The stunning unique design of the Combined Office Tower (COT), now rising above the windswept prairie at Edmonton International Airport, captures the attention of travelers and all who see it. The new 107,000-square-foot building adds dramatic impact to the Edmonton arrival and departure experience. The new cutting edge NAV Canada air traffic control tower is perched at the top of the outer edge of the 8-story structure, filled with administrative offices, retail space, dining outlets and an observation deck.

The facade features an undulating wrap of RHEINZINK Interlocking Flat Lock Shingles applied to a complex, continuously curving surface system. Approximately 50,000 square-feet of prePATINA blue-grey RHEINZINK was used to create the ribbons that wrap the building. The profile of the exterior zinc cladding provides optimal passive solar shading on the south and west facades, while allowing maximum light penetration on the north. The project is targeting LEED Silver certification.

The exterior wrap begins 43 feet above the ground and twists upward to an overall height of 148 feet. Each metal ribbon contains either two or three facets that vary in height, width, thickness and angle as they trace around the building. Approximately 35,000 individual RHEINZINK panels, each measuring 1-foot by 2 feet, were installed.

The architectural design for the project—provided by DIALOG—was inspired by the unimpeded Alberta wind. It sculpts the tall prairie grasses as well as the seasonal snowdrifts. “We felt this imagery expressed a sense of place and its people,” said Principal Stephen Boyd at DIALOG.

The design represented both challenge and opportunity for the building envelope contractor, Thermal Systems KWC Ltd., Calgary. Thermal Systems partnered with Gehry Technologies, parametric modeling experts, and Radius Track—the innovative curved steel framing provider.

The fabrication challenge was to find a way to make the metal curves smooth, while accommodating the undulating design of the wrap. Collaboration by the three companies yielded a solution that worked well and helped produce the building’s graceful curves. The team developed a curving hat channel system that provided a smooth attachment surface for the RHEINZINK shingles.

“The challenge was all about the geometry, ”said Tyler Weisgerber, Thermal System’s commercial division manager. “Our design team partners were essential assets in providing the necessary 3D modeling and BIM technology to create the system. But you can only assume that a material is going to react a certain way until you actually apply it to a certain type of geometry. To be absolutely certain, we built a proof-of-concept mock-up to test and refine our system. We constructed an actual ribbon section from the building and wrapped it around a 40-foot sea container in our yard. Once we built all of the components, we quickly found out what worked and what needed some tweaking. Our leadership trades support was crucial while refining the system. Experiencing the mock-up process was key to the success of the project. These same craftsmen lead the teams that completed the installation in spectacular fashion.”

Fabrication of the RHEINZINK shingles was done by Grant Metal Products, Rocky View, Alberta. RHEINZINK was also used extensively in the interior concourses as a design accent element and to highlight various retail storefronts.

Thermal Systems is a long-time RHEINZINK systems partner and has extensive experience with the material. “RHEINZINK is near and dear to my heart,” Weisgerber said. “I‘ve always enjoyed working with zinc. It has amazing characteristics. The life span and maintenance-free aspects of the product make it very appealing to our customers.”

In addition to the 50,000 square-feet of RHEINZINK shingles, the project utilized 50,000 square-feet of metal decking, 1128 individual support trusses and 700 square-feet of architectural louvers. The general contractor on the project was EllisDon, Edmonton.

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