm or nongovernment 

research organization is involved and they pay a percentage, then IP issues become relevant. There is an 

increasing incremental portion that is coming from private interest groups. 

Have efforts been made to look at heat transfer? Heat transfer of lateral connection systems may be a 

research area. Efforts are going to be made at looking at the deformation compatibility of the 

connections. That is a test that is good for seismic and fire testing.

Is shake and bake testing being planned? The UCSD shake table is an option, but a burn test would have 

to be off the shake table. It might be possible to construct the test assembly on a movable platform that 

can be moved off after the shake test. 

Some shake and bake tests have been conducted but the fire was in a compartment.

National Science Foundation does not mix shake and burn. 

Besides fire resistance, are there CLT grading procedures after a fire event? Has anyone looked at that?

Tall wood building in Portland—Has anyone looked at sandwiching two panels together to create the 

larger cross sections needed. 

What about flexible diaphragms? Current R value of 1.5 is based upon rigid diaphragm. For diaphragms, 

the connections have such a large effect; we are not certain how close the FEM equations will be. A fullscale diaphragm test is a high priority. A light frame wood diaphragm—gaps that closed versus closed 

gaps did not have a great difference analytically. Connections will have a large effect on the behavior of 

the CLT diaphragm. 

We have great modelers, but we are being asked to show the models are accurate with full-sized test. 

Some people we are dealing with are treating CLT as dangerous systems because of the unknowns. One 

research need is more large-scale testing to validate the models, and there are tests being planned for 

full-size diaphragms. 

Need exists for multistory shake table tests. Some engineers are concerned with a failure mode between 

walls and floors. 

Should be testing the entire diaphragm and evaluating platform construction vs balloon construction. 

Once we have diaphragm behavior, then we extrapolate to uses in 3D. 

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A nail laminated platform will be difficult to test because it will likely take 500 kips.

The walls have a big effect over the chord action. Light frames don’t count that, but found it has a large 

effect. How many buildings will have CLT walls that go the length of the diaphragm?

Where can you get information regarding connections other than nails for CLT diaphragms? If the 

connections are proprietary, then the vendor should have that information. 

R-value and diaphragm are critical. Should we put all our resources in achieving good R-value and 

diaphragm information on a fast track? 

Tall wood buildings—deformation of panels with regards to connections needs to be looked at. Wood 

gave more play and torsional effects. Is there a way to work with the connections to avoid that rather 

than bulk up the system? 

Is there value in understanding rocking walls vs nonrocking walls? 

Resilience requirements/market need. Rocking wall systems—idea of a big test. It is feasible, but is it a 

priority? Likely earthquake will be an event with aftershocks. How many shakes will this take before it 

fails? If we set up a big test, we are going to run multiple tests. So this issue would likely be addressed 

in a large-scale test. It should be a priority. Is there a way to do the diaphragm tests? Maybe isolate 

horizontal and vertical tests? How about doing two-story tests, where the diaphragm tests could be 

performed, to improve the models and then do the seismic tests? Could do an assembly test, then do a 

diaphragm test? It can be done, but everyone needs to buy in to justify that type of testing. 

If post tensioning is a solution, there is a great deal of information available in the bridge area. There are 

small tests that can be started regarding creep and deformation. With regards to LVL there is 

information. There needs to be detail regarding how these systems will be used to avoid crushing. 

CLT in post tensioned systems makes sense. The next progression might be prestressing, but we need 

answers to questions and the precast concrete industry might be a resource. 

Design guides help get the technology into the community. This is what the post-tension balloon vs. 

platform framing testing will provide. Researchers have to publish for credit prior to widespread 

distribution. 

Need early design guide for second tier level users for architects and engineers just starting in the area of 

CLT. Simpler than the CLT Handbook. 

Is there any software for CLT? Feeling regarding models: is there more modeling needed or are people 

comfortable with them? Numerical modeling software. Design software. REVIT plug-in potentially. 

Building information modeling. Need to update CLT handbook on structural design. 

Standard drawings for using CLT by architects, or protocols would be helpful. 

Any need to come up with repair procedures for CLT if a building has gone through an event and some 

of the connections have been dislodged? All the codes are written for life safety to let the people get out. 

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Post-event recovery is not part of the code. Those living in the building may be willing to pay for some 

of the resilient systems and it would be good to anticipate that now. 

Is there value in seismic retrofit to buildings? CLT has an advantage because it can be sized per 

application. 

Connections aren’t a “sexy” area. Most of the shear walls will be clad so you won’t see the connections. 

