resilient wood E X P LO R AT I O NS I N T I MBER ARCH ITECTURE
A L E X Z E L AYA CAVI N FA M ILY TR AVE LIN G FE LLOWSHIP 2015
CONTENTS
T HE CAS E FO R T IMB ER
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S USTA IN A B ILITY
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MAT E RIA LITY
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CO NSTRUCTA B ILITY
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ECO N OMY
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R ES EARCH MAP
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CAS E ST UDI ES MASS TIMB ER EA RTH SCIEN CES B UILD IN G
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PU LPIT ROCK MOUN TA IN LOD GE
ELEPH A N T H A B ITAT TH E WOOD CU B E
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HYBRID SYSTEMS
LIFE CYCLE TOWER ON E
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ILLWERKE ZEN TRU M MON TA FON
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H OU SE OF N ATURA L RESOURCES
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CO MPLEX STRU CTURES
KU PLA OB SERVATION TOWER
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TA MED IA H EA D QUA RTERS
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GC PROSTH O CEN TER
SU N N Y H ILLS
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I NDEX O F VI S I TS
CEN TRE POMPID OU METZ
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THE CASE FOR TIMBER “The clearest way into the universe is through a forest wilderness.� john muir
There is no doubt that the world we live in is constantly changing, it has been for centuries, but no generation has had such an effect on our future than now. Climate change, population growth, and industrial advancements in technology are major factors which designers must address and respond to. Architecture and the built environment account for half of all greenhouse gas emissions in the world today. The impact each project has on the natural world is significant. Looking to nature may be the answer, or at least one solution to restoring a more resilient, healthier world. The quote above from renowned naturalist John Muir speaks to his own affinity with nature and how natural elements can influence our future. Trees, in particular, are primitive examples of incredible living resources that reflect who we are and where we came from. Around the world, designers are proving how wood can be ecologically implemented to shape where we are going. Through an endowment of the Cavin Family Traveling Fellowship, this research was allowed to occur, creating a cross-cultural dialogue about the potentials of wood in architecture. This research investigates the use of wood in buildings as an innovative, sustainable resource in three regions - central Japan, Scandinavia, and the Alpine region of Europe. These regions exemplify communities that are reliant on forestry products, have a strong tradition of crafted wood buildings, and are redefining how we can sustainably implement wood in architecture. Timber is guaranteed to play an important role in the future of sustainable building, and the hope is that this global knowledge can be expanded and shared with other communities to have a positive impact.
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SUSTAINABILITY
The most basic principle of building with wood, as well as the most critical, is the fact that wood is one of the most inherently sustainable building materials on the planet. In its most basic form, timber comes from trees grown in the ground, surviving purely on water from the atmosphere, light from the sun, and carbon dioxide in the air. Through photosynthesis, trees absorb pollutants in the air and turn them into energy allowing the tree to grow. In that respect, trees filter our environment, making it healthier. When thinking of wood as a building material, it is important to note the embodied carbon contained in wood. A single cubic yard of wood contains one ton of carbon dioxide. The sequestration of carbon is an advantage over traditional building methods such as steel and concrete, which produce carbon dioxide through their creation. This heavily weights the decision of what materials we choose to build with when designing a building. Forests have a resiliency for growth, yet need to be maintained and managed in order to be used for future generations. Deforestation threatens many forests in the world, but improving regulation is helping to maintain our collective forests. The production of timber building materials has greatly improved as well, oftentimes becoming a zero-waste production stream. In a typical mill where logs are milled into dimensional lumber, every part of the tree is used. Off-cuts, wood chips, and saw dust are often used to create by-products. An example would be the mill town of Maniwa, Japan, which produces wood pellets to sell to the community to heat their home. A co-generation plant connected to the mill burns wood bio-waste to produce electricity for the region.
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MATERIALITY
It is often said that wood has a warmth to it. People have a tendency to gravitate towards wood spaces because of the material’s natural character. Of all the species that exist in the world, no piece of wood is the same, every piece is unique. This phenomenon can be linked to how humans react with their natural world. As natural beings, we are inherently connected to materials and spaces that evoke the organic character of nature. Wood has this effect and is often strategically placed in tactile areas where people can touch it, like furniture or door handles. Many worship spaces, such as the Kuokkala Church in Finland (right), use wood to heighten the experience as well as soften the mood within the space. In a place like Finland, whose land area is covered mostly by forests, the application of wood can reference the local industry and landscape. Studies have shown that natural materials can have a directly positive influence on the inhabitants of a space. Research completed by the University of Michigan have shown how “restorative environments” that contain direct and indirect elements of nature greatly improve a person’s mental state, restoring mental clarity and allowing one to focus. Joanneum Research in Graz studied the effect a new timber kindergarten had on children’s behavior. The study found that most students had an inherent awareness of wood’s natural characteristics and did not damage the material. More so, the students had lowered measured heart-rates, were less aggressive, could focus longer, and showed improved academic performance.
