All posts in Sustainability

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Carbon Stacked

The country’s tallest timber building wraps up in Portland
As the race heats up to demonstrate that timber is a viable alternative to concrete for mid and high-rise buildings, Portland, Oregon, has been leading the way in realizing mass timber projects. The latest to claim the country’s tallest timber building crown is Carbon12, an 85-foot tall mixed-use building in Portland, designed by PATH Architecture. Built with a mix of glulam beams and cross-laminated timber (CLT) surrounding a central steel core, the eight-story building was designed to have a minimal environmental impact and promote Oregon’s local timber industry. As downtown Portland addresses a growing demand for housing, timber projects constructed with prefabricated CLT panels cut off-site, like Carbon12, hold a speed advantage over traditional steel and concrete techniques. Carbon12 features a mix of 14 residential units, each with their own recessed balcony, as well as retail on the ground floor and a mechanized underground parking system. While the exterior is clad in vertically striated metal paneling that recalls timber grain, PATH chose to accentuate the natural materials of the interior spaces by leaving the wood columns, beams, and undersides of the CLT slabs exposed for a warmer feel. PATH’s focus on sustainability as a requirement in part drove their decision to use timber for Carbon12. Because locally grown timber can sequester more carbon dioxide than is used to grow and transport the wood, it often has a smaller carbon footprint in production than steel or concrete. Carbon12 will also feature solar panels on the roof. Although Carbon12 is currently the tallest timber building in the U.S., it won’t be for long. The 148-foot tall, 12-story Framework building, also in Portland, is shooting to take the title once it finishes in winter of 2018. Designed by LEVER Architecture and the Framework Project, Framework will feature a wood core as opposed to steel. Still, as timber buildings continue to push higher and higher, they may be paving the way for the eventual acceptance of timber as a mainstream urban construction material. Carbon12 is now fully complete and units are available on the market.
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Timber Time

2017 Best of Design Awards for New Materials
2017 Best of Design Award for New Materials: Indiana Hardwood Cross-Laminated Timber Project Designer: IKD Location: Columbus, Indiana The Indiana hardwood cross-laminated timber (HCLT) project is the first commercial pressing of HCLT and the first use of HCLT in a built project in the United States. IKD aspires to create a new timber product by upcycling low-value hardwood sawn logs that are extracted from Indiana forests. Indiana’s largest cash crop is hardwood, but over 55 percent of each log processed is of low value. The firm set out to demonstrate how low-value hardwood can be used to create high-value HCLT, which can then be used as the primary structure for buildings. This process has the potential to initiate a cascade of effects: positive job growth in rural forestry and manufacturing, hardwood lumber market expansion, forest land value increase, and improved forest management practices. HCLT offers numerous benefits over softwood, including superior mechanical properties, material volume savings, and increased fire resistance. “The use of hardwood in mass timber is appealing on many levels. Its added strength and durability over softwoods makes it ideal for exterior applications.” —Nathaniel Stanton, principal, Craft Engineer Studio (juror) CLT Fabricator: Smartlam Timber Engineers: Bensonwood General Contractor: Taylor Brothers Construction Hardwood Material Supplier: Koetter Woodworking Grant Funding: United State Forest Service Wood Innovation Grant
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CLT Superstore

2017 Best of Design Awards for Office & Retail
2017 Best of Design Award for Office & Retail: Albina Yard Architect: LEVER Architecture Location: Portland, Oregon

Albina Yard is the first building in the United States made from domestically fabricated cross-laminated timber (CLT). This new 16,000-square-foot speculative office building utilizes mass timber construction, with a glue-laminated timber frame and CLT panels manufactured and prefabricated in Riddle, Oregon. The project’s primary goal was to utilize domestic CLT in a market-rate office building that would pave the way for broader adoption of renewable mass timber construction technologies in Oregon and the United States. The design approach reflects a commitment to this sustainable technology by developing an architecture focused on economy and simplicity, material expression, and the careful resolution and integration of all building systems to foreground the beauty of the exposed Douglas fir structural frame.

