e-mosty June 2018 American Bridges American Bridges | Page 52

GLACIER SKYWALK
Project Team
Fabricator: Beauce Atlas Steel Fabricators
Engineers: Read Jones Christoffersen Ltd.
In the fall of 2010, Brewster Travel Canada issued an
Expression of Interest request for design build teams
to create a new and exciting tourist attraction.
They wanted to create an experience that would
attract people from around the world to Jasper
National Park. “Gobsmacked” and “Visceral” were
terms Brewster used to describe their expectations.
The resulting Glacier Skywalk is a thrilling and
dramatic structure featuring 30m of curved glass
walkway extending 30m beyond the cliff face and
suspended 280m above the Sunwapta River.
By cantilevering the structure, Read Jones
Christoffersen Ltd., as design lead and structural
engineer, was able to deliver the unique and
exhilarating experience they wanted while blending
the Skywalk in with the natural environment.
The Brewster company, which operates various
tourist sites in the Rocky Mountains, began and
started in 2012 the construction of this observation
bridge whose half-moon end composed of a floor and
glass railings allowing spectacular sighting on the
Sunwapta River and the Athabasca parish priest.
This bridge is embedded on a cliff sidewall mounting
on a slope of 280 meters and with a 45-meter
cantilever.
Brewster engaged the services of the RJC Consulting
Engineer located in Calgary to execute the structural
plans and specifications. They chose a structure of
steel caissons of variable geometry to support the
half-moon-shaped glass bridge with a radius of 10
meters at the end of these caissons and attached to
blocks of glass, with anchors weighing 10 imperial
tons each at each end.
The overhang of the two box girders was 35 meters
and 15 meters. The ratio of the dead weight of the
steel versus its high resistance convinced the
professionals to use steel as the material for this
structure overhang which respected the allowed and
anticipated deflections.
The box structure remained apparent “uncoated”.
The client opted for a finish showing the raw
appearance of steel exposed to the elements and
blending into the rocky landscape. The atmospheric
steel was therefore chosen and retained for the
execution of the caissons and secondary floor
structure.
The constructability challenge was to not exceed the
weight and size limits for transporting and erecting
these parts. The contractor PCL awarded the contract
to Constructions Beauce Atlas in June 2012 for the
supply and delivery of the box girders, transverse
beams and secondary beams.
This project located 4,200 km from the Beauce Atlas
facilities in Ste-Marie of Beauce was in itself a
challenge because of the distance separating the
fabricator plant from the site and also because the
assembly granted by the customer directly to a steel
fitter included a logistics and a schedule set at quarter
of tower that had to be respected because otherwise
would have caused significant impacts.
2/2018