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CONSTRUCTABILITY
Fabrication and construction techniques in timber design have seen huge advancements in recent years. The tools available to us today are widely different than what were available to us 100 years ago. The advent of digital modeling and production has played a significant role in changing how architects design and what is actually possible to build. New software programs have opened doors allowing complex modeling to be executed through complex milling. The bench wall in the Snohetta Reindeer Viewpoint in Norway is an example of an organic shape using new technology. The form was modeled in Rhino, refined through 3D printed models, and executed with a large scale 5-axis CNC machine normally used in boat-building. Advancements in gluing technologies have redefined the production of wood as well. No longer are we dependent on large logs from old trees, which require time, resources, and can have varying structural deficiencies throughout the member. Now, younger, faster-growing trees can be cultivated and used to make smaller boards that can be glued together into a dense, solid timber element that can be used as a column, beam, floor, or wall. Gluing multiple members creates a more structurally stable element when compared to a sawn lumber member containing knots and checks that can limit the member’s structural potential. In addition, prefabrication methods have begun to be utilized to maximize control and quality over built elements and greatly improve efficiency of the entire construction process. More overlap between architects and builders is happening earlier on in the design phase, which has shown to reduce overall labor costs and construction times, all while ensuring a quality result.
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ECONOMY
The impact a local forest can have on its economy can be significant. A forest is not only a resource that benefits the environment, but it is a major employer and source of income in forested regions. Not limited to only building products, trees provide the resources for many other industries, from pulp and cellulose to make paper products, to bark and wood chips for landscaping materials. In the case of Vorarlberg, in western Austria, it is renowned for its focus on timber production, craft, and fundamentally sound building techniques with wood. With its popularity growing, cultural events such as craft fairs have formed, bringing tourism from around the world for people to witness the wood craft that exists in the region. In Maniwa, Japan, the local milling industry collaborates with locallyowned forests to source their wood. The forests have sustained generations of families. The mill uses its sawdust and offcuts to product wood pellets which the local community can purchase to heat their homes in colder months. In the Pacific Northwest, many regional economies are based around the production of trees and forestry products, coining certain places as “mill towns.” Riddle, Oregon is an example of one place where forestry products are central to the region’s vitality. The local mill D.R. Johnson has received a grant from the state government to assist the development of North America’s first certified Cross Laminated Timber panel mill. Having this product produced domestically, as opposed to being imported from Canada and Austria, brings more value to the state’s economy and creates more local jobs.
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RESEARCH MAP
PACIFIC NORTHWEST
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SCANDINAVIA
CENTRAL ALPINE
JAPAN
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CASE STUDIES
MASS TIMBER
EARTH SCIENCES BUILDING LOCATION: VANCOUVER, BC ARCHITECT: PERKINS + WILL
The ESB is a five-story educational and research building for the UBC. Completed in 2012, this building was one of the first to be designed under Canada’s Wood First Act, which is an initiative set in place in 2009 to promote the use of wood as a sustainable material in all publicly-funded projects. The design team saw this new legislature as an opportunity to use wood as the primary structural frame for the building. Although it was used in composite with steel and concrete, especially in the floor systems due to concerns of noise transfer between labs, the wood frame is highlighted throughout the building. The floor slabs are actually a series of prefabricated panels of cross laminated timber and rigid insulation, topped with concrete. Once inside the main lobby, a grand stair commands the atrium. An engineering feat of its own, the cantilevered stair is built primarily out of wood, with structural steel supports and embedded connections. A glulam post and beam system was used throughout. Timber braces handle lateral loads and become architectural elements on the interior. One of the most inviting aspects of the building from the outside is the glulam wood canopy extends out into the public walks that surround the building. This overhang creates a welcoming gesture to the rest of campus and shelters spill-out space from the building’s interior cafe and lobby. A life-cycle analysis was completed by the design team to show how the use of wood affected the carbon footprint of the facility. The ESB contains approximately 6,169 tonnes of embodied energy, but that number was calculated to be 5,075 when the carbon stored in the structural wood frame was accounted for, a reduction of over 1,000 tonnes of carbon dioxide.
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*Construction Image Credits: Churchill Timberworks, Structurlam, Perkins+Will
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PULPIT ROCK MOUNTAIN LODGE LOCATION: JØRPELAND, NORWAY ARCHITECT: HELEN & HARD
Jørpeland is a land where prehistoric glacial movements have carved stunning rock formations, leaving jagged cliffs overlooking deep blue fjords. The main attraction is Pulpit Rock, which is a sheer cliff face that tops out with a flat platform at 600 meters above the water below. The start of the trailhead for Pulpit Rock is a camp and lodge area four kilometers down the slope. Athe the start of the trailhead is a new lodge constructed for visitors of the area which includes hotel rooms, a visitor’s center, a small conference space, and restaurant. The building is extremely site sensitive to how it is placed and sized. The plan bends to follow the terrain and avoid a series of large existing boulders. The roof slopes and peels to protect areas of entry from the wind and elements, while relating to the jagged peaks that can be seen from the site.
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For the structure, the architects looked to the region’s heritage of building lodges out of giant tree logs. A modern-day mass timber solution was derived. The concept was to use one single wood approach to accomplish many different design problems. The concept emerged as a mass timber shell that folds to be come both walls and roofs. This shell, as well as the floors, are supported by a series of mass timber ribs. The ribs are the most unique and special element of this building. They are extremely thick double walls of solid wood. They are thick enough to support the loading of floors, and the fact that they are double-walled helps accomplish the acoustical requirements between rooms. The architects utilized the product Holz100, which is a method of building mass timber wall and floors without glue or steel. Instead, holes are drilled into the sandwiched assembly and beech wood dowels are inserted. The beech dowels swell after injection, thus unifying the material. The build up of the assembly consists of a central core of vertical lumber which takes the main gravity load. On either side of the core is a layer of diagonal lumber, which helps stiffen the panel. Beyond that, a layer of horizontal wood is placed for even more directional stability.
