Si x do l l ars
Nu m be r
Pu bli c ati o ns Ma i l agr eem ent #40063877
Fa l l
Washington Fruit & Produce Co. An oasis in a sea of industrial concrete
New tech accelerates North American adoption
BCâ&#x20AC;&#x2122;s seismic upgrade program uses wood as primary structural material
The strong & silent type AWARD WINNING DEVELOPER ADERA CHOSE MASS TIMBER PRODUCTS FROM STRUCTURLAM FOR THEIR STRENGTH AND ACOUSTIC PERFORMANCE. QUIET BUILDINGS WITH LOW SOUND TRANSMISSION
REDUCED CONSTRUCTION TIME
CROSSLAM® CLT ROOF
CROSSLAM® CLT FLOORS
CROSSLAM® CLT ELEVATOR CORE
GLULAM PLUS COLUMNS
When real estate developer Adera designed Virtuoso — a 6 story multi-family building at UBC, they choose mass timber for its strength and acoustic performance. In comparison to concrete, building with mass timber offered Adera a compelling array of advantages including sustainability, reduced construction time and low noise levels. Constructed with CrossLam® CLT by Structurlam and Adera’s Quiet Home™ technology, the result is a serene and healthy indoor environment that has minimal impact on Mother Nature.
Setting a new standard in real estate development through innovative design, sustainability & quality customer service. Adera.com
Blending wood science together with advanced manufacturing to produce the finest mass timber products & packages. Structurlam.com
c o n t e n t s
Washington Fruit & Produce Co. Headquarters 11 An exposed structure lends this building a contemporary aesthetic.
Above and on the cover:
Washington Fruit & Produce Co. Headquarters, Seattle, WA Photo Credit: Kevin Scott
Writers Theatre 16
Timber Vierendeel trusses and light wood lattice come together to form a dynamic performance space.
Cadboro Bay Residence 20 Residence resurrects ancient Japanese technique of flame-charred wood.
Against the Grain 6 Ceilings
Vimy Visitor Education Centre 26
Architects pay tribute to the sacrifice of Canadian soldiers in the construction of new center.
The Evolution of CLT Manufacturing in North America 31
News and events on wood-related subjects
Low-cost CLT manufacturing equipment is opening the door to mass timber.
Wood Ware 46
Seismic Design with Wood 42
Gaming Systems Covers
Ductility is an important consideration when designing earthquake-proof wood structures.
Technical Solutions 38
Partners conduct research and testing to validate fire safety of mass timber buildings with promising results.
PHOTO CREDIT: Laura Hasburgh (FPL)
Would you like to see your project in the pages of our 2017-18 Celebrating Excellence in Wood Architecture book? Enter the Wood Design & Building awards. Go to www.wooddesignawards.com and submit your entries online. The deadline is midnight, Nov. 21, 2017. Good luck! Don’t forget to follow along on Twitter @WoodDesignAward and @WoodDesignMag !
Taking it Outside I can’t believe it’s fall. With time flying by and everyone busier than ever, I’ve been making an effort to connect with friends and family outside – outdoors and outside of the city – away from daily stresses. My summer was filled with camping and hiking around Ontario. Nothing feels better to me than being out in the forest. One recent day hike took us on an 11-mile trek of forest trails and lookout points in the Rattlesnake Point area outside of Toronto. The park includes a 15th century Iroquoian village which is open to the public and is a great chance to explore local history. Between 1973 and 1987, excavations uncovered 11 longhouses on the site and more than 10,000 artifacts from the lives of the Iroquoian people who once lived in the village. Three of the longhouses have been reconstructed based on the archaeological findings. We explored the village, marveling at the bark siding and construction techniques used 600 years ago. One longhouse has been finished and wired to modern standards and houses First Nations art exhibits and educational videos. (See photos, right.) Speaking of history, make sure you check out the Vimy Visitor Education Centre on p. 26. The historic site is a 107-hectare battlefield complete with trenches and tunnels, situated in the French countryside. A temporary visitor center was built in 2005 but was not able to support the needs of the vast number of people that visit each year. Architects were engaged to create a new permanent visitor center, which opened earlier this year. Wouldn’t it be great to visit on Remembrance Day (Canada) and Veterans Day (U.S.)? Though it’s fall, we’ve finally got summer-like weather in southern Ontario and I’m going camping again this weekend. I’m looking forward to more hiking. This time it will be even better with the changing colors of the trees framing the views. I hope your fall is inspiring!
Theresa Rogers Executive Editor firstname.lastname@example.org
Wood Design & Building magazine invites you to submit your project for consideration and possible publication. We welcome contributed projects, bylined articles and letters to the editor, as well as comments or suggestions for improving our magazine. Please send your submissions to Theresa Rogers at email@example.com.
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The Turtle Clan Longhouse would have been home to about 30 people, making it the smallest longhouse found in the village. There are three fire pits inside, with one family sleeping on each side of the fire. People would have slept on the bottom bunks to be close to the fires and away from the smoky air above. Cedar boughs and warm fur blankets would have covered the sleeping platforms while the fragrant cedar would have helped keep insects away.