For braces, they will be visible and can be detailed beautifully. However, it is an area of possible 

differentiation that could be an advantage. 

General comment regarding USDA award buildings. There will be funding for testing. Is there any 

coordination for the testing? There was discussion for a smaller group to coordinate activities as a 

whole. That was partially the objective of this meeting to bring interested parties together to be that 

group. There have been discussion regarding the FPL or AWC leading that group, but this meeting was 

the first step. Canadian Wood Council is somewhat doing that in Canada. We need a similar effort in the 

US.

Bottom line is that some organization needs to step up and coordinate the research information related to 

mass timber research.

A lot of time and effort goes into finding information regarding CLT and a well-maintained, easy-toaccess industry data base is needed.

Appendix 2—Discussion Notes for Breakout Session 2, Building 

Performance: Durability, Sound, Vibration, Life Cycle Assessment (LCA)

Jim Bowyer and Sam Glass reported discussion points from attendees for this session as follows: 

LCA-related comments

LCA: what are some of the key considerations? 

• Need to identify realistic projects

• Need to look at four alternative systems (in design)

What makes a good LCA project? 

• Reproducible

• Willing partner, data sharing, publishable

Looking for comparative LCA study—wood, concrete, and steel-framed buildings. Question posed as to 

whether we can skip the comparison study and just do an LCA on CLT as a component. Response was 

generally “no” as we need to identify a project suitable for a comparative LCA analysis because the 

competition of high importance is dominantly steel, concrete, or composites, and comparative LCA is 

needed to provide answers needed by designers. 

Look at LEED, Green Globes, and restrictions on comparative LCA—what does it mean in practice?

Environmental building declaration vs. product declaration. Current work on whole-building LCA. Do 

we have LCA for CLT? Comparative LCA on Burnaby building (CLT vs. concrete). CLT higher fossil 

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impact from adhesive. One goal of LCA is to lower environmental impact at manufacturing. Need to 

develop EPDs on 5-year basis. 

Comparative operational energy analysis needed: CLT vs. other structural systems. Passive house 

examples could be used. 

What are the wood thermal resistance benefits? Need exists for whole building energy modeling and 

monitoring. 

Develop actual operational cost data from Redstone CLT project vs. identical building in steel stud. 

Moisture issues

Research on adhesives to provide lower environmental impact, better resistance to heat and moisture; 

bio-based alternatives needed.

Water vapor permeability of adhesives needs to be better understood. 

Long-term research on mold on interior, decay, termites, carpenter ants, etc.—need for preservative 

treatment is needed? What happens at concrete–wood intersections in hybrid construction? 

Preservative treatments—do they affect the performance of CLT? 

Does building physics change with mass timber? E.g., types of weather barriers?

Long-term moisture effects on mass timber: potentially a huge problem; solutions for construction 

moisture; recommended moisture content before enclosing the building. 

Design optimization for CLT building envelope performance is needed to evaluate value vs. cost. 

What is the impact of wetting at CLT lamina that is not edge-glued? 

What is the effect of bulk water on CLT such as wetting by sprinkler activation or plumbing leak? 

Procedures for retrofitting/remediation after wetting from post-fire-sprinkler need to be investigated.

What is the impact of concrete topping over mass timber on moisture, durability; look at data on gypcrete over OSB; do differences in adhesives come into play?

Vibration/creep-related comments

It is claimed that vibration drives CLT design; how solid is the research basis? More data needed to back 

up design; what can be done to optimize? Can the application of stiffeners help to increase spans? 

U.S. codes don’t have objective approach for floor vibration; performance is a design choice. Need to 

define range of mass of floors as basis for vibration. Many guidelines: which one should the designer 

use? Many parameters affect performance—spans, connections, etc. 

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Wind-induced vibration in tall buildings: is dampening needed? At what height does it become a design 

issue? Interaction between building vibration and floor vibration? Monitoring on tall buildings in 

Canada shows it’s an issue. What about tornado, hurricane? Extreme events can be designed for 

structurally, but how about from a vibration perspective.

How does the layout of panels in relation to partition walls affect vibration issues? 

Creep performance of CLT panels: do we know what we need to know? No, and additional research is 

needed.

Acoustics

Anecdotal solutions. Mitigation methods differ by frequency; need to focus on critical range; low 

frequency; how to manipulate mass and stiffness and how does it affect fire rating? 

Where should research be focused on vibration and acoustics? Sound transmission through columns; 

detailing between columns/floors.

Perceptions of sound differ geographically and internationally; need to develop methods that account for 

different expectations.

Overall building performance 

What kind of building monitoring equipment is needed that is unique to mass timber to provide useful 

building performance information for practitioners? 

