CONSTRUCTION OF THE NAVIGATION SPANS OF THE RIO NITEROI BRIDGE, BRAZIL.

The paper describes the fabrication, assembly and erection of the large steel box girders forming the navigation spans of the Rio Niteroi Bridge. The centre span of 300 M is the largest girder span in the world. The twin box girder cross-section carries six lanes of traffic on a steel orthotropic deck topped with 60 mm of surfacing. The all-welded box girders were assembled at the site at ground level at an assembly area which had a water frontage enabling large girder sections to be floated to the navigation channels in the centre of Guanabara Bay. The largest sections thus transported were the side spans, each 292 M long and weighing 2250 t. The side spans were landed on temporary ring girders surrounding the pier bases. The jacking up of the side spans was the second heaviest bridge jacking operation in the world and was carried out twice. The 176 M section for the centre of the bridge, weighing 3400 t, was used initially as a pontoon for carrying the side spans; it was then lifted up from water level some 67 M by jacking up tension members hanging from the already erected steelwork. The smaller link spans, each 44 M long, were lifted from the water using conventional blocks and tackle. The paper discusses the shop and site welding of the 13100 t of steel in the spans, some 8000 t of which was grade 55e to BS 4360. The effects of the erection scheme on the design of the permanent works are also described, including the stress-relieving effects of the scheme on the welded steelwork. /TRRL/