“As a structural strategy, mass timber is very similar to a cast-in-place concrete structure in terms of layout and function of its individual elements. The main difference is the character and humaneness of the remaining spaces.  It is very well-suited for this type of use.” —Nathaniel Stanton, principal, Craft Engineer Studio (juror) General Contractor: Reworks Structural Engineer: KPFF Consulting Engineers CLT Supplier: DR Johnson Lumber CNC Routing: Cut My Timber   Honorable Mention Project: Cummins Indy Distribution Headquarters Architect: Deborah Berke Partners Location: Indianapolis, Indiana This new office building reinforces an active pedestrian experience that is connected to downtown Indianapolis and its parkland. The unusually slender floorplan and high ceilings provide abundant natural daylight for every space and minimize reliance on electricity. A high-performance “calibrated” facade and an integrated system of fins and shades limit heat gain and increase thermal comfort.   Honorable Mention Project: Zurich North America Headquarters Architect: Goettsch Partners Location: Schaumburg, Illinois Located on a 40-acre expressway site in suburban Chicago, the North American headquarters of the Swiss Zurich Insurance Group reflects the company’s global reach and commitment to sustainability. Composed of three primary “bars” that are offset and stacked, the arrangement creates unique spaces for collaboration, opens views of the surrounding landscape, optimizes solar orientation for amenities, and provides programmatic flexibility.
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Windows 2049

Microsoft reveals renderings for its new Silicon Valley campus upgrade
Microsoft has gone big and broken ground on its new Silicon Valley headquarters, with a sustainability-minded plan to modernize its Mountain View, California outpost. The 32-acre campus might seem small when compared to the company’s sprawling, 500-acre flagship location in Redmond, Washington, but Microsoft’s pursuit of a net zero non-potable water certification under the Living Building Challenge will make them the first tech company to totally reuse non-potable water. The redevelopment plans come as WRNS Studio replaced SOM early last year as Microsoft’s designers of choice. The redevelopment is leaning hard on a green modernization, with Microsoft pursuing LEED Platinum certification for all of its new buildings, committing to the WELL Building standards for the interiors, and integrating cross-laminated timber (CLT) throughout all of the new buildings to cut material usage. In trying to meet their water-use reduction goals, and acknowledging California’s limited groundwater availability, the campus will feature rainwater catchments and an on-site wastewater treatment plant so that drinkable water can be recycled for other uses. Because the campus is next to Stevens Creek, the tech giant is also introducing a 4-acre, occupiable green roof solely planted with native species. Rooftop solar panels will also help cut the campus’s energy usage, while the buildings will let natural light in through their uniformly large windows. Not to be outdone by the main, Seattle-adjacent campus, the project will also include an underground parking garage topped by a soccer field and a new athletics facility, while returning the former parking lots to nature. Besides modernizing the office space of their 2,000 San Francisco Bay Area-employees, the new campus will feature a renovated dining hall, new theater, conference center, and a “Microsoft Technology Center.” Microsoft has provided a full fly-through video of their plans below. The new Mountain View campus plan increases the existing 515,000-square-foot campus to 643,000 square feet, and comes amidst the recent opening of Apple’s new space-aged campus nearby. Similarly, Microsoft's renovation of its main headquarters in Redmond, announced at the same time as its Silicon Valley campus, feels like a direct response to Amazon’s city-hopping HQ2 plans. Microsoft's Silicon Valley campus is on track to re-open sometime in 2019.
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Concrete Jungle

New timber research finds exciting potential in steel and concrete composites
With mass timber projects on the rise around the United State, Skidmore, Owings & Merrill (SOM) and Oregon State University (OSU) have partnered to produce two new reports on how timber buildings can overcome their technical limitations by integrating steel and concrete. The new composite systems being proposed would allow timber construction to rise higher than before, with longer floor spans. The OSU Testing Report, released earlier this month, looked into the possibility of combining cross-laminated timber (CLT) floor systems with a concrete topper, to improve the strength of the flooring as well as lengthen its span. To accurately represent real-world conditions, the SOM team first drew up plans for a “typical” 11-story residential building and indicated where the wood columns would normally be. With the floor span determined, the CLT flooring was stress tested for load, bending, cracking and shearing, before and after the application of a concrete slab. A 2.25-inch thick concrete layer was applied over a 6.75-inch thick CLT floor for the experiment. After testing smaller, individual sections, an eight-foot-by-36-foot full-sized mockup was created and subjected to load testing, only failing after engineers applied eight times the normal service load, or around 82,000 pounds of pressure. One complicating factor is that CLT can be charred for a higher fire rating at the expense of its strength, and any real-world application of CLT would need to be thicker than in testing conditions. Still, the results are a promising first step to increasing floor spans in timber buildings as well as improving their acoustic properties. The second report was produced in conjunction with the American Institute of Steel Construction (AISC) and examined how steel framing can best be integrated with timber floor systems. Because steel framing can span much greater distances than timber with smaller columns, and because CLT is lighter than concrete, a building that uses both should get the best of both worlds. In SOM’s modeling, this combination model was equally as strong as a steel and concrete building while offering window bays of the same size as a typical residential building. Ideally, high-rise timber construction of the future would combine both of these techniques, as the concrete slab topper adds extra seismic protection. With timber construction offering the potential for more sustainable, durable and quickly assembled towers, hybrid research could be a stepping stone towards bringing mass timber construction into the mainstream. All of SOM’s timber research reports can be found here.
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School Cabins

