The Wood Revolution – Innovations in Structural Systems


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This presentation highlights inspiring architecture with innovative structural systems. There is an architectural movement towards using wood, where many buildings are selecting it to express modern and innovative structures. From wooden structures in the community to tall modern timber buildings, the use of wood in structural systems is expanding in North America. See great examples in this presentation.

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The Wood Revolution – Innovations in Structural Systems

  1. 1. Presented on [Date] by [Author’s Name](Edit the Master Slide to change this text)The WoodRevolutionInspiring Architecture WithInnovative Structural SystemsPresented by Lisa Podesto, PESenior Technical DirectorWoodWorks, an initiative of the Wood Products Council
  2. 2. Copyright MaterialsThis presentation is protected by US andInternational Copyright laws. Reproduction,distribution, display and use of the presentationwithout written permission of the speaker isprohibited.© The Wood Products Council 2013
  3. 3. I started noticing there was a movement in modern woodarchitecture in 2008, thought it’s clear now it started longbefore that.The Richmond Olympic Oval was completed in 2008 and is oneof many iconic wood buildings that express structure in amodern and innovative way. The largest structure built for theVancouver 2010 Olympic Games, it was designed to house thelong track speed skating events and an audience of more than8,000 spectators.The Oval features a 6-acre free spanning roof. The wood-steelarch system spans 310 feet – one of the longest clear spans innorth America. The roof also features a unique “wood wave,”which I’ll talk about shortly.Richmond Olympic Oval, Richmond, BC, CanadaDesign Team: Cannon Design Architecture, Fast + Epp, Glotman SimpsonPhotos: Stephanie Tracey, Craig Carmichael, Jon Pesochin, KK Law Creative, Ziggy Welsch
  4. 4. The Cathedral of Christ The Light in Oakland,California is the first cathedral commissioned by theRoman Catholic Diocese in the 21st century.Oakland is in a high seismic zone and the structure isdesigned both to last 300 years and to withstand aonce-in-a-millennium earthquake. Architecturallystunning, the building features a space-framestructure comprised of a glulam and steel-rodskeleton veiled with a glass skin. The skeleton consistof 26 vertically arching Douglas fir glulam ribsvaulting 108 feet high and supporting glulam louvers.Sophisticated natural daylighting and convectionsystems were employed as major design elementand led to the name, Cathedral of Christ The Light.The Cathedral of Christ The Light, Oakland, CA, USADesign Team: Skidmore Owings & Merrill, Craig W. Harman, Webcore BuildersPhotos: Timothy Hursley, Cesar Rubio, and John Blaustein,
  5. 5. In 2009, the Stadthaus apartment building inthe UK set the record for “tallest moderntimber building,” with eight stories of woodover one story of concrete.It’s made from cross laminated timber (CLT),a mass timber product that’s popular inEurope and now also available in NorthAmerica. It was the first building of its heightto include load-bearing walls and floor slabsas well as an elevator core and stair shaftsmade entirely from wood.While you can see the appeal of exposedCLT, the developer wanted this building tolook like others in the neighborhood. Theinterior finish is drywall and the exterior isclad with tiles made from wood pulp andcement which mimic the shadows on thesite, thus providing texture without the useof brick.Stadhaus, London, UKArchitect: Waugh Thistleton ArchitectsPhotos: Waugh Thistleton Architects
  6. 6. The Centre Pompidou-Metz in Metz Francewas completed in 2010.An art exhibit center, it includes a 12,000-square-foot hexagon (1,200 m2) roofstructured around a 245-foot (77-m) centralspire. Three rectangular galleries protrudethrough the structure at different levels, withlarge windows angled toward Paris landmarks.The roof is made from glued laminated timbercovered with a white fiberglass membrane anda coating of teflon.Centre Pompidou Metz, Metz FranceDesign Team: Shigeru Ban Architects, Jean de Gastines Architects, ARUPPhotos: ARUP
  7. 7. The Metropol Parsol in Seville, Spain was completed in 2011. At 490 feetby 230 feet by 85 feet tall (150m by 70m by 26m), it is said to be thelargest modern timber structure in the world.Rising up from the ground like giant mushrooms, six parasol structureshouse a farmers market, metro station and numerous bars. There is anelevated plaza where people can watch concerts or sporting eventsbelow.The project was intended to revitalize downtown Seville and the localpopulation definitely think it has. Initially, the consessionaire/contractorhad concerns about using wood because it isn’t widely used in the southof Spain. However, wood was the only material light enough to beaccommodated by the foundation, which was already in place. I’ll talk abit more about this project later as well.Metropol Parasol, Seville, SpainDesign Team: J. Mayer H. Architects, ARUP Consulting EngineersPhotos: ARUP
  8. 8. When in history has there been so many examples of iconic woodstructures? Before World War II, perhaps. The industrial revolutionwas marked by changes in agriculture, manufacturing, mining,transportation and technology, all of which had a profound effect onthe use of wood in buildings. After that, wood’s role seemed to focusprimarily on home construction while most non-residential andmulti-family buildings were made from other materials.So what’s changing? To begin with … the climate.