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The state-of-the-art Deer Clan Longhouse opened in 2014 and features seasonal contemporary art exhibits from local First Nations artists. Photo Credits: Theresa Rogers
Canadian Wood Council 99 Bank St., Suite 400, Ottawa, ON Canada K1P 6B9 1-800-463-5091 www.cwc.ca www.WoodDesignandBuilding.com www.WoodDesignAwards.com ISSN 1206-677X Copyright by Canadian Wood Council. All rights reserved. Contents may not be reprinted or reproduced without written permission. Views expressed herein are those of the authors exclusively. Publication Mail Agreement #40063877 Printed on recycled paper Printed in Canada
Against the GRAIN
Kelly Townsend What would be your response if you were asked to provide an example of a well-designed ceiling? Would your mind immediately jump to the Vatican’s Sistine Chapel? Frescos can add undeniable aesthetic value, but their function is purely decorative; they don’t contribute to the structure itself. Wood materials, however, can do both, offering a unique opportunity to build upon and support the design elsewhere in the space. The porous wood liner that fans across the ceiling of the Bloomberg Tech Hub is a striking design element visitors will note immediately upon entry. The individually sculpted boards create a three-dimensional look and define the area. Invoking natural formations found outside is often the intention behind a unique ceiling design. The exhibition hall of Shanghai’s “The Hub” purposefully parallels the forest found outside, with walnut and oak-covered aluminum “sticks” adorning the ceiling to mimic tree branches. At the Student Zone, Polytechnique Montreal, the undulating birch slats form the ceiling and curve down the wall to create built-in seating. This installation connects meeting and service areas while defining the space. The Bon Lait Sports Center ceiling’s laminated timber slats serve an important purpose, providing terrific acoustics for this dynamic recreational building. They are formed as wooden pyramids to evenly distribute sunlight. The Collaborative architects were charged with designing a modern, inviting core for the new La-Z-Boy Headquarters. Armstrong’s WoodWorks Grille panels were installed in the ceiling to add texture and warmth to the space. The slats are reminiscent of the company’s original wooden patio chair design from the 1920s. Utilizing the variable properties of wood is an effective way to add visual interest to a project. Whether it’s a simple arrangement or intricate machine-carved pieces, wood ceilings are versatile – fun, elegant, understated, modern, or tailored – in a way other materials are not. 1. Bloomberg Tech Hub (2015) Architect: IwamotoScott Architecture Location: San Francisco, CA PHOTO CREDIT: Bruce Damonte 2. The Hub Performance and Exhibition Center (2015) Architect: Neri&Hu Design and Research Office Location: Shanghai, China PHOTO CREDIT: Dirk Weiblen 3. Student Zone, Polytechnique Montreal (2016) Architect: Menkès Shooner Dagenais LeTourneux Architectes Location: Montreal, QC PHOTO CREDIT: Stéphane Groleau
4. Bon Lait Sports Center (2016) Architect: Dietrich | Untertrifaller Architects, Tekhnê Architectes Location: Place du Traité de Rome, Lyon, France PHOTO CREDIT: Julien Lanoo
5. La-Z-Boy World Headquarters (2015) Architect: The Collaborative Location: Toledo, OH PHOTO CREDIT: Armstrong Ceiling Solutions
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k George Brown College Set to Build
Ontario’s First Tall Wood Institutional Building
Toronto’s George Brown College is planning to construct a 12-story wood building to house its new Tall Wood Building Research Institute. “The Arbour” will be Ontario’s first tall wood institutional building and will serve as a living laboratory both during its construction and once complete, where students and researchers will learn to design, construct, operate and monitor climate-friendly buildings. It will be located on George Brown’s Waterfront Campus, to the north of the LEED Gold certified Daphne Cockwell Centre for Health Sciences. The college recently purchased the land from the City of Toronto. In the fall, the college will launch an international design competition among the firms uniquely qualified to undertake such a project. The project will include research facilities, George Brown’s Centre for Information and Computer Technology to support and complement the City of Toronto’s Smart City initiative, and a new child care facility. “This distinctive new location will help us contribute to the mitigation of climate change and environmental sustainability while supporting our continued intention to create campus environments that are innovative, creative and stimulating for student learning,” says Anne Sado, President, George Brown College. www.georgebrown.ca
k Connection Design Discussed at Wood Solutions Fair The Mid-Atlantic Wood Solutions Fair took place recently in Washington, D.C., including day-long educational events on the use of wood in non-residential and multi-family buildings. Attendees were given the opportunity to earn up to 6 AIA/CES LUs (HSW) or PDH credits. Sessions included wide-ranging topics such as sprinklers in wood frame construction, off-site wood construction, connection design solutions, building enclosure design, fire resistance design, and advanced detailing techniques. Mark these upcoming Wood Solutions Fairs on your calendar: Oct. 4 – Pasadena, CA Nov. 14 – Vancouver, BC Oct. 5 – Halifax, NS Dec. 13 – Edmonton, AB Nov. 2 – Charlotte, NC Feb. 1/18 – Montreal, QC Nov. 2 – Toronto, ON www.woodworks.org/events-calendar/upcoming www.cwc.ca/events/wood-solutions-fairs/
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k Structurlam Receives SFI Certification Penticton, BC-based Structurlam has become the first Canadian manufacturer of cross-laminated timber (CLT) to be certified to the SFI 2015-2019 Chain-of-Custody Standard. SFI (The Sustainable Forestry Initiative) is an independent, non-profit organization that works with individuals who share a commitment to healthy forests, responsible purchasing and sustainable communities. Structurlam produces CLT at its Penticton facility in southern BC’s Okanagan region. The company is part of a global movement to use wood in mid- and high-rise buildings. Structurlam will be able to use chain-ofcustody certification to position itself as a supplier in the green building market that is officially recognized by green building rating systems. Wood products sold as certified under the SFI Chain-of-Custody Standard allow CrossLam CLT to earn Leadership in Energy and Environmental Design (LEED) credits through the LEED Alternative Compliance Path or credits through the Green Globes Rating System. www.structurlam.com
k Study Shows Urban Trees are Critical to City Weather
Even in the city, trees play an important role moderating wind pressure on buildings and keeping pedestrians comfortable, according to a new study by the University of British Columbia. Researchers at UBC used remoteResearcher Marco Giometto, formerly sensing laser technology to create a postdoctoral fellow in civil a highly detailed computer model engineering at UBC. of a Vancouver neighborhood down to every tree, plant and building. They then used computer simulation to determine how different scenarios – no trees, bare trees, and trees in full leaf – affect airflow and heat patterns around individual streets and houses. The researchers found that removing all trees can increase wind speed by a factor of two, which would make a noticeable difference to someone walking down the street. Trees also moderated the impact of wind pressure on buildings, particularly when it goes through small gaps in and between buildings. “Wind pressure is responsible for as much as a third of a building’s energy consumption,” says Marco Giometto, the study’s lead author, who wrote the paper as a postdoctoral fellow in civil engineering at UBC. “Using our model, we found that removing all the trees around buildings drove up the building’s energy consumption by as much as 10 per cent in winter and 15 per cent in summer.” The paper, “Effects of trees on mean wind, turbulence and momentum exchange within and above a real urban environment”, has been published in Advances in Water Resources. www.news.ubc.ca
Williams Invests in New National Training Center
Sherwin-Williams, through its Industrial Wood Coatings Division, has formalized a $300,000 Sherwin-Williams, MiLL donation ceremony. investment in the Manufacturing Industry Learning Lab (MiLL), a new national training center teaching the next generation of wood manufacturing tradesmen and women. The investment was formalized during a ceremony at the AWFS Fair on July 19 and included a $30,000 commitment for 2017 activities. The 46,000-sq.ft. MiLL opened in August in Colorado Springs, and will offer classes to primary and post-secondary students in the Peyton and Widefield School Districts, industry personnel, and members of the military. Its curriculum will center around hands-on education that uses machines and technologies students will encounter on the job. “The MiLL provides a fantastic opportunity for students to master the skills that will launch their trade careers with unparalleled access to industry-leading educators and equipment,” says Dennis Karnstein, President and General Manager, Sherwin-Williams, Industrial Wood Coatings Division. “There is no greater way to support our mission to grow the success of the wood industry than to ensure our future leaders have the best tools and knowledge.” www.sherwin-williams.com
k Winner of Bostik Hardwood
Flooring Design Contest Announced
