Tall Wood Takes a Stand

Tall wood buildings proven safe and cost effective

Earn 1 AIA/CES HSW learning unit

CEU Publish Date: December 2012

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Best Practices

reThink Wood sponsors this Continuing Education Unit provided by McGraw-Hill Publishers. This course is registered with AIA CES for continuing professional education.

As such, it does not contain content that may be deeded or construed to be an approval or endorsement by the AIA of any materials of constructions or any manner of handling, using, distributing, or dealing in any material or product.

Credit earned on completion of this course will be reported to AIA CES for AIA members. Certificates of completion are available for self-reporting and record-keeping needs.

Questions related to the information presented should be directed to reThinkWood upon completing this program.

AIA Provider Number: K029AIA Course number: K1212CAIA Credit: 1 HSW/SD hour

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© 2014, reThink Wood, www.rethinkwood.com

Learning Objectives

Recognize that mid-rise (six to 12 stories) and tall buildings (up to 30 stories) can be safely, efficiently, and economically built using mass timber construction techniques.

Discuss the different types of design approaches to mass timber construction for tall wood buildings.

Explain the similarities and differences between the structural composite panel and lumber products that allow building professionals to design and construct tall wood buildings.

Distinguish the differences between design approaches to accessing the acceptable structural passive fire protection measures in a mass timber building.

Table of Contents

Section 1

Tall Wood Building Report

Section 2

The Inspiration Behind Tall Wood Buildings

Section 3

What is Mass Timber Construction?

Section 4

Why Use Wood in Tall Structures

TALL WOOD BUILDING REPORTSECTION 1

Why Wood?

Cost-effective Renewable resource with lower manufacturing

greenhouse gas emissions Lowest embodied energy among major building

materials Negative carbon footprint due to wood’s carbon

storage

Photo courtesy of naturallywood.com

How Mass Timber Offers a Safe, Economical, and Environmentally Friendly Alternative for Tall Building Structures

The Case for Tall Wood Buildings

Study by Architect Michael Green of mgb and J. Eric Karsh from Equilibrium Consulting Inc.

Photo courtesy of Cree Buildings, Inc.

Tall Wood Report

We must find solutions for our urban environments that have a lighter climate impact than today’s incumbent major structural materials. The Tall Wood report is a major step in that direction. Indeed, it introduces the first significant challenge to steel and concrete in tall buildings since their adoption more than a century ago.

- Michael Green, Architectmgb

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THE INSPIRATION BEHIND TALL WOOD BUILDINGS

SECTION 2

Environment

Photo courtesy naturallywood.com.

“Architects are realizing that the old ways of doing things will not continue to work; we are ruining the environment. Because of this, we’re now seeing an industrial revolution for wood. Wood is a renewable product that can do much more than we have yet asked of it.”

- Nabih Tahan, AIA,with Cree Buildings, Inc.

Advancements in Mass Timber Building Techniques

Cross laminated timber (CLT)

Laminated veneer lumber (LVL)

Laminated strand lumber (LSL)

Glued laminated timber (Glulam)

Rendering courtesy of mgb

Cross Laminated Timber(CLT)

Engineered wood panel

3, 5 or 7 layers of dimension lumber oriented at right angles to one another then glued to form structural panels

Exceptionally strong, dimensionally stable and rigid

Photo courtesy of naturallywood.com

Laminated Veneer Lumber(LVL)

Thin wood veneers bonded together

Wood grain oriented parallel to the length of the member

Predictable structural performance and dimensional stability

Free from warping and splitting

Photos courtesy of naturallywood.com

Laminated Strand Lumber(LSL)

Engineered structural composite lumber

Thin chips or strands of wood up to 6” in length glued under pressure

Wood grain oriented parallel to the length of the member, then machined to finished sizes

Strong when face- or edge-loaded

Photo courtesy of naturallywood.com

Glue Laminated Timber (Glulam) Composed of individual wood laminations

Bonded together with durable, moisture-resistant adhesives

Grain runs parallel with length of member

Used horizontally as a beam or vertically as a column

Photo courtesy of naturallywood.com

Bridport House

Location: Hackney (London), UK

Architect: Karakusevic Carson Architects

Contractor: Willmott Dixon Group

Timber Engineer: EURBAN

Year of completion: 2011

Developers chose to use wood for Bridport House for several reasons: structural capabilities of CLT, speed of construction, and environmental advantages. When it was completed in 2011, this eight-story structure formed the largest timber-built apartment block in the world.

Photo courtesy of Karakusevic arson Architects

WHAT IS MASS TIMBER CONSTRUCTION?SECTION 3

Mass Timber Construction

Uses large prefabricated wood members such as CLT, LVL and LSL for walls, floors and roof

Glulam for beam and columns applications

Engineered for strength

Photo courtesy of naturallywood.com

CLT Panels

Resists high racking and compressive forces

Cost effective for multi-story and long-span diaphragm applications

Photo courtesy of Land Lease

At 10 stories, Forté in Melbourne, Australia, was the tallest timber apartment in the world when it was completed in 2012.

LifeCycle Tower

Prefabricated hybrid wood / concrete slab system

Central stiffening core for elevator, stairs and shafts

Glulam posts on exterior

Structures up to 30 stories

LifeCycle Tower ONE’s prefabricated hybrid wood / concrete slab system is supported by

a central stiffening core on the interior and by glulam posts on the exterior.

