The tall timber arms race is heating up. On January 22, the Milwaukee City Council's City Plan Commission unanimously recommended that a requested rezoning at 700 East Kilbourn Avenue move ahead, clearing the first hurdle for the Korb & Associates Architects–designed, 21-story mass timber tower. The mixed-use Ascent’s first five stories would rise on cast-in-place concrete, with up to 8,100 square feet of ground-floor retail and four stories of enclosed parking above that. The remaining 15 stories would contain 205 rental units and be built from mass timber fastened with steel connectors. Korb & Associates plan on leaving the wooden elements exposed as an interior finish wherever possible. The 238-foot-tall tower is being developed by New Land Enterprises, which has partnered with Korb & Associates on a number of projects across Milwaukee previously. According to Urban Milwaukee, the developer hopes to break ground on the Ascent this year, assuming the rest of the approvals process continues apace. The rezoning for the site still needs approval from the city’s Common Council’s Zoning, Neighborhoods & Development Committee. If Ascent’s design remains unchanged, it will slightly edge out Shigeru Ban’s 232-foot-tall hybrid timber Terrace House in Vancouver for the title of North America’s tallest timber building. According to partner and project architect Jason Korb, Ascent’s prefabricated timber components means that the top 16 floors can be installed in only four months. In a fire, the mass timber used for the structural elements will only char, not burn through, and Korb told Urban Milwaukee that, “The entire wood structure, and this would never happen, could burn down and the cores would be left standing.” Mass timber construction has been making slow progress in the United States compared to the rest of the world, but that may be about to change. The International Code Council, from which many state and local municipalities derive their building codes, recently embraced tall timber after two years of testing. With the new code adjustments in place, tall timber in the U.S. will only continue to rise.
Posts tagged with "Tall Timber":
This article originally appeared as part of our January 2019 print issue in the timber feature. The timber industry has long thrived on its small-scale, local nature due to the sourcing of its materials as well as the limits on project size set by the building code. With this has come a good deal of fragmentation and disorganization, so we decided to map out the different schools, organizations, and manufacturers that are leading the way in the research and development of mass timber across the United States and Canada.
Timber construction is on a roll, whether it be in Olympic stadiums or high-rise residences. Codes are changing as more municipalities embrace mass timber and the industry shifts away from concrete. Not to be left out, California is holding a Mass Timber Building Competition. The California Government Operations Agency (GovOps) is hosting the competition, and WoodWorks – Wood Products Council, an organization that offers free guidance for designers using timber, will be administering the program. As GovOps notes, California is one of the largest consumers of engineered wood products in the country, but almost none of it is harvested or produced in the state. At a time when the buildup of forest density in California has contributed to an ever-worsening fire season already acerbated by climate change, GovOps is pitching this competition as a chance to kill two birds with one stone. Interested parties in California—including real estate developers, designers, institutions, and other organizations—have until March 18, 2019, to submit a proposal. GovOps is going big and is only accepting proposals for multistory, 10,000-square-foot-plus mixed-use, commercial, industrial, institutional, or multi-unit housing projects. Preference will be given to projects over 100,000 square feet that clear six stories. A full list the competition guidelines are available here, and it looks like proposals will be evaluated on cost as well as “narrative” in an attempt to create thoughtful applications of timber. WoodWorks will also be available to offer guidance to entrants on both feasibility as well as design. The two (or possibly more) winning teams will split a $500,000 grant to continue their research into developing repeatable, sustainable, and affordable timber construction.
Alphabet subsidiary Sidewalk Labs has revealed their vision for a proposed “smart city” on Toronto’s waterfront in a (now) 12-acre parcel in the formerly-industrial port district of Quayside. This is the first time the company has released concrete design details on their forthcoming neighborhood, but information on how data will be collected—and how much—is still being kept under wraps. If the project is approved as is, the neighborhood could eventually be home to 3,000 residential units built entirely from mass timber. Sidewalk Labs has enlisted the help of the Katerra-owned Michael Green Architecture (MGA), which is no stranger to working with timber, to design the large mixed-use Quayside buildings. At the base of all of the proposed buildings would be “stoas," open-air retail and communal gathering spaces with adjustable protection from the elements. If built, the three-million-square-foot development would be the largest timber project in the world. All of this was revealed during a briefing yesterday ahead of the latest round of public input. Sidewalk Labs released a suite of new details during the public roundtable, including their plans for activating the streets, integrating the adjacent waterway, and doubling the amount of time residents can enjoy outdoors. While the open nature of the modular stoas is meant to encourage pedestrian mingling at ground level, MGA has also designed a series of collapsible, umbrella-like structures to block out wind, rain, and snow. The expandable canopies, when combined with heated streets that melt snow, will supposedly mitigate some of the more unpleasant weather during the winter. Sidewalk Labs is also testing a modular paving system that can be embedded with sensors and rearranged depending on how the street is being used. The team is designing a new multimodal street grid for the neighborhood that prioritizes public transportation, biking, and walking, and that narrows the allotment for cars in anticipation of autonomous vehicles. Of course, Sidewalk Labs’ attempt to create a ground-up, fully-developed smart city is still in the planning phases and faces several hurdles. While tall timber construction was recently permitted in Oregon, Toronto still caps mass timber buildings at six stories; Sidewalk Labs reportedly wants to build as tall as 50 stories in Quayside. As previously mentioned, the company has also been tight-lipped on the type and quantity of data their neighborhood will collect, and it remains to be seen if the proposed technology will be mature enough to support a robust, interconnected infrastructure for 3,000 residents. We’ll find out more as we get closer to the project’s spring groundbreaking date.