  9. 9. While market research shows that sustainability is not the deciding factor in everyday construction here in the US, it is elsewhere.Design and building professionals—and governments—are recognizing that using wood from sustainably managed forests has real benefits from a carbon footprint perspective.Put briefly, growing trees absorb carbon dioxide from the atmosphere. They release the oxygen and incorporate the carbon into their wood, roots, leaves or needles, andsurrounding soil. One of three things then happens:• As trees mature and then die, they start to decay and slowly release the stored carbon back into the atmosphere.• The forest succumbs to wildfire, insects or disease and releases the stored carbon quickly.• The trees are harvested and manufactured into forest products, which continue to store the carbon. In the case of wood buildings, the carbon is kept out of the atmosphere forthe lifetime of the structure—or longer if the wood is reclaimed and used elsewhere.In all of these cases, the cycle begins again as the forest regenerates and trees once again begin absorbing and storing carbon.This slide illustrates a carbon calculation for the Richmond Oval. In total, the wood products in this building are storing an estimated 2,917 metric tons of carbon dioxideequivalent, or CO2e. Another 6,207 metric tons of emissions were avoided by using wood instead of materials that require large amounts of fossil fuels as part of theirmanufacturing processes. According to the US EPA’s Greenhouse Gas Equivalencies Calculator, this equates to the annual emissions from more than 1,700 cars or the energy tooperate an average home for 776 years.Source: Estimated by the Wood Carbon Calculator for Buildings, based on research by Sarthre, R. and J. O’Connor, 2010, A Synthesis of Research on Wood Products andGreenhouse Gas Impacts, FPInnovations. Note: CO2 on this chart refers to CO2 equivalent. The carbon calculator is a free tool that design professionals can use to estimate thecarbon benefits of wood buildings. It is available at of wood used 3,525 m3Carbon sequestered andstored (CO2e) 2,917 metric tonsAvoided greenhouse gases(CO2e) 6,207 metric tonsTotal potential carbonbenefit (CO2e) 9,124 metric tonsCarbon savings from the choice of wood in this onebuilding are equivalent to:1,743 passenger vehicles off theroad for a yearEnough energy to operate ahome for 776 yearsRichmond Olympic Oval, Richmond, BC, CanadaDesign Team: Cannon Design Architecture, Fast + Epp, Glotman SimpsonPhoto: Stephanie Tracey
  10. 10. In the UK there is a requirement to show carbon offsets for all constructionprojects. That is usually done in the form of on-site renewable energy. However,that can be quite costly for a building owner so the thought of not requiring carbonoffsets at all was a big selling point. According to the architect, the amount ofcarbon stored in the Stadthaus was equal to reducing the energy consumption ofthe building by 10% for 210 years or 21 years of 100% savings.Source: Estimated by the Wood Carbon Calculator for Buildings, based on researchby Sarthre, R. and J. O’Connor, 2010, A Synthesis of Research on Wood Productsand Greenhouse Gas Impacts, FPInnovations. Note: CO2 on this chart refers to CO2equivalent. The carbon calculator is a free tool that design professionals can use toestimate the carbon benefits of wood buildings. It is available, London, UKArchitect: Waugh Thistleton ArchitectsPhoto: Waugh Thistleton ArchitectsVolume of wood used 950 m3Carbon sequestered andstored (CO2e) 659 metric tonsAvoided greenhouse gases(CO2e) 255 metric tonsTotal potential carbonbenefit (CO2e) 914 metric tonsCarbon savings from the choice of wood in this onebuilding are equivalent to:175 passenger vehicles off theroad for a yearEnough energy to operate ahome for 78 years
