The Dulles International Airport Main Terminal is located in Loudoun and Fairfax counties in Dulles, Virginia, United States. The original structure, long and wide, was designed by Eero Saarinen and completed in 1962 as the first terminal at Dulles International Airport. Annexes to the west and east were completed in 1996 as part of a renovation designed by Skidmore, Owings & Merrill (SOM), bringing its total length to . The terminal is operated by the Metropolitan Washington Airports Authority, which operates Dulles Airport as a whole. The terminal's design is a suspended structure with roof panels of precast concrete suspended between cables which span the width of the building.
The Main Terminal's design includes parallel slanted colonnades on the terminal's north and south facades, interspersed with glass walls. The landside facade to the north is taller than the airside facade to the south; a concave roof supported by cables connects the two facades, descending toward the center. A concourse and control tower extend south toward the airport's apron. The interior was originally divided into two levels: an upper story for departing passengers and a lower story for arriving passengers. Saarinen's original design included mobile lounges that ferried passengers directly to planes, reducing the need for long walks or taxiing while increasing the airport's operational flexibility. The modern terminal includes four airline gates known as Z gates, where aircraft could unload passengers directly. In addition, two basements contain security screening facilities and an AeroTrain people-mover station.
The 1950 Washington Airport Act provided funding for Dulles Airport, land for which was acquired in January 1958. Saarinen was selected that May to design the terminal, construction of which began in early 1960. After several delays, the terminal was dedicated on November 17, 1962, along with the rest of the airport. Initially, Dulles Airport saw lower-than-expected usage, but increased patronage prompted the airport's original operator, the Federal Aviation Administration (FAA), to contemplate an expansion in the early 1970s. Hellmuth, Obata & Kassabaum (HOK) built two small annexes to the south in 1978, and further expansions and additional terminals were contemplated in the 1980s following increases in patronage. SOM designed annexes to the west and east, which began construction in October 1993 and were dedicated on September 6, 1996. Additional expansions took place in the 2000s, including the Z gates and the basements.
The structure was widely acclaimed when it was completed, particularly regarding its shape; Saarinen reportedly considered it his best work. The terminal has received numerous awards, including the American Institute of Architects' Twenty-five Year Award, and other terminal buildings have been compared with it. Though the Main Terminal was deemed eligible for inclusion on the National Register of Historic Places in March 1978, it has not been added .
Description The Main Terminal of Dulles International Airport is in Dulles, Virginia, United States, some from Washington, D.C. The airport, serving the Washington metropolitan area, straddles the border between Loudoun and Fairfax counties. The terminal is placed between Dulles Airport's original north–south runways. It is one of several terminal structures at Dulles Airport, along with several outlying "midfield concourses" and the International Arrivals Building, all of which were developed after the original terminal. The terminal was built to smaller dimensions than comparable terminals at other airports because it used mobile lounges, which transported passengers from the terminal to planes and, later, to the concourses.
The original terminal was designed in a mid-century modern style by Eero Saarinen and was his only work in Virginia. Saarinen worked with structural engineering firm Ammann & Whitney, mechanical engineering firm Burns & McDonnell, and airport consultant Charles Landrum. The Corbetta Construction Company was the main contractor, while Humphreys & Harding installed the finishes. Other figures involved in the building's construction included lighting consultant Richard Kelly and landscape designer Dan Kiley. The Main Terminal was intended to symbolize the Jet Age and, from the outset, was designed with future expansions in mind. Saarinen described his design as a "huge continuous hammock suspended between concrete trees", saying it represented a solution for what to put "between earth and sky". The western and eastern annexes were designed by David Childs, Michael McCarthy, and Marilyn Taylor of Skidmore, Owings and Merrill (SOM) in a similar style to the original building. Ammann & Whitney was also the engineer for SOM's expansion.
Exterior
The original terminal measured long and wide. Both ends were built with provisions for extensions measuring long, for a total length of . The base of the original terminal, including vehicular ramps, was intended to support such an expansion, which was intended to have the same cross-section as the original terminal. In particular, the vehicular ramps paralleled the terminal for its entire proposed length, and Saarinen added empty openings at the terminal's base to accommodate future entrances. When the annexes were eventually built in the 1990s, they were long, giving the terminal a total length of . Just west of the Main Terminal is the International Arrivals Terminal, which abuts the Main Terminal's base.
