Volume 24, Issue 6 - November-December 2010

feature



Glass Plays a Critical Role in Downtown Pittsburgh’s First New Skyscraper in 20 Years

More and more developers and planners are searching for ways to restore the life, culture and excitement of cities, culminating in the revitalization and renewal of many urban areas. Consider downtown Pittsburgh. For centuries this Pennsylvania locale was known for its strong industrial ties, particularly in coal mining, steel production, aluminum and glass. And today, while manufacturing remains a big part of Pittsburgh’s economy, the city’s industrial focus has evolved into more high-tech fields, ranging from robotics to healthcare. And just as the city’s economy has changed, so too, has the face of its downtown district.

“Cities are trying to create more diversity in the use of their downtown areas so they are not just a financial district or a business district. Developers are trying to get people living and shopping downtown and getting more 24/7 use out of their urban core,” says Ben Tranel, a project architect with San Francisco-based Gensler. “You see that among the post-industrial towns, such as Pittsburgh, but you also see it in smaller communities that aren’t necessarily post industrial but have been subjected to a lot of urban sprawl and urban growth and are trying to find a way to create an identifiable downtown urban core.”

Earlier this year downtown Pittsburgh saw the completion of its first new high-rise in 20 years, when the Fairmont Hotel at 3 PNC Plaza opened its doors. Designed by Gensler, 3 PNC Plaza is a 752,000-square-foot, 23-story, mixed-used high-rise constructed to meet LEED standards. The cladding area of the building was 250,000 square feet and about 4,000 pre-glazed frames were installed. Construction began in 2008 and the office portion was completed in 2009.
The 3 PNC Plaza project was one about urban renewal, renovation and bringing some life back to downtown Pittsburgh. It changed the city’s skyline, and would not stand as it does or have achieved the desired performance measures without the use of glass.

Key Considerations
“The idea was to create a building that would be a part of the skyline in a light, bright and refreshing way,” says Tranel. “We were looking for glass products that would feel light and airy, as we did not want something heavy like stone. We also wanted a glass that would have some coloration and warmth so on those cold, gray, winter days the building would still have warmth and brightness.”

Another design consideration was the fact that the tower would be a mixed-use building, having a hotel, condo and office portion, as well as different aspects in the base, such as a retail component.

“We were looking to break down the mass of the building so it would not feel too big and massive and we wanted to articulate the different programs inside the building, both formally, but also through the type of glass,” says Tranel, who explains that the condo portion incorporates a different glass type, as well as some articulation in the architecture, so it has a different mass offsetting it from the rest of the building.

“The different glass type creates a differentiation as you read the building from the exterior,” he explains. “Then between the offices and hotel we used ceramic frit on the office, but not on the hotel, and we differentiated the mass by using the ceramic frit in some areas but not others. In the storefront portion it’s all very clear and open to activate the street from the pedestrian level when you’re walking by. People can see in and those inside can see out so it’s like an urban room, which was one of the concepts we were working with—the hotel lobby wanted to feel like an open room that was connected to the urban fabric around it and revitalizing to the streetscape. Glass was just a natural material to support a lot of those ideas.”

Glass Selection
When it came to selecting the glass, the culture and history of Pittsburgh came into play, particularly since PNC is headquartered in the city.

“There was a desire to, if at all possible, work with PPG because its headquarters are a block and a half away,” says Tranel.
“The company provided us with a new coating that had not been used extensively before; it wasn’t brand new and it wasn’t the first time it was used, but it was something relatively new for them. It was exciting to work with them in, not only revitalizing downtown, but also supporting a local business.”

The majority of 3 PNC Plaza features PPG’s 70XL, as well as a green body tinted glass.

“Those products, together with the coating on the number-three surface and the frit on the number-two surface, gave us the energy efficiency we needed because the building is also targeting LEED certification,” says Tranel. “Part of that achievement is energy performance so the glass was carefully selected based on environmental performance and its aesthetic.”

Trulite Industries in Mississauga, Ontario, fabricated the insulating glass (IG) for the project.

The company had previously served as the glass fabricator for Heinz Field Football Stadium, also in downtown Pittsburgh.