Do species, grade, adhesive used to construct CLT impact sound transmission, vibration, stiffness, 

deflection, creep, thermal resistance? Probably, but additional testing on each building performance 

element is needed.

Post-occupancy interviews regarding perceptions of acoustics, vibration—research ISO method for 

evaluations. 

Can building performance issues be addressed at manufacturing? Maybe, but it is mostly a 

design/system issue.

What happens at panel joints—need for flexibility for seismic, but how to treat joints for moisture, 

thermal, and air control. Multiple performance criteria: fire, structural, building envelope need to be 

further evaluated.

Foam gasketing at joints for acoustics, vibration, air sealing—are they effective and what is the 

cost/benefit proposition? What is the range of density to choose for specific applications? 

Relation between thermal resistance (R-value) and heat capacity (thermal mass) in building energy 

performance important and needs to be better understood for mass timber systems. 

Need to evaluate coating technologies for CLT for moisture protection and intumescent coatings for fire; 

effect on system cost vs. benefits derived. 

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How does the application of coatings during manufacture vs. on-site affect performance and costs?

Steps after CLT is constructed: how to build CLT structures for compatibility with trades with standard 

details for mechanical, electrical, plumbing.

Critical details for CLT based on archetypes—test for each design criterion (acoustics, vibration, fire, 

moisture); note differences between residential and non-res structures.

Major issue

Who is going to train next generation of designers on wood and mass timber design? Need to think 

strategically about research and education and training. Is there a role for the FPL similar to the FPL’s 

Clark Heritage training program of educators in the 1970s?

Appendix 3—Discussion Notes for Breakout Session 3, Fire Safety 

Kuma Sumathipala and Sam Zelinka reported discussion points from attendees for this session as 

follows: 

Key elements of fire performance of mass timber are life safety/property protection/firefighter safety. 

How do we address each of these?

Sprinkler reliability claimed as 95%, but what happens if sprinklers do not activate and there is no 

immediate fire service response?

• For steel, allow burnout, steel regains strength as temperature drops as long as buckling 

temperatures are not reached and the steel has not collapsed.

• For mass timber, char develops, minimizing fire prorogation, self extinguishes and high level of

residual strength retained.

Options for increasing the fire performance of mass timber systems:

• Encapsulation so that the wood doesn’t burn

• Increase sprinkler reliability

• Challenge the fire service to better extinguish fires

What about having more sprinklers—is that a viable option or needed with taller mass timber buildings?

If there’s a lot of water, what happens to the CLT if it gets wetted as a result of sprinkler activation (fire 

or accidentally)?

There is always water damage when there is a fire. Not a fire issue, but a durability/building science 

issue (i.e., no different than other wood-framed buildings). Steel and concrete structures are also 

damaged in a fire, and structures need to be rehabilitated. 

How do we effectively transmit the needed information about fire performance of CLT-framed buildings 

to fire code officials and the insurance industry? 

Do we need to conduct a shake/bake/wash test program? 

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Fragility model/insurance model needed to demonstrate that the fire performance of mass timber is 

different and superior to stick frame and other competitive framing systems. 

CLT is now classified as mass timber and codified as Type IV in the 2015 IBC. 

Fire performance of CLT is also addressed in Chapter 16 of the 2015 NDS. 

Many code jurisdictions do not accept these code provisions and it is still up to local authorities to 

approve the use of mass timber. 

What additional fire testing is required to gain broader building code approval for mass timber—beyond 

Type IV construction? 

Performance-based route, without the ICC sanction. How do we achieve this on a larger scale? 

ICC heights and area table needs to be addressed to permit increases for mass timber systems. 

Proposal to ICC to increase heights for Type IV from 85-100 feet opposed by two groups. 

• Seismic group in Portland

• Sector of the fire service

Height and Areas—political issue (not technical)

How do we get around that? Perhaps by creating an ICC committee on tall wood buildings? Public 

comment period on creating such a committee initiated by ICC. Maybe if that is not a possibility, set up 

an open (ad hoc) committee outside of ICC to propose changes. 

IBC—fire protection strategies for fire-protected steel in alternative design SPFE 29 (standardized 

methodologies for structural steel). Can the industry (AWC/APA, etc.) create similar methodology for 

mass timber and get backing by SFPE/ASCE guideline for performance based design- consistent 

platform? Good idea, but it’s probably 10–15 years off. We just don’t have the technology/evidence to 

do this yet. 

Maybe once the “showcase tall buildings” in NYC and Portland are built, this attitude will change.

