Soil contamination prompted construction of a 7-km-long extension of Cairo Metro’s Line 3 on a viaduct instead of below ground, as first planned. A major challenge overcome by the Egyptian joint venture stemmed from the line’s location along the median of one of Cairo’s main highways. To minimize disruption to the utilities and nearly halve the amount of foundation concrete, the team built the viaduct on a single row of 2-m-dia concrete columns up to 16 m tall. Each column was founded on a 2.4-m-dia monopile.
As well as its six new stations, the project included a 65-acre workshop area with 32 buildings, which is said to be the largest depot in the Middle East and Africa. Despite congested urban conditions, the metro’s third line’s phase 4B was completed on time and budget, according to the team.