Design collaboration brings mass timber residence halls to the University of Arkansas
A national design collaboration led by Boston-based Leers Weinzapfel Associates and including Arkansas-based Modus Studio, St. Louis–based Mackey Mitchell Architects, and Philadelphia-based OLIN has created America’s first large-scale, mass timber interactive learning project, already under construction at the University of Arkansas. Working off of a “cabin the woods” concept, 708-bed Stadium Drive Residence Halls feature fully exposed, locally harvested wood structural elements. The residence halls are a pair of snaking buildings joined in a central plaza, and include classrooms, dining facilities, maker-spaces, performance spaces, administrative offices, and faculty housing. The five-story buildings, totaling 202,027 square feet, are clad in a zinc-colored paneling, while copper-toned panels are scattered along each floor that appear to float above the heavily planted backdrop. Inside, wooden columns, beams and cross-bracing are all displayed to present a sense of warmth, and to connect students with Arkansas’s local ecology. The halls terminate with large study rooms at the end of each floor, which light up at night and act as beacons for the rest of the campus. The panels were constructed from Cross Laminated Timber (CLT), while the structural columns and beams are made of glulam, where layers of wood all facing the same direction are laminated together under pressure. Each arched building curves around a courtyard or common park area and students enter the complex through a covered “front porch” at the northern building’s main entrance. The central gathering room that connects the hall’s two wings has been dubbed the “cabin,” and despite being relatively small, packs in a hearth, community kitchen, lounge spaces, and a planted green roof. Each hall also features a double-height ground floor lobby with floor-to-ceiling windows that allow uninterrupted views of the surrounding landscape. “The interwoven building and landscaped courtyards, terraces, and lawns; the beauty of timber structure and spaces; and the excitement of performing arts and workshop facilities will make this newest campus residential community a destination and a magnet,” said Andrea P. Leers, principal of Leers Weinzapfel Associates. Leers Weinzapfel is no stranger to working with timber, as its multidisciplinary design building for UMass Amherst wrapped up construction late last year. The project is expected to finish in 2019, and will anchor a new master plan for the University of Arkansas campus.
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Rising Ideas

Van Alen competition on Miami's sea level rise comes with $850,000 budget
Recognizing how vulnerable southern Florida is in the face of climate change, the Van Alen Institute has launched Keeping Current: A Sea-Level Rise Challenge for Greater Miami. Targeting the Greater Miami Area, Keeping Current is a multi-disciplinary design challenge that is not only looking for answers about how to build a more resilient coastal city, but also offers sites ready to turn the winning plans into reality, with an $850,000 budget to implement them. Hurricane Irma’s near-miss this past summer only served to underscore just how vulnerable Miami really is, in a city already under threat from rising sea levels, where saltwater bubbles up through the porous limestone bedrock below. Recognizing the problem’s urgency, Van Alen has teamed up with the Greater Miami Area municipalities’ resilience, procurement, and budget teams to evaluate resilient infrastructure projects that both adapt to climate change as well as safeguard the investment that local municipalities will put into the project. The contest itself is spread out over three challenges across two sites, scheduled for the winter, spring and fall of 2018. Working with local elected officials, stakeholders, academics and business leaders, design teams will propose resilient solutions for a variety of sites facing different climate change-related problems. Winning entries will focus on addressing “economy, ecology and equity” or balancing budget concerns with community input, and will be given a total of $850,000 to realize their designs in real life. Ultimately, the goal is that the winning designs be scalable and replicable across all of Florida. Keeping Current is about more than safeguarding existing infrastructure. What Van Alen and the municipalities want from this contest is to turn Miami into a leader in urban coastal resilience, while encouraging growth in an area that would be devastated by only a three-foot rise in sea levels. With everything from drinking water, to agriculture, to billions of dollars’ worth of residential and commercial buildings at risk, interdisciplanary solutions are needed now more than ever. Keeping Current is sponsored by the Rockefeller Foundation, the John S. and James L. Knight Foundation, the Kresge Foundation, The Miami Foundation, and Target. The full design and community engagement guides will be made available by the Van Alen Institute in February of 2018.
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Timber's Mount Royal