  11. 11. Deconstructability and life cycle assessment have received less focus than carbonbut they’re growing in importance—and wood structural systems have advantagesin both of these areas.In this project in Santiago, Chile, laminated Radiata Pine was used to create a fullydeconstructable office building.Deconstructability involves screwed and bolted connections—which is more difficultthan it sounds when you factor in lateral load resistance. It has benefits in terms ofboth economic value and reduced environmental impacts associated with futuredemolition.Life cycle assessment studies consider the environmental impacts of materials overtheir entire life cycle, from extraction or harvest of raw materials throughmanufacturing, transportation, installation, use, maintenance and disposal orrecycling. These studies consistently show that wood is better for the environmentthan steel or concrete in terms of embodied energy, air and water pollution, andgreenhouse gas emissions. Deconstructability contributes to reduced life cycleimpacts, as does using exposed wood as an alternative to other finishes.The amazing part about the motivation to contribute to a healthier planet is thatpeople are spending time working these things out and the rest of us are able toutilize their findings.BIP Computers, Santiago, ChileArchitect: Alberto MozoPhotos: Alberto Mozo
  12. 12. This three-story school in Norfolk, England is said to be the largest CLT project to date. Cross laminatedtimber is basically asolid wood panel with layers of laminated 1x or 2x dimensional lumber laid up at 90 degrees to one another.Norwich Open Academy is 102,257 square feet (9,500 m2). It includes 3,500 m3 of timber, which stores approximately2,430metric tons of CO2 equivalent. The structural engineer, Ramboll, estimates that the carbon stored offsets the building’soperationalcarbon for a period of 10 years.Speed of construction is a major advantage of CLT and this building took just 17 weeks to construct. It cost ₤20 million(approx ₤195/sf).Likewise, CLT offers advantages in terms of operational energy. CLT’s thermal performanceis determined by its U-value, orcoefficientof heat transfer, which relates to panel thickness. Thicker panels have lower U-values; they are better insulatorsand therefore require less insulation for the same performance. Since CLT panels can be manufacturedusing CNC equipmentto precise tolerances, panel joints also fit tighter, which results in better energy efficiencyfor the structure. Because thepanels are solid, there is littlepotential for airflow through the system.Source for carbon storage: Estimated by the Wood Carbon Calculator for Buildings, based on research by Sarthre, R. and J.O’Connor, 2010, A Synthesis of Research on Wood Products and Greenhouse Gas Impacts, FPInnovations. Note: CO2 on thischart refers to CO2 equivalent.The carbon calculator is a free tool that design professionals can use to estimate the carbonbenefits of wood buildings. It is available at Open Academy, Norfolk EnglandDesign Team: Sheppard Robson, Romboll UKPhotos: KLH
  13. 13. This school for mentally handicapped students in Germany demonstrates anotheradvantage of wood: occupant environment.The architect made use of another mass timber system—known as ‘thermallymodified timber’ or TMT—which is lumber that’s been transformed by heat into acondition of higher resistance and durability. After more than a decade in use, thebuilding has performed spectacularly.Evidence suggests that the use of exposed wood can contribute to an individual’ssense of well-being. In an office or school, wood is thought to improveperformance and productivity. In a hospital it may have a positive impact onpatient recovery.However, in a school or hospital, architects who love the look and feel of woodmay be challenged by the life safety aspects of building codes. Designing a 50,000-square-foot (5,000 m3) school for mentally disabled entirely out of wood was notan easy choice for the client, who assumed low durability, high maintenance costsand lots of fire gates restricting barrier-free movement. However, a schematiccollaboration with the engineers demonstrated that mass wood products offer anadvantage in a fire because they char on the outside while retaining strength,slowing combustion and allowing time to evacuate the building. Fire gates weren’trequired and the surfaces have also needed much less maintenance than ordinarydrywall or plastered walls.School for Mentally Handicapped, GermanyArchitect: Despang ArchitecturePhotos: Martin Despang
