The bridge forms part of the future motorway between Luanda and Lobito and it crosses the Longa River, around 40km north of Porto Amboím in Angola.
The bridge is a bow-string steel arch which suspends the deck by steel cables. It has two access viaducts on both sides of the river. The main span of the bridge is 106m long and the currently adopted spans of the viaducts measure 35m, forming a totally continuous 547m long structure with only two expansion joints located at the abutments.
The circular steel arches have a hollow rectangular cross-section, are skewed transversely to the interior of the deck and are connected on top by hollow rectangular X cross-beams. The circa 28m maximum width deck has two solid, longitudinal, reinforced, prestressed concrete beams. The two beams are connected transversely by the reinforced concrete top slab and by steel cross-beams placed every 4m. The access viaduct’s deck is constituted by a slab and four longitudinal girders.
The foundation soils are composed by alluvial deposits of loamy sand and clay of variable thickness up to a depth of 40m over a sandstone substrate. The foundation piles are 1.20m in diameter.
It is proposed that the whole structure will be cast “in situ”, with the exception of the arches.
The construction Tender is expected to be launched in the near future.