Arbora housing complex in Montreal points to the future of timber construction
This is an article from our special November timber issue. Comprising three eight-story buildings totaling just shy of 600,000 square feet, the Arbora Complex near downtown Montreal is one of the largest mass timber projects in the world. The notability of this project is not just its size, but its ability to be a competitive, marketable, environmentally responsible alternative to increasingly affordable steel and concrete construction—an ability we might not associate with mass timber structures. The $130 million project offers 434 units, 130 of which are rental. According to U.S. Market Development Manager Jean-Marc Dubois at Nordic, a Quebec-based company that, among other services, supplied wood for the project, “The market in Montreal is more suppressed than Vancouver and Toronto. To be able to build means you must have a design that is viable and efficient—something that brings value to the developer. There’s a lot of press surrounding high-rise wood construction, but Arbora shows there’s a place for affordable, viable mid-rise construction.” Arbora involves cross-laminated timber (CLT), composed of layers of dimensional lumber stacked perpendicularly and glued together to create structural panels. CLT panels are typically made of layers of three, five, or seven, and, because they offer two-way span capabilities, can be used for floors, walls, and roofs. The result is a material that is lightweight, strong (up to seven times the strength of concrete), efficiently shipped, and less labor-intensive than its steel and concrete counterparts.
“With mass timber structures, you can use less employees and get more work done,” said Dubois. “There’s a shortage of skilled labor across North America, so the fact that you can raise structures with considerably less skilled employees is very critical. Typically we operate with as few as four to six tradespeople on a jobsite. The output per person is much greater.” These benefits come with a cost, however: increased upfront coordination and design time. Engineered wood components are designed, optimized, cut to millimeter precision, and then shipped to site for assembly. Dubois reports that Nordic is involved on multiple fronts of mass timber projects like Arbora, coordinating design, engineering, fabrication, construction sequencing, and regulatory parameters. “This is one of the things that distinguishes Nordic,” he said. “There’s a tremendous amount of involvement and engagement with our team that you don’t necessarily see as you’re looking at the construction process. We’re taking an active role in the design process, in addition to sitting in meetings with local authorities.” The key to Arbora’s commercial success in a competitive housing market is design efficiency, and an acknowledgement of the inherent structural properties of CLT from the outset of a project. “There are efficiency gains in replication,” Dubois said. The project was organized around a 20-foot grid, an ideal structural span and shipping dimension for the beams and panels. The consistency of the grid allowed an efficient manufacturing process, and abbreviated on-site assembly time. Early adopters of CLT in North America have tended to be more custom projects like schools and sports venues, but Dubois sees demand for mass timber shifting into commercial real estate, namely office workplace typologies, where the unique look of a wood structure can offer differentiation in the marketplace. Mass timber adoption in the United States has lagged behind that in Canadian markets. Dubois attributes this to a number of factors including the litigious nature of the United States, and the tendency of Canadian authorities to be receptive to performance-based design. “In Quebec, we don’t promote one building material over another, so we have to make a market against steel and concrete, which is exceedingly inexpensive,” he said. “We have to be economically viable and prove we are meeting the same structural and safety requirements that other systems must abide by. “Performance-based design typically runs into more red tape in the United States,” he continued. “I think it’s a fear of the unknown. This has led the American Wood Council, the U.S. Department of Agriculture, and the wood industry to promote the tall wood agenda, to try and get coded options so that it is prescriptive as opposed to alternative means and methods.”
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Wood Laws