Oldcastle BuildingEnvelope (which acquired contract glazier Antamex in 2006) handled the glazing portion of the project. R. (Rocco) Parzanese, vice president of contracts, said they were brought on to the job by P.J. Dick, the general contractor.
“We were pretty well involved beginning with the design-assist stage of the project. There were architectural drawings available when we came on board, but a lot of the architectural details were not developed yet,” says Parzanese. “We went through all of the development details and conditions with the architects, which involved several meetings and a lot of conference calls.”

Parzanese explains that while architects already had a vision of what the project would be, his company was involved helping finalize the working details. He says his company was responsible for completing the envelope of the building, which included the pre-glazed curtainwall, aluminum cladding, doors, soffits, grills, etc.

“The architects wanted to work with one entity as much as possible and we took on that role,” says Parzanese. “They already had in mind what the glass and colors and finishes were going to be. We were on board to make sure it would all work properly.”

Form and Function
For a project so heavily focused on the glazing element, both performance and aesthetics were critical. Tranel says one of the challenges with which they were faced involved making sure the color of the glass was exactly right.

“It was tough to get the right combination of substrate and low-E coating to get the color we wanted,” he says. “While it was a challenge to get the right color and balance with environmental performance, in the end we were happy with the way it turned out.”

He says a unique feature of the glazing was the use of the low-E coating on the number-three surface.

“In Pittsburgh this was somewhat unexpected that it would work out as well as it did from an environmental performance,” says Tranel. “Being able to do that and still get the ceramic frit to read through from the number-two surface was something we were excited about.”

Also, on all the condos a laminated inner lite was used on the IG unit to reduce ultraviolet infiltration so there wouldn’t be fading of fabrics, carpet or upholstered furniture in the condo units.

“It’s a unique amenity that’s not typically offered to a condo owner,” says Tranel.

Working with large glass lites also posed
challenges.

“There were some very large pieces of glass, especially in the storefront of the hotel lobby. So it was a bit of a challenge to get some of those made because they were 7-feet, 6 inches wide—quite big insulating, low-E coated units,” says Tranel.

Parzanese adds that his team spent a lot of time at the main entrance of the hotel because of the large glass lites.

“It took quite a bit of planning and logistics to make sure they would work,” he says. Speaking of the project in its entirety, he adds, “[The glass work] was quite intricate in the sense of some of the interfacing details, especially at the terrace areas and the soffit areas where we had to integrate with the curb and roof conditions.”

He adds that they also spent a lot of time on levels 12 and 13 where there is a roof terrace.

“They also have an outside patio, where we had to work through the details for the soffit conditions. The space was comprised of column claddings and doors in those areas, all of which were within view at the roof area. Everything had to be integrated for a presentable look,” says Parzanese, who adds that they also went through visual mock ups with PPG.

“We also had a number of tests to do in order to get our system approved. It was essentially a custom system; we started with a clean sheet of paper and probably had a minimum of 18 new extrusion dies.”

In It Together
According to Parzanese, one thing about this project that made it different compared to others was the fact that Gensler, the design architect, and the local architect, Astorino of Pittsburgh, were on two different coasts.

“So [working around] the time difference could sometimes lengthen the time to communicate between all the parties,” Parzanese says.

However, he points out that despite the logistical considerations, everyone involved was able to work well together.

“We had a number of face-to-face, on-site meetings [which had to be coordinated when Gensler architects were in town] and we also had weekly conference calls and those conversations took place [from the beginning],” says Parzanese. “It wasn’t a case of coming to a certain point in time and saying, ‘OK, I guess we better ask some questions.’ The questions [were asked] continually and we worked through them every week with the architects and contractor.”

Tranel agrees.

“It was a very positive experience,” he says, adding that this project, like many others, provided a learning opportunity and lessons that will be valuable on future jobs. “You always learn about how products go together and it’s enlightening to experience the differences in how a material appears from a 12 x 12 standpoint to a mock up to the actual site,” he says. “And that’s also an experience that you accumulate and take with you to the next project.”

Ellen Rogers is the editor of the Architects’ Guide to Glass & Metal magazine.

Architects' Guide to Glass & Metal
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