What are the fire-related issues with the 11 and 12 story tall buildings in NYC and Portland? What is 

the strategy to get these approved? 

Portland project—jurisdiction at state building code level, and they are willing to look at alternatives 

such as a one-off building code approval including fire protection methods by looking at the mass timber 

framing as a unique system.

NYC—different issue with BOs being less open to change and focused on fire performance of 

traditional buildings. Lots of work needed to gain this approval since NYC has own building code. 

Approach—alternative material (not holistic) combustibility of structure and more focused on each 

component of the building system

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Both jurisdictions want to understand how exposed wood behaves in taller buildings. 

Do we need to demonstrate superior fire performance of mass timber and if so how? 

Stick frame constructions, wall cavities exist where fire can transfer. CLT framing essentially provides 

continuous fire blocking. 

Each burn of a test structure costs $1M to test. What kinds of models can be used? Can we show 

that mass timber is safe in taller buildings? 

If CLT passes a fire component test, could it be applied to the whole building? 

Fire engineering community would accept modeling, but the fire service not as favorable to this 

approach. 

It’s a prescriptive code, and what happens, for example, if someone changes gypsum in the apartment 

versus what has been tested?

Issue—fire safety of mass timber shafts in Canadian structures. Need exists to demonstrate fire 

performance for CLT shafts.

How do we demonstrate fire performance of connections used in mass timber framing? 

Do the fastener manufacturers have a UL test for fire performance of connectors? 

Does the entire fire safety approval process need to be under UL listing? 

General acceptance of the fire performance of glulam because it’s been around for a long time and NDS 

has been around for a long time. Authorities have seen it before, and we need to achieve that for CLT. 

Wood industry question—do we need to test every single CLT manufacturer’s product combination? 

This is not what we’ve been doing. Then there’d be no end of testing and this is a very expensive 

proposition. Some disagreement exists among experts on this. Can we treat it more generically like 

glulam and lumber? For example, glulam char rate is applied to all. Same with lumber. CLT needs a 

concerted industry wide effort to achieve this. DCA-1 flame spread. Class C, Class B, etc.

Some people think every single CLT combination will need its own test report. 

Wood products in general have few fire test reports and none exist for CLT. Example—wood I-joist fire 

related problems mostly addressed through UL testing and reports for both proprietary and typical 

systems.

Significant “diffusion of CLT information” and we need to optimize this education. 

Need survey of tall wood buildings in Europe. What is done related to educating fire services? How 

much education is done at the planning stages? 

Is fire resistance enough to prove property protection or do we need to do more? 

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Extensive discussion of risk—what is the likelihood of fully developed fire in a CLT framed structure?

Return periods—risk analyses studies needed. 

Risk analysis/risk modeling needed. Is there an additional fire risk associated with mass timber 

buildings? Probably not, but how do we prove it? 

Designing building to facilitate more rapid evacuation and improving life safety aspect is desirable but 

not directly related to mass timber.

Codes address this. All buildings need the same fire protection systems. Level of safety relatively the 

same for all building types. 

Anecdotal discussion of a fire in the UK at the Nottinghamshire chemistry building (under construction). 

Happened before tours and it was a non-sprinklered building. 

• Fire service didn’t even attempt to put it out because the fire was too hot. Lithium ion battery of an

electrical vehicle next to building caused fire. How can we address that since it’s rare?

• Truth is that fire service did not have the right equipment to put it out: 120 kW/m2 fire services

didn’t have right clothing 

• Fire services don’t put out fire. They just stop it spreading to neighboring structures. It’s about

protecting neighboring buildings once fire reaches a certain size.

• How do we address higher fuel loads with the fire service? How to we address this perception (super

high intensity)? 

Significant problem associated with timber buildings is that fire risk is highest during construction. 

Construction fires—not addressed from a code issue at all. Building fire protection is one of the last 

things to be installed.

May need to consider a new method of building mass timber buildings where fire protections installed 

during construction. Minimize risk during construction. 

San Francisco now has a fire safety during construction document for wood structures. 

CWC provided document on construction site safety. Water supply, etc. 

AWC has construction safety document. 

Could consider the approach taken with prefabricated modular buildings. Fire-stopping could be done 

off-site, making it safer for construction.

Based on fully involved building and fire service fighting it from the outside 

What about adhesives allowed in North America vs adhesives allowed in Europe. What glues are 

allowed in Europe/North America and what standards are applied for acceptance. How do they perform 

in CLT exposed to fire? 

Is there a comprehensive database on adhesive performance in CLT? 