Congress gears up for a fight over mass timber legislation
This is an article from our special November timber issue. The battle over the 2017 Timber Innovation Act is gaining momentum in Washington, D.C., where two new Senate sponsors and four new Congress members have signed on to it since this past May. The pending legislation would provide funding for research into innovative wood materials and mass timber structures above 85 feet. The bill’s proponents are hoping that it will be an impetus for transforming cities and towns across the country with a bevy of mid-rise and high-rise mass timber buildings. “I am very impressed with the large cross-aisle support,” Chadwick Oliver, director of Yale University’s Global Institute of Sustainable Forestry, said. “You have Bruce Westerman, a Republican congressman from Arkansas and Peter DeFazio, a Democrat from Oregon who has been on the side of environmental groups. This looks like a bill that is quite serious about moving forward.” However, the concrete and steel industries are vigorously lobbying to derail the legislation, and have established a website called Build with Strength that contains a detailed critique of the new generation of wood buildings. “It is a piece of legislation that props up one industry over another and we think that it is misguided and dangerous,” Kevin Lawlor, a spokesperson from Build with Strength, said. “We don’t think that it is safe in three-to-five story buildings, and we don’t think that it is safer in taller buildings.” The wood products industry, the U.S. Forest Service, and other advocates claim that technological advances make the new generation of tall timber buildings more fire resistant. In fact, according to Dr. Patricia A. Layton, director of the Wood Utilization + Design Institute at Clemson University, that is because of the way it chars in a fire: By insulating its interior, an exposed wood beam can actually be structurally stronger than a steel one. “Steel loses its strength at a lower temperature than does wood,” she explained. “If you expose concrete or steel it is combustible, and it does feel the effects of fire.” Many of the act’s supporters say that allowing buildings to be built from wood technologies such as cross-laminated timber (CLT) will result in a host of economic and environmental benefits. Most of the Timber Innovation Act’s sponsors hail from states where the wood industry is struggling to recoup from the recent housing downturn and also suffering from the decrease in demand for paper that is a result of the increasing digitalization of the economy. “A big part of the innovation act is having the U.S. Forest Service work to expand markets and attract business to heavily forested states, particularly those that have a major timber industry,” said Andrew Dodson, vice president of the American Wood Council, who notes that the U.S. Timber Innovation Act is a way to help jumpstart a sagging wood-products industry. “Mills are running at much lower capacity,” he said, “two shifts versus three or four—we want to put more mill jobs back in place.” However, some in the mass timber industry say that the Timber Innovation Act will be of limited utility until building codes are changed to allow for the use of CLT. “The code issue is more critical than the Timber Innovation Act,” Jean-Marc Dubois, director of business development for the Montreal-based Nordic Structures, said. He believes that New York City’s restrictive building codes have helped stall progress on tall timber, pointing to the wooden skyscraper designed by SHoP architects that was killed earlier this year as an example. Even though the 2015 International Building Code (IBC), which New York City has not adopted, allows for the use of CLT, Dubois said that building departments throughout the country haven’t updated their codes to allow for the use of CLT. Having the SHoP project, which received a lot of publicity, fail to get built was a major setback for the industry, according to Dubois. “New York City had the ability to be a real-world leader with timber innovation,” he said. “It was disappointing.” A $250,000 grant from the U.S. Forest Service’s Wood Innovations Grant program helped Yugon Kim of Boston-based IKD develop what he believes is the first hardwood CLT structure in the U.S.: An outdoor sculpture in Columbus, Indiana, which consists of a series of ascending arcing forms. Congress is not the only place in Washington where the merits of tall mass timber are being explored. Steve Marshall, assistant director at the U.S. Forest Service, has been working with the International Code Council to develop standards for the use of CLT. In addition, the U.S. Department of Defense has been conducting blast tests with CLT to determine whether it is an appropriate material to use on its bases. Marshall said there are other potential sources for government support for CLT projects aside from direct funding from the Timber Innovation Act. In the third week of October, his agency will be releasing a new round of grants of up to $250,000 under its Wood Innovations Grants program. Next year, the Forest Service is planning on making $8 million available under the same program, and applications will be due by mid-January. One of the most notable examples of how government funding can play a difference is with LEVER Architecture's innovative design of the 12-story (148-foot-tall) Framework building under construction in Portland, Oregon, which will be the first wood high-rise in the U.S. A $1.5 million U.S. Tall Building Award sponsored by the U.S. Department of Agriculture helped fund the seismic and fire-safety tests that enabled it to pass muster with Portland building department officials. Thomas Robinson, principal of LEVER Architecture said that the concrete and steel industries shouldn’t be worried about losing market share because in the future most tall timber structures will be hybrids that include concrete and steel as well as wood. “We need to look at each material for its appropriate purpose,” he said.
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Not All Bark

