Extech Fabricates a Custom-Engineered Glass Canopy for Port Authority’s Transit Station

Glass Magazine
October 7, 2019
COMMERCIAL, FABRICATION
Photos by Dave Bryce Photography.

The new transit station at 5th Avenue and Atwood Street in Pittsburgh's Oakland neighborhood features a glass canopy and custom aluminum framing system engineered and fabricated by Extech/Exterior Technologies Inc. The station's canopy shelters commuters from rain and snow, while allowing in natural light and views.

Atwood station is the highest use station outside of downtown Pittsburgh. The station connects to more than a dozen different routes operated by the Port Authority of Allegheny County. The Port Authority's 2,600 employees operate, maintain and support a fleet of more than 700 buses, 80 light rail vehicles and one inclined plane. These vehicles provided more than 62 million rides in 2018, an average of 220,000 rides on weekdays, and 50,000 rides on Saturdays and Sundays.

Located in Pittsburgh, Extech provided the transit station's team with a local resource drawing from national expertise. Extech worked closely with architect Greg Maynes from concept to completion. The 1,473-square-foot, low-rise, segmented, glass canopy features three taller sections overlapping three shorter sections. "These two types of canopies could be scaled to form different station sizes,” says Maynes. “The station's asymmetrical columns resemble a tree structure supporting the cantilevered glass canopies."

The canopy's modular, angled design also conveniently avoided utility lines and more effectively shed water into the gutter system, according to Maynes. Extech engineered the custom gutter and downspout as integral to the canopy system's extruded aluminum framing.

"The custom gutter extrusion combined glass support, an indirect LED light shelf, electrical wire management and drainage within a single element, which reduced the overall canopy profile and cost. Its unique cross section was developed to accommodate the wide variety of mounting angles dictated by the elegant undulating design of the canopy," says Kevin Smith, Extech's director, product application and design.

"The canopy system was complicated," says Maynes. "We needed to know it would be properly engineered. That's the reason we did the work with Extech. We were able to go back and forth throughout the project's design. They engineered the entire system and proposed a slicker solution that required less maintenance." The gutter design enhancement also made the canopy system more economical to install and more effective at managing precipitation, according to the company.

The canopy underwent rigorous testing to ensure it withstands constant exposure to both Pittsburgh's high volume of bus riders and its seasonal changes including spring rain, summer heat, autumn winds and winter snow, ice and road salt.

To verify the intended performance and appearance, Extech provided a mock-up for the architect's and owner's review. Once approved, Extech fully fabricated the canopy in its facility then shipped the components to the jobsite for a quick installation.

"Mock-ups are an important step in the design of custom projects, and especially in the case where lighting is involved," says Jim Leslie, Extech's general manager. "For this project, the mock-up process allowed us to verify that the unique geometry of the spider fittings and curved gutters worked as planned, and allowed the architect to confirm that the lighting would meet their design intent."

Each section of the canopy spans approximately 20 feet wide by 12 feet long and comprises 9/16-inch-thick, clear, laminated Viracon glass. "There is an 80 percent frit pattern on the underside of the glass to let the light through without the unwanted solar heat," Maynes notes. "It seems like it rains 365 days per year here, so it's dark a lot. We wanted to make it feel as bright as possible during the daytime."

Adding more brightness to the station, LEDs were incorporated along the glass edge. "The glass essentially glows at night," says Maynes.

Supporting the glass, the custom aluminum framing was finished in a Class I clear anodize. The asymmetrical steel support columns were finished in white. The neutral color palette was intentional. Maynes says, "The station's design is architecturally unique, but not in conflict with any of the other types of architecture surrounding it. It's meant to be light on the landscape and should not interfere with the visual nature of the neighboring buildings."