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PRG 320 sets minimum adhesive standards. Most of the fire testing of CLT done in Canada with single 

component PUR, where delamination is observed during fire tests. 

All CLT manufacturers in Europe using PUR glues. 

PUR is the choice because of the ease of use. It’s easy to glue up with a longer open assembly time and 

lends itself to CLT manufacturing. But we need to get acceptable fire performance along with the easy 

to work with aspect. Adhesive manufacturers can make it happen but they need to know what the 

performance standards are. 

Some other adhesives exhibit different char layer development and fire performance is impacted. 

Testing program needed. 

Formaldehyde-based glues perform better in fire with no delamination. 

Glulam in North America has traditionally used MF/PRF adhesive but now moving towards other 

adhesives such as PUR adhesives. Fire performance unknown, with 20–30% difference possible. 

Is FRT CLT an option and how could that impact fire rating and glues? Possibly pressure impregnate the 

lumber and then glue up the CLT. 

Certain things need to be tested right away to help get things through alternative means and methods. 

Documentations. How can we make this easier? 

1. Suppliers with third-party test reports but there is a gap between 1-hour ratings and 2-hour ratings.

Reluctance for fire testing in wood industry, holds everything back. How can code officials accept it 

if the suppliers won’t pay for their own test reports? 

2. Glulam connections is a concern with little research to support industry recommendations. Don’t

have a tested 1-hour fire-rated glulam connection. No 2-hour fire-rated glulam connection exists, and 

this is needed for tall wood building. Suppliers need component tests. 

3. Education of fire service and code acceptance officials. They need 1-hour seminars

Perception—whole building is going to burn. Engage fire service at early stage. 

NJ fire where fire started in between compartments—caused whole building to burn down (300 units). 

500 firefighters involved, so maybe some of them broke down compartmentalization. 

Go through historical data and characterize historical failures. 

How does wood compare with steel/concrete (way better), but how do we effectively communicate this 

information? 

Need to “dumb down” technical information to YouTube level video. 

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Appendix 4—Discussion Notes for Breakout Session 4, Material Resources 

and Other Topics

Brian Brashaw and Xiping Wang reported discussion points of attendees for this session as follows: 

The session was started with a review of the six topics presented the previous day. 

1. CLT Supply Chain from Forest to Market, Rusty Dramm, USDA FPL

2. Timber–Concrete Composites, Benton Johnson, SOM

3. Mass Timber in Utah: Research, Practice and Futures, Ben Hagenhoffer-Daniel, University of Utah

4. Blast-Resistant Testing for Massive Timber Exterior Wall: Expanding Timber Opportunities in

North America, Lisa Podesto, WoodWorks

5. Development of a Mass Timber Tornado Safe Room, Bob Falk, USDA FPL

6. More with Less—An Overview of the first CLT Hotel in the U.S., Jeff Morrow, Lendlease

Blast-resistant aspects of CLT

What is the Department of Defense (DoD) role in supporting CLT projects? 

• DoD is very impressed with CLT as a potential solution to construct wood framed buildings that are

safe from blasts.

• DoD has a large portfolio of buildings and is interested in pursuing strategic objectives for blast

proof structures that advocate sustainability 

• The DOD is currently seen as a cheer leader for CLT projects

Regarding the blast aspect, when does GSA come into play? Can FPL play a role in this effort?

If blast testing is successful, what are the next steps?

Research is needed to identify details on connection design, windows and doors. What details can we 

take advantage of in multi-story CLT?

Progressive collapse is important and more work is needed to develop guidelines for design. 

It is also important to determine energy absorption in CLT structures as related to blast resistance.

Safe room application 

The safe room is an exciting concept, but how does CLT fit into safe room research? Tests to date 

indicate that a four-ply CLT worked. For the market, it needs to be easy to assemble by consumers, and

a hardware package is needed. A thesis on CLT shelter design is needed, and models dealing with 

impact and blasting at the same time are needed.

Manufacturing-related issues

From a manufacturing stand point, a number of concerns were raised that need further study: 

• Supply chain: (1) quality materials needed; (2) competitive price; (3) applications such as

composite-CLT may help manufacturing process; (4) inventory management, (5) resource 

procurement issues need to be addressed. 

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• Are standardized sizes and grades needed? Engineered products industry is different from the

traditional lumber industry and tends to focus on proprietary custom products.

• How uniform are the materials that actually go into the CLT panels?

• Optimization of manufacturing process is needed

• Time to delivery, chain of custody needs to be better understood.

• How we manufacture CLT panels? Reengineering design lay-out, put connections in interior; make

it more efficient.

Need to identify ways to increase manufacturing efficiency (manual vs. automation). 