The lumber industry responds to the rise of mass timber
This is an article from our special November timber issue. North America’s lumber industry helped define what it means to build in the modern era. With the invention of the light balloon–frame, lumber became an indispensable resource to the quickly expanding United States in the 19th century. Over the past 150 years, the process and politics of wood have shaped a highly efficient industry that still provides the vast majority of the U.S.’s house-building material. With new technology, wood is pushing into new territories, and the lumber industry is bracing to respond to these demands. The process of harvesting lumber has dramatically changed since the industry began to standardize and organize in the late 1800s. No longer will you find any teams of two-person saws felling ancient trees or a Paul Bunyan-esque worker swinging an axe. Most of the industry became highly mechanized in the 1970s with the invention of the harvester. Harvesters, invented in Scandinavia, are tree cutting, moving, and trimming vehicles that have drastically reduced the danger and time involved in lumber work. Crawling through the forest, harvesters reach out with an articulated arm, grab a tree by the base with its nimble claw, then cut, trim, and lift the bare log onto the back of a transport vehicle. This can all be done by one operator, and during the process the tree is measured and catalogued. This entire process has added efficiency and sustainability to an industry that carefully balances a fine line of production and conservation. In North America and Europe, long gone are the days of clear-cutting forests and destroying an entire region’s ecology. While clear-cutting “slash and burn” operations still happen in parts of South America and Africa, they are due to the expanding, unregulated livestock and agriculture industries, not the timber industry. The careful regulation and scientific study of the lumber industry in the United States and Canada have led to a net increase of 1 percent of forested land over the last 50 years. That means the forests of North America are stable, with a slight increase, even as roughly 45.5 billion board feet of lumber are harvested in the United States in a single year. This is thanks to precise tree selection, sometimes using satellite imagery and GPS, and aggressive tree-growing programs. While much of the harvesting techniques have been streamlined, the politics behind harvesting have been anything but. Most notably, the Canada-U.S. softwood lumber dispute is considered one of the greatest points of trade tension between the two countries. The disagreement is directly linked to how and where lumber is coming from. In the United States, most lumber comes from the property of 11 million private U.S. landowners. In Canada, most land dedicated to lumber harvesting is owned by the government. In the interest of maintaining a healthy economy, Canadian provincial governments subsidize the industry, effectively keeping the price of lumber low and stable. This is in direct conflict with the private-market-driven prices U.S. companies charge. Over the past 40 years, a number of lawsuits and agreements have been filed and disputed between the two countries over Canada’s subsidies and the movement of lumber over the border. While this dispute is currently at an uneasy truce, the potential of new wood technologies is promising to drive the demand for lumber to new heights. Roughly 80 percent of all lumber harvested in the world is softwood. Despite its name, softwood, as opposed to hardwood, is not defined by its softness, but rather by the species of tree it comes from. Softwoods are generally conifers, such as pines, firs, and cedars, while hardwoods come from broad-leaved trees, such as oaks, maples, and hickories. Softwoods have long been used for light-frame construction, while hardwoods have been traditionally used for heavy timber construction, as well as fine woodworking due to its often-fine grain. Although the lumber industry is confident it can handle an increase in demand, there are factors that will need to be addressed. As of yet, there are few standards for producing heavy timber, CLT in particular, and legal definitions are also lacking. The industry is developing so fast that local fire codes have not been established for the material. At the same time, architects, lumber producers, and manufacturers across North America are looking to Canada and Europe for a way forward, while innovating in their own right.
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Photo Finish