Jennifer Sheets, an interior designer with Studio R Interiors, has won Bostik’s Signature Spaces design Competition, “The Art of Hardwood Flooring Design Contest”. Sheets’ winning design will be installed in a new steakhouse within Las Vegas’ new Park MGM Resort, currently under development by MGM Resorts International and Sydell Group. Her design entry was inspired by the Art Noir movement and involves interlocking geometric shapes and stylized symmetry that was specified in the contest guidelines as a prerequisite of the project, Sheets says. “The pattern depicts an array of interchanging shapes that harmoniously fit within a symmetrical medallion. I created my “Array” design to complement, as well as enhance, the herringbone-featured floors throughout the main restaurant space.” The interior designer will also receive a trip for two to Paris, courtesy of Bostik. Bostik, Inc., a leader in specialty adhesives and installation systems for building construction, partnered with the National Wood Flooring Association, MGM Resorts International, Oshkosh Designs and Eagle Bay Hardwood Flooring on the competition. www.bostik.com/us
k SFI and Habitat for Humanity Join
Forces for Women in Wood Build Day
The Sustainable Forestry Initiative (SFI) teamed up with Habitat for Humanity Greater Ottawa (Habitat GO) to hold a special “Women in Wood” Build Day on August 15. A diverse team of Ottawa women and volunteers came together from various sectors – including the government, the forest industry, as well as the environmental, education and social sectors – to build homes alongside families in need of affordable housing. This was the second-ever “Women in Wood” Build Day (the first one took place in Ottawa in 2013) and was led by SFI president and CEO, Kathy Abusow. It took place at Habitat GO’s largest build to date, Leacross Landing, which consists of 16 townhomes being built in Orleans, an Ottawa suburb. Phase 1, involving four townhomes, will be completed this year, with the other homes finished over the next two years. The volunteers helped with a wall raising and building the framework of the four townhomes. Since 2008, the SFI community has donated countless volunteer hours and certified products to numerous Habitat for Humanity builds across Canada and the U.S. www.sfiprogram.org
k Metsä Wood
Pioneers New Open Source Initiative
A new initiative from wood product manufacturer Metsä Wood seeks to accelerate innovation and growth in large-scale wood construction. The Open Source Wood initiative was inspired by the open source ideology championed by the software industry to drive innovation further and faster, and to increase speed to market. Metsä Wood is taking the first step by sharing its own intellectual property for modular Kero LVL wood elements, making them freely available for everyone. Additionally, the company will award innovation in modular design by offering €$30,000 in prize money during 2017 to exceptional designs using its Kerto LVL material. “Not enough knowledge about modular wood design and building is shared, so wood construction remains niche,” says Esa Kaikkonen, Executive Vice President at Metsä Wood. “We believe that with open collaboration, the industry can achieve significant growth.” Open Source Wood is a continuation of Metsä Wood’s project Plan B, launched in 2015 as an ambitious blueprint to explore the possibilities of using wood in urban construction. www.metsawood.com
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Washington Fruit & Produce Co. Headquarters Warm materials and non-boxlike forms redefine family-owned fruit operation Yakima, WA
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Surrounded by the world’s most high-tech fruit packing warehouses, the 16,500-sq.ft. Washington Fruit & Produce Co. headquarters is conceived as an oasis amidst a sea of concrete and low-lying brush landscape. Tucked behind landforms and site walls, this courtyard-focused office complex provides a refuge from the noise and activity of the industrial processing yards nearby. Taking its design cue from an aging barn that the client had identified as a favorite, the concept seeks to capture the essence of an utilitarian agricultural aesthetic. A simple exposed structure that employs a limited material palette and natural patina, the design merges rural vernacular with an equally spare contemporary aesthetic. The L-shaped building is nestled into the landscape through the use of board-formed concrete site walls and earthen berms that wrap the perimeter to form a central, landscaped courtyard. Soil excavated for foundation work was repurposed for the perimeter berms, eliminating the need to remove it or add more. A notch through the berm provides access from the parking area to the formal courtyard and building entrance. Crossing the courtyard via a boardwalk, the visitor is embraced by a fully glazed facade, punctuated by a series of wood columns that march across the building in regular intervals. The boardwalk aligns with an off-set building entry, which is formed as a woodwrapped passageway inserted into the glazed facade.
The building recalls its agricultural roots by pulling the 18-foot-tall scissored glulam structural columns to the outside, revealing the physics of its construction and enabling the 175-foot interior volume to be column-free. Topped with 68-foot exposed truss girders, the interior reaches 20 feet at its peak. The repetitive nature of the structure ensured easy fabrication and assembly, saving costs and resources. The north-facing courtyard facade is glazed along its length, visually extending the interior space into the courtyard. Interior light is balanced via a long clerestory dormer on the south, while the extensive use of large, south-facing overhangs and high efficiency glazing limits summer heat gain. Reclaimed barn wood siding and a weathering steel roof round out the exterior materials. Spartan, daylight-filled interiors are complemented by a warm, simple palette of natural materials. Private offices line the south wall, while conference spaces and back-of-house functions are set in wood-clad boxes. Interior furnishings terminate well below the ceiling. The open feeling of the structure is reinforced by keeping furnishings low and allowing them to float within the space. Lighting consists of custom-designed uplights, which keep the ceiling plane tidy. A raised flooring system further ensures that the clean aesthetic is preserved and free of cabling. The deep agricultural roots of both the company and location underlie the simple design concept and attention to detail throughout the project.
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The sales office is located in the short arm of the L to isolate noise and enhance privacy. Adjacent to the sales office is a separately enclosed structure featuring a 30-foot table where farmers with whom the company works gather for communal meals. The exposed structural system connecting the lunch room to the main building creates a small, partially covered courtyard, nodding to a remnant of an aging barn. Views throughout the 30-acre complex are controlled, whether to the courtyard, the distant hills, or to the shallow private office views created between the building and the berms. Everything is curated to create a peaceful environment in which to work.
Graham Baba Architects Seattle, WA
MA Wright, LLC Seattle, WA
G e n e r a l C o n t r a c to r
Artisan Construction Yakima, WA
Selkirk Timberwrights Priest River, ID
P h oto g r a p h y
Kevin Scott Seattle, WA
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Writers Theatre Second-floor canopy walk’s structural system shines a spotlight on local theater’s innovative design Glencoe, IL
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Theater’s ability to bring people together across social boundaries makes it an important aspect of urban living. Writers Theatre in Glencoe, IL, is designed to build on that as a 21st-century theater company that serves as a cultural destination for the region. Organized as a village-like cluster of distinct volumes that surround a central hub, the building’s form resonates with the character of Glencoe’s downtown. The theater’s two performance spaces, a main stage and a smaller black box venue, employ staging and seating configurations to maximize the sense of intimacy between actors and audience and enhance the immersive experience. Both performance venues, in addition to rehearsal space and public zones, open onto the central gathering space of the lobby. Designed to accommodate informal performances, talks and community events, the lobby is structured by great timber Vierendeel trusses with a lighter wood lattice supporting its second-floor canopy walk. This walk employs an innovative structural system, putting wooden members into strict axial tension. Using Port Orford cedar battens with a 2 x 3 cross-section, the canopy walk is hung from wooden glulam roof beams. An outer layer of battens connects to the suspended glulam beams below without mechanical fastening, instead relying upon the material properties of wood to produce a flared wedge connection. The connection is designed to fit into matching grooves cut into the lower glulam beams, akin to traditional Chinese and Japanese wood joinery methods; a slight undercut prevents the batten from slipping forward when in its locked position. The shape of the detail likewise ensures this strong connection. Animating the facade through its pattern and experiential quality, the canopy walk creates an iconic identity for Writers Theatre while also providing a dynamic space for people to gather. It works to extend the drama of performance from the main stage to the lobby to the streetscape beyond, revealing the forces and materials that make the structure possible. Lowering the project’s overall carbon footprint by replacing steel structural systems with wood, the canopy walk also improves the environmental performance of the building through self-shading.