What are best business models for CLT? Do we need new business models to promote CLT to large 

timber companies like GP and LP? 

Species issues

Supply quality of the materials vs. quality of products. Tension exists between using low-grade materials 

and supplying high quality products. 

MSR lumber vs. visually graded? Which one is best for CLT? Does it make a difference? Both are 

permitted in PRG320. 

Issue of custom products vs. standardized products was discussed? Should the CLT industry follow the 

lead of the glulam industry, which promotes both products? 

Lumber supply issues

Shortage of lumber, how much is true? Industry has capacity. Market drives production. Need exists to 

differentiate between raw material supply and production capacity? 

One of the biggest challenges is identifying material properties for design purposes. 

Should we look at the economics of using thermally modified timber; a lot of interest seems to exist 

from the designer’s perspective. 

Huge resources of beetle kill and dead timber are available. Can these effectively be used to 

manufacture CLT? If so, what testing is needed? 

Local materials, is there a better way to access local supply chain?

How do we bridge the gap between resource and CLT manufacturing? In Montana, a couple of mills in 

the area have resources available but need to better understand CLT manufacturing.

High priority: sourcing timber for CLT from federal and nonfederal lands. Timber supply is a big issue. 

20% mortality in FS, something needs to change. FS takes long time to go through the process of 

salvage from dead timber. How can this be optimized? 

A large supply of hardwood species also exists. Testing needed to evaluate the performance of these 

species in CLT. 

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What about Hybrid CLT? Hardwood and softwood, low grade and high grade intermixed. 

ICLT system, discussion on lack of material resources. 

Composite CLT/concrete systems

Where can composite CLT design best fit in?

• Design methodology: material characterization, variation

• Bridge engineering: guidance for bridge design, durability by design

Composite timber/concrete approach: acoustic and vibration control. How do we handle it? 

Initial research provided guidance on vibration design; acoustics depends on mass. 

Research is needed? How to track it is important consideration? 

Do we need a committee on composite CLT in NDS process?

What trade association is appropriate? 

Durability issue for concrete–timber composite: Interface between concrete and CLT; we need studies to 

make sure there are no concerns on durability issue. A pilot study has been done and is ongoing. 

What can be improved in concrete-CLT composites? Depends on applications. Money saving such as 

reduce mass to meet seismic performance demands. 

Building performance concerns

Concealed spaces in CLT construction? Fire performance? How can design details be improved so that 

there is no concealed space issue?

Need an approved guideline for after fire exposure: post fire inspection, reparability after fire? 

Missing gap: most current work focused on architecture aspects. No information on preservation side; 

such as water protection, more environmental friendly preservative treatments. 

Are there issues with phytosanitation? Bugs? Fungi? If so, research is needed. 

Need to understand the impact of pressure treating CLT with fire-retardant or preservatives on structural 

performance.

Wood–moisture relationship is important for CLT. Dimensional stability. Impact of system and 

manufacturing modifications.

Need to know how important it is for the materials to be kept dry during the construction process? What 

problems will occur if it gets wet? Needs to be addressed and solution identified.

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Redstone project was a good demonstration of how to deal with standing water? Panels exposed to 

moisture and a wet condition? Dried out in sun; did not absorb excessive water, did not swell; didn’t 

have that issue. 

Other issues

Certification work around mass timber needs to be clarified? Should it be the same as for other wood 

products or is a different certification system needed? APA is currently certifying all N.A. production. 

CLT projects: Pricing/cost analysis, information should be shared. Labor, training, etc. saving is 

there. There is an advantage in on-site labor.

CLT is a viable product and is very efficient in labor. How do we translate this to the best markets? 

Need to identify other applications for CLT to expand market potential. 

How do we educate the labor force to ensure quality of CLT buildings? 

• Steel erectors. Should we get them involved in CLT building construction?

• Barrier at DOL; unions; need DOL support to classifications; crew sizes.

Deconstruction industry: Collective industry collaboration, all players need to be involved. How to 

demolish CLT buildings needs study? 

What types of research forums for CLT should we have? 