The vehicular drop-off and pick-up ramps are on the north, or landside, facade of the terminal; there were originally separate loading bays for taxis, private vehicles, and buses or limousines. The ramps loop around a parking area nicknamed the "bowl", while later parking garages were built away from the terminal to preserve views of the building. The ramps are reached by the Dulles Access Road, which leads east toward Washington, D.C. The Dulles Access Road, the airport's original main approach road, was intended as a major part of the terminal's design, providing passengers views of the building as it emerged from the landscape; it was landscaped by Kiley. Plans for a Washington Metro line to serve the terminal had been considered since the 1960s, though the Dulles International Airport station did not open until 2022. A 1996 expansion to the original terminal contained provisions for connections to a future Metro station.
Along the terminal's south or airside facade, a concourse extends southward. Initially, the southern facade had loading docks for 24 mobile lounges, with 12 on either side of the south concourse. There is a airport control tower above the south concourse. The tower itself is tall and is topped by a radome measuring in diameter; the tower was decommissioned in 2007 but remains in place. The Main Terminal also has four gates known as the Z gates, where aircraft can load and unload passengers directly; these are located along the southern facade, east of the south concourse. South of the terminal is the airport's apron.
Facade
The concave roof is supported by two parallel colonnades to the north and south, which divide each facade into bays measuring wide. In the original portion of the terminal, there are 16 columns in each colonnade. The northern colonnade's columns (facing the land side) are high, while the southern colonnade's columns (facing the air side) are high. The columns are all made of reinforced concrete, which is bush hammered; the rebar, or reinforcing steel, in the columns was manufactured by Bethlehem Steel. Each of the taller columns has of reinforcing steel, while each of the shorter columns is reinforced by of steel. The columns slant outward at an angle of either 10 or 15 degrees, counteracting the forces of suspension cables that carry the roof. At the top of each column are edge beams, which hold the roof's cables in place. When the terminal was extended west and east in the 1990s, the new columns were built to the same dimensions as the original terminals' columns.
The landside columns support a canopy that protrudes above the landside drop-off ramp. The curtain walls between the columns are made of glass, slanting outward at the same angle as the columns. Each glass pane is placed on rubber gaskets and fastened to the columns using rubber strips; these gaskets tended to fall off after they were installed. The Pittsburgh Plate Glass Company made of glass for the terminal, which were cut into 1,137 shapes. The window panes are embedded within aluminum frames, which are curved and tilt outward at their tops. The curtain walls in the annexes are similar in style to the original curtain walls, though they use modern gaskets that were less susceptible to falling.
Roof The roof is composed of precast concrete panels, suspended between cables that span the width of the building. Nitterhouse Concrete Products in Pennsylvania manufactured the slabs. There are 1,792 concrete slabs in the roof, which each weigh and measure thick, including a styrofoam layer on the underside of each panel. The slabs, which measure across, create a deck spanning . The cables, similar in design to the suspenders used on suspension bridges, are in diameter and are spaced apart. Concrete stiffening ribs encase each of the cables, preventing the cables from bouncing around; these ribs are deep. Because the columns are slanted outward, the ribs are about or wide.
To improve acoustics, the roof dips at the centerline of the terminal, reaching as low as or . The roof's centerline slopes down from both ends toward a drainpipe at the center of the building. The drainpipe is about wide and can drain from the roof every minute. Water from the drainpipe is funneled into a catch basin nearby. The roofs over the 1990s extensions are similar in design to the original roof.
Interior Originally, the terminal spanned . During a 1996 expansion, the size of the Main Terminal was more than doubled, increasing to about . The interiors were initially designed in a palette of green, blue, brown, and gray hues, to match the landscape. Originally, the Main Terminal's upper level was for departing passengers, while the lower level was for arriving passengers. The west and east wings have a combined and contain an additional basement level that is not present under the original terminal.
Structural and mechanical features The cable roof allowed Saarinen to construct the upper story without columns. The lower story sits on a concrete floor slab, and the upper story's floor slab is made of reinforced concrete. On the lower story, columns are placed at regular intervals, supporting concrete beams above; these beams are aligned with the colonnades on the facade. The lower-story columns flare outward at their bases purely for decorative purposes. The original interiors are divided into bays measuring , spanning the terminal's entire width and corresponding to the facade's bays. Each interior bay could be configured with its own ticket counter, baggage facility, concessions, and two loading bays for mobile lounges. Saarinen's original design allowed bays to be added on either end of the terminal as necessary.
Saarinen's master plan for Dulles Airport called for service buildings both east and west of the Main Terminal; these structures were designed with low roofs so they did not obstruct views from the Main Terminal. The original service building, to the east, included equipment for hot and chilled water production. When the terminal was completed, it was cooled by two large refrigeration units, which had a daily cooling capacity equivalent to of ice.
Facilities