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11 13 8 7
4. box office
8. 250-seat theater
12. green room
9. black box theater
13. performers’ suite
3. lobby seating
6. coat check
10. rehearsal room
11. theater back-of-house
ground FLOOR PLAN
4 1 5
1. lobby seating 2. 250-seat theater
3. black box theater below
5. grand gallery walk
7. donor lounge
6. event terrace
9. green roof
Second FLOOR PLAN
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An alternating pattern of Port Orford cedar clads the exterior of the 99-seat theater, complementing the wood detailing of the canopy walk. On the interior, stained elm harvested on site was used to clad the lobby’s tribune seating and concessions, contributing to its inviting ambience. Elm harvested on-site was also used for woven millwork, which serves as a natural marquee, and bookshelves that house playbills, programs, and past scripts, invoking both the history of the theater company and the site. The theater itself engages its surroundings through transparent visual connections and ivy-covered backdrops to the surrounding parks. In fair weather, the lobby can open to the adjacent Women’s Library Club Park, allowing the energy and interaction of the theater to extend outward into the community beyond. At night, the theater glows from within, drawing interest and activity to this important civic and cultural anchor. A RCHITECT
Studio Gang Architects Chicago, IL
S TRUCTUR A L ENGINEER
Halvorson and Partners Chicago, IL
GENER A L CONTR A CTOR
W.E. O’Neil Construction Chicago, IL
TIM B ER S UPPLIER
Trillium Dell Timberworks Knoxville, TN
PHOTOGR A PHY
Steve Hall/Hedrich Blessing Chicago, IL
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Cadboro Bay Residence House combines ancient wood-charring techniques with modern design Vancouver Island, BC
Situated on a seaside bluff above a sandy beach on Vancouver Island, this house was designed for a young family. Window walls and corner glazing frame expansive views of the bay and strait beyond, while large integrated sliding doors allow the facade to open to the adjacent terrace. The home’s living roof, planted with grasses and flowers native to the Pacific Northwest, sits low in the landscape and features operable ventilated skylights. The entry sequence is framed by retaining walls, weathered planter boxes and a recirculating pond fountain. The ceiling of the main living/dining/kitchen volume combines cedar planks, perpendicular notched Douglas fir beams, and a recycled denim fabric for sound attenuation. Heating vents from a high-efficiency wood burning 20
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fireplace are integrated into the recessed steel C-channel above the hearth. Hydronic heating is deployed in the exposed concrete floor slab throughout the woodframed home’s living and service spaces, master suite, children’s bedrooms and attached nanny suite. An existing garage, perched on the bluff’s edge, was repurposed as a guest suite, overlooking the bay and beach below. Following studies and experimentation based on the centuries-old Japanese technique of Shou Sugi Ban (flame-charred wood), the tongue and groove vertical cedar cladding was torched on-site prior to installation. The result is a textured, dark, and lustrous exterior facade, which contrasts with the home’s bright, modern interior.
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4 2 3
1. entry courtyard
6. rear entry/boot room
11. suite bedroom
2. entrance foyer
7. powder room
12. suite washroom
18. master ensuite
8. storage shed
19. master bedroom
21. garden guest suite
10. suite kitchen/living
The architect says the beauty and warmth of wood plays an essential role in the design of functional spaces, especially in the context of the Pacific coast. Here, the collaboration between designers, owners, and the team of skilled builders, has resulted in a beautiful, one-of-a-kind home in a stunning setting. A RCHITECT
D’Ambrosio Architecture + Urbanism Victoria, BC
S TRUCTUR A L ENGINEER
Spar Consultants Victoria, BC
GENER A L CONTR A CTOR
Taylor Made Builders Victoria, BC
PHOTOGR A PHY
Sama Canzian/Nathan Flach Victoria, BC
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Submit at www.wooddesignawards.com Winners will be featured in: Wood Design & Building magazine and website Wood Design Awards book 2017-18 Architectural conferences throughout North America
Have questions? Contact: Ioana Lazea or Natalie Tarini, Awards Coordinators 1-800-463-5091 ext. 227 or 225
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Vimy Visitor Education Centre Wood helps tell the story of First World War sacrifices and contributions Vimy, France
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The Vimy Ridge National Historic Site is a 107-hectare site of battlefield terrain situated in the French countryside, complete with trenches and tunnels, with development located only at the monument and the visitor center. A temporary visitor center was built in 2005 but was not able to support the needs of the vast number of visitors that travel to the site each year. Architects were engaged to create a new permanent visitor center to honor those from Canada who served in the First World War. Site topography and terrain studies revealed previously unknown spatial linkages and historic relationships which were integrated into the new design. In 1917, the front lines at the Battle of Vimy Ridge inscribed an arc on the landscape, which intersects the axis of the treed allée between the Vimy Memorial and nearby steeple at Neuville-Saint-Vaast. The architects proposed using this feature by defining an “axis of history”’ reflecting movement of the front lines, and an “axis of memory” connected to the monument itself. The history axis is represented by corten steel and earth materials, which speak to the rusted iron and steel instruments of war, many of which remain on the Vimy grounds. The memory axis is represented by materials that play off the sculptural, white purity of the monument and grave markers. 28
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Once inside the 7,535-sq.ft. building, views open to the forest with an expansive glass wall that looks out onto the scarred landscape. The lightness of the wood structure and curtainwall play off the filtered light of the Austrian pines on the grounds. Wood was chosen for symbolic and aesthetic effect – to represent people from a forested nation who came to France, and in contrast to the complete devastation of the landscape, denuded of its trees following the war – and for its cost-effectiveness. The use of the spruce Raico heavy timber framing and curtainwall system (pre-engineered and finished off-site) combined both structure and glazing, boosted thermal performance, and benefitted the aggressive construction schedule. Working with a talented group of museology interpreters, the architects proposed the idea of layers of history that are part of Vimy Ridge and that visitors weave multiple interpretations of history by the telling of stories and evoking of emotional connections. The interpretive exhibits are designed to reinforce these themes of history and memory, echoing the materiality of the building, using digital material and artefacts, and maintaining the connection to the battlefield through the wood and glass wall. The ceremonial opening of the new Vimy Visitor Education Centre was held on April 9, 2017, to commemorate the 100th anniversary of the significant Canadian-led battle at Vimy Ridge during the First World War, and as part of the events to commemorate the 150th anniversary of Canadian Confederation.
