Page D1.2 . 09 June 2004                     
ArchitectureWeek - Design Department
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Bridging Brasilia

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According to Chan, the idea was to create a landmark for the enjoyment of the community as much as to simply traverse a body of water. He used structural constraints as a means not of restraint but of expression. The JK Bridge is also becoming respected among professionals an example of collaboration between architecture and engineering.

Three large arches dominate the view, and each crosses over the roadway midspan to land on the opposite side of the roadway. Radial cable stays between the roadway and the underside of each arch form a sort of tunnel for travelers. The road itself is three lanes in each direction, with a sidewalk on each side.

The architect explains his structural approach: "To explore that pure image of 'less is more' and reduce foundations in bad soil, ... [we envisioned] not four pylons for each arch, but only two. So each arch will cross the road in diagonal jumps, adding still more emotion and tension to the structure-sculpture."

The bridge totals 4000 feet (1200 meters) in length, with each steel arch spanning 800 feet (240 meters). The 80-foot (24-meter-wide) roadway curves subtly, to a radius of 10,300 feet (3,150 meters). Below, there is a 60-foot (18-meter) clearance, allowing small craft to pass under. The arches reach a height of 200 feet (60 meters) above water level.

There are 16 stays for each arch, spaced every 65 feet (20 meters) along the deck and every 60 feet (18 meters) along the lower face of the arch. Their inclination gives a 15-foot (4.5 meter) clearance for vehicles. The stays are made of strands of galvanized steel, protected by a coat of wax and sheaths of high-density polyethylene (HDPE). The lower anchor point of each stay is fixed while the upper is tunable, making it possible to correct the tension.

New Symbol for the City

In addition to performing its intended job of transporting commuters, the bridge has become a visual icon for the community, electrically illuminated at night and reflecting sunlight during the day. Views of and from it have become popular with tourists and postcard producers, and it is one of the first built landmarks visible to those arriving by air.

In 1998, when the bridge design was selected by competition, the jury commented: "The discontinuous design of the arches brings, in a new way and with the use of bold technology, an almost poetic component in both scales of users, those who pass under them or those who look at them from a long distance."

In 2003 the bridge won the Gustave Lindenthal Medal at the International Bridge Conference.

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Project Credits

Architect: Alexandre Chan
Engineers: Mario Vila Verde, F. B. De Barros, and P. Slawinski
Contractors: Via Dragados and Usiminas Mecânica

AW

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President Juscelino Kubitscheck Bridge in Brasilia, by architect Alexandre Chan and structural engineer Mario Vila Verde.
Photo: Courtesy of Usiminas Mecanica

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The bridge represents a special collaboration between architect and engineer.
Photo: Rui Faquini

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The cables stretching between arches and roadway form a tunnel for travelers.
Photo: Rui Faquini

 

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