The Hyperbolic Brick of Eladio Dieste
At floor level, the plan of the church is a simple rectangle, from which undulating walls rise to the maximum amplitude of their arcs. These thin but self-stabilizing walls carry continuous double-curvature vaults with tie-rods concealed in the almost-level troughs that are anchored in the brick edge-beams projected beyond the walls. These complex forms achieve a stunning simplicity as the walls and roof meet in a level plane.
Dieste wrote of his desire to unite the congregants with the officiants in a single space, which the nave of this church provides. The space also presents a spiritual itinerary for the rite of baptism, symbolizing acceptance into the family of the church: parallel to the main entrance, a projected, tunnel-like entry descends to the circular baptistery, from which another passage ascends to join the congregation in the unified space. The realm of the altar is demarcated through a slight change of level and careful use of light.
Light is a compelling force on the interior of the church. The accent at the altar and the suffused light throughout the nave emanate from obscured origins: shielded light sources at the choir above the entry; multiple small windows cut into the curves of the brick wall that orient toward the altar; and a small crown of skylights let into the vaults above the altar.
Revealing of the structure is the perimeter of light, which separates the structurally complete nave walls and roof from the freestanding entrance wall.
Forming Structural Brick
The highly dynamic form of the church imbues visitors with wonder in the way grand cathedrals do. Although approached as an engineer to assist with the construction of the church, Dieste used his skills to create a remarkable building. Through care, accuracy, and precision of construction, he elevated the process of building in simple brick — a material familiar to the poor agricultural workers who formed the congregation — to create an effect normally reserved for expensive stone and stucco.
Consider one detail: the connection between the wall and the roof of the nave. A Gaussian vault without glazing, the roof sits directly on top of the side walls. These two surfaces meet at the eaves, one undulating in a vertical plane and the other undulating in a horizontal plane. The wall and the roof work together, in effect forming a two-pinned portal frame.
The structural action can be read in the section of the building and approximates the shape of the bending moment diagram for the structure. The junction between the wall and the roof is a most lucid exposition of Dieste's desire to "resist through form."
The crest of the undulation on the inside of the wall coincides with the trough of the Gaussian vault. A hidden horizontal tie runs within the trough, tying the side walls to each other. The ends of the tie connect to an edge beam on top of the walls. The edge beam follows the curve of the wall but widens at the junction of the tie.
Fitting Curve to Curve
It would be wrong, however, to think this building's form is created solely through the representation of structural action. The juncture of the wall and roof not only deals with the complex collision of the two curved surfaces, but it also resolves the difficult interface between two different construction methods — one of traditionally laid brick and the other of shell construction using prefabricated formwork.
The accuracy of the two side walls, each 23 feet (7 meters) high by 105 feet (32 meters) in length, in relation to one another is critical for the insertion of the formwork. In order to fit the formwork, these walls have to be constructed to an accuracy of one- or two-tenths inch (2.5 to 5.1 millimeters) in both the horizontal and vertical dimensions.
This level of accuracy is successfully maintained in the building. Nothing is hidden: the surfaces of the wall and roof simply meet. There is no compensating interface such as a shadow gap or cornice, habitually incorporated in buildings as a practical compromise that concedes the attainment of perfection before attempting it.
This precision is not the predilection of a pedantic technologist obsessed with the minutiae of construction. The ultimate success of the church at Atlántida consists precisely in the achievement of the necessary accuracy in its making.
The underside of the vault presents a patterning of joints that is literally the three-dimensional manifestation of a wire-frame model. The pure expression of surface form, unencumbered by any framing or ribbing, creates a richness in the abstract quality of the constantly changing juxtaposition of surfaces.
The organization of the construction using simple, familiar materials and indigenous skill, elevated in application almost to the limits of perfection, has a spiritual quality that speaks directly to the ordinary working people of the congregation.
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Stanford Anderson is an architect and historian. Head of the Department of Architecture at the Massachusetts Institute of Technology, he recently received the AIA/ACSA Topaz Medallion for Excellence in Architectural Education.
This article is excerpted from Eladio Dieste: Innovation in Structural Art, copyright © 2004, available from Princeton Architectural Press and at Amazon.com.