Form Follows Nature: Building a Net Positive Environment
Public Service Procurement Canada (PSPC)
THURSDAY OCTOBER 5, 2017
Toronto Marriott Downtown Eaton Centre
Robertson Martin Architects Ottawa, ON
John G. Cooke and Associates
› Kevin Flanagan, PLP Architecture, London, UK › Russell Acton, Acton Ostry Architects Inc., Vancouver, BC › Bill Dunster, ZED Factory, London, UK
G e n e r a l C o n t r a c to r
Aix-les-Bains, France P h oto g r a p h y
When matters. When execution execution matters.
Innovative glulam glulam Innovative & timber timber solutions. solutions. &
The Evolution of CLT Manufacturing in North America Patrick Chouinard
CLT made using Panolam.
While North America is in its infancy in mass timber use, Europe is well into a second-generation of Cross-Laminated Timber (CLT) manufacturing equipment and methodology. Access to this new technology is accelerating North American adoption and changing the way in which we’re likely to see our industry evolve. Mass timber has the potential to become the core structure for almost every type of building, across all industry segments, but it will take years, decades, perhaps a century or more, to realize it. That degree of adoption cannot happen from the top down. Large, high-investment manufacturers will not be able to supply CLT across the country economically or competitively. It’s simply too expensive to ship long distances. ‒ f a ll 2 0 1 7
Lower cost CLT manufacturing equipment is removing the barrier to entry and what we’re likely to see are mom and pop-type CLT plants sprouting up all over North America with a narrow geographic focus using a new generation of vacuum versus hydraulic press, and modern methodology. It’s already happening.
How Does Vacuum and Hydraulic Press Technology Differ? Methods: First generation CLT panels are made with cross laminated layers of 2” x 6” dimensional lumber and a hydraulic press. The press is a complex, heavy, highly automated piece of equipment that applies pressure on the stack of layers until the glue between layers sets. The press requires a lot of space and a thick concrete foundation to sustain force. Glue is used between each laminate layer, but not between the 2 x 6s, which lay side by side. Second generation CLT manufacturing methodology introduced “Panolam” and a vacuum press. Panolam are prefabricated single layer panels up to 2.95m wide by 16m in length, made up of strands of wood (lamella) that are edge-glued. In other words, glue is used not only between the layers of Panolam panels but also between each lamella. A vacuum press is like a large rectangular flat bottom bathtub with a large, retractable, rubberized membrane on top which creates a vacuum seal. Vacuum presses are simple, light, largely hand-operated, and do not require a heavy foundation or a lot of space. Air is drawn from the press to create vacuum pressure on the stack of Panolam. 32
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Appearance: One of the key advantages of CLT over other construction materials is the fact that it is both a structural member as well as a finished surface. Often, however, owners and architects demand a better looking visible surface than that which is available in the form of 2 x 6 dimensional lumber. Though subjective, Panolam are much more refined in appearance and edge gluing helps ensure that there are fewer, less visible separations between lamella and checks (or cracks) on the surface of panels. Versatility: Hydraulic presses are designed for one purpose, to produce standard CLT panels as fast and efficiently as possible. With a vacuum press, manufacturers can produce a multitude of different CLT panel types. For example: using a mold, manufacturers can produce curved CLT. Innovators are using vacuum presses to create new types of panels such as “CLIPs” – Cross Laminated Insulated Panels. For those customers who require high-quality visible surfaces, a vacuum press can be used to adhere virtually any type of wood species as a decorative layer to the surface of a CLT panel for walls, countertops, stair treads, custom furniture, etc. Variety of Thickness: First generation CLT panels were made with 35mm-thick dimensional lumber. Later, 17mm-thick lamella were introduced. Panolam, on the other hand, is available in 20, 30 and 40mm thickness. Whereas first generation CLT manufacturers offer eight or nine variations in panel thickness, second generation manufacturers offer 36 or more variations ranging from 60mm (three layers of 20mm Panolam) up to 400mm in increments of
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vacuum press for approximately CDN $375,000. Anyone wanting to “get in the game” can be producing panels with a vacuum press and framing them by hand for approximately $1 million, excluding the cost of the building.
How Will New Technology Impact the Evolution of the Industry?
CLT stair treads with decorative top layer.
10mm. Since the volume of wood in a CLT panel impacts price, engineers can optimize layups to more precise requirements reducing wood volume and cost. Electrical Chases: First generation CLT manufacturers produce and sell “billets” – slabs of cross-laminated solid wood panels without openings. Although holes can be drilled into panels to create chases for electrical wiring, it’s problematic to do so once a billet has been pressed, and designers are forced to conceal wiring otherwise mounted on the surface of panels. Vacuum press methodology differs. Manufacturers can stop at each layer in the panel layup process and leave out Panolam where chases are required for electrical wiring. In other words, chases are typically built into panels and wiring is concealed within.
Market Positioning: First and second generation CLT manufacturing methods have their place. Early adopters brave and bold enough to have pioneered CLT in North America now have an established market. They’re the ones producing the 13- and 18-story buildings. Production capacity for such a market is critical and speed of fabrication is paramount. Hydraulic presses and CNC equipment serve them well. Tall wood building opportunities, however, are few and far between, at least for the time being. The rest of the market is evolving from the bottom up. It’s wide open and likely to be dominated by local producers. Brave owners and architects, also willing to explore mass timber, generally prefer to start with small, more manageable, less risky projects and work their way up with experience. This market is well served by new technology which allows local manufacturers to start small and scale up as the market matures.
Waste: Though the billet layup process is much faster using a hydraulic press, involving less manual labor, the industry is challenged to find aftermarket uses for the portions of billets removed for window and door openings and customers who buy billets versus panels end up paying for the wood removed. Cost: Fully automated CLT manufacturing lines can cost $10 million to $25 million or more depending on the degree of automation. Today, you can buy a
Panels with Panolam left out for chases, windows and doors.
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Vacuum-pressed CLT panels.
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Grass Roots Evolution: Regardless of capacity and speed of production, CLT is expensive to transport across long distances. In addition, many of the owners and architects interested in working with mass timber ask for locally harvested wood for many reasons including LEED certification. Every state and provincial government is mandated to create jobs and establish markets for their own forestry industry, and are prepared to invest in homegrown companies that can help make that happen. In an emerging market, CLT manufacturers can mitigate risk by using low-cost manufacturing equipment that serves many purposes, equipment that can be used to produce a variety of different CLT products. They also need to be flexible and adaptable to the requirements of small to medium-sized, unique projects. Many may not realize it yet, but a revolution in the use of mass timber in construction is upon us. When it takes hold at the community level, the heart and soul of the movement will be revealed. The innate human desire to connect with our space, to connect with nature, will manifest in the form of beautiful buildings made of wood, using locally harvested material, fabricated by local producers, and assembled using local labor. Patrick Chouinard is the Founder and CEO of Element5 Co. Inc. and an advocate for greater use of wood in construction. He can be reached at email@example.com.