• High on research (develop test matrix),

• Highlight project showcases

• Establish new bench marks

A lot of work published and we need to take advantage of the database in publisher; technical report; 

citations; etc. Use NSF system to access data

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List of Attendees

Marc Alam

malam@cwc.ca

Canadian Wood Council

Dave Anderson

davea@rfpco.com

Roseburg Forest Products

David Barber

david.barber@arup.com

ARUP

Andre Barbosa

andre.barbosa@oregonstate.edu

Oregon State University

Marshall Begel

mbegel@fs.fed.us

USDA Forest Products Laboratory

Richard Bergman

rbergman@fs.fed.us

USDA Forest Products Laboratory

Butch Bernhardt

butch@wwpinstitute.org

Western Wood Preservers Institute

Todd Beyreuther

beyreuther@wsu.edu

Washington State University

Todd Black

tblack@drjlumber.com

DR Johnson

Hans-Erik Blomgren

hans-erik.blomgren@arup.com

ARUP

Keith Bourne

kjbourne@fs.fed.us

USDA Forest Products Laboratory

Jim Bowyer

jimbowyer@comcast.net

Dovetail Partners, Inc.

Brian Brashaw

bbrashaw@fs.fed.us

USDA Forest Products Laboratory

Scott Breneman

scott.breneman@woodworks.org

WoodWorks–Wood Products Council

Taylor Cabot

taylor@kaisergroupinc.com

Kaiser Group Inc.

Keith Calder

kcalder@sereca.com

Jensen Hughes Canada Ltd.

Linda Caudill

lcaudill@vt.edu

Wood-Based Composites Center

Kevin Cheung

kcheung@wwpa.org

Western Wood Products Association

Mark Clark

mark.clark@hexion.com

Hexion, Inc.

Carol Clausen

cclausen@fs.fed.us

USDA Forest Products Laboratory

Max Closen

max@my-ti-con.com

MyTiCon Timber Connectors Inc 

Jennifer Cover

jennifer@woodworks.org

WoodWorks—Wood Products Council

Paul Crovella

plcrovella@esf.edu

State University of New York

Christian Dagenais

christian.dagenais@fpinnovations.ca

FPInnovations

Thang Dao

tndao@eng.ua.edu

University of Alabama

Emily Dawson

edawson@srgpartnership.com

SRG Partnership

Hannah Derrico

hkd40@msstate.edu

MSU-Sustainable Bioproducts

Mark Dietenberger

mdietenberger@fs.fed.us

USDA Forest Products Laboratory

James Dolan

jddolan@wsu.edu

Washington State University

Rusty Dramm

jdramm@fs.fed.us

USDA Forest Products Laboratory

Chris Duvall

chrisd@cplinc.com

Coughlin Porter Lundeen

Russell Edgar

russell.edgar@maine.edu

University of Maine

Omar Espinzoa

espinoza@umn.edu

University of Minnesota

James Evans

jwevans@fs.fed.us

USDA Forest Products Laboratory

Bob Falk

rfalk@wisc.edu

USDA Forest Products Laboratory

Kathryn Fernholz

katie@dovetailinc.org

Dovetail Partners

Julie Frappier

jfrappier@nordicewp.com

Nordic Structures

Charles Frihart

cfrihart@fs.fed.us

USDA Forest Products Laboratory

Bill Gareis

wgareis@ashland.com

Ashland

Sam Glass

svglass@fs.fed.us

USDA Forest Products Laboratory

Hongmei Gu

hongmeigu@fs.fed.us

USDA Forest Products Laboratory

Klas Hagberg

klas.hagberg@wspgroup.se

WSP

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Ben Hagenhofer-Daniell

ben.hagenhofer.daniell@utah.edu

University of Utah

Laura Hasburgh

lehasburgh@fs.fed.us

USDA Forest Products Laboratory

Daniel Hindman

dhindman@vt.edu

Virginia Tech

Patrick Holmes

patrick.holmes@osec.usda.gov

USDA

Dan Hovanec

dan.hovanec@tecotested.com

TECO 

Melissa Jenkins

melissaljenkins@fs.fed.us

USDA Forest Service

Lehong Jin

ljin@viance.net

Viance LLC

Benton Johnson

benton.johnson@som.com

Skidmore, Owings & Merrill LLP

Bevan Jones

bevan.jones@holmesfire.com

Holmes Fire

Steve Kalinosky

skalinosky@fs.fed.us

USDA Forest Products Laboratory

Steve Kelley

sskelley@ncsu.edu

North Carolina State Univ

Greg Kingsley

gkingsley@klaa.com

KL&A Inc.

Grant Kirker

gkirker@fs.fed.us

USDA Forest Products Laboratory

Dennis Krueger

dennsk@smartlam.com

SmartLam LLC

Brian Kukay

bkukay@mtech.edu

Montana Tech

Archie Landreman

archie@woodworks.org

WoodWorks

Stan Lebow

slebow@fs.fed.us

USDA Forest Products Laboratory

Cameron Lewis

cnlewis@fs.fed.us

US Forest Service

Steve Lidicker

slidicker@dci-engineers.com

DCI Engineers

Phil Line

pline@awc.org

American Wood Council

Marco Lo Ricco

mloricco@uwm.edu

University of Wisconsin–Milwaukee

Timm Locke

locke@ofri.org

Oregon Forest Resources Institute

Bobby Loper

bobby.loper@hexion.com

Hexion Inc.

