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+.
Glacier Skywalk’s Corten cladding pays homage to the color and texture of the surrounding mountains. (Robert Lemermeyer)
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.”A structural glass floor and railing magnify the sense of exposure. (Robert Lemermeyer)
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.”The walkway encourages visitors to exit their cars and come face to face with the shrinking Athabasca Glacier. (Robert Lemermeyer)