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The ribs functioned extremely well for the modular construction of the majority of the hotel since the rooms are on a consistent modular, but the team faced a challenge when trying to create a larger volume of space, for instance, in the dining area. The team worked with engineers to find that if they reversed the layering of the ribs for those spaces, it would work. The horizontal and diagonal stability layers were flipped in the panel and this provided enough structure to form a hollowed space for the restaurant’s dining hall. In addition, this altered the shape of the volume, creating a cavernous space with a rhythm of faceted ribs. Since all the wood is exposed, users can perceive the structural solution first-hand. The project utilizes wood in an extremely resourceful and sustainable application, and celebrates the material throughout. It is clear that the building is deeply connected to its site, even the textile pads on the chairs were woven by local craftsmen. Most of all, everything seems appropriate for the use and setting, becoming a primitive shelter for those seeking it.
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*Image Credits: Helen & Hard Architects
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ELEPHANT HABITAT LOCATION: ZURICH, SWITZERLAND ARCHITECT: MARKUS SCHIETSCH ARCHITEKTEN
The new enclosure for the Thai Elephants at the Zurich Zoo is a giant dome that resembles something similar to a tortoise shell. All together, the roof structure uses 1,200 metric tons of wood The design for an enclosed habitat for a large animal like an elephant requires a large open space. In general, keeping elephants in captivity is a very sensitive issue since they are accustomed to having a lot of space in the wild, so the more space the better. For this reason, the designers looked into using a domed structure that could support a lot of open space for them to move around. The area of the structure is approximately 60,000 square feet and the longest span is 80 meters long. The primary shell structure is built of three layers of CLT panels that each have three layers of wood. These were fabricated and milled before being installed. To install them, a massive formwork and scaffolding project was undertaken. Once in place, they were connected by extremely long custom screws that were drilled in at very specific angles in order to transfer the appropriate forces from panel to panel. The wood had to be protected in the winter months, and therefore a large weatherproof canopy was created to keep the wood dry. The footings that support the structure are all concrete. This was required due to the thrusting forces created on the perimeter. Furthermore, there is a ring of cast-in-place reinforced concrete that wraps the perimeter.
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Between the footings are thick wood and concrete panels that create a vertical rhythm at its base. The canopy is punctured with many holes, creating skylights that bring in much daylight into the space. The openings were designed and planned for, but only added once the whole frame was installed. It wouldn’t have been possible to construct the dome with the openings already in place without significantly changing the design of the building. The skylights are custommade translucent ETFE plastic membranes. In this photo you can see the thickness of the wood combined with the integration of the mechanical air handling equipment, lighting, and skylight. A good digital model was an important part of the process for the project. The company Kaulquappe was hired to manage the digital planning and modeling for the structure. Through this process, the team was able to identify the forces, panel sizes, and production schedule. The elephants are a species from tropical Thailand. To re-create the environment they are accustomed to, the atmosphere is adjusted to have warm air and high humidity. Due to the high moisture content in the air, the humidity levels are monitored very closely at each roof opening. The monitors regulate air changes and ensure then wood is not being affected. If humidity rises to certain rates, the sensors alarm the facility manager. The exterior of the shell is covered with a waterproofing membrane and wood cladding assembly. The wood cladding is spaced off the main structure about 8 to 10 inches, allowing air to move behind the cladding and over the waterproofing membrane. This is exactly how a rain screen wall system works, except it is the walls and roof. The cladding is plywood cut down to complex shapes. It has weathered to a grey color since it was installed. 30
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THE WOODCUBE LOCATION: HAMBURG, GERMANY ARCHITECT: ARCHITEKTURAGENTUR
The Woodcube is a five-story apartment building that holds 9 units, though the units are designed to be converted to accommodate flexibility over time. The project’s life-cycle has been analyzed and it is the first apartment building of its kind, emitting zero greenhouse gases over its life-cycle. Much can be inferred about the building simply by its name, the Woodcube; a small compact box built of primarily mass timber elements. The wall assembly used in the exterior structural walls is the Holz100 product (used in Pulpit Rock Lodge). The combination of layers of wood are all connected by wooden beech dowels, without the use of glue. The assembly is almost entirely fir wood, with 5% being spruce. An interesting difference between this application of the Holz100 product is how it thermally performs. The composite assembly includes a sheet of thermal fiberboard insulation. In addition, some of the boards are notched with grooves on either side, creating small air cavities in the massive wall. These air gaps add up to improve the thermal performance. The floor, ceiling, and roof elements are constructed similarly with dowels. Since acoustical insulation is a big issue in multi-unit housing projects, a thick layer of acoustical mat is laid over the mass timber for impact resistance and kraft paper is used to protect against sound trickles. Floors are sealed with natural linseed oil. The exterior cladding is all untreated larch boards.
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An important design feature of the project is how the designers thought of the building’s long term life, beyond the point of the building’s use. The architects created a building that can be disassembled and taken down in the future. All the wood elements can be taken apart as single components and recycled individually (since no glues were used). Overcoming the fire code was another obstacle which the project was able to manage. The team was able to work with the authorities to find allowances to certain building code items which are not fully covered in regards to mass timber buildings. In addition, testing was done in collaboration with the Technical University of Darmstadt. Through this exercise, it was shown that mass timber is three to five times more resistant to fire than concrete and has an exceptionally higher tolerance to high temperatures as compared to reinforced concrete slabs. Rather than fully combusting, a char layer forms on the outside of the wood, slowing and even stopping the movement of flames. Beyond the solid wood construction, the units are highly energy efficient in terms of environmental control. Radiant heating occurs within the floors and facade ventilators with heat recovery regulate thermal comfort, eliminating the need for a central ventilation system. Adding a ventilation system would also require installing a ceiling and plenum. Without this, the ceiling of the units is allowed to remain wood. Photovoltaic panels on the roof supply an excess of electricity that what is required for the building.
