The Atrium

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The Atrium: Concrete Coffers

In November 1970, with ground breaking only months away, Pei and his team turned their attention to the vexing question of the roof for the central atrium. To help the designers envision the appearance of the interior space, Pei called on artist/architect Paul Stevenson Oles to make perspective drawings that also depicted the textures of the building materials and the effects of light in the space.

The first idea for the atrium called for a coffered concrete ceiling (the underside of a high upper floor) over the enormous expanse. In drawings Oles made to test this concept, the ceiling seems to overpower the interior, creating what the architects feared would be a "barnlike" atmosphere. This discovery led to a major rethinking of the atrium design.

		In the study at left, a high upper floor covers much of the atrium.
		Paul Stevenson Oles. Perspective study for garden court, National Gallery of Art East Building, 6 November 1970. Graphite on paper

The drawing at right shows that after nearly a month of study the upper level has been cut back to cover less of the atrium and an aerial walkway has been introduced to provide circulation at the museum's upper floor.
Paul Stevenson Oles. Perspective study for garden court, National Gallery of Art East Building, 1 December 1970. Graphite on paper

The Atrium: Skylights

By January of 1971, Pei had agreed that instead of a concrete ceiling a skylight system should be designed, which would open the atrium to natural light. The tops of the towers at the three corners of the triangular atrium would be visible through the glass to help orient visitors.

Here the effect of the high skylight system in the atrium can be seen, dwarfing trees, visitors, and potentially works of art. Paul Stevenson Oles. Perspective study for skylight system, National Gallery of Art East Building, 25 January 1971. Graphite on paper

This drawing was prepared within a week of the one above. It introduces a concrete bridge, seen in the upper foreground, to help bring human scale to the enormous space. The architects still were dissatisfied with the result. Paul Stevenson Oles. Perspective study for skylight system with bridge, National Gallery of Art East Building, 1 February 1971. Graphite on paper

The concept of an open interior court was an important breakthrough, yet Oles' drawings again revealed problems in the design. The drawings showed that the high skylights with their small panes of glass would be out of proportion to the grand atrium space. The architects also feared that the many small metal pieces of the skylight frame would read as a heavy cobweb, distracting attention from the essential geometry of the space.

The Atrium: Space Frame

In the end, the architects turned to the building's triangular geometry for their solution: a sculptural structure composed of steel-framed modules. The base of each module forms an isosceles triangle, the sides of which have the same 2:3 ratio found in the building.

This was the first workable plan for the space-frame system, the steel and glass structure spanning the atrium. The space frame is composed of larger three-dimensional modules resting at a lower level than the skylights. Paul Stevenson Oles. Perspective study for space frame, National Gallery of Art East Building, 1 March 1971. Graphite on paper

In the final design for the space frame, tubular aluminum bars were placed against the glass panels to reduce glare in the atrium without diminishing the play of light in the space. The atrium as built appears remarkably similar to this rendering, completed in June 1971. Paul Stevenson Oles. Perspective study for space frame with light diffusion bars, National Gallery of Art East Building, June 1971. Graphite on paper

The Atrium: Technology

The study to the left shows a design for one of the nodes that supports the space frame and locks the beams into place. As built, each of the space-frame tetrahedrons measures 30 feet by 45 feet. The proportions of the entire span of the atrium are in the same 2:3 ratio: 225 feet on two sides by 150 feet on the other. I. M. Pei & Partners, National Gallery of Art East Building Design Team. Study for space-frame node, 15 March 1971. Pen on tracing paper

When the architects conceived the atrium space frame spanning 16,000 square feet, no similar structure had been successfully built on such a scale. The framework consists of enormous five-ton nodes of cast steel welded in place to beams of rolled steel at very high temperature. Craftsmen contributed enormously to the project's success, ultimately earning twenty-three awards for their work. Unfinished space frame from above, 25 July 1977. Photograph by Stewart Brothers

		East Building of the National Gallery of Art shortly after it opened in June 1978. The space-frame structure is visible above the main entrance.
		Photograph by Dennis Brack/Black Star

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