Detailed design on all approach viaducts for three major river crossings, the Bonny River, Escravos River and Forcados River. The main spans of these crossings were a 1500m span suspension bridge, 700m cable-stayed bridge and 350m cable-stayed bridge.
Our work included the detailed design of the approach viaducts to the main spans, including the superstructure with 100m spans and the substructure with pier column height up to 55m and piled foundations through 20m depth marine clay soil. The decks consisted of precast segmental concrete box girders used.
There are 2 deck modules for the approach spans, 75m – 4x100m – 75m and 75m – 3x100m – 75m span arrangements. End span are erected using the false cantilever method.