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*Construction Image Credits: IBA Hamburg, DeepGreen Development
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CASE STUDIES
HYBRID SYSTEMS
LIFE CYCLE TOWER ONE LOCATION: DORNBIRN, AUSTRIA ARCHITECT: HERMANN KAUFMANN ARCHITEKTEN
Dornbirn is one of the largest cities in the Vorarlberg region of Austria, well-known for their long-standing culture of wood building. The area is also home to the Rhomberg corporation, a large umbrella company which has invested a lot of resources in innovative technology. One of the channels that it does this through is CREE, a subsidiary of Rhomberg that is developing and building advanced wood building systems and expanding the possibilities of how high-rise timber buildings are being built. The major project the company began with is the Life Cycle System, which is a research report with Hermann Kaufmann Architects and ARUP engineers. This report developed a concept for a high-rise timber building that within a few years led to the prototype project of the LCT One office building project. The primary structure is built of timber, with the exception of the concrete core. The core was constructed in concrete due to building requirements in the region. CREE’s pilot project, the Lifecycle Tower (LCT One), is a landmark project in many ways. Not only was it the tallest wood building in the region at the time, but it overcame many hurdles within the building regulations and was assembled on site in unprecedented time. The building is an 8-story office building. Each floor’s leasable area is 50 square meters, not ideal for a speculative office building. Nonetheless, when costs were balanced with the desire to build higher, the floor sizes shrunk. The bottom two floors are dedicated to teaching spaces and exhibition spaces that explain the functions and systems of the building. The floors above are office spaces, the top floor being CREE’s own office work space.
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Once inside the building, visitors are welcomed with an abundance of exposed wood structure. The structural assembly and how it was installed is the most notable part of this project. All of the elements are pre-fabricated within a shop and delivered to site. The structure uses pairs of glue-laminated columns to support a hybrid wood and concrete panel floor structure. The timber beams are pre-built into a wall panel system which includes the wall framing, the windows, insulation, and siding. Basically everything is ready to be craned into place, and the only additional work left to do is finish sealing, gypsum board, and exterior cladding. Since the windows are all punched openings and the same size across the elevation, the assembly of these panels can go relatively quickly. The floor panels are made off-site as well. Each panel is approximately 3 meters wide by 10 meters long. The beams are set into a form and concrete is poured into the formwork and allowed to cure. The spruce wood beams are one-directional and a concrete beam is poured going the cross-direction at each end. It was important to have the concrete at each end of the panel for two reasons. The concrete helps take the compression forces and transfer them to the columns, when the wood beams would otherwise have been crushed. In addition, the concrete perimeter prevents the spread of fire between floors. A metal tube is set into the concrete at each corner. These tubes align with Metal rods which the whole panel slots into which is connected to the columns. Once the concrete has set, the panel is taken out and stacked for delivery.
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The LCT One project really becomes a teaching tool to visitors. Everything is well displayed and graphically explained. The mechanical system on the second floor is exposed so people can see the routing of the ventilation ducts. The building uses the passive house standard for its environmental control approach. This process exploits the advantages of modularity to extremes. The ambitious construction process for this project can boast the fact that each floor was installed in a single day, completing the construction of an 8-story building in 8 days! This process was able to save much time and money during the construction phase. When cost items are factored in, such as the cost of renting a crane per hour, this accelerated construction period can be a huge advantage to the overall cost of the project. This method also allows much less on-site laborers, which for this project only required five carpenters on-site to install the major structure. This method of building may save time in the construction phase, but it is important to note that much more time is required in the planning phase. More time and effort is required to think through how materials will be fabricated in the shop and moved to the job site. This also required buy-in from both the architect and builder much earlier. With construction decisions being made in what typically would be referred to as a schematic design, this construction method requires much of the design to be decided in advance. In addition, since elements are prefabricated ahead of time, it is much harder to make changes to the design. It can be done, but usually is accompanied by a high price tag. Having the contractor on board earlier in the process can add value as well, because construction input can be given to the design team earlier, rather than completing a set of drawings and then having the contractor analyze them and propose other alternatives. 42
*Construction Image Credits: CREE, Hermann Kaufmann, ARUP
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ILLWERKE ZENTRUM MONTAFON LOCATION: VANDANS, AUSTRIA ARCHITECT: HERMANN KAUFMANN ARCHITEKTEN
CREE’s second pursuit of the life-cycle building system approach is the Illwerke Zentrum Montafon located in Vandans, Austria, about one hour from the Dornbirn area. The Illwerke corporation is an Austrian energy production company that produces a significant amount of energy for the Vorarlberg region, southwestern Germany, and beyond. Most of this energy is produced from hydroelectric plants which use the water from the surrounding alpine mountains. With a company so focused on sustainable energy resources, the Illwerke company realized a need to expand and upgrade their facility that parallels their ecological vision. As the foundation was being constructed, work was initiated off-site for the timber facade and floor components. Similar to the LCT One project, this building uses a hybrid timber and concrete floor system that is made in panels and hoisted into place. They fit directly onto steel dowels that are placed within wood columns in a wall panel system. The prefabrication of the panels was strategically planned so that products could be delivered to the site “just-in-time” for installation. This sped up construction time and eliminated the need to store a lot of materials on site. All the wood for the building was sourced from local forests. One third is from Vorarlberg, one third from Montafon, and one third from Southern Germany. For the construction of the new building, seven hectares of wood was used. This amount is what can be grown back in two days within the regions own forests. This fact gives real perspective to how sensible a timber construction approach is for a region like Austria.