Steve Lovett

lovett@softwoodlumberboard.org

Softwood Lumber Board

Robert Malczyk

rmalczyk@eqcanada.com

Equilibrium Constulting Inc.

Steve Marshall

smarshall@fs.fed.us

US Forest Service

Karen Martinson

klmartinson@fs.fed.us

USDA Forest Products Laboratory

Eric McDonnell

eric.mcdonnell@kpff.com

KPFF

M. Mohammad

mohammad.mohammad@fpinnovations.ca

FPInnovations/NRCan

Jeff Morrow

jeff.morrow@lendlease.com

Lend Lease

Eric Mucklow

eric.s.mucklow.civ@mail.mil

Headquarters, Corps of Engineers

Edwin Nagy

edwin.nagy@maine.edu

University of Maine

Mojgan Nejad

m.nejad@msstate.edu

Mississippi State University

Douglas Nyseth

scott.nyseth@stonewoodstructural.com

Stonewood Structural Engineers

Elaine Oneil

eoneil@uw.edu

CORRIM

Weichiang Pang

wpang@clemson.edu

Clemson University

Bill Parsons

bill.parsons@woodworks.org

WoodWorks

Shiling Pei

spei@mines.edu

Colorado School of Mines

Don Peterson

kari@renewableresourcesolutions.com

Renewable Resource Solutions

Ciprian Pirvu

ciprian.pirvu@fpinnovations.ca

FPInnovations

Lisa Podesto

lisa@woodworks.org

WoodWorks.

Steve Pryor

spryor@strongtie.com

Simpson Strong-Tie

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Neethi Rajagopalan

nrajago3@ncsu.edu

North Carolina State University

Douglas Rammer

drammer@fs.fed.us

USDA Forest Products Laboratory

Craig Rawlings

craig@forestbusinessnetwork.com

Forest Business Network

John Redfield

jredfield@drjlumber.com

DR Johnson Lumber Co

Michael Ritter

mritter@wisc.edu

USDA Forest Products Laboratory

Thomas Robinson

Thomas@leverarchitecture.com

Lever Architecture

Bob Ross

rjross@fs.fed.us

USDA Forest Products Laboratory

Mark Rudnicki

mrudnick@mtu.edu

Michigan Technological University

Ann Sarnecki

asarnecki@fs.fed.us

USDA Forest Products Laboratory

Laurence Schimleck

laurence.schimleck@oregonstate.edu

Oregon State University

Adam Senalik

christopherasenalik@fs.fed.us

USDA Forest Products Laboratory

Doug Sheets

doug@leverarchitecture.com

Lever Architecture

Rubin Shmulsky

spf11@msstate.edu

Mississippi State University

Deepak Shrestha

dshrestha@pfscorporation.com

PFS Corporation

Nicholas Sills

nsills@structurlam.com

Structurlam

Charles Starck

charles.starck@lendlease.com

Lend Lease

Douglas Steimle

doug.steimle@schaefer-inc.com

Schaefer

Kuma Sumathipala

ksumathipala@awc.org

American Wood Council

Erik Timmons

erikt@yorkeandcurtis.com

Yorke & Curtis, Inc.

Bill Tobin

bill.tobin@lendlease.com

Lend Lease

Robert Tudhope

michelleh@smartlam.com

SmartLam, LLC

John van de Lindt

jwv@engr.colostate.edu

Colorado State University

Steve Verrill

sverrill@fs.fed.us

USDA Forest Products Laboratory

Mark Vuong

mark@udplp.com

Urban Development Partners

James Wacker

jwacker@fs.fed.us

USDA Forest Products Laboratory

Hui Wan

hw2@msstate.edu

Mississippi State University

Jasmine Wang

jwang@cwc.ca

Canadian Wood Council

Xiping Wang

xwang@fs.fed.us

USDA Forest Products Laboratory

Steve Wellenstein

stevew@uihlein-wilson.com

Uihlein-Wilson Architects

Tom Williamson

tomwilliamson@live.com

Timber Engineering LLC

Borjen Yeh

borjen.yeh@apawood.org

APA - The Engineered Wood Assn

Samuel Zelinka

szelinka@fs.fed.us

USDA Forest Products Laboratory

364