A bridge in the sky: Glacier Skywalk

280 meters above the Sunwapta River.

Perched some 280 metres above the rushing Sunwapta River sits a glass floor observation deck that appears to float from the limestone bedrock cliff. The structure cantilevers out 30 metres from the bedrock face, with weathering steel, glass and wood to mirror the natural environment. It has won numerous awards, and Thurber is proud to have been the geotechnical engineers for the project. Our client for this project was Read Jones Christoffersen (structural engineers) who were part of a design-build team that included PCL Construction and Sturgess Architecture. The owner is Brewster Travel Canada who worked closely with Parks Canada.The Glacier Skywalk Project is located in Jasper National Park in Alberta, about 6.5 km northwest of the Columbia Icefields Visitor Centre on Highway 93. The project includes a receiving area, an interpretive cliff edge walkway and the cantilevered glass floored observation platform that offers breathtaking views of ice-capped mountains and glaciated valleys.

The cantilevered asymmetric structure results in significant compression and tension foundation loads which combined with the desire to integrate the structure into the native bedrock presented significant geotechnical foundation support and slope stabilization challenges. Bedrock mapping, rock coring and laboratory testing were completed to characterize the bedrock. The bedrock mapping included the use of a large crane to access the rock cliff below the structure foundations. Rock coring was completed using wet rotary diamond methods to 35 m depth. Laboratory testing included point load tests, uniaxial compressive strength tests and direct shear tests on bedding joint discontinuities.

Structural foundations at the crests of steep slopes are typically setback to address slope stability issues. The desire to integrate the structure into the natural slope resulted in high foundation loads close to the slope crest where zones of weathered and fractured limestone bedrock were present. Kinematic stability analyses were conducted to check the stability of the slope below the two large concrete footings. Micropiles, tension anchors and rock bolts up to 15 m long were designed to resist foundation loads and address slope stability.

The walkway was designed to cantilever in areas where rock slope stability issues were present. Gabion basket walls up to four metres high were also designed along the cliff edge walkway to support Highway 93 above. The gabion baskets were filled with rock excavated from the observation platform foundations and pathway footprint to blend into the natural environment.

Thurber provided field mapping, rock coring, laboratory testing, stability analysis, micropile expertise, construction inspection, anchor testing and materials services. We continue to return to site to inspect the structure.