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The new IZM building is located adjacent to a few of the energy plants. An older existing building was demolished to make space for the new facility. Approaching the building from across the water, one is presented with an amazing view of a building that appears to float above the still lake. One-third of the building is actually constructed over the water. This was necessary due to the amount of program (10,000 sq meters) that was required for the project. The building is primarily used as an office and occupied by about 275 engineers and other Illwerke employees. The linear building has 4 floors above the ground entry level and is 120 long and 60 meters wide. The ground floor consists of a lobby, administrative spaces, and a cafeteria hall that looks out onto the water.
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*Construction Image Credits: CREE, Hermann Kaufmann, ARUP
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The plan of the building depicts how the office plan is designed. With future flexibility and modern workplaces being the major design drivers, the team devised a linear plan with workspaces along the perimeter. The central portion of the building is left for meeting spaces, kitchens, and storage. The stairwell cores protrude out on one edge of the building. The ground floor is made out of concrete and steel. Piles were driven into the ground where the building projects over the water. The planning and formwork for this part of the project is fascinating. Two steel bulkhead walls were built to dam the water back and construct the foundations. The building utilizes the nearby lake with its heat pump system and can pump cool water in the building in the summer time. The building uses passive house standard technology and has a smart control system to optimize human comfort. Individual controls connect to the light source at a person’s workstation, allowing each person to modulate their personal workspace. Despite the open office layout, this feature gives users a sense of control over their environment. Operable windows are also located at the exterior, giving people the choice to open the windows for fresh air. Each window has a sensor on it, which triggers an alert to the building facility’s software if a window is left open after the day is over. The large picture windows are situated at desk height, preserving incredible views outside. They also provide workspaces or storage spaces for each employee.
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*Construction Image Credits: CREE, Hermann Kaufmann, ARUP
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HOUSE OF NATURAL RESOURCES LOCATION: ZURICH, SWITZERLAND
The House of Natural Resources is a living laboratory building on the Honggerberg Campus of ETH Zurich. The building has a concrete ground floor and two floors of offices above, although it has been designed to have multiple floors added on as needed over time. One part of the concrete facade is currently being used by the chemistry department to study effects of wood stains. The exterior is most entirely glass with a metal frame that holds external shading devices. This frame also works to hold temporary research projects such as a robotic solar PV array that can be controlled by the user. The most fascinating part of this building is the structural approach. The building is a 20-meter square, with a 9-square timber grid structure. The project takes advantage of hardwood in the structure. Today, Zurich’s region has a strong demand for softwood forest products, but a surplus of hardwood forestry materials. The new office building is an example of how hardwood can be applied to construction to take advantage of its material characteristics. Hardwood is exceptionally strong and can deal with heavy compression forces. All the columns used in the project are 40 cm thick square columns made of Ash wood. These columns are notched to interlock with the beams.
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The beams are unique as well. They are post-tensioned wood glulam beams. Post-tensioning, which is typically used in concrete construction, is a method of running steel cables inside a beam and tightening them once they are installed. This method was chosen to test how it would perform using timber construction. Another amazing potential of this method is how it allows the building to be disassembled after its use and the wood is still intact and can be used for something else. The beams can be tensioned to be tighter over time. The building is also wired with load cells at every exterior joint to measure vertical deformation of the beams as well as lateral movements caused by strong winds. You can see the metal boxes on the exterior which house the testing equipment. All the testing goes directly to software which can be accessed and monitored from a computer. This gives the engineering department an excellent tool to see real-time data and analyze the structural performance over time. Because of the compression forces exerted on the beams by the floor above and the lateral forces as they meet the columns, ash hardwood was used in the bottom of the beam. The upper portion is made of spruce wood.
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The floor slabs are constructed from wood and concrete. This system uses panels of beech laminated veneer lumber that are 4 cm thick. They are coffered on the top to create zones of interlock once the concrete is poured. This is a very thin slab of wood compared to mass timber panels. The panels act as the formwork when the concrete is poured and when finished, allow wood to be exposed on the inside. It was found in this project that this floor structure is cost competitive with conventional concrete slab construction. A hybrid slab made sense for acoustic and cost reasons. Going all timber in the slabs would be expensive considering, in Switzerland, the unit cost per liter of concrete is less than that of mineral water. Jumping up and down on it, there is little vibration caused by impact. The roof over the center of the building on the top floor is a lattice grid structure made of ash. The roof slab is a bi-axial timber slab made of a combination of ash and beech. This was an experimental application that was considered for the floor structure, but not chosen due to the cost of the system. Hardwood also reacts differently to humidity, and this is being especially measured in this room. This space houses the main conference space in the building. The roof lattice and clerestory windows add to the quality of space. The building is being closely monitored to analyze its performance. It has become a lesson in building with hardwood. Since there is not a lot of testing done for this type of building, the House of Natural Resources will be able to contribute to a body of research over time.
