More surprises

In the summer and fall of 2002, when archaeologists discovered even more ruins on the 5.68-acre site, the design team was forced to move and rotate the foundation structural grid. Although design was still in the schematic phase, the process of resolving the conflicts between the excavations and the new building was “traumatic,” requiring negotiation of each column location, says Joel Rutten, Tschumi Architects’ project director.

When NAM opens next spring, after a 10-month-long installation period, visitors will enter by way of a bridge that crosses over an area of excavations at the northwest portion of the site. Then, in an ascent that mimics the climb up the Acropolis, they will travel from the lobby, through exhibition spaces organized in a chronological sequence around a skylit atrium, to the top of the four-story building. There, surviving Parthenon frieze elements, of which Greece currently possesses about half, will be displayed, surrounded by a glass-enclosed court. The dimensions and orientation of the space will replicate the 2,500-year-old temple’s cella.

This top-floor Parthenon Gallery, supported by a steel post-and-beam cantilevered structure, sits on top of a three-story reinforced-concrete base. The lower floors, trapezoidal in plan to maximize the constricted site, rest on a field of 43 pilotis and seem to hover over the excavations.

Sandwiched between the pilotis and the lobby level is a system of seismic isolators. Because they minimize the transfer of ground motion to the structure above in the event of a temblor, the isolators allowed designers to create a more transparent and open museum than they otherwise could have in earthquake-prone Athens. “We did not have to encumber the building with many large walls,” says Leo Argiris, a principal in the New York City office of Arup. His firm, with Athens-based ADK, was the project’s mechanical and structural consultant.

Climate and clarity

Transparency, especially that of the 19-foot-tall glass-enclosed Parthenon Gallery, is one of the building’s defining qualities. Here, visitors will be able to view the marbles in daylight and also see, about 1,000 feet away, the ancient temple where they were originally installed. Obviously, creating a glass box in a climate where temperatures can reach 120 degrees was not an easy task.

To mitigate heat gain in the brutal climate, the design team created a ventilated facade for the Parthenon Gallery. The double skin, hung from the steel roof structure, has an outer layer of double-glazed low-iron glass with a glare-cutting frit. The density of the pattern decreases from 100 percent near the ceiling to zero at eye level, so that views of the Parthenon and Athens are not obstructed. The inner layer, which is suspended about 8 feet above the floor, is made of single-glazed laminated low-iron glass. Separating the two layers are 26-inch-wide vertical glass fins with roller blinds installed between each to further control glare.

The gap between the glazed surfaces is part of a displacement ventilation system. Cool air supplied at the floor is drawn through the cavity and evacuated at the top. A chilled slab also helps maintain comfortable gallery temperatures. The arrangement keeps the facade and ceiling free of distracting mechanical apparatus, explains Raymond Quinn, Arup principal. “Nothing detracts from the view toward the marbles or the Parthenon.”