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NMAAHC: A Deeper Look

In my interview with Hal Davis, FAIA, senior vice president at SmithGroupJJR, Washington, D.C., one of the four architecture firms involved in the Smithsonian's National Museum of African American History and Culture (NMAAHC), featured in this month's Building Profile, he shared so much more information than I could fit into my article. So, I went back over some of the points he mentioned, and thought I'd share some additional insights into the 19th museum on the National Mall.

NMAAHC, blog

The Porch

On the south side of the museum from Madison Drive is an entry porch that is a defining element of the design, and oneDavis says is clearly derived from African American homes. "The porch was the welcoming area to homes and the place where families gathered," he said. "The porch at the museum is a representative gesture of that welcoming."

The porch is supported by two columns at each end of a 200-foot span and cantilevers out over the water feature below. The water feature itself is evocative of African Americans crossing the water to arrive in America, Davis adds.

Lenses and Views

Throughout the corona, Davis says there are certain openings or lenses that allow visitors to view various points of significance on the Mall and to provide moments of context. "Lenses on the north face the Ellipse and the White House," Davis said. "On the east, the lens views are to the Capitol and the National Archives. On the south, they are to the Jefferson Memorial and Tidal Basin."

"On the west," Davis continued, "there are two major openings, one slightly angled vertical opening focused on the Washington Monument. This particular lens you can walk out into as it cantilevers into the west atrium inside the museum and brings the visitor very close to the exterior glass. The other west-facing opening is the long horizontal window at the top that allows the visitor a wide expansive view of the Washington Monument grounds down to the Lincoln Memorial."

NMAAHC, blogGalleries

The museum features a variety of galleries for visitors to explore. The History Gallery is part of the 65 percent of the museum that resides below grade. It is a three-level space to which visitors arrive by a large elevator. "This space moves the visitor from fairly tight and confined entry spaces to an expansive 65-foot-high exhibit hall, which I believe symbolizes the incredibly confining space on slave ships to the hoped for freedom to come," Davis explained. "Each level in this portion of the History Gallery rises above and is accessed by a series of ramps that exits into the north atrium."

As you exit from the History Gallery, on the right is the contemplative court, which allows visitors a moment of reflection and decompression. The upper galleries are the celebration galleries expressing the many accomplishment, talents and contributions made by African Americans to this county and the world, said Davis.

The Museum Roof

When designing the museum's roof, Davis said the roof had to be designed to eliminate any visible equipment or other materials that might provide the appearance of a typical building rooftop. This is because the building rooftop is uniquely visible from the top of theWashington Monument, making it the "fifth façade."

NMAAHC, blogExcavation Challenges

As with all projects, there are always challenges to be figured out. For the NMAAHC, the challenges came as early as during excavation, since as Davis explained, much of D.C., and this area in particular, was once part of Tiber Creek. The site is comprised of deep earthen fill and a high water table that is within 10 to 12 feet of the surface.

"The original design was based upon constructing a support of excavation wall (SOE) around the full perimeter of the site, 6 to 8 feet outside the actual foundation walls of the building," he explained. "It was to extend down to disintegrated rock and provide a cut-off of the surrounding groundwater. The area below the building would then have a network of drain tile to capture whatever water seepage came into the site and convey that to sump pumps. That removed the issue of the water table surrounding the foundation walls and bottom slab from creating hydrostatic pressure on the building below grade. However as the SOE was being installed, large boulders and other deleterious materials interrupted the integrity of the SOE, creating breaches in the SOE and allowing water to flow at a high rate into the site excavation. That required the entire foundation system to be redesigned to add more piles to hold down the slab and the change to a complete waterproofing of the foundation and walls."

To read more about the Smithsonian's National Museum of African American History, click here.


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