  14. 14. The Stadhaus, which I showed you earlier, is another example of newtechnology. Cross laminated timber is popular in Europe and elsewhere becauseit offers exceptional strength and dimensional stability with almost noshrinkage, and it’s now available to North American building designers. Panelsare manufactured using CNC machines and prefabricated off-site.A few other points of note:• The Stadhaus is an infill project in London.• In addition to lower material costs, the building was projected to weigh fourtimes less than a similar concrete building, which lowered transportation costs,allowed the design team to reduce the foundation by 70 percent and eliminatedthe need for a tower crane during construction.• It took four carpenters nine weeks to erect nine stories. They arrived everyTuesday with materials and completed a story on Thursday, and the entirebuilding process was reduced from 72 weeks to 49.Stadhaus, London, UKArchitect: Waugh Thistleton ArchitectsPhotos: Waugh Thistleton Architects
  15. 15. In 2006, I came across several articles about the FMO Tapiola building, winner of Finland’stop wood design award. While not necessarily an example of modern architecturalstructure, it does illustrate factory prefabrication and modular construction techniques.The project team for this five-story office building had a steep learning curve bothstructurally and from a life safety perspective. A major achievement was convincingauthorities that a wood building could meet strict European codes for fire.The primary architect was quoted as saying, "A modern wooden office building shows howwood can meet todays architectural demands for more human and environmentally-friendly structures. I see a bright international future for such buildings as the woodrenaissance continues.”FMO Tapiola Building, FinlandArchitect: Helin & Co ArchitectsPhotos: Voitto Niemelä and Michael Perlmutter
  16. 16. Here are some other non-residentialexamples of innovative wood use.For this school renovation project, acombination of materials gave amodern feel to what is essentially aheavy timber structure. Notice theunique detailing with the steelconnection at the center of the shapedglulam beams.Stevenson London School, Richmond, BC, CanadaDesign Team: McFarland Architecture, Fast + Epp Structural EngineersPhotos: Stephan Pasche
  17. 17. Arena Stage at the Mead Center for American Theater is thefirst modern building of its size to use heavy timbercomponents in Washington, DC. The design includes 18parallel strand lumber (PSL) columns around the perimeter ofthe glass façade, each measuring 45 to 63 feet tall andsupporting steel roof trusses. The columns are designed tobrace the façade against wind loads and to carry roof loads upto 400,000 pounds, and have no internal steel support.Local code authorities were skeptical about allowing woodand about fire safety in particular, so the design teampresented an in-depth fire report along with the results of asmoke study undertaken by a code consultant. They also did achar analysis, and showed DC code officials how char protectsthe interior of the wood.Arena Stage at the Mead Center for American TheaterDesign Team: Bing Thom Architects and Fast+Epp Structural EngineersPhotos: Nic Lehoux
  18. 18. While timber is often the more economical choice for conventionalstick-frame structures, you wouldn’t imagine the same could be saidfor the wood system used in the Cathedral of Christ The Light.However, the use of timber proved to be a pivotal economicadvantage that actually won Skidmore Owings & Merrill the designcontract for this $80-million project.Given the close proximity of fault lines and non-conformance of thedesign to a standard California Building Code lateral system, the City ofOakland hired a peer review committee to review SOM’s design fortoughness and ductility. Engineers were able to achieve theappropriate structural strength and toughness by carefully definingductility requirements for the structure, using 3-D computer modelsthat simulate the entire structure’s nonlinear behavior, testing ofcritical components and verifying their installation.The Cathedral of Christ The Light, Oakland, CA, USADesign Team: Skidmore Owings & MerrillPhotos: Timothy Hursley, Cesar Rubio, and John Blaustein