Thanks to a recent addendum to Oregon’s building code, the state is the first in the country to allow timber buildings to rise higher than six stories without special consideration. Portland has become something of a hotbed for timber innovation as of late. Carbon12, PATH Architecture’s eight-story glulam and cross-laminated timber (CLT) tower with a steel core, recently became the country’s tallest timber building and was set to be surpassed by LEVER Architecture’s 12-story Framework. Alas, that project was put on hold due to mounting financial difficulties last month, but it seems the precedent that the project achieved in securing a building permit from the State of Oregon and City of Portland will live on. The timber allowance comes courtesy of Oregon’s statewide alternate method (SAM), a state-specific program that allows for alternate building techniques to be used after an advisory council has approved the “technical and scientific facts of the proposed alternate method.” The allowance comes after the International Code Council (ICC)–the nonprofit group that Oregon models its building codes after–established the ICC Ad Hoc Committee on Tall Wood Buildings in 2015 to explore the benefits and challenges of using timber in tall buildings. A Committee Action Hearing was held in April of this year, where the Ad Hoc Committee, made up of code experts, stakeholders, and industry members presented their findings. All 14 of the committee’s suggestions were adopted, introducing standards and best practices for fireproofing, the load-bearing potential of CLT and heavy timber, water resistance, sealing, seismic ratings, and more. Three new building classifications were introduced as a result: Type IV A, timber buildings permitted up to 18 stories and 270 feet tall, Type IV B, timber buildings with a maximum height of 12 stories and 180 feet, and Type IV C, which is permitted to rise nine stories and 85 feet tall at maximum. The shortest of the timber typologies is allowed to use exposed structural timber as an interior finish, whereas the tallest, type A, must enclose all exposed surfaces and include a three-hour fire-resistance rating for the structural elements. “We congratulate the State of Oregon on becoming the first state to provide building code recognition for construction of tall, mass timber buildings,” said American Wood Council President & CEO Robert Glowinski in a statement. “Mass timber is a new category of wood products that will revolutionize how America builds and we’ve seen interest in it continue to grow over the last several years. This action by the Codes Division Administrator helps code officials in Oregon by making provisions consistent throughout the state. In adopting this new method, Oregon has also recognized the significant environmental benefits that accrue from greater wood product use.”
