Expanding an iconic structure

Washington Dulles International Airport was the first airport in the United States designed for commercial jet aircraft. Eero Saarinen’s terminal building, with its iconic swooping roofline, is considered to be one of the designer’s finest works. Decades later, SOM led an expansion project that more than doubled the narrow structure’s length, with a design that respects the 1962 building and helps integrate previous additions.

In the new spaces, SOM replicated the distinctive catenary structure as well as the concrete finishes, windows, and terrazzo floors. Below grade, the expansion carved out space for new, automated baggage-handling facilities.

Construction proceeded in phases to allow the facility to remain open during the project. When completed in 1997, the expansion nearly tripled the airport’s passenger handling capacity to 40 million a year. Within two years of the project’s completion, passenger totals increased by 65 percent.

Active at Dulles since 1985, SOM has designed a master plan that includes six midfield concourses, a new international arrivals hall, and main terminal station for a new transportation network.

Creating faster connections

Saarinen’s original fleet of “mobile lounges,” an innovative solution for transporting passengers from the compact terminal to remotely parked planes, had become inefficient after years of changing security needs and rising passenger counts. SOM conceived an AeroTrain system that, since opening in 2010, has provided rail and pedestrian links between the main terminal and midfield concourses.

To preserve sightlines and keep Saarinen’s landmark building intact, the Main Terminal station is located entirely underground. A faceted roof structure supported by 105-foot-long concrete beams contains skylights and luminous panels, bathing the subterranean space in daylight. The floor is envisioned as a single-folded plan floating between concrete walls, with a terrazzo surface similar to the flooring in Saarinen’s terminal above.