  19. 19. The Raleigh-Durham airport terminal features aninnovative timber roof system that’s the first of itskind in the US.Inspired by the rolling hills of North Carolina,designers envisioned a seamless rolling roof line, anoverhang at the entrance that extended 100 feetover the road, and an interior without columns. Torealize the design, a hybrid structural system wascreated featuring lenticular, long-span king posttrusses built from glulam members, steel sections,and locked coil cable tension chords—a highlyunusual combination.Raleigh Durham Airport, North Carolina, USAArchitect: Fentress Architects, ARUP EngineersPhotos: Nick Merrick, Hedrich Blessing, Brady Lambert, Jason Knowles
  20. 20. It’s a common misconception that steel has a monopoly on the braced framevertical lateral resisting system market, especially for projects located in highseismic areas. The Simpson Strong-Tie Materials Demonstration Lab at CalPoly San Luis Obispo was one of the first Heavy Timber Brace Frame buildingsdesigned and approved under the 2007 California Building Code and ASCE 7-05.The building serves the interactive teaching needs of all five departments inthe College of Architecture and Environmental Design: Architecture,Architectural Engineering, City and Regional Planning, ConstructionManagement, and Landscape Architecture. The design, engineering, andinstallation of different materials in the built environment is one of the keyunifying subject areas that brings all five of these departments together. Theproject architect chose to showcase the structural materials in the design ofthe building envelope through the use of translucent panels over thestructure.Simpson Strong Tie Demonstration Lab, Cal Poly San Luis Obispo Campus, CADesign Team: OmnImages: Omni
  21. 21. As I showed earlier, the Richmond Oval is an incredible exampleof engineering … but it also demonstrates the trend insophisticated prefabrication techniques.The use of materials to achieve the 330-foot span had to bevery efficient. Two 5-foot-3-inch deep glulam beams are joinedwith a hollow steel frame that houses electrical, mechanicaland sprinkler systems while creating a composite arch element.Between the arches are prefabricated WoodWave StructuralPanels. These panels use 2x4 dimensional lumber sourced fromstanding deadwood from areas infested by the mountain pinebeetle. The wave is a series of deep zigzags factory fabricatedwith a perforated pattern that was structurally efficient whilecontributing to acoustical performance and concealing thebuilding services.The roof required 1 million board feet of SPF lumber and19,000 sheets of plywood.Richmond Olympic Oval, Richmond, BC, CanadaDesign Team: Cannon Design Architecture, Fast + Epp, Glotman SimpsonPhotos: Stephanie Tracey
  22. 22. Completed in 2011, this 50,000-square-foot school wasviewed as an opportunity to promote sustainability andutilize the building itself as a teaching tool. Wood wasused for the post-and-beam structure (which is visuallyexpressed), wall framing, roof decking, millwork andinterior doors, and protective wall panels. An undulatingwood roof in the atrium is the signature architecturalfeature and demonstrates the beauty and structuralcapacity of dimension lumber. Prefabrication of the woodroof panels allowed an accelerated construction schedulewith shop and field construction proceeding concurrently.Much of the wood was harvested from forests affected bythe mountain pine beetle.Samuel Bridghouse Elementary School, Richmond BC, CanadaDesign Team: Perkins + Will Canada, Fast + EppPhotos: Stephan Pasche
  23. 23. This two-storey, 3,050-m2 (33,000-ft2) projectfeatures the extensive use of wood, which iswell suited to the demanding atmospherefound in swimming pools and ice rinks. Woodtolerates high humidity and is capable ofabsorbing and releasing water vapour withoutcompromising its structural integrity. In thepool spaces, the roof structure features glulambeams, purlins and columns, which support ametal roof on a metal deck. The glulambeams provide long, clear spans over wish-bone shaped columns, giving a dramatic firstimpression when visitors enter the facility.Aquatic Centre at Hillcrest Park,Design Team: Hughes Condon Marler Architects, Reed Jones ChristoffersenPhotos: Hubert Kang Photography