Fire Testing Completed on Full-Scale Mass Timber Building with Promising Results Kenneth Bland During the decay phase of test three, the charred surface of exposed CLT is visible. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017) Photo credit: Sam Zelinka (FPL)
While heavy timber construction (Type IV in U.S. building codes) is one of the oldest wood construction methods recognized in the codes, there are promising new framing technologies that have expanded what’s possible within this category using mass timber. This category differs markedly from traditional lightweight wood construction more commonly seen in the U.S. and building with these new mass timber structural systems represents the first significant challenge to concrete and steel in more than a century. However, as they gain broader acceptance among building designers for a variety of low- to mid-rise building types, the next hurdle to overcome is height and number-ofstory limitations set by the International 38
Building Code (IBC), which are currently 85 feet and six stories tall, respectively. Other countries have already begun to realize the benefits of tall wood building construction, including its low carbon footprint, ease of construction and reduced construction time, to name a few. From the Brock Commons Tallwood House demonstration project in Canada to Treet in Norway, several tall wood buildings have emerged across Canada, Europe and other parts of the world as interest mounts to find safe, carbonneutral and sustainable alternatives to incumbent structural materials of the urban world. To address current barriers and help create a pathway for high-rise mass timber
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buildings in the United States, the International Code Council (ICC) formed an Ad-hoc Committee on Tall Wood Buildings in 2015 to research the building science of tall wood buildings. This is a multi-year effort supported by numerous working groups made up of stakeholders, design professionals, code officials and other interested parties who are investigating the feasibility of and taking action to develop code changes for the use of mass timber in taller or “beyond current code” buildings. The goal is to introduce code provisions for the 2021 code cycle, with non-structural provisions expected to be submitted for consideration during 2018, and structural provisions to be submitted for review and approval during 2019.
As part of this work, the American Wood Council (AWC) and the U.S. Forest Service Forest Products Laboratory have partnered with the Ad-hoc Committee to conduct research and testing necessary to understand the performance and validate the fire safety of mass timber buildings. This summer, five fire tests were completed in a full-scale, multi-story mass timber apartment building with promising results. Based on test data so far available, mass timber provided the kind of fire safety performance that should allow its use in larger buildings and even expand the option for exposed wood structure in smaller projects. The recent fire tests were intended to demonstrate that it is possible to construct a mass timber building with exposed wood while maintaining fire resistance and limiting contribution to fire growth. The Ad-hoc Committee provided each of the five fire scenarios for two, one-bedroom apartments with various arrangements of exposed and unexposed cross-laminated timber (CLT), with open doors between living and sleeping areas. The tests were conducted at the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives Fire Research Laboratory, the world’s largest research laboratory dedicated to fire scene investigations.
Test 1 Ignition: The first of five fire tests conducted on a cross-laminated building shortly after ignition. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017) Photo Credit: Laura Hasburgh (FPL)
In summary, the five tests entailed: • Test 1: A mass timber structure fully protected with gypsum wall board subjected to a large furnishings and contents fire. The test was terminated after three hours without any significant charring on the protected wood surfaces of the structure. • Test 2: Thirty per cent of the CLT ceiling area in the living room and bedroom was left exposed. The test was terminated after four hours, providing additional time to determine if there would be any significant fire contribution from the exposed CLT. Notably, once the furnishings and contents had been consumed by the fire, the exposed CLT essentially self-extinguished due to the formation of char that protected the underlying wood.
Test 1 Living Room and Kitchen Flashover: Researchers from the Forest Service’s Forest Products Laboratory completed a series of fire tests that will help take building with wood to new heights. Wood buildings provide an array of economic and environmental benefits, and interest in capitalizing on those benefits by constructing mid- to high-rise buildings using mass timber products is growing. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017) Photo Credit: Laura Hasburgh (FPL)
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Test 1 Decay: Test one lasted approximately three hours. No sprinkler systems were activated during this test and the fire decayed on its own. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017) Photo Credit: Laura Hasburgh (FPL)
Test Matrix: Detailed construction specifics for each of the five fire tests, conducted by Forest Products Laboratory researchers on a structure built using cross-laminated timber. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017)
Data Acquisition: Data was collected once per second at 500 points throughout the structure. Once the data is analyzed, results will be published in a report and presented to the International Code Council Ad-hoc Committee on Tall Wood Buildings. (Two-story cross-laminated building fire tests; Beltsville, Maryland; June 2017) Photo Credit: Laura Hasburgh (FPL)
• Test 3: Parallel CLT walls were left exposed with 30 feet of separation, one in the living room and one in the bedroom. Similar to Test 2, once the apartment furnishings and contents had been consumed by the fire, during which a protective surface char formed on the CLT, the mass timber surfaces essentially self-extinguished. 40
• Tests 4 and 5: These two tests examined the effects of sprinkler protection. For both tests, all mass timber surfaces in the living room and bedroom were left exposed. Test 4 demonstrated that under normal operating conditions, a single sprinkler easily contained the fire. For Test 5, the fire was allowed to grow in the compartment for 23 minutes before water was supplied to the sprinklers, which quickly controlled the fire. While the fire test data is still being analyzed, the initial results and findings are extremely promising. AWC and its partners will continue to study the data, which will ultimately help inform code change recommendations from the Ad-hoc Committee later this year. A General Technical Report FPL-GTR-247 on the fire tests will also be available from the Forest Products Laboratory in the coming months. In Canada, where several demonstration projects of tall mass timber buildings have been built, current building codes also place limits on prescriptively permissible maximum heights of wood buildings. Importantly, however, discussions similar to those taking place within the ICC Ad-hoc Committee are also occurring in the Canadian national model code pro-
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cess, with the goal of implementing code changes to permit tall wood buildings in the 2020 model National Building Code of Canada. As a result, it is expected that the research undertaken by the Ad-hoc Committee also will be very useful in Canadian code deliberations. With technological advances in mass timber and other wood products regularly affecting the industry, AWC is committed to advancing these new technologies in the codes in a manner that foremost protects public safety. Backed by this fire test research, we will continue advocating not only what is permissible using wood, but also to what is possible using wood. To learn more, visit www. awc.org/tallwood. Kenneth Bland, P.E., is the Vice President of Codes & Regulations at the American Wood Council (AWC), which represents the interests of the North American wood products industry that provides approximately 400,000 men and women in the United States with family-wage jobs. On behalf of the industry it represents, AWC is committed to ensuring a resilient, safe, and sustainable built environment. To achieve these objectives, AWC contributes to the development of sound public policies, codes, and regulations which allow for the appropriate and responsible manufacture and use of wood products.
FROM WELL-MANAGED FORESTS IS AN EXCELLENT CHOICE FOR ANY GREEN BUILDING PROJECT
SFI IS A CORNERSTONE FOR SMALL AND TALL WOOD BUILDINGS
Using wood products from responsibly managed forests is key to any green building project. Third-party forest certification standards, like the Sustainable Forestry Initiative® (SFI), are a proof-point that wood comes from responsibly managed forests that have been managed for multiple environmental, social and economic values — today and into the future. Architects and builders are turning to products certified to the SFI Standard to meet their green building needs. Learn more at sfiprogram.org/green-building.
Products certified to SFI are recognized by many leading green building rating programs around the world like Leadership in Energy and Environmental Design (LEED) and Green Globes.
