Oscar Niemeyer's bridge in Brasilia

Designed by Oscar Niemeyer in 1967, the bridge officially named Costa e Silva Bridge (former president during the military regime) was planned to allow a fast communication between two neighborhoods which are in opposite sides of the lake of Brasilia, Lake Paranoa. In his project Niemeyer remarked that the bridge should touch the lake surface so that no foundation would be seen. This aesthetic decision confers its 440 meters and its 220 meters free span remarkable architectonical and structural lightness. Since the project until the conclusion, several hazards occurred, including the bridge work halt, being open only in 1976. This article presents, based on primary sources, the conception and design of Niemeyer's unique built bridge, among his three designs. In sequel is presented the construction accident; and the structural repair using in the central span a steel Gerber girder. A qualitative structural analysis is presented searching the reason of its lightness.