Extraordinary Library

by Jonathan McGaha | June 2, 2014 12:00 am

A geometric façade and aluminum shade canopy link literature and architecture

The new Francis Gregory Library is built at the edge of Washington, D.C.’s Fort Davis Park where a Civil War-era fort once stood to defend the nation’s capital. The LEED Gold, 22,500-square-foot library strives for a high level of design excellence, while all the time challenging traditional library typology. Porous and open, it seats more than 200 users and allows easy access to available materials and technology. Lighting accommodates multiple functions and carefully illuminates readers and computer users.

The two-story library echoes the natural environment. Set on a terrace, the glassy pavilion’s reflective geometric façade is a network of quadrilateral openings that frames outside views of the nearby greenery. Designed as a thick structure oriented toward the street, this curtainwall, from Wilson, N.C.-based McMullen Inc. and Woburn, Mass.- based Tower Glass Co. Inc., allows visitors to sit within the apertures.

London-based Adjaye Associates worked in collaboration with Washington, D.C.-based Wiencek + Associates to design and conceive the library as an extension to an adjacent, leafy park. Its materials and lighting, along with the large canopy overhanging the entrance, welcome the public inside, providing a smooth transition from the street. “The library’s steel columns and X-bracing are incorporated into the walls with doors strategically located to miss the bracing,” says Hal Zaslow, AIA, LEED AP BD+C, studio director at Wiencek + Associates. “The X-bracing is at the first floor conference room. There are no load-bearing walls.”

Cantilevered canopy

A massive, aluminum canopy cantilevers over the library’s main glass structure, creating the image of an outdoor pavilion while still providing shade and protection from rain, snow and ice. The canopy was designed with structural aluminum framing in a diamond pattern to support the sunshade grilles and to add a signature to the overall building exterior. The canopy structure’s design utilizes a non-corrosive, all-aluminum strut and gusseted plate design concept. Initially, a welded steel structure was proposed but was ultimately rejected because it could corrode, be too costly and not meet the project’s aggressive schedule requirements. Also, “Steel is too heavy to cantilever out as far as the design defined,” says Zaslow.

Grace Ferretti is the global business development manager within the architectural division of Conroe, Texas-based CST Covers, a division of CST Industries Inc., the company that designed, engineered and fabricated the canopy. “We got involved with the project during the early conceptual stage with the architects,” Ferretti says. “One of the goals of David Adjaye and his architectural team was they wanted the canopy to float over the roof. They wanted a 24-inch-deep beam to give it some girth, so you could read it from a distance. They didn’t want it to appear like toothpicks in the sky. CST designed a custom 12-inch-deep extrusion with a female/male joint mechanically affixed to another identical beam to create the right depth. The way it was extruded was to create a perfect hairline fracture between the two beams.”

A challenge with the canopy was that the library’s roof is completely flat. “Because of the deflection and the snow loads in the D.C. area, CST engineered the structure with a camber,” Ferretti says. “This means the canopy bows upward like a dome and once the dead loads are applied onto the structure, it actually sinks into a perfectly flat structure.”

Integrated sunshade grilles

Solar shading was achieved by utilizing diamondshaped extruded louver panels secured in the diamond pattern framing to allow for natural sunlight to penetrate through the roof skylights. KennettSquare, Pa.-based Metalwërks’ custom diamondshaped pattern grilles were designed for a unitized installation onto the roof structure suspended above the library creating a unique shadow pattern designs which shaded and were reflected in the glass curtainwall.

“The sunshade grilles were also diamondshaped in plan with custom-extruded, diamondshaped blades integrated into a solid frame,” says Steve Scharr, director of business development, at Metalwërks. “The grilles were closely coordinated with the aluminum canopy structure to fit in between the diagonal beams because almost every diamond-shaped cell in the canopy structure was geometrically different.”

Aluminum’s ability

Aluminum’s ability to be extruded was important to this project because the canopy’s diamond shapes are not all the same size. “This made a little bit of a fabrication nightmare for us because each piece is different,” Ferretti says.

Ferretti says the architects really liked working with aluminum because it is completely non-corrosive for the life of the structure. Also, “The fact that aluminum is one-third the weight of steel means it puts less load onto the library’s building columns,” she says. “The structure is literally floating on top of the roof.”

Aluminum’s excellent strength-to-weight ratios for good spanning capacity and reliable structural properties provided the library with clean, true and crisp lines. “Aluminum can be custom shaped to almost any profile by bending, forming, extruding and mechanical or welded assemblies,” says Scharr. “Long-life architectural coatings in a wide array of finish choices were applied post-fabrication to ensure a high-quality bond concealing all tool and die markings.”

Custom curtainwall

A continuous two-story-high custom glass curtainwall has a diamond motif with glass lites varying in width from 5 to 8 feet. “It’s an expansion and contraction that reflects the notion of growth, like the forest,” says Adjaye.

Just behind the limpid glass exterior surface stands an open web of diamond-shaped plywood modules. The modules are 1-foot, 3 inches deep and contain the actual structure of the curtainwall- an X-shaped steel diagrid next to the glass with vertical steel supports backing it up. The exterior glass that skims by the plywood modules alternate between low-E, double-insulated panes allowing views out and spandrel panels with a mirrored finish on the inner surface that reflects the leafy trees.

Where access to the library is needed, such as at the entrance on one end of the south façade, Adjaye has inserted portals of composite metal panels into the curtainwall. Architectural Metal Designs Inc., Millville, N.J., manufactured the metal panels, and CVT Construction, Arlington, Va., was the installer.

The curtainwall and canopy both helped the library attain its LEED Gold rating. The glass walls promote thermal heat gain during the winter, but the canopy cuts unwanted solar gain in the summer. Shading studies helped find the right dimensions of the canopy to best reduce cooling loads and soften natural daylighting. Energy conservation principles helped calculate the balance between vision glass and mirrored glass at insulated panels that form this concealed prefabricated modular system. In addition, the ground paving is pervious to prevent storm runoff.

While the architectural community has found real interest in the new library, perhaps some of the most positive feedback has come from the library staff and its patrons. Ginnie Cooper, the District of Columbia Public Library’s chief librarian says the community has been “warmly responsive” to its design and that many find it “jaw-dropping.”

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Francis Gregory Library, Washington, D.C.

Completed: July 2012

Total square feet: 22,500 square feet

Building owner: District of Columbia Public Library

Architect: Adjaye Associates, London, in collaboration with Wiencek + Associates, Washington, D.C.

General contractor: Hess Construction, Gaithersburg, Md.

Metal panel installer: CVT Construction, Arlington, Va.

Architectural aluminum sunshade supplier/fabricator/installer: Metalwërks, Kennett Square, Pa., www.metalwerksusa.com[1]

Canopy fabricator/designer: CST Covers, a division of CST Industries Inc., Conroe, Texas, www.cstcovers.com/architectural[2]

Glass curtainwall: McMullen Inc., Wilson, N.C., and Tower Glass Co. Inc., Woburn, Mass., www.towerglassco.com[3]

Metal wall panels: Architectural Metal Designs, Inc., Millville, N.J., www.amdnj.com[4]

 

Source URL: https://www.metalarchitecture.com/articles/extraordinary-library/

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