FIRST CLT MANUFACTURERS CERTIFY TO SFI SmartLam and Structurlam are the first crosslaminated timber (CLT) manufacturers, in Canada and the U.S. respectively, to be certified to the SFI Chain of Custody Standard. This standard is a rigorous environmental accounting system that tracks forest fiber content through production and manufacturing to the end product.
Seismic Design with Wood Jim Taggart Wellington Secondary School. Photo Credit: Artez Photo.com
To understand the principles of seismic design, one must first understand the nature of seismic forces. Initiated by the movement of the Earth’s tectonic plates, they take the form of waves that travel either in the body of the planet or at its surface. Body waves are further subdivided into primary (P) waves – behaving like the repeated compression and release of a spring – shaking a building in the horizontal plane, and secondary (S) waves – transverse in nature – shaking a building in the vertical plane. As knowledge of earthquake behavior has evolved, more sophisticated approaches to the seismic design of buildings have been developed. An important consideration is that of ductility. In the case of major earthquake events, the energy-dissipative components are designed to perform ‘plastically’ – absorbing energy through deformation and permitting a certain level of damage to the structure, but preventing the catastrophic collapse of the building. In typical wood buildings, the main source of ductility are the connections. (Even after moderate earthquakes, it is prudent practice for building owners to have an inspection carried out by a qualified struc42
tural engineer to ensure that the integrity of the structure has not been compromised). Although seismic events occur all over the world, the areas most susceptible to large earthquakes lie along the boundaries of tectonic plates, including those on the so-called ‘Ring of Fire’ encircling the Pacific Ocean and passing through British Columbia.
British Columbia’s seismic upgrade program With several major earthquakes having struck other countries on the Ring of Fire in the past two decades, there is a heightened awareness of the risk faced in British
The "Ring of Fire" encircling the Pacific Ocean
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Columbia. A survey commissioned by the provincial government and conducted by the Association of Professional Engineers and Geoscientists of British Columbia (APEGBC) in 2004 determined a significant number of older BC schools did not meet the then-current safety requirements in terms of seismic design. Of these, 339 were found to include structures in the highest risk category (known as H1) – those most likely to experience widespread and irreparable damage or structural failure in a seismic event. In response to these findings, the province initiated a seismic upgrade program, which has retrofitted or replaced 224 of the highest risk schools in 37 districts to date. A number of these projects used wood as the primary structural material. (The seismic mitigation program and the associated risk categories are described on the province of British Columbia website. It is important to note classifications are applied not to schools as a whole, but to ‘blocks’ within the building. Blocks represent areas within a school that are of different construction types and have different structural characteristics. For
example, gymnasiums will typically have a different structural system than classroom or administration blocks, and as a result may have a different risk rating).
In 2012, structural engineers from Nanaimo-based Herold Engineering prepared a Seismic Project Investigation Report identifying four of the blocks (all except C and D) as risk category H1. Two seismic mitigation options were considered: comprehensive upgrades to bring all the structures up to current code standard; or a partial upgrade, together with the demolition and replacement of the highest risk portions of the building (Blocks A and F).
More detailed consideration of site constraints, the provision of temporary classroom accommodation, parking, site access, and staging confirmed demolition and rebuild was the more economical option. This option included the seismic upgrades of Blocks B, D, and E, the demolition and rebuilding of Block F, and the demolition and replacement of Block A with a new classroom block (in another location referred to as Block G). The upgrading of Blocks B and E were carried out at the beginning of the renovation. Both had been constructed in 1987 with a combination of precast concrete panels, unreinforced (or partially reinforced) concrete masonry unit (CMU) walls, and heavy timber roofs with glued-laminated (glulam) beams, tongue-and-groove decking, and plywood sheathing. The seismic upgrade included additional reinforcement of the masonry walls, higher ductility connections between the walls and roof, and the strengthening of the roof diaphragm with an additional layer of plywood. (Crosslaminated wood products, such as plywood and CLT, are particularly well-suited to use as diaphragms as they resist racking when subjected to lateral forces).
Wellington Secondary: dismantling of Block F. Photo Credit: Herold Engineering Ltd.
Wellington Secondary: New structural members in Block F. Photo Credit: Artez Photo.com
Seismic upgrading of Wellington Secondary School Located in Nanaimo on Vancouver Island, Wellington Secondary School is a two-story, 115,712-sq.ft. structure with a capacity of 900 students. It was built in several phases from 1969 to 2000, on a radial plan with a circular central block – known as Block F – surrounded by five other blocks (Blocks A, B, C, D, and E).
Seismic assessment and design approach
Seismic analysis of Block F The original 1969 library structure (Block F) presented a considerable challenge to upgrade, and the analysis merited a more detailed discussion. The roof structure consisted of radially arranged concrete T-beams, resting on inner and outer concrete ring beams supported on concrete columns. In turn, these columns were supported on concrete walls at the basement level. The entire structure was heavy and, having been designed to a much less demanding seismic standard, had neither the required ductile connections between the elements nor the adequate lateral restraint in the radial direction. Generally, when comparing two buildings of equal height, in the same geographic location, and with the same soil conditions, a heavier building will attract larger seismic forces than a lighter building. The heavy weight of the Block F structure would have required a large number of custom steel brackets, substantial cross-bracing, and enlarged foundations to transfer the required loads to the ground. The more desirable, and cost-neutral, alternative was to dismantle the existing structure and replace it with a new lightweight building.
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Wood was chosen for this replacement structure due to its economy, speed of construction, and esthetics. The wood solution met the constraints of a fast-track schedule and a tight budget, while introducing a warm look to the core of the school. Demolition of Block A opened up an area adjacent to this core that is now a new glazed entrance.
Detailed design The structural engineers developed a retrofit system for Block F that used the existing foundations and replicated the geometry of the original structure. Block F is divided into two distinct but connected components. The ‘main street’ surrounding the central courtyard forms a circle with an inner and outer ring of columns connected by beams that support a sloping roof. The inner ring of columns delineates the exterior glazed wall that encircles the courtyard, while the outer ring forms a colonnade separating the main street from the rest of the school. The main street is circular in plan, and the surrounding school is in the form of a pentagon, leaving an irregularly shaped zone between them. This zone was covered by an existing flat roof originally framed with solid timbers. The longest of these members were reinforced with laminated veneer lumber (LVL) beams, so the roof could perform as an effective diaphragm between Block F and the surrounding blocks. The engineers also added a second layer of plywood sheathing to meet load transfer and drift requirements. This upgraded roof connects to the outer ring of posts below the eave line of the central sloping roof. This results in a discontinuous section where the roof diaphragms are not in the same plane, requiring lateral loads be transferred into the vertical structure by a pair of drag rings consisting of continuous steel cross-bracing. In the vertical plane, lateral resistance is provided by a series of 16 steel crossbraced frames that tie into adjacent pairs of glulam columns in the outer ring. Full-height cross-bracing is also used between pairs of columns in the inner 44
ring. Throughout the timber structure of Block F, connections are designed to be relatively simple and economical – the majority being exposed steel plates and brackets. The light weight, versatility, and economy of wood have combined to bring this project to a successful resolution, on time and on budget. Wood has also contributed additional value, creating a warm and welcoming atmosphere, one that has transformed the identity of this aging school.