AN Midwest Editor Matthew Messner spoke with Daniel Safarik, editor for the Council on Tall Buildings and Urban Habitat (CTBUH), about its “Tall Timber: A Global Audit.” The audit documented proposed, under-construction, and built tall buildings that use mass timber as their primary structural materials. The Architect’s Newspaper: What Prompted the CTBUH to conduct an audit of timber projects around the world? Daniel Safarik: We track all kinds of tall building construction routinely for the Skyscraper Center database and for our Global News feed on our website. The first well-publicized tall timber building was Stadthaus in London, which was completed in 2009. We noticed what seemed like a spike in announcements of timber tall buildings being proposed and constructed about four years ago , and everything that has happened since has reaffirmed this impression. When we saw the buy-in from the U.S. government represented by the U.S. Tall Wood Building Competition, in October 2014, that confirmed the impression that this really had momentum behind it, so we committed to tracking the two resultant projects through to completion. Unfortunately, the New York project was canceled due to market feasibility concerns, but the Portland project is now under construction. So the momentum began to build from that point, and we formed a Tall Timber working group in late 2014. The group started working on a design manual in mid-2015, and that effort has now gotten a turbo boost with the audit and the upcoming workshop at our 2017 conference, which is bringing together a lot of the key participants. Were there any interesting surprises once the information was gathered? The most striking thing was the diversity of construction methods that are being used to create these buildings, which are specific to local jurisdiction and the nature of the timber supply in each region. Of course, herein lies the difficulty of generalizing about what’s going on in tall timber worldwide, as well as coming to a consensus about classification and best practices—that is our challenge. What are some of the interesting discussions happening around mass timber? It’s encouraging to see the range of proposals, from both a stylistic and construction standpoint. The primary discussions revolve around fire safety and code, sustainability, and the feasibility of modifying fabrication techniques from mass production of stick-built single-family and platform-framed low-rise buildings to something that is workable for high-rise. What do you think the next steps are, or barriers to overcome, for mass timber to become a common building method? The foremost obstacle is local fire codes. Most fire codes prohibit wood structures from rising above five or six stories. Many codes stipulate that a building of this height must also have a concrete base, particularly if there are commercial uses on the ground floor, such as restaurants, or if there is vehicle parking, to give one to three hours of fire protection that would allow safe exiting before structural collapse. This is predicated on the assumption that wood high-rises would use platform construction, with dimensional lumber such as two by fours, beams, and joists, similar to those currently permitted. The key to mass timber’s viability as a structural material for tall buildings lies in its name. Massive wood walls and structural beams and columns comprised of engineered panels have demonstrated fire performance equal to concrete and, in some cases, superior to steel. Wood unquestionably burns, so there would be smoke issues, as with any fire, which would require proper sprinklering, pressurization, and other tactics used in tall buildings today. But mass timber has to burn through many layers before it is structurally compromised—basically it “chars” long before it collapses. As more jurisdictions come to appreciate the aesthetic, economic, and environmental advantages of tall timber, fire codes are expected to change. The second-biggest obstacle is a lack of standardization of construction materials, methods, and definitions. There are many forms of mass timber, and a wide degree of variance in approach when it comes to supporting tall timber structures. Thus, there is a range of techniques, from assemblages of highly similar panels for both floors and walls, to complex column/beam/outrigger combinations, such as are found in high-rises of steel and concrete. There are numerous proprietary systems, and the connections between elements also vary widely—often it is the location and orientation of the steel connectors between wood elements that can make all the difference in how long a structure can withstand fire or seismic action, and thus determine its feasibility under local code. Are there any proposals, speculative or real, that you are particularly excited about? I like the one we published in the CTBUH Journal for Chicago: the River Beech Tower. It would be great to see that go up in our home city.
An expanse of sustainable timber just clinched the Chicago Architecture Biennial’s Lakefront Kiosk Competition
Officials with the Chicago Architecture Biennial today announced the winners of the Lakefront Kiosk Competition, choosing a team whose stated goal was “to build the largest flat wood roof possible.” Dubbed Chicago Horizon, the design is by Rhode Island–based Ultramoderne, a collaboration between architects Yasmin Vobis and Aaron Forrest and structural engineer Brett Schneider. Their pavilion uses cross-laminated timber, a new lumber product that some structural engineers call carbon-negative for its ability to displace virgin steel and concrete while sequester the greenhouse gas carbon dioxide during its growth. Ultramoderne's long, flat roof “aims to provide an excess of public space for the Architecture Biennial and Chicago beach-goers,” according to the project description. Their design rose above 420 other entries from designers in more than 40 countries, and will receive a $10,000 honorarium, as well as a $75,000 production budget to realize the kiosk. BP is providing those funds as part of a $2.5 million grant to the inaugural biennial. Three teams—Lekker Architects, Tru Architekten, and Kelley, Palider, Paros—were finalists for the top honor. Fala Atelier, Kollectiv Atelier, and Guillame Mazars all received an honorable mention. The Biennial has posted a selection of submissions to the Lakefront Kiosk Competition on its Pinterest page.
After the biennial, Chicago Horizon "will find a permanent home in Spring 2016, operating as a food and beverage vendor, as well as a new public space along the lakefront.During the Biennial three other kiosks will be installed along the lakefront. Details on those are due to be announced next week, but here are the preliminary project descriptions:
The Cent Pavilion, designed by Pezo von Ellrichshausen in collaboration with the Illinois Institute of Technology, is a forty-foot tower meant to convey silent and convoluted simplicity. Rock, the kiosk designed by Kunlé Adeyemi in collaboration with the School of the Art Institute of Chicago is a pop-up pavilion a public sculpture composed from the raw and historic limestone blocks that once protected the city’s shoreline. Summer Vault, designed by Paul Andersen of Independent Architecture and Paul Preissner of Paul Preissner Architects, in collaboration with the University of Illinois, Chicago, is a lakefront kiosk that consists of basic geometric shapes combined to create a freestanding hangout within the park.