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*Construction Image Credits: ETH Zurich
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CASE STUDIES
COMPLEX STRUCTURES
KUPLA OBSERVATION TOWER LOCATION: HELSINKI, FINLAND ARCHITECT: AALTO UNIVERSITY WOOD PROGRAM
This viewing platform is located within the Helsinki Zoo and was one of the first projects built as a student design-build project through the Aalto University Wood Program in 2002. Being that the zoo is on the island of Korkeasaari, the Kupla tower is a visible marker that can be identified as one approaches the park by ferry. The structure is an entirely open structure and has the appearance of a woven basket. The structure is diagrid lattice of timber beams that function to create walls and provide support for two upper viewing decks. Each timber lattice member is made out of pine timber that measures a little over 3� by 3�. To make such a complex shape each timber is bent to a completely custom shape. Since the structure was modeled using computer software, each member could be accurately bent to shape, but since this would be incredibly expensive to do, the students worked with the builders to find a solution. The final design ended up using about 8 custom shapes, and off of those eight major shapes, custom shapes could be field bent into place. Once in the field, the builders devised a duct-steaming system to get the timbers to bend into place. A flexible duct was sleeved over each individual curved shape and steam was piped into the duct to make the wood flex into place. The structure was originally unfinished and left to be weathered. Since a decade passing, the facility chose to finish the structure in a semisolid grey stain. It does not have the same warmth as the original design, but seems to be slowing down the deterioration of the timber members.
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*Construction Image Credits: Aalto University Wood Program
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TAMEDIA HEADQUARTERS LOCATION: ZURICH, SWITZERLAND ARCHITECT: SHIGERU BAN ARCHITECTS
The media and communications company Tamedia completed an extension to their headquarters in the city center of Zurich. The project was initiated directly with Shigeru Ban after the head of the company had visited a building by Ban and was amazed by the design quality. Ban, known for creating incredibly organic and resourceful structures, approached this project with the same sensitivity. Aware of the Swiss regions amazing forestry resources, Ban made a conscious decision to use wood wherever possible. This delivered a concept where wood is exposed and seen throughout the interior spaces, and due to the glass facade, the outside as well. The glass facade not only gives visibility to the structure, but it is also a statement about the work that goes on inside the building. The Tamedia corporation and Ban wanted to create a building that highlights transparency, so that the news delivered can be thought of as direct and honest as possible. The staff at Tamedia have enjoyed the building so much that they have adopted the nickname of “chalet” for the building, comparing the building to a Swiss alpine wood lodge. One is welcomed by craftsmanship upon entering the building. The surface on the ground floor is made of a beautiful custom terrazzo, with pre-cut river rocks that recall the river that runs directly adjacent to the building. The color and scent of the wood warms the space. The lobby is even full of Ban’s custom furniture, which uses paper tubes as the structure as well as the surface for sitting.
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The atrium space not only houses the main stair, but the lobby area and conference spaces as well. This volume is separated from the office spaces by a glass wall. Since this interstitial space is mostly used for circulation and brief meetings, not a lot of energy is used to heat and cool the space. The landings and conference zones create acoustically separated, porch-like spaces for people to meet and chat. The facade even has stacking garage door windows that can be operated to be open and bring in breezes. These openings occur throughout the facade and vary in size from 1-story to 2-stories. Stepping inside the office space, one can see the incredible wood joinery of the structure. Columns and beams are assembled and finished like a fine piece of furniture. The design team worked very hard to achieve an all timber structure, with no steel connections. The result is glue-laminated columns that measure 20 meters tall. The columns run continuously from the top of the concrete foundation to the top of the building. These members was fabricated with slots for intersecting beams. The intersecting beams are giant, oval-shaped dowels that slot into the holes in each column. At each beam and column joint, a laminated key piece is placed to lock the system together. This element is made of laminated beech wood. 66
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The design planning of the structure was undertaken by BlumerLehman, the same company who worked on the Center Pompidou Metz as well as other complex timber structures. A parametric model produced elements that could be milled. The tolerances for this building were so precise that they were required to be produced digitally. While concrete construction would have 3 centimeters of tolerance or more, the wood joining had a tolerance of 0.5 centimeter! The frame was constructed in pieces, face to face. Each bay was built sequentially, one after the other beginning with the southernmost bay. The first frame assembled was full height and included each floor, as a kind of template. After that, the next frame in the next bay was built, stacked exactly next to it and moved into place to ensure that alignments were made. This was done for each bay until the volume was completed. This is uncommon because as most buildings are erected from the bottom up, this building was built from left to right. Arriving on the top floor of the building, the roof structure is clearly defined. The columns angle in as they reach the top of the building. This creates a Mansard roof, relating to its surrounding buildings. The slope of the roof is covered with slatted shading, blocking direct light exposure, but still allowing views to the city. 68
*Construction Image Credits: ARUP, Blumer-Lehman, Shigeru Ban Architects
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GC PROSTHO CENTER LOCATION: NAGOYA, JAPAN ARCHITECT: KENGO KUMA & ASSOCIATES
Located in a residential district of Kasugai, outside of the city center is a research center for the GC Research company. They produce dental prosthetics and other products in the dental industry. The new building was designed for the company’s 50th anniversary and also to be a landmark within the community for the company to showcase their work. The ground floor houses a small exhibit. The third floor has a research laboratory, the second floor has an office space and the basement is a conference space. The design was partly inspired by an old Japanese toy. There are many types of puzzle toys made of wood, that interlock only if they are assembled just the right way. A little more advanced than your average lincoln logs as often-times the joints require the assembly of multiple pieces of wood. These toys utilize notches that become hidden once put together, spurring wonder at how they are constructed. The wood system is called Cidori. It is a technique that has been used for many years by master wood craftsmen, originally from the region of Takayama. It involves three timber members that are notched a very specific amount in their center so that when they are rotated, they interlock together. The system is constructed out of approximately 6,000 square sticks made from locally-sourced cypress wood. The wood sticks come together to form an incredible experience from the inside and outside of the building. And to answer your question, yes those are giant teeth in the exhibit space. The project was assembled by master carpenters. Built stick by stick, the carpenters hand carved approximately 1500 joints each.