Other applications of wood in seismic design Two other recently completed BC school projects illustrate alternative approaches to seismic design using wood. Cordova Bay Elementary in Victoria employs a combination of cross-laminated timber (CLT) and nail-laminated timber (NLT) panels, while Surrey Christian School combines a glulam post-and-beam system and light-wood frame shear walls with NLT roof panels.
CLT and NLT panel solutions Cordova Bay Elementary dates from 1945, and like Wellington Secondary, has undergone multiple renovations and expansions since. Of these, the 1965 addition, constructed with unreinforced concrete masonry exterior walls and a glulam and heavy timber roof, was designated as risk category H1. As with Wellington, a detailed assessment of site logistics temporary accommodation resulted in the decision to replace the existing structure. It was proposed the new classroom block be built with CLT walls and roof panels, and light-wood frame construction for interior non-loadbearing partitions. Despite the replacement option having been chosen for its low cost, the project came in a little over budget. The low bidder for the supply and installation of the CLT components, offered a savings to change the roof panels to NLT. The final result is all the loadbearing and shear walls are constructed from five-ply CLT, and the roof is NLT panels made from 2 x 8-in. material nailed together face to face, creating a solid deck.
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Cordova Bay Elementary School: Interior of lobby showing exposed CLT and NLT panels. Photo Credit: StructureCraft Builders Inc.
The CLT panels are set vertically, extending from the ground floor slab to the underside of the roof. Base connections are steel plates set into the concrete and recessed into rebbates factory-milled into the panels. The plates are secured using long, high-strength, self-tapping screws, then covered with a wood plug so the connections are hidden and the CLT can be left exposed. The vertical edges of the panels are milled with a profile so they form a lap joint when brought together. This joint is then stitched together using pairs of similar self-tapping screws set at opposing angles. Where an internal wall meets an external wall, the butt joint is secured in the same manner. The use of a large number of small connections (rather than a smaller number of large connections) is the most efficient way to dissipate seismic forces. This is because it spreads the load more evenly through the structural section.
The NLT panels bear directly on the CLT walls and are connected to them in a similar way. They arrive onsite with a plywood diaphragm factory installed over most of the panel, but held back from the edges. The panels are lifted into place by a crane, and the diaphragm is completed by installing a final row of plywood sheets that cover the joint between panels. This approach results in a continuous diaphragm across the entire roof, requiring only a single layer of plywood. This project demonstrates that factoryproduced CLT and NLT panels can be successfully combined to create economical and esthetically pleasing buildings. It also confirms simply detailed CLT panel systems can provide a cost-competitive, code-compliant solution for lateral design in high seismic zones.
Glulam post-and-beam and light-wood frame shear walls Located in the Lower Mainland, the new two-story Surrey Christian School building includes a total of 15 daycare, kindergarten, and primary classrooms, along with their support spaces. The classrooms are organized along a linear two-story atrium extending the full length of the building. The need to connect at main floor level to the adjacent middle school meant the new building, which is on a sloping site, was constructed atop a new single-level parking garage that is partially tucked into the hillside. To address the client’s concerns for economy and speed, and deliver an attractive, high-quality building simultaneously, the design team proposed a simple engineered wood post-beam-panel structure that could be prefabricated. The vertical structure consists of glulam posts at 8.8-ft. centers along the length of the building. Each bay consists of four posts – two at the exterior walls and two at the atrium walls. The glulam posts were factory-fitted with custom steel base plates that were attached using long, highstrength, self-tapping screws installed at opposing angles. The posts on the main floor were
bolted to the concrete slab of the parking structure, and braced longitudinally using light-wood frame infill panels. There are no longitudinal beams in the building. The posts were then ready to receive prefabricated floor and roof panels, 8.8 ft. in width and spanning the full 27.8-ft. depth of the classrooms. Each panel has two glulam edge beams, connected with light-wood frame header panels at both ends and bridged by a deck made up of nail-laminated 2 x 4-in. material. These panels were installed in alternate bays along the length of the building, leaving the spaces between them to be filled with a second panel type that consisted only of 2 x 4 nail-laminated timbers. The edge beams of the main panels rest directly on top of the posts, and are connected to them with a similar detail to that used at the base. Once all the main floor panels were installed, plywood sheathing was laid by the general contractor in order to create a horizontal diaphragm. (Carpenters used plywood reclaimed from the formwork for the concrete parking garage. It was field-installed one sheet at a time). For the vertical plane, lateral stability is achieved by plywood-sheathed light-wood frame walls running north-south at either end of the building, and east-west along the length of the corridor between door openings. These shear walls were also prefabricated. The lateral system was designed to resist all the required seismic loads, enabling the exterior walls of the classrooms to be fully glazed. For this project, the use of factory prefabrication compensated in part for the additional time required to construct the parking garage. It was possible for the wood components to be prefabricated at the same time as the concrete was being poured. Installation of all the prefabricated wood components took approximately one week. Prefabrication in wood was also compatible with the use of site-built light-wood frame construction for the interior partitions. The result is a building with a warm and welcoming atmosphere that greatly exceeded the client’s expectations.
A final note The projects described in this article were all designed to meet the requirements of the 2012 edition of the British Columbia Building Code (BCBC), which was based on the 2010 edition of the National Building Code of Canada (NBC). It is worth noting the seismic design values used in the new 2015 edition of the NBC (upon which subsequent editions of the BCBC will be based) are significantly higher than those in the 2010 edition of the code. Therefore, the solutions described here may not comply with those more stringent requirements – although new solutions using the same basic principles will of course be developed. (Of course, designing structural wood buildings goes far beyond solely seismic requirements. For more information, see this author’s previous Construction Canada case studies and articles, including “Mid-rise Makeovers,” by visiting www.constructioncanada.net. Other features of interest would include “Specifying Combustible Construction in Canada” by Jack Keays, MSc., P.Eng., and “Specifying Modern Timber Connections” by Maik Gehloff, Dipl.-Ing. (FH), M.A.Sc. For further reading, also visit www.constructionspecifier.com for the article, “Solid Timber, Solid Construction Performance,” by Ryan E. Smith). This article originally appeared in the May 2016 issue of Construction Canada (vol. 58, no. 3), the official publication of Construction Specifications Canada (CSC). For more information, visit www.constructioncanada.net. Jim Taggart, FRAIC, teaches architecture at the British Columbia Institute of Technology (BCIT) in Vancouver. He is also the editor of Sustainable Architecture and Building Magazine (SABMag) and the author or editor of more than a dozen books, including the award-winning Toward a Culture of Wood Architecture (2011). Taggart has also lectured extensively on this subject throughout North America, Scandinavia, and Australasia. He is a Fellow of the Royal Architectural Institute of Canada (RAIC) and the recipient of the 2012 Premier of British Columbia’s Wood Champion Award. He can be reached at firstname.lastname@example.org.
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