Dulles International Airport Terminal
Chantilly, Virginia. USA
Eero Saarinen & Associates, architects
Location
History
The Dulles International Airport in Chantilly, Virginia, is considered as one of Eero Saarinen's most expressive edifices. Built in the 1960's, the Dulles Airport is unique in that it was planned for the jet airplane from the start. Extensive research d
etermined its compact layout and circulation. One interesting innovation is the mobile lounge, one that brings the passenger to the plane rather than vice versa; an attempt to cut down on the extensive cost of taxiing the planes. The concept of the mobi
le lounge made it possible for the terminal to be a single, compact building. Saarinen decided that the terminal should have a monumental scale (not to mention form) in the landscape and in the vastness of the airfield.
Physical Description
The massive steel reinforced concrete roof is supported by a row of columns forty feet apart on each side of the concourse, sixty-five feet high on the approach side and forty feet high on the field side, giving it its distinct catenary shape. It is made
of light suspension bridge cables between which concrete roof panels fit. The concrete piers slope outward to counteract the pull of the cables. "Saarinen exaggerated this outward slope as well as the compressive flange at the rear of the columns, in o
rder to give the colonnade a dynamic and soaring look." (1) Steel mullions coupled with quarter inch plate glass form a curtain wall, neoprene gaskets provide an airtight seal. Stainless steel glashing gives an elegant touch to its perimeter. The end w
alls require stronger mullions than the short, curved segments of the side walls. Trussed members were used to minimize weight and visual bulk.
Some special features of the building design include the marked difference between structural fact and structural expression. What appears to be the long edges of the roof are parts of the supporting structure from which the roof is hung. Contrary to it
s appearance, the roof and its supports are entirely separate elements. Saarinen expresses the roof form as an element that is hung from hook-like piers, although the break between the roof and supports is not in fact where it is expressed. Here, Saarin
en definitely breaks the conventions of 'form follows function', although in an elegant way. Due to the catenary shape of the roof, a roof drain shaped like an ocarina was incorporated in the center. Altogether the building lends itself to an aesthetica
lly pleasing "swooshing" form characteristic of flight and lightness, an expressive form very appropriate for an airport terminal.
Building Process
We began examining the building from the ground up, taking into account the process in which the loads both dead and live travel to the earth. Upon our investigation we found that the massive columns support the structure on the surface, while hidden fro
m our eyes, underground were also massive footings that transfer loads to the earth. Hence, our building process began at the ground. Our choice of materials were white foam core laminated between two skins of white museum board to represent the reinfor
ced concrete. At the basement we placed four footings that sprout up into four columns. By taking a bay of the entire structure, we were able to fucus our attention on the details. We noticed that the roof is not one continuous structure, but it is act
ually hung from the closest part of the columns. We decided to exaggerate that effect (unlike Saarinen), we actually hung our roof. We also decided to show a cut away section of the roof, because the actual construction is of tension cables with inlaid
concrete panels. The mullions were left out because they were non-structural, as was the glass. We also noticed that the columns flange out on the surface to give the effect of lateral support, but this does not follow through in the footing. This lead
us to believe that the lateral support must be taken up in the rigidity of the roof.
Structural Descripton/Aspects
The suspended roof structure is made up of lightweight suspension bridge cables in between which are placed concrete roof tiles. The cables are suspended on each end by massive reinforced concrete piers. These piers slant outward to resist the tension i
n the cable, thus giving the roof it's catenary shape. A distributed load that finds itself atop this structure is transferred horizontally to the piers. The shallow roof curve means that the horizontal force is greater than the vertical force at the pi
er connections. Therefore, the piers lean out to counteract this horizontal force. The vertical component is then transferred down the pier, staying within the middle third of the section. The pier gets progressively wider at the base to incorporate th
is line of action, as well as to resist the greatest moment force on the structure. These piers can be seen as cantilevers jutting out vertically into space, their profiles decrease the further out they span. At the ground, the load is then dispersed ou
t into the soil via massive foundations. These splay outward similar to the roots of trees to resist the moment force implied by the load at this base point. Curiously, the foundations do not take on the same profile as the splaying columns, this might
indicate the lateral load implied by the columns is taken up possibly in the roof. The long axis of the piers are in line with the horizontal force, this orientation maximizes the pier's resistance to any bending force that micht be acting on it. This s
ystem of cantilevers and catenaries leaves the inside space free of columns or any other forms of barriers. A space that can change with the expansion of the airport. Our hypotheses about how the rinforced concrete piers function are, as well as being a
esthetic, adds weight and helps to maintain the force vector within the middle third of the pier.
The low profile of the Dulles airport helps to resist any lateral loading as well as the leaning piers that support the roof. A lateral wind force acting on the structure will be directed downward through the piers since the windows are at the same angle
as the supports. The wind load will be broken up into a horizontal component that is counteracted by the force of the leaning piers, and the remaining vertical component will be directed to the ground. A lateral load acting perpendicular to the strong
axis of the columns will be resisted in part by their large foundations, but also by the concrete panels of the roof. This is apparent by the pseudo splaying of the columns. The panels together form a massive horizontal plane that resists any lateral fo
rce.
Conclusions
Our analysis of the Dulles International Airport shows that Saarinen chose not to show the true nature of the structure, but he rather fooled the eye by imitating the hanging roof. We learned that the supports for the roof did not actually take up the la
teral load, but the roof was the answer to the lateral loads. All in all, this structure is efficient in that it allows for the maximum space within the structure.
Bibliography
- Architectural Record. v 134, pt 1, July 1963. pp 101-110.
- Global Architecture, "The Series of Global Architecture No. 26". ADA EDITA Tokyo Co., Ltd., 1973. pp 9-23.
- Progressive Architecture. v 44, pt 2, August 1963. pp 90-106.
Associated Buildings
Dean Masukawa and Jill Enomoto
ARCH 461/561 Spring 1995
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