  24. 24. Motivated by the successful use of wood in previous projects, thearchitects of the Metropol Parasol decided on laminated veneerlumber with a polyurethane coating, which is less expensive thanmetal but still durable. The polyurethane coating protects the woodand allows it to breathe—a sort of natural air conditioning—andthere are no hazardous fumes if it burns.The parasols are a composite structure, with a concrete base (used asskate park), massive wood members and epoxied pre-tensioned steelconnections between the wood.Interior fountains and plants help to provide a cool climate duringthe intense summer heat. The coat of the structure is self cleaning,and only needs repainting every 20 to 25 years.Metropol Parasol, Seville, SpainDesign Team: J. Mayer H. Architects, ARUP Consulting EngineersPhoto Credit: ARUP
  25. 25. This 1,230 sq. m. two-storey building provideslaboratory, seminar and office space for a fieldresearch station on Vancouver Island. The ribsare a composite hybrid of concrete and glulamprovide a flexible column-free space at theupper level. The solid wood floors are madefrom timber killed by the Mountain PineBeetle.Malaspina Centre for Shellfish Research, Deep Bay, BC, CanadaDesign Team: McFarland Marceau Architects, Fast + EppPhoto Credit: Michael Elkan, Stephan Pasche
  26. 26. The Yusohara Wooden Bridge Museum in Japanlinks two public buildings that were separated by aroad. The bridge-like facility functions as a passagebetween the two buildings as well as anaccommodation and workshop, ideal for artist-in-residence programs. The building includes acantilever structure often employed in traditionalarchitecture in Japan and China. It is a greatexample of sustainable design, as a large cantileverwas achieved without large-sized materials.Yusuhara Wooden Bridge Museum, JapanArchitect: Kengo Kuma & Associates
  27. 27. Located on Chicago’s North Side, the South Pond Pavilion at the Lincoln ParkZoo is an open-air, wood and fiberglass structure that welcomes publiclearning opportunities and informal community gatherings.As part of Studio Gang’s larger work rehabilitating and restoring the oncepolluted South Pond to its original, natural state, the pavilion overlooks apure example of reclaimed wetlands in the middle of a highly developed,urban environment. Functioning as part refuge, part outdoor classroom, thepavilion is integrated into an educational boardwalk sequence that teachesvisitors about the pond’s ecosystem.Inspired by a tortoise shell, the laminated structure consists of prefabricated,bent wood members and a series of interconnected fiberglass pods that givethe pavilion its organic form. The double curved beams test the limit ofwood’s abilities while creating an inviting space for visitors.Nature Boardwalk at Lincoln Park Zoo, Chicago, IL, USAArchitect: Studio Gang ArchitectsPhotos: Beth Zacherle, Spirit of Space
  28. 28. Described as the greenest commercial building in the world, the Bullitt Center in Seattle, Washington pushesthe envelope in urban sustainability. The 52,000-square-foot structure includes four stories of heavy timberframing over two stories of concrete and meets stringent requirements of the Living Building Challenge (LBC).One of the interesting aspects from a wood perspective is the use of dimension lumber to form solid woodfloor panels, which allowed the design team to increase the height of the ceilings to 14 feet to maximizedaylighting.According the architect, the general rule of thumb is that, for every additional one foot of height on theperimeter of the building, daylight penetration increases by two feet. So by getting an extra two feet in thefloor-to-floor height, they got an extra four feet of daylight penetration. Relatively shallow floors—achieved byusing solid 2x6 wood floor panels instead of deeper floor joists—allowed the team to increase the daylightpenetration even further. Plus, the 2x6 deck easily spans the 10-feet 6 inch dimension, effectively eliminatingthe need for a perimeter beam. This allowed the windows to extend all the way to the bottom of the decking,improving daylighting even further.Bullitt Center, Seattle, WA, USAArchitect: Miller Hill PartnershipImages: Miller Hull Partnership, John Stamets
  29. 29. The race to the top is one of the most interesting aspects ofthe wood revolution. Most countries have caps on how highyou can build with combustible construction materials.However, these boundaries are being pushed in a very realway.
