Architecturally expressed structural-steel beams erected in a part of Washington, D.C., where concrete buildings are common, more than make their mark on the city’s bustling L’Enfant Plaza. Built above the plaza’s retail level and an active three-story parking garage, a nonprofit museum seeks to explore the craft, practice, history and contemporary role of espionage. The 140,000-sq-ft, eight-story museum is also designed with large, column-free exhibit spaces.

The building’s most prominent feature is a pleated glass “veil” suspended in front of an enclosed black box exhibit space. The design allows visitors moving through the museum to be visible from both inside and outside the building. One judge called the museum and its curtain wall system a “dramatic public expression.” Another judge said, “This was just a really cool feat of construction…. They had great teamwork all around to make sure that everything was going to fit together correctly with some pretty tight tolerances.”

A series of unusual Y-shaped, 10-in.-dia metal tubes extend horizontally from the building to support the veil. The three-story veil’s panels are held together with structural silicone, eliminating the need for vertical framing. A steel staircase connecting the exhibit floors enclosed in the veil is suspended along the outside of the metal-paneled west facade. The design team built flexibility into the veil’s design, but the stair connections still had limited tolerances. A 1-in.-dia tension rod for the stairs passes through one Y-tube at three separate locations with only 1.5 in. of space between them.

The project was completed on time and under budget. The team says that reaching substantial completion in only 27 months categorized the project as “fast-tracked compared to standard museum construction.”

Approximately six weeks was saved from the schedule and $500,000 from the budget by using hollow-bar micropiles instead of traditional micropiles. Ten micropiles were driven into existing footings at the lowest level of the existing garage. Existing concrete columns below the plaza couldn’t support the new museum. But heavy equipment for driving piles couldn’t fit in the existing space, which had less than 6 ft of clearance height. Crews demolished the slab on grade to create an additional 2 ft of room for driving the hollow-bar micropiles.

Building above the existing parking garage also meant that heavy equipment and material had to be distributed over the existing columns. Two tower cranes on the plaza level had counterweight systems with custom bases to avoid uplift.

One judge called the binary coded message hidden in the corrugated metal panels on the building’s east facade “really neat.” The judge also said, “I’m trying to think of when to schedule a time” to go and take a look at it.

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