HOK’s oscillating Atlanta stadium is now LEED Platinum certified
HOK’s Mercedes-Benz Stadium in Atlanta, Georgia, just became the first LEED Platinum–certified professional sports stadium in the world. The $1.5 billion project opened in August and is best known for its operable, aperture-shaped roof, but HOK and Buro Happold Engineering have also integrated a suite of sustainability features into the base design of the stadium. Replacing the now-defunct Georgia Dome as the home of the Atlanta Falcons, the 2-million-square-foot, 71,000-seat Mercedes-Benz Stadium is styled after the Roman Pantheon, as the entire arena is centered around a domed oculus. Because the building is multi-use—designed for holding football, soccer, and basketball games—and because Falcons owner Arthur Blank had wanted to build what he described as an “iconic stadium” with a retractable roof, a watertight aperture was designed for the roof. Comprising eight 200-foot-long, 450-ton blades clad in Ethylene Tetrafluoroethylene (EFTE) film, the roof’s semi-transparent iris is capable of opening and closing in only nine minutes. Because every petal needs to swing into place at a different speed, not rotate like a true aperture, the roof uses an algorithm to judge how much counter-balance is needed while the blades are cantilevering out over the field. Reinforcing the centralized focus of the design is a 350-ton, six-story, ring-shaped “Halo Board” seated inside the oculus itself that’s viewable from every seat and angle. Outside, the stadium’s base is a wall-to-ceiling glass curtain wall meant to give uninterrupted views of the surrounding city as fans make their way to their seats. Eight steel and glass “leaves” radiate out from the aperture at the top of the stadium and drape down over the glass at the bottom, referencing the swooping wings in the Falcons’ logo. According to HOK, Mercedes-Benz Stadium’s LEED score of 88 points is the highest of any sports venue. Through the use of its 4,000 photovoltaic panels, the stadium produces enough solar electricity to power nine football games, or 13 soccer games. By using water-conserving fixtures and infrastructure adjustments, the building uses up to 47 percent less water than a building of comparable size. The location was also key, as the stadium is located between three MARTA bus lines and next to a forthcoming 13-acre green space that fans can use between games. The site also features electrical vehicle charging stations, bike parking, and new pedestrian paths. An incredibly complex project that required coordination between architects and structural engineers at every step of the way, the stadium still isn’t fully operational even though it’s in use. Work on the roof is still ongoing, and engineers hope to have the aperture fully functional by the time Atlanta hosts the Final Four basketball tournament in 2020. The stadium's innovative high performance facade will also be discussed more in-depth at Facade Plus's Atlanta conference in January 2018.
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Life's A Beech

Experimental Swiss apartment wants to bring timber into the 21st century
The Wood Materials Science department at ETH Zurich in Switzerland is pioneering new ways of utilizing timber and wood construction by imbuing the traditional material with extraordinary properties using its new Vision Wood apartment prototype. The multidisciplinary team—guided by department head Tanja Zimmermann and wood materials science professor Ingo Burget, and joined by a slew of industry partners—developed the prototype apartment in an effort to find new uses for the continent’s abundant, but mostly underutilized, beech lumber. Beech lumber is a hard and versatile wood with superb structural capabilities, but it is also prone to sun damage, rot, and warping. To combat these maladies, the team developed a slew of experimental applications of beech wood building components that have been waterproofed, magnetized, and mineralized in order to broaden their residential applications. The team, for example, subjected the wood to laccase-catalyzed reactions in order to derive a wood fiber–based insulation that eliminates the need for synthetic binding agents. The fully sustainable biopolymers—made from lignin compounds and modified starch naturally found in wood—were molded into tongue-and-groove-shaped insulation blocks that can be packed into building cavities, providing a nontoxic insulation material. Another innovation came in the form of an exterior-cladding coating application developed from gelatinous nanofibrillated cellulose. The varnish improves UV protection, waterproofing, and resistance to microorganism infestations and cracks for exterior wood treatments. The apartment interiors—which will be occupied by a pair of doctoral students—are rife with new applications, including antimicrobial wood surfaces treated with an enzymatic method developed by university researchers that utilizes a bacteriostatic iodine coating to kill bacteria. The application has been used on door handles in kitchens and bathrooms in the unit in an effort to improve indoor hygiene. The apartment features hydrophobic wood sinks in the bathroom that have been treated in situ with polymerizing agents that not only repel water from their surfaces but are also designed to give the appearance of untreated wood. The researchers inserted iron oxide nanoparticles into wooden blocks to develop a magnetized task board that utilizes the natural structure of wood to create a material that can be selectively magnetized as well. On top of that, the team developed a fire-resistant mineralized wood panel system that can be used for doors and other interior applications in lieu of toxic flame-retardants. This panel system can be entirely sourced and fabricated in Switzerland and features reduced dimensions relative to traditional lumber construction due to the wood’s structural capabilities. In all, the test apartment points a way forward for wood construction that relies on abundant and local wood sources, while also pursuing sustainable and nontoxic material applications.