  30. 30. Mass timber goes beyond post and beam applications typical ofheavy timber and introduces plate construction techniques thatcan be used for wood buildings. Mass timber plate elements offerless surface area to volume ratio than light-frame and heavytimber, which in turn offers improved fire performancecharacteristics. Another differentiating feature between heavytimber and mass timber Is the efficient utilization of smallerdiameter trees. While glulam and other SCL products can be usedin heavy timber construction, it is more common to use solid sawnmembers. Mass timber products use large prefabricated woodmembers such as CLT, LVL, LSL and glulam for wall, floor and roofconstruction. Also common in mass timber applications is the useof the mass timber element as both the lateral and verticalresisting system. In traditional post and beam construction, theheavy timber elements are only providing a load path for verticalloads.What is mass timber?• Plate constructiontechniques gobeyond post-and-beam• Excellent fireperformance• Provides load pathfor lateral and verticalloads
  31. 31. Internationally, this is where we are today.In Melbourne, Australia, a ten-story CLT apartment building was completed in 2012. The developer and contractor, Lend Lease,used a conventional platform-based CLT system to build the $11-million project, which includes 23 apartments and fourtownhouses. Speed of construction was a huge benefit. They began installing the CLT in May and completed the wood portionof the structure in August.The center image is the eight-story Life Cycle Tower (LCT) ONE in Austria. LCT is a wood-hybrid construction system developedby Cree GmbH. The timber-based construction system relies on a central stiffening core for the elevator, stairs and shafts. Aprefabricated hybrid wood/concrete slab system is supported by the core on the interior and by glulam posts on the exterior.The UK is home to two of the tallest timber apartment buildings—the Stadthaus, which I showed you earlier and has eightstories of CLT over one story of concrete, and Bridport House on the right. When it was built in 2011, this five- and eight-storystructure formed the largest timber apartment block in the world. The site required a lightweight structure because of thebuilding’s location over a large storm sewer, making CLT an ideal solution.Credits: Lend Lease; CREE GmbH; Karakusevic Carson ArchitectsForté, Australia LCT ONE, Austria Bridport House, UK
  32. 32. Right now, designers of CLT buildings like the two-story Long Hall (shown) make of the alternatemethods provision in the code and rely on theANSI/APA Standard for Performance-Rated Cross-Laminated Timber published last year, which detailsmanufacturing and performance requirements forqualification and quality assurance.In the next version of the code, recently approvedchanges will streamline the acceptance of CLTbuildings. The 2015 IBC will recognize CLT productswhen they are manufactured according to thestandard. In addition, CLT walls and floors will bepermitted in all types of combustible construction,including Type IV buildings. Type IV wall provisionsrequire the exterior side (only) of exterior CLT wallsto be protected by FRTW sheathing, gypsumsheathing, or a noncombustible material; however,there are other requirements for the exterior wall,floors, roof, etc. Floors are required to be 4-innominal minimum and roofs 3-in nominal minimum.While this code change will not go into effect officiallyuntil the 2015 IBC is adopted by a jurisdiction, thisinformation could be used to simplify an alternativemethods argument under current codes.CLT in North America• CLT buildings approvedusing “AlternateMethods” argument• Designers rely onANSI/APA Standard• Recent code changesreflected in 2015 IBC
  33. 33. Conclusion: Evolving building codesrecognize wood’s safety and structuralperformance capabilities and allow its usein a wide range of building applications.This hasn’t been lost on designprofessionals seeking to have it all—costeffectiveness, functionality, designflexibility, beauty and environmentalperformance—who, through theircollective projects, are leading arevolution toward the greater use ofwood.For more information or project supportrelated to the design of non-residential ormulti-family wood building, visitWoodWorks at is an initiative of the WoodProducts Council.The Wood RevolutionArena Stage at the Mead Center for American TheaterDesign team: Bing Thom Architects, Fast+Epp Structural EngineersPhoto Nic LehouxWoodWorks provides freeone-on-one project supportand technical resourcesrelated to the design of non-residential and multi-familywood