Canadian Architect

Feature

Steel Skywalker

A structurally daring walkway cantilevers visitors over and above a valley in the Canadian Rockies.

July 1, 2014
by Alexandra McIntosh

The Skywalk's glass-floored walkway is visually counterbalanced by massive Corten steel arms that connect to the rock face. Brewster Travel Canada

The Skywalk’s glass-floored walkway is visually counterbalanced by massive Corten steel arms that connect to the rock face. Brewster Travel Canada

PROJECT Glacier Skywalk, Jasper National Park, Alberta
DESIGNERS PCL Construction Management with Read Jones Christoffersen Ltd. and Sturgess Architecture
TEXT Alexandra McIntosh
PHOTOS Robert Lemermeyer unless otherwise noted

The Icefields Parkway, a scenic two-lane highway connecting Lake Louise and Jasper, runs parallel to the North American continental divide and draws over 1.5 million visitors a year. Formidable in its successive vistas of mountain peaks, rushing rivers and hairpin turns, the winding route has no shortage of attractions.

The Glacier Skywalk aims to improve upon such natural perfection. A striking glass-floored observation deck cantilevered over the Sunwapta Valley, the Skywalk is a $21-million project commissioned by Brewster Travel Canada and designed by Read Jones Christoffersen Consulting Engineers (RJC) and Sturgess Architecture.

The Skywalk, opened this May, occupies the site of the previous Tangle Ridge Viewpoint. It also achieves the odd distinction of providing the only lookout in the Rockies where visitors feel compelled to look at their feet.

Site Map 1 bus dropoff 2 Discovery Walk 3 Glacier Skywalk

Site Map 1 bus dropoff 2 Discovery Walk 3 Glacier Skywalk

To mitigate traffic congestion at the apex of a steep hill, the Glacier Skywalk is only accessible by a Brewster-run bus from the Columbia Icefield Glacier Discovery Centre, a few kilometres down the highway. Once at the site, visitors pass through a faceted canopy structure that serves as a kiosk, its angled planes of Corten steel undercut with warm wood cladding. Beyond, a thin band of pathway cut into the hillside conveys visitors to and from the glass-floored observation deck. Gabion walls and steel plates delineate the dual pathway, which gently rises and falls following the contours of the terrain.

A dramatic Corten steel arch and cantilevered lookout. Robert Lemermeyer

A dramatic Corten steel arch and cantilevered lookout. Robert Lemermeyer

Six interpretive stations, executed in the same weathering steel, punctuate the 300-metre route. The stations feature didactic panels that address the glaciology, biology, plant life and hydrology of the area as well as the technology behind the Skywalk. The first of these is a sharply jutting steel viewpoint–a scaled-down iteration of the cantilevered structure to come–that introduces visitors to the Sunwapta Valley.

Other interpretive stations, however, lack cohesion: the folded steel canopy of the Ecology node is muddied by two-dimensional cutouts of wildlife, while the Phytology station seems an afterthought, consisting of little more than a steel planter box dwarfed by its surroundings.

A wood-clad seating area offers spectacular views of the surrounding mountains. Robert Lemermeyer

A wood-clad seating area offers spectacular views of the surrounding mountains. Robert Lemermeyer

In terms of its overall architectural gesture, the Discovery Trail successfully creates a dramatic approach that conceals the highway. As architect Jeremy Sturgess explains, the route “aims to heighten the experience, to create a sense of progression and tension as you walk along the mountainside, exposing you to the wonder of the thing, and winding down along the return.”

An ingenious cable suspension system runs below and beside the cantilevered arc, maintaining eye-level views free from obstructions. Robert Lemermeyer

An ingenious cable suspension system runs below and beside the cantilevered arc, maintaining eye-level views free from obstructions. Robert Lemermeyer

The pathway culminates in the Skywalk proper: a parabolic arc dramatically suspended over the valley. Two massive steel arms, connected by a bridge, thrust out from the cliff face. The faceted planes of steel echo the sheer angles and serrated peaks of the mountains beyond. At the tip of the arc, the raw steel is replaced by a glass-floored walkway, suspending visitors over a sharply pitched slope of scree that descends to the valley floor 280 metres below. At the tip of the arc, visitors are held an impressive 35 metres away from the cliff face.

The cantilevers are constructed as immense box girders, anchored by steel rods drilled 16 metres into the rock face and put into tension. The 30-metre structural glass walkway is supported by cables that sweep in beneath and alongside the inner curve of the path. The cable system gives an intentional and slightly unnerving bounce to the structure. Though tempered by four half-ton dampers, the movement is still keenly felt during peak visitor periods.

Vista Isometric

Vista Isometric

According to Simon Brown, principal in charge of the project for RJC, the cable suspension system is unique in that it supports the structure on one side only. “The parabolic shape is exactly what was required to enable and counterbalance this,” he explains. This structural strategy allows the balustrade to be made of glass and requires no cables above eye level, resulting in completely unobstructed views.

The structure was conceived and designed by RJC, while Sturgess Architecture “twisted it with RJC’s blessing,” says Sturgess. He explains that his firm “folded the Corten parts and manipulated structural materials to create an architectural expression that would be a sensitive extension to the mountainside.”

The Corten steel used throughout has oxidized to a deep-brown rust colour and will continue to darken over the next five to 10 years, altering alongside the landscape. The gabion baskets were hand-layered with rocks excavated from the site during construction. Only recently exposed to the elements, they too will weather and deepen in colour like the surrounding landscape.

Floating, thrill-chasing structures seem to be cropping up recently over mountain escarpments and river gorges from Austria and Italy to British Columbia’s Capilano River. In Norway, the government has funded a series of architect-designed lookouts to boost tourism along scenic highways. (It’s a pity that the Glacier Skywalk could not also be free to access, although perhaps a sign of the increased pressure faced by Parks Canada to entice tourists and approve commercial amenities following budget cuts.) Among parallel structures, the Glacier Skywalk has its clearest antecedent in the glass-floored Grand Canyon Skywalk (2007). The Albertan structure, however, is more refined than the clunky horseshoe-shaped promenade in Arizona, where visitors are obliged to remove their shoes and prohibited from taking photographs. At the Glacier Skywalk, the almost instantaneous response by visitors is to photograph themselves sitting or lying down on the glass floor.

While some visitors may be more attracted to the Skywalk itself rather than the view, the combination of infrastructure and landscape provides a thrilling experience. The Skywalk is an aesthetic and structural feat, both otherworldly and at home in the Canadian Rockies. It is resolutely a response to the landscape, its powerful gesture and raw materials executed in a language abstracted from its surroundings.  CA

Alexandra McIntosh writes on architecture, design and visual arts. She is based in Calgary, Alberta.

Client Brewster Travel Canada | Design Team PCL Construction Management (Design-Build Team Leader)–Scott Updegrave, Keith Bowers. Read Jones Christoffersen (Prime Consultant)–Simon Brown, Geoff Kallweit, Mark Ritchie. Sturgess Architecture (Architect)–Jeremy Sturgess, Jan Kroman, David Tyl, Bob Horvath. | Structural Read Jones Christoffersen Ltd. | Electrical SMP Engineering | Traffic Urban Systems LTD. | Dynamic Wind Modelling Rowan Williams Davies & Irwin Inc.  | Environmental Golder Associates | Geotechnical Thurber Engineering | Contractor PCL Construction Management | Area 5,500 ft2  | Budget $21 M | Completion May 2014




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