Features: What We Build — September/October 2006

Through the Looking Glass

Project team builds new museum pavilion almost entirely of glass

By Sheila Bacon

Gallery 3 of the Glass Pavilion features works of art from the exhibition, "The Art of Glass: Masterworks from the Toledo Museum of Art." Featured in the gallery is a newly acquired 19th-century medallion with a portrait of Louis XIV, one of only eight known in the world. Credit: photo courtesy of sheroian associates inc.

People who live in glass houses shouldn't throw stones, and apparently, they have to be pretty careful where they put their heating systems, too.

oordinating ductwork inside walls and creating an unobtrusive structural system can be difficult in any building. In a structure made almost entirely of glass-both inside and out-the task seemed downright impossible. But the project team that designed and built the Toledo Museum of Art's new $30-million Glass Pavilion made it work. The 76,000-sq-ft pavilion houses the Ohio museum's extensive glass art collection. It opened to the public in August.

The structure's nearly complete transparency, which includes
473 glass panels that form the pavilion's exterior skin and most of its interior walls, led to a number of issues, from structural support and fire-sprinkler placement to heat gain and panel installation.

The one-story, 15-ft-tall Glass Pavilion joins the neo-classical main building, the art-deco professional building and the Frank Gehry-designed Center for Visual Arts as the latest addition to the museum.
Founded in 1901, the museum is a privately endowed, privately funded institution that opens its collection to the public free of charge. The pavilion is located directly across the campus' central thoroughfare from the main museum building.

Hot Shop 1 features seating for classes and demonstrations, along with four overhead monitors to capture the intricate details of the glassblowing process. Credit: photo courtesy of sheroian associates inc.

Toledo has long been known for its glass production. In fact, the museum was founded in 1901 by one of Toledo's primary glass makers, Edward Drummond Libbey, president of the city's Libbey Glass Co.

The architects' "elegant and refined designs, emphasizing glass as a structural building element, and their respect for natural settings" led to the museum board's unanimous selection of Tokyo-based Sejima and Nishizawa and Associates (SANAA) Ltd. as the pavilion's designers, says Don Bacigalupi, museum director.
The decision was not taken lightly. Board members, staff and community experts considered the work of 17 major firms, Bacigalupi says. The pavilion is the Japanese firm's first design in the U.S., although SANAA has since been selected to design the New Museum of Contemporary Art in New York City.

The general contractor was Rudolph/ Libbe Inc. of Walbridge, Ohio, a member of both the AGC Greater Detroit Chapter and AGC of Ohio.

Transparent Design

The northeast corner of the Glass Pavilion features the GlasSalon, a multipurpose space that can be rented for weddings, gatherings and other special events. Credit: photo courtesy of sheroian associates inc.

"The design is about carrying along the museum's tradition of being open and transparent to the public," says lead architect Kazuyo Sejima, who partnered on the design with Ryue Nishizawa.

"The inner workings of the museum are open to the outside so the people can have a connection to it. Glass allows this sort of transparency. But it also reflects the outside. This allows the building to nestle in among the grove of old-growth trees because the glass reflects this greenery and the surrounding site."

The Glass Pavilion hosts the museum's collection of glass from around the world, including the famed Libbey Punch Bowl, made for the 1904 St. Louis World's Fair, and a dress of glass fibers exhibited in the 1893 Chicago World's Fair. The pavilion includes exhibition spaces, classrooms, multipurpose rooms and two "hot shops," where visitors can watch glassblowers.

Unconventional Construction

Below-grade is one of the few places concrete is used in the Glass Pavilion's construction. The conventional foundation features an 18-in.-thick concrete slab-on-grade with concrete basement walls and columns and a poured-in-place concrete deck atop the basement walls. Credit: photo courtesy of sheroian associates inc.

Below-grade construction of the Glass Pavilion was conventional: an 18-in.-thick poured-concrete foundation mat and walls with a poured-in-place deck at grade level. But unique methods took center stage once the structure rose above ground level.

The building's exterior skin is made of glass panels, most of them 8 ft wide and 131/2 ft high. The glass was made by the Pilkington Glass Co. in Toledo, then fabricated in China. There, the panels were placed into custom metal frames and heated in an oven until they relaxed into the proper curve.

Two panels were then laminated together for strength. The exterior has 122 1-in.-thick panels, 30 of which are curved. Inside are 91 flat panels and 129 curved panels. Each interior panel is 3/4-in. thick and weighs between 1,300 and 1,500 lb.

Once the fabricated panels arrived at the jobsite, they were installed by subcontractor Toledo Mirror and Glass. The glass panels are set into embedded floor and ceiling tracks, so they look like they disappear into the floor and ceiling with no frame, Sejima says. The small horizontal gaps between the glass panels are filled with clear silicone sealant. Crews laid the track where the panels would fit before the glass arrived on site, requiring precise measurements and considerable coordination with the field drawings to ensure the glass panels would fit.

The panels ride on specially designed "rocking devices," or dampers, allowing them to move only up and down when the floor or roof deflects under live loads. This mechanism eliminates horizontal shifts that might cause the panels to buckle against each other.

The glass panels were staged on site, then lifted and moved using a small crane with an articulating head that supports a frame of suction cups. The panels were set into the lower track, then leaned into the upper track and fastened, says Lowell Metzger, a project manager with Rudolph/Libbe.

Curved glass panels form both the pavilion's interior and exterior walls. The glass was manufactured in Toledo, then fabricated in China, where the panels were fitted into a frame and heated in an oven until they reached the correct curvature. Credit: photo courtesy of sheroian associates inc.

The Glass Pavilion is Rudolph/Libbe's 20th project with the Toledo Museum of Art. The contractor also built the museum's Center for Visual Arts and the Georgia and David K. Welles Sculpture Garden, as well as interior and exterior renovations.

Creating structural support and running ductwork in an all-glass building can be difficult, especially if the design requires near-uniform transparency. The roof steel is supported by 35 small-diameter round steel columns-nine of them hollow and 26 solid-located in discreet positions and buried inside the structure's few nonglass interior walls.

Nearly all of the pavilion's HVAC system was installed beneath the ground floor. Supply air is fed upward into the rooms through grills located in the floor and opaque walls.

Most of the return air is routed through a ceiling plenum system, allowing the designers to minimize the amount of ductwork in the ceiling. The sprinkler system was integrated into the roof through steel penetrations.

Dale Chihuly (American, born 1941), Campiello Remer Chandelier, 1996, glass, free- blown and cut, steel. Credit: photo courtesy of sheroian associates inc.

"Because you can't route pipe through glass walls, water pipes route through the walls of the drywall-construction opaque spaces and then fan out through the ceiling to feed the sprinkler system," says Terry Beamsley, assistant museum director.

To further minimize the bulk of the pavilion's heating and cooling system, the physical plant was located away from the building. "A remote location on adjacent property was chosen for the emergency generator, cooling towers and pumps so equipment would operate remotely from the glass pavilion," Metzger says.

Special sunlight-reflecting curtains were installed in the spaces surrounding many of the galleries, and the location of the curtains can be adjusted seasonally. "The material of the curtains is semi-transparent so outside views are preserved," Sejima says.

Those views are a key to this "looking-glass house," built around a series of open courtyards so visitors feel "like they are walking under the trees" while they experience the art inside.

The pavilion opened in late August after a week of inaugural events that included a black-tie gala and an open house.