Parabola cantilever walkway delivers park visitors to the brink.Concerned that visitors to Canada's national parks were becoming increasingly disengaged from both the experience of the outdoors and the reality of climate change, Parks Canada launched a search for private-sector initiatives to reverse the trend toward drive-through tourism. Brewster Travel Canada answered the call with a limited design competition for a walkable structure in Jasper National Park's Sunwapta Valley. "One of the bus drivers suggested that we do something over this particular gorge, Trickle Creek Canyon—something that could be suspended off the side of the mountain that brought visitors into a more intimate relationship with the Athabasca Glacier and its melting," explained Sturgess Architecture principal Jeremy Sturgess. With design-build team lead PCL Construction Management and structural engineer Read Jones Christoffersen (RJC), Sturgess' firm crafted a cantilevered walkway that, clad in weathering steel and glass, defers to its natural surroundings while providing breathtaking views of the glacier and valley floor. Though not a facade itself, Glacier Skywalk warrants discussion within the context of high-performance building envelopes for its innovative structure and streamlined approach to materials—the "+" in Facades+. Though the expected solution to the competition brief was a suspension bridge or other high-masted element, "we thought as a team that this approach would not be appropriate to the site," recalled Sturgess. "As much as we were going to make something courageous and heroic, we also wanted it to be subtle." RJC's Simon Brown came up with the idea of a parabola cantilever that draws visitors 35 meters beyond the face of the cliff. Sturgess Architecture focused on minimizing the material palette, relying primarily on Corten and glass, plus gabion mats filled with local rocks and concrete on the adjoining interpretive walk. "The idea was that the Corten would emulate the ferric oxide outcropping that you see on the existing mountainside," said Sturgess. "We wanted the whole element to feel fractal and extruded from the mountainside. As much as it was clearly manmade, it was to be as sensitive to the local environment as possible." Glacier Skywalk's signature design element is its glass floor, constructed in three layers—two structural, the third designed to be easily replaced if broken or otherwise damaged. "I'm a little nervous about walking on glass floors," admitted Sturgess. Several times he suggested replacing the glass with an opaque material to save money, but the rest of the team refused to let go. "Normally when I've worked in design-build, the gun is to our head and the finger's on the trigger," said Sturgess. "In this case, every time we suggested, 'We can save money here,' everyone on the design team was so in love with the concept, we couldn't lose anything lightly." Sturgess Architecture swapped Rhino models with PCL, RJC, and Heavy Industries, who formed all of the Corten work, throughout the design development phase. "I've never gone through such an extraordinary hands-on design process working with the actual craftsman of the solution," said Sturgess. "This iterative process of working with the team as we crafted every piece kind of by hand—though on the computer—is what led to the success of the project." In combination with its geologically inspired cladding, Glacier Skywalk's minimal structure delivers an illusion of weightlessness that only adds to the sense of exposure. The curvature of the walkway allowed RJC to install a nearly invisible cable suspension system to counterbalance its outward propulsion. "It expresses the thrust from the mountainside, and it does it in a way that makes it feel like a really integral fit with the [landscape]," said Sturgess. "The success is that it's not too much."
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Photoengraved concrete connects past and present in Montreal student housing.Though the site on which KANVA's Edison Residence was recently constructed stood vacant for at least 50 years, its emptiness belied a more complicated history. Located on University Street just north of McGill University's Milton gates, the student apartment building lies within one of Montreal's oldest neighborhoods. Photographs dating to the mid-19th century show a stone house on the lot, but by 1960 the building "had disappeared; it was erased," said founding partner Rami Bebawi. Excavation revealed that the original house had burned to the ground. Prompted by the site's history, as well as an interest in exploring cutting-edge concrete technology, the architects delivered a unique solution to the challenge of combining old and new: a photoengraved concrete facade featuring stills from Thomas Edison's 1901 film of Montreal firefighters. Knowing that Edison Residence would be subject to heavy use by its student occupants, KANVA chose concrete—featured on the interior as well as the building envelope—for its durability and sustainability. But the architects were not interested in sticking to tried-and-true building methods. "Being right in front of a university, we took it upon ourselves to say, 'We're going to push concrete technology,'" explained Bebawi. "We wanted the building itself to be a laboratory to experiment with concrete, and to make this innovation public and accessible to all." Because they also hoped to use the facade to tell a story, they turned to photoengraving, a technique developed by the German firm Reckli. Reckli translates black and white images into grooves of different depths and widths that offer a total of 256 shades of grey. "It brings the building to life, just like cinematography brings photos to life," said Bebawi, noting that the images may appear and disappear according to one's viewpoint. "It's not a stain. We're