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SUNNY HILLS LOCATION: TOKYO, JAPAN ARCHITECT: KENGO KUMA & ASSOCIATES
Sunny Hills is a unique Taiwan-based company that specializes in pineapple cakes. The simple small loaves of pineapple cake is the single item they sell, and they have stores in Taiwan, China, Singapore, and Japan. The Japan location is in the Aoyama district in Tokyo, a few blocks from a prominent shopping street. Sunny Hills offers a unique customer experience to the community because it opens its doors to anyone from the community to come in for a fresh cup of tea and pineapple cake, no matter if you purchase anything or not. This approach builds a friendly relationship with those in the neighborhood, and thus has been welcomed with open arms. For the Sunny Hills store, the building is the extreme opposite of a concrete block. The building is constructed out of Japanese cypress in a way that it looks like a cloud of small sticks, an anti-shape. The use of Japanese cypress, or Hinoki, recalls an abundant Japanese building material used heavily in traditional buildings. The form and wood, though faded a bit on the exterior from being exposed to the elements, does an exceptional job at creating intrigue from passers-by on the street. The stick-like building skin is even more interesting when you know that it is the structure which supports the three two upper levels and roof terrace. The building technique is called “Jigoku-gumi,” which when translated directly to English, means “intersecting hell.” This is mainly because it is an extremely difficult system to build, requiring exceptional carpenters to build all-wood joints with no glue, nails, or screws.
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Simplified into two dimensions, the system relies on a lattice of long timber members that span from floor to floor. These members are notched to allow the interlock between pieces. The depth of the notch is typically 2/3rds of the material thickness, to allow crossing members to be threaded through the lattice at an angle. With the full length members in place, a third layer of smaller sticks are placed between joints to add another level of stiffness. One single lattice is not sufficient to support the floors, so more lattices are added to contribute to the structure, dependent on the load needed. In the image below, you can see the wall is composed of two vertical lattices, connected by slanted members that transfer loads from joint to joint. The joint construction gets quite complex at the intersection of four members, yet is accomplished so seamlessly by craftsmen. It is hard to believe these facades were built by builders, assembled stick by stick. The floors and roof are constructed with a similar, yet different lattice structure. A bit more simpler than the facade, the system consists of two grid lattices, one orthogonal and the other rotated 45 degrees. Due to either construction abilities, costs, and seismic loading criteria in the area, not all joints could be constructed entirely out of wood. At certain locations, metal splicing connections can be seen.
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*Diagram Image Credits: Kengo Kuma & Associates
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Together, the system contributes to Kuma’s concept of creating “a forest within the city.” The dynamic facade changes throughout the day as light passes through it. This project in successful in showing ways how wood can be used in an innovative way, but using more of a lighter frame, stick-built approach rather than a mass timber approach. This building also reflects the heritage of timber craftsmanship. Though the building was modeled intricately using computer programs, it would have been difficult to build without the assistance of a “daiku,” or Japanese master builder. With advancements in technology, it is important to maintain the tradition and knowledge of building with wood, and this project depicts that importance.
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CENTRE POMPIDOU METZ LOCATION: METZ, FRANCE ARCHITECT: SHIGERU BAN ARCHITECTS
Through an international design competition, a jury selected Shigeru Ban for the design of the new museum for the Centre Pompidou Foundation. Ban’s concept stemmed from a traditional Chinese hat that uses simple methods to accomplish many different things. The structure, consisting of woven bamboo to give the coned shape represented an idea of a lattice-like timber frame. Interwoven between these strips of bamboo are leaves, which provides the insulation under the cover and protection from the sun’s heat. Lastly, the hat is oiled to make it highly impenetrable to water, inspiring an approach for using a thin membrane shell for waterproofing. The hat structure is translated into a gigantic timber canopy that wraps the interior spaces. The wood is covered by a PTFE membrane which uses a mixture of teflon and woven fiberglass. The membrane is translucent white, providing shade and diffused light (15% light permeance). The entire building covers approximately 10,700 square meters, yet about half of that is dedicated to gallery exhibition. The galleries are divided into three long rectangular tubes that are stacked onto each other. Each tube opens to a view, creating six very distinct experiential views out to the city of Metz; one is directed to the main gothic cathedral in the old town. At first glance, the canopy appears to be draped over these stacked volumes, supporting the entire structure. Philippe clarified that the canopy is completely independent from the concrete core and galleries. This was necessary due to the contrast in material behavior and movement between concrete and wood. The image below shows how the timber frame connects to a white steel tube which has the ability to flex.
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The canopy is supported vertically by numerous basket columns. The lattice form seeps into the ground and connects to massive concrete footings underground that extend about 12 meters below grade. The compound columns are visibly different from the lattice frame above. The wood used on these columns are actually larch, due to the ability to endure moderate exposure to water and moisture. They are also more durable to deal with exposure to people at the ground level. Due to this exposure, the columns have greyed more than the protected lattice above. Since each column is a low point in the roof, a valley collects rainwater and connects to pipes routed inside the columns. These pipes transfer the water underground to the adjacent gardens on-site. The construction of the lattice canopy is unlike anything I have seen. When I first saw images of the project, I had assumed that the structure was a lightweight frame that had active bending members throughout. It was not until seeing it in real life where I experienced the large scale of the members. The lattice is a combination of multiple layers of wood going in multiple different directions. In three interlocking directions, members made of two glulam beams intersect, which you can see in any of the triangular shaped openings in the image below. These two glue lams are spaced by blocking to allow the system as a whole to flex. At the overlap between every member moving in a different direction, the beams are notched and a hexagonal hardwood-laminated dowel is placed in between to space them similar to a washer. The dowel is hollow to allow a steel bolt to connect them. Together, the system transfers shear forces between the glulams and helps in resisting lateral forces.