Photo courtesy of Cree Buildings Inc.

Finding the Forest Throughthe Trees (FFTT)

Uses mass timber panels and glulam as primary structural members to achieve potential building heights of up to 30 stories

‘Strong column-weak beam’ balloon-frame approach

Building performs well under wind and seismic loading conditions

Structures up to 30 stories

Quick installation

Rendering courtesy of mgb

WHY USE WOOD IN TALL STRUCTURESSECTION 4

Environmental Benefits

Grows naturally and is renewable

Photos: naturallywood.com

Forté

Location: Melbourne, Australia

Architect / Contractor / Developer: Lend Lease

Year of completion: 2012

Rising 10 stories, Forté is Australia’s first CLT building and first high-rise timber apartment. Lend Lease cites the environmental benefits as their primary reason for building the tall building out of wood. Speed of construction was a huge benefit to the global company – with an estimated cut in construction time of 30 percent.

Photo courtesy of Lend Lease

LCA and Wood

Wood outperforms other materials in terms of embodied energy, air

and water pollution, and greenhouse gas emissions.

Source: Data compiled by the Canadian Wood Council using the

ATHENA EcoCalculator with a data set for Toronto, Canada.

The Carbon Connection

As architects, we have to ask ourselves: Is there a material that minimizes or eliminates carbon in the environment?

-- Michael Green, MAIBC, AIA, MRAIC

Michael Green Architecture

“ “

Prince George Airport

British Columbia

Architect: mgb

Photo: mgb

Cost Competitive

Cost competitive up to 30 stories

Different configuration choice offers flexibility

Installed much quicker leading to faster occupancy

Photo courtesy of Land Lease

Development company Lend Lease estimates that the $11-million

Forté apartment building in Melbourne, Australia was built 30 percent faster because

the materials were prefabricated.

Applewood Pointe at Langton Lake

Location: Roseville, Minnesota

Architect: JSSH Architects

Occupancy: 48 units

The 48-unit four-story wood structure had a one-hour fire rating; it was sited over a three-hour rated pre-cast concrete parking garage, for a total of 123,964 square feet. According to Roger Johnson with JSSH Architects of Minnetonka, Minnesota, wood-frame was the most cost-competitive option, at $80 per square foot complete.

Photo courtesy of Applewood Pointe

Cost Benefits

Emory Point

Location: Atlanta, Georgia

Structural Engineers: Ellinwood + Machado Consulting Structural Engineers

Occupancy: 442 units

Type of construction: One five-story wood-frame building over slab-on grade and three four-story wood-frame buildings over one-story concrete podiums

A number of systems were considered, and wood was the most economical. For the structural frame portion only, the wood design cost approximately $14 per square foot compared to $22 per square foot for a 7-inch post-tensioned concrete slab and frame. The huge wood-frame project was completed in just over a year, which provided additional cost savings.

Photo courtesy of Ellinwood + Machado Structural Engineers

Fire Safety

Two design approaches to access structural passive fire protection measures

1. Encapsulation

2. Charring

Research shows mass timber buildings behave very well in fire

Photo: iStock (stock)

Advances in building science and fire suppression systems have expanded the scope and role for wood structural and finish materials.

CLT Fire Testing Results

American Wood Council test on a load-bearing five-ply CLT wall

Test specimen lasted 3 hours, five minutes & 57 seconds

Well beyond the two-hour goal

Photo: FPInnovations

Shake Table Test – Six Story Wood Building

In 2009, a full size prototype of a six-story wood-frame building successfully passed a seismic ‘shake table’ test conducted in front of 400 international observers in Japan. Subjected to seismic forces greater than those of the 1995 Kobe earthquake, the structure suffered no visible damage.

Photo courtesy of IVALSA

Acoustics

The mass of the wall contributes to its acoustic performance

Additional acoustic benefits with sealants and other types of membranes to provide air tightness used by builders

CLT Handbook, FPInnovations, 2011

Mass timber building systems provide appropriate noise control for both airborne and impact sound transmission.

Photo courtesy of Karakusevic Carson Architects

Building Height Considerations

Mass timber buildings have minimal shrinkage over time

The 10-story Forté project used a conventional platform-based CLT system.

Photo courtesy of Land Lease

Code Approvals

U.S. and Canadian building codes do not explicitly recognize mass timber systems – this does not prohibit their use

2015 edition of the IBC will recognize CLT products when they are manufactured according to the new ANSI/APA standard

CLT walls and floors permitted in all types of combustible construction

LifeCycle Tower ONE

Location: Dornbirn, Australia

Architect / Contractor / Developer: Cree GmbH

Year of completion: 2012

When Cree GmbH developed their LifeCycle Tower system, they knew the best way to sell the concept was to prove its viability. Wood’s environmental and structural benefits were key considerations for LCT ONE.

Photo courtesy of Cree Buildings, Inc.

Responsible Revolution

Tall wood buildings are not only possible, but the design and build concepts are being proven around the world.

Photo courtesy of Cree Buildings, Inc.

Photo courtesy of Karakusevic Carson Architects Rendering courtesy of mgb

Photo by David Lena;courtesy of HMC Architects

For more information on building with wood, visit rethinkwood.com

THANK YOU!