looking at something that is permanent, yet dynamic." Choosing the content of the photoengraved panels proved more difficult. "Here's a tool that's powerful, but very scary," said Bebawi. "It's like a billboard in Times Square, but it doesn't change every 30 seconds. You have this kind of social responsibility [to make an appropriate choice]." Thinking about photoengraving's capacity to animate a building led KANVA to early moving pictures, or "tableaux mouvants," and in turn to Edison's role in developing film technology. When they discovered his Montreal Fire Department on Runners, filmed just blocks away from the Edison Residence site, they knew they had it. "All of sudden we closed the loop," recalled Bebawi. "Fires transformed the city." The architects extracted twenty images from the film and sent them to Germany, where Reckli manufactured rubber liners for use during the pouring of the precast panels. Local prefabricated concrete company Saramac fabricated and installed the panels back in Montreal. For continuity, all of the street facade's glazing (manufactured and installed by Groupe Lessard) features additional screen-printed stills from Edison's film. Depending on the position of the sun, the film sequence becomes more or less visible. Variations in the facade depth form a base and cornice, and add to the effect. "When the sun's not at the right angle, the grooves make it look like it's simply an inserted masonry building," said Bebawi. "At other times, it comes to life." Other aspects of the building, including the prominent porte-cochère, nod to local architectural traditions. Yellow metal accents offer additional animation "by sort of an urban signal," said Bebawi. "This yellow is screaming out. It pulls you into the porte-cochère entrance and is expressed on lateral and rear facades." The remainder of the building is unornamented concrete, in keeping with the quarter's environmental code. "It had to be a masonry building according to the heritage standards," said Bebawi. "Obviously, we played with that: 'I can fit your rules, but speak in terms of 2014.' It was a great collaboration with municipal and provincial authorities." Edison Residence embodies a third way to reconcile new construction with history. "When you think about our relationship to the past in terms of architecture, you can demolish it, imitate it, or contrast it," said Bebawi. "This building takes a different position. Depending on the way you place yourself, sometimes the past appears, and sometimes it doesn't."
A renovation and addition bring an historic church complex into the 21st century.The Diocese of Toronto approached architectsAlliance (aA) about renovating the St. James Cathedral Centre with two objectives in mind. On a practical level, they wanted more space for the cathedral’s outreach program and the Diocesan archives, as well as quarters for the Dean of the Cathedral and visitors. At the same time, the Anglican leadership wanted to make a statement about the Church’s relevance to contemporary Canadian society. “The idea of the addition was to convey an image of the Church itself as a kind of more open institution, much more transparent and contemporary,” said aA’s Rob Cadeau. “[It was] really driven by the dean, who wanted to refresh the image of the Church.”The architects designed the addition to the Parish Hall as a glass cube. “There’s a lot of use of glass, both as a contemporary material, but also to convey that idea of transparency, for the symbolism of the project,” said Cadeau. At the same time, the see-through extension “defers to the old building. It doesn’t take away from the presence of the old building as opposed to solid masonry construction.” The upper stories of the stick system curtain wall are wrapped in a floating sunscreen comprising repeating bands of laminated glass. “It was very important to the church that there be a sort of green aspect to the design in the way it’s conceived and constructed,” said Cadeau. “So the sunscreen was designed as a passive means of providing shading.” To maximize shading during the summer and solar gain during the winter, aA ran the sunscreen design through shadow analysis testing in ArchiCAD. They worked with Stouffville Glass to engineer both the sunscreen and the curtain wall. The sunscreen hangs on a vertical system of stainless steel brackets anchored to the HSS beams surrounding the slab edge of the second and third floors. The glass panels’ interlayer is printed with a linear pattern recalling the original building’s narrow button bars. “The idea of the lines within the sunscreen was to create a finer grain of detail on the glass,” explained Cadeau. The curtain wall itself is built of Solarban 60 glass. “It still provides the U value we wanted, but we didn’t want too much reflectivity because it’s a fairly small building,” said Cadeau. The firm also improved the thermal performance of the original Parish Hall building, which opened in 1910. With help from a building envelope consultant, they ran a thermal analysis of the structure to determine how much spray foam insulation to insert between the masonry wall and a new stud wall. The goal was to boost insulation while allowing some heat transfer. “That’s very important in heritage upgrades,” said Cadeau. “[T]he mistake you can make is over-insulating. Masonry walls rely in some sense of heat loss so that the water [trapped inside] never freezes. If the water absorbed in the brick freezes it will start to crack the brick.” The new St. James Cathedral Centre unites a previously disconnected cluster of buildings across an enclosed courtyard. In that way, aA suggests, the glass addition functions as a contemporary cloister. “In a larger, urban planning sense [the objective] was to complete the ensemble of buildings, create more of a connection between the buildings as a whole,” said Cadeau.
