Features Architectural design Contracting
Rocky Mountain high

Named in honour of the Wild Rose Country’s Centennial year, Centennial
Place is a set of two LEED Gold certified towers with a linked podium
occupying a full city block in the Eau Claire region of Calgary

Named in honour of the Wild Rose Country’s Centennial year, Centennial Place is a set of two LEED Gold certified towers with a linked podium occupying a full city block in the Eau Claire region of Calgary. A typical floor features six corner offices and with minimal structural intrusion for greater layout flexibility and access to breathtaking views of the Rocky Mountains.

The spires on both buildings include lighting features that were built at Antamex’s Delta factory and shipped to the site to be hung in place. “We designed and fabricated the spires near the end of the job with very little detail, which was fairly challenging,” says project manager Otto Ward.

The buildings represent a completion of a campus of offices that Oxford Properties has built in the Calgary area over the last 30 or 40 years, many of which were designed by WZMH and various generations of the firm. The project is almost like an addition to the family.

Tom Schloessin, project architect of Centennial Place for WZMH, recalls how the Oxford family of buildings progressed as technology and best practices improved. “Over time the styles of the buildings have changed,” says Schloessin, “so it is interesting to see how the buildings have evolved. We were quite proud to achieve LEED Gold for Centennial Place. We were told that at the time it was the largest single LEED Gold project in Canada.” 

Creative freedom
“Effectively, we filled a city block with this development,” says Schloessin. “When you are creating a two-tower project, you want to situate the buildings relative to one another so they perform well and optimize things like daylighting. In that aspect, Centennial Place was very successful in that the buildings don’t shadow each other. The other feature that is exploited by the orientation of the towers is the view of the Rocky Mountains to the west, which we wanted to optimize with a lot of vision glazing. We wanted as much sense of natural light as possible. It wasn’t low iron glass, however; it was as clear as we could get it within our budget.”

Keeping with the ongoing trend for these types of projects, the glazing contract was split between the tower, which was completed by Antamex International (now known as Oldcastle BuildingEnvelope) from Delta, B.C., and the podium, which was supplied and installed by Global Architectural Metals from Welland, Ont. “This happens frequently with these types of buildings,” explains Schloessin. “The tower was completed by a company in the curtain wall trade and the perimeter podium glazing is completed by someone with a structural glass system or a basic curtain wall system. For the tower, we were working with Antamex just as they were opening their manufacturing facility in Delta, so they had a tremendous incentive on that project. It worked out very well.”

“With a building like Centennial, we were dealing with a standard unitized curtain wall system which is designed to be modular, however, we wanted to introduce new features,” says Schloessin. The solution was to incorporate a patterning effect in terms of protrusions in the mullions and cap treatments. “That’s how we achieved the play in the facade and Antamex was very good at achieving that effect.”

Schloessin continues, “On each tower, one wall is sloped so we had an inclined plane and were putting the unitized glazing system on a slight angle, which was interesting and achieved by Antamex without issue. They were well versed in the technology of curtain wall and very knowledgeable in terms of sequence of production and fabrication. We had the benefit of some very experienced people. The end result was quite successful.”

“It was a very interesting job for us,” says Herb Resar, vice-president of western operations for Oldcastle Building-Envelope, the company responsible for design, engineering and overall operations for Centennial Place. “We had one of the best construction managers in the country in PCL and it was a privilege to work with them on this project. Antamex/Oldcastle BuildingEnvelope was part of the design–assist for this project, which went very well with the co-operation of WZMH as there was the need for interaction and communication in the design development. Pressure equalized, unitized, rainscreen curtain wall designs have existed for a number of years; however, the extrusions for this job were all custom manufactured and adapted to the architect’s requirements for the esthetics, while we concentrated our efforts on function and durability of the system.” 

“The main parts of the towers were relatively straightforward and went smoothly because there was a lot of repetition, even though WZMH added character to the facade by using different glass types and alternating details in different areas,” explains Otto Ward, Antamex project manager for Centennial Place, now business development leader for Garibaldi Glass. Ward continues, “But when you get to the top, there are recesses and cantilevered beams, decks louvres and other architectural features with steel that penetrated the system, requiring complex framing configurations to maintain air and vapour seals throughout.”

“There was a point where both buildings were being built at the same time so it was a challenge in keeping enough supply for both towers, in particular with the tops as there was a delay in the steel work,” says Ward. “So near the end of the project we were asked to speed up the job, which made it difficult to find space at the top of the building for the frames while the steel work was still going on. Even though both buildings look similar except for the heights, the steel work at the top of each building was actually designed very differently, so our connections had to be different for each tower. Even though it all looks the same, it is not.”

“It worked out extremely well and was a good job for everybody,” says Resar. “It was the type and size of project that we do well. It had the repetition that we are looking for from a manufacturing point of view and the complexity to really put your head into the design and engineering, especially at the tops of the buildings and the spires.”

Connected inside and out
“Another feature of the glazing design that we really like about Centennial Place is that even though it is a full city block, the building is really light in terms of how it comes to ground,” explains Schloessin. “There is a lot of openness. You have the effect that you can look through the entrance lobbies and see the tower elevator cores and the main interior concourse. When you are dealing with a full-block development like Centennial, there is a risk of losing clarity in design and having large stretches of wall that don’t really tell you anything. We were trying to eliminate the idea that there is a clearly perceived front or back door to the development. We don’t really have that. The logic of the buildings is very apparent from the street and it was very important to us when we designed the building and we were able to achieve it in the final product.”

“We couldn’t really afford to use a heavy duty structural system,” recalls Schloessin. “It just wasn’t in the cards; however, we were able to achieve huge transparency and a lot of interconnection between inside and outside space simply by using high span curtain wall. We were able to use fairly conventional, accessible technology and maximize the limits of the glass sizes available. Because Global Architectural Metals was able to engineer the overall wall area using curtain wall, backup support and sag rods to cover off deflection, we were able to get a very light looking wall.”

“The front entrance was another collaborative effort where we drew something that was technically impossible and Global was able to find a way to make it happen,” says Schloessin. The challenge was that when you put a canopy over a front door into a tower you have to break down the scale. However, you don’t want to shrink it down to the size of the person. “The concept was to float an all-glass canopy in a space where your main structural supports are nine metres apart. Global was able to run a steel V-profile between the major support points and install the entire remaining canopy with an all-glass gable construction. Very nice work.”

“The project turned out very well, considering the context in which we were working and how busy Calgary was at the time,” says Schloessin. “There were lots of pressures and I think we weathered the storm.”