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As accuracy was vital during assembly, a computer model was highly used to generate models for each element. The computer model significantly impacted the design as well. The curvature of each element was first derived by setting the perimeter boundary of the roof, high points and low points, and elements were then interpolated between. The glulam members are double curved, which required them to be machined precisely. The wood in the roof is all high quality spruce from forests in Austria and Switzerland. Just under 2,000 custommilled elements combine to make the roof, which also adds up to be 18 kilometers of linear feet of lumber. Shigeru Ban is well know for implementing innovative and lightweight wood and paper products in his buildings. Beyond the timber frame canopy, cardboard tubes are used to provide acoustical values in a performance hall. Furthermore, the galleries use a wood pulp fiber product called Valchromat for all the gallery walls. This material is similar to MDF board, except it is tinted with color integrally, so the entire material can be colored throughout, and when cut, the color is still present. One barely notices this when in the galleries, but it can be easily machined, is lightweight to be moved, and is a sustainable alternative to using gypsum boards in the gallery spaces. Also looks a bit like concrete.
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*Image Credits: Design to Production, Holzbau Amann, ARUP
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CASE STUDIES
INDEX OF VISITS
Pacific Northwest The Bullitt Center UBC Wood Science Facility CIRS Building Earth Sciences Building North Vancouver City Hall Richmond Oval Arena Cut My Timber Mill DR Johnson Mill
Seattle, WA Vancouver, BC Vancouver, BC Vancouver, BC Vancouver, BC Richmond, BC Portland, OR Riddle, OR
Scandinavia Kamppi Chapel Aalto University Wood Program Kupla Observation Tower Saie Pavilion Sibelius Hall Kuokkala Church Puukuoakka Housing Project Sayanatsalo Town Hall METLA Center Jyvaskyla Airport Kindergarten Fagerborg Gol Stave Church Wild Reindeer Pavilion Viewpoint Glacier Museum Urnes Stave Church Knarvik Church TREET Housing Tower Stavenger Wood Housing Lanternen Pavilion Pulpit Rock Mountain Lodge Vennesla Public Library Kilden Performing Arts Center Rebildporten Rold Skov Forest Louisiana Art Museum
Helsinki, Finland Espoo, Finland Helsinki, Finland Helsinki, Finland Lahti, Finland Kuokkala, Finland Kuokkala, Finland Sayanatsalo, Finland Joensuu, Finland Jyvaskyla, Finland Oslo, Norway Oslo, Norway Dovre, Norway Fjaerland, Norway Sognefjord, Norway Knarvik, Norway Bergen, Norway Stavenger, Norway Sandnes, Norway Jorpeland, Norway Vennesla, Norway Kristiansand, Norway Rebild, Denmark Rebild, Denmark Helsignor, Denmark
Central Europe Woodcube/IBA Expo Projects ARUP Engineers Centre Pompidou Metz La Cite Des Artes WIPO Conference Hall
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Hamburg, Germany Berlin, Germany Metz, France Besancon, France Geneva, Switzerland
Central Europe Immuebles Pommiers Housing EPFL - Lausanne House of Natural Resources ETH Zurich Elephant Habitat Tamedia Headquarters Building LCT One Tower Kunsthaus Bregenz Frauenmuseum Hittisau Pfarrhaus Krumbach Werkraumhaus Bregenzerwald Gemeindezentrum Ludesch Chaserugg Tram Station Roman Ruins Enclosure Saint Benedict Chapel Therme Vals Leis Cabins Illwerke Zentrum Montafon Technical University - Munich Bader Hotel Salzburg University - Kuchl Binderholz Mill Wood Box Traveling Expo
Geneva, Switzerland Lausanne, Switzerland Zurich, Switzerland Zurich, Switzerland Zurich, Switzerland Zurich, Switzerland Dornbirn, Austria Bregenz, Austria Hittisau, Austria Krumbach, Austria Andelsbuch, Austria Ludesch, Austria Unterwasser, Switzerland Chur, Switzerland Sumvitg, Switzerland Vals, Switzerland Leis, Switzerland Vandans, Austria Munich, Germany Munich, Germany Kuchl, Austria Hallein, Austria Vienna, Austria
Japan Nezu Museum Sunny Hills Cake Shop Musashino Art University Library Meiji Jingu GC Prostho Museum Center Ise Jingu Grand Shrine Kyoto University of Art & Design Ryon-ji Temple Meiken Lamwood Mill Oita Prefectural Art Museum Yusuhara Town Hall Yusuhara Marche Wooden Bridge Museum & Onsen Isamu Noguchi Garden Museum Chichu Art Museum Benesse House Art Museum Teshima Art Museum Horyu-ji Temple & Pagoda
Tokyo, Japan Tokyo, Japan Tokyo, Japan Tokyo, Japan Nagoya, Japan Ise, Japan Kyoto, Japan Kyoto, Japan Maniwa, Japan Oita, Japan Yusuhara, Japan Yusuhara, Japan Yusuhara, Japan Takamatsu, Japan Naoshima, Japan Naoshima, Japan Teshima, Japan Nara, Japan
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