Boston Valley Terra Cotta restored the Alberta Legislature Building's century-old dome using a combination of digital and traditional techniques.Restoring a century-old terra cotta dome without blueprints would be a painstaking process in any conditions. Add long snowy winters and an aggressive freeze/thaw cycle, and things start to get really interesting. For their reconstruction of the Alberta Legislature Building dome, the craftsmen at Boston Valley Terra Cotta had a lot to think about, from developing a formula for a clay that would stand up to Edmonton’s swings in temperatures, to organizing just-in-time delivery of 18,841 components. Their answer? Technology. Thanks to an ongoing partnership with Omar Khan at the University at Buffalo’s School of Architecture and Planning, the Orchard Park, New York, firm’s employees are as comfortable with computers as they are with hand tools. On site in Edmonton, technicians took a 3D laser scan of the dome prior to disassembly. They also tagged specific terra cotta pieces to send to New York as samples. These pieces, which ranged from simple blocks to gargoyles and capitals, went straight to the in-house lab for scanning into Rhino. The drafting department combined the overall scan with the individual scans to create a total picture of the dome’s surface geometry and depth. The individual scans, in addition, were critical to making the approximately 508 unique molds employed on the project. To compensate for the eight percent shrinkage clay goes through during drying and firing, the craftsmen at Boston Valley used to have to perform a series of calculations before building a mold. “[Now we] take the scan data and increase by eight percent by simply doing a mouse click,” said Boston Valley national sales manager Bill Pottle. In some cases, the craftsmen converted the scan data into a tool path for the five-axis CNC machine used to make the molds. “We’re doing that more and more in some of our mold making. It also allows us to ensure that we’re recreating them to the most exacting tolerance and dimensions that we can,” said Pottle. The data from the 3D scans also helped the craftsmen replicate the dome’s complicated curvature. “Between the scanned pieces and the scan of the dome itself, we were able to figure out some very complex geometry where each of these individual pieces had the correct shape to them,” said Pottle. For sustainability and durability, the designers at Boston Valley reconfigured the dome as a rain screen system, with terra cotta components attached to a stainless steel frame. But while the rain screen boosts environmental performance, it also demands incredible precision. Again, the 3D models proved invaluable. “The models allowed these tight tolerances. [We] could explode it and make sure everything was connected. It would have been impossible without that level of sophisticated software,” said president John Krouse. The Alberta Legislature Building dome restoration is the first major project on which Boston Valley has unleashed its full array of digital design tools. Krouse hopes its success—he estimates that the digital tools speeded fabrication by 200 percent—will send a message to designers interested in experimenting with terra cotta: “What we’re trying to say to the architecture and design community globally is don’t be afraid to start designing domes with complex geometry, because we’re equipped with all this technology. It doesn’t have to be a square box.”
StructureCraft fabricates an orchid-shaped roof that supports vegetation and Living Building Challenge principles.After serving patrons at one of Vancouver’s oldest botanical gardens for nearly 100 years, the VanDusen Gardens Visitors Centre had fallen dangerously into disrepair. Perkins+Will Canada conceived of a new, orchid-shaped center that meets CaGBC’s LEED Platinum ratings, and is the country’s first structure to target the International Living Building Challenge with features like geothermal boreholes, a 75-square meter photovoltaic array, and a timber roof that supports vegetation. To help fabricate the wooden structure to Perkins + Will Canada’s vision, the team contracted StructureCraft, a Vancouver-based design-build studio specializing in timber craftsmanship and structural solutions. Initial designs for the 19,000-square-foot building were delivered to StructureCraft as Rhino files. The uniquely shaped rooftop, which mimics an outline of the indigenous British Columbia orchid, had to be economically fabricated in a way that took net carbon effects into account. Within Rhino plugins—mainly Grasshopper—and with the help of strucutral engineers Fast + Epp, the StructureCraft team sliced the shape of the building into 71 long, curved panels of repeatable geometries. “Each curve is unique, so there’s a different radii for each beam,” said Lucas Epp, a structural engineer who worked on the project. “We optimized the global geometry of the roof so the radii of all the beams were in our fabrication tolerances but still achieved the architect’s desired aesthetic.” Also within Rhino, the team integrated all of the building’s services into each of the panels. Since much of the piping and wiring for other trades like insulation, sprinklers, and electric utilize flexible formats and conduits, modularizing the panels significantly reduced site time from months, to weeks. And to protect the wooden structures, moisture barriers and closed-cell thermal insulation were applied throughout. The parametric model was then imported to Solids modeling software to develop a bespoke fastening system. StructureCraft used jig and table sawing methods to mill panels of Glulam, chosen for its flexibility and strength. Timber battens were affixed as cladding in sizes that were thin enough to naturally accommodate the curves of each panel. Solid timber support columns, carved on StructureCraft’s in-house lathe, taper at both ends to Perkins + Will Canada’s design specifications. Business development engineer Brian Woudstra, who worked on the project, attributed the accuracy of fabrication and the speed of installation to the expansive capabilities of parametric modeling. “We could model every joist, Glulam panel, and ceiling batten to help with conflict detection and feasibility,” he said. “We always prefabricate our projects in our shop, so it’s like a kit of assemblies that all clicks into place.”