Custom aluminum screen adorns atrium inside NYU’s library

October 2012 - When gazing upward in the lobby of New York University’s Elmer Holmes Bobst Library, it takes a moment to adjust your vision, following the central staircase down 12 stories. The floors are open to the left, right and center of the atrium, revealing the library’s stacks articulated by balconies on each level.

During the summer, when the hustle of academia typically tapers off, the university had aluminum screen walls installed on the exposed balcony sections as a part of a multi-year renovation to areas of the Bobst Library. First and foremost, the aluminum screens are a functional safety consideration, designed to enclose the balconies and stairways. Within the last 10 years, three students took their lives by leaping over the railings—each in separate incidents, according to the New York Times. One occurred after NYU erected Plexiglas barriers in 2003.

Although the screens clearly are visible, they’re perforated with rectangular patterns, pixelating the perimeter of the atrium. This allows for an unobstructed view from behind the screen.

“The design itself is very sympathetic to the openness of the library,” says Mike McGrath, project manager at MG McGrath, Maplewood, Minn., the sheet metal fabricator for the screen. The screen is sound enough structurally so that it can’t be damaged should someone climb on it. “Its primary function is safety. All of the attachments were done using tamper-proof fasteners.”

Hidden pattern
The screen patterns come across as random rectangles raining down from the library’s ceiling (imagine a supersized game of Tetris). But the screen has five patterns that repeat through each elevation. The south elevation has the smallest “openness” percentage, while the north has the most. The east and west faces are mirror images of each other.

“It is almost impossible to pick up the pattern,” says McGrath. The company worked alongside SHoP Construction, New York, an engineering firm. SHoP provided paperless design blueprints and engineering review throughout the project.

Each panel, which MG McGrath waterjet cut with a direct-to-fabrication method from a CATIA model, is 1/4 inch thick and cut from 6061 T6 aluminum sheet. They are installed on a custom aluminum tube and mullion that is fastened to each floor below the carpet and fastened on a floating clip concealed in the plaster soffit. This allows the floors to move and deflect under live loads, says McGrath.

Overall, the Bobst renovation follows the original 1968 design by Philip Johnson, one of the library’s architects. The library opened in 1973. Joel Sanders Architect, New York, designed the screen. The aluminum fit best with the atrium’s prevailing aesthetic and was chosen over other designs, including glass and steel cable structures.

Additionally, aluminum’s light weight put the least structural stress on the atrium’s existing cantilevered balconies, consistent with NYU’s requirement that the design preclude modifications or reinforcement of the existing structure, says Philip Lentz, NYU’s director of public affairs.

Both the color (a 70 percent Kynar gold metallic paint) and the aluminum match those used by Johnson in the original library railings. Plus, the underlying design of the screens is based on 4-inch spacing, which aligns the screens with the original balusters of the balconies.

“The variety of pixel shapes in squares and rectangles are reminiscent of the square and rectangular array of light fixtures within the library and the main lighting feature at the top of the atrium,” Lentz says.

Erecting the screens was no small feat. The project had an extremely tight installation schedule to be installed between June 1 and Aug. 31. Installation took place at night while the library was closed.

“The intention for installing the sections was to create a simplified load path from a complicated surface,” says Russell Davies, associate principal and director of facade engineering at SHoP Construction.

But the biggest challenge was getting the material to the floors 135 feet in the air, McGrath says. “We had three hoists set up to move materials to the floors. Everything was staged in the center of the atrium space.” MM