Artificial tunnel
Breaking out of the mould, towards excellence.
Works: Algiers Underground
Location: Algiers, Algeria
Project features: the construction project for the first underground railway line in Algiers (total length 23 km) was divided into several lots. The second lot, between Hamma and Hai El Badr, included the construction of 4.1 km of tunnels, four stations in the neighbourhoods of Jardin d'Essai, Les Fusillés, côte Amirouche and Mer et Soleil, and numerous auxiliary structures, including ventilation shafts. To construct the four stations, ALPI supplied a range of structures built using standard components of the MECCANO 120 system. The solution for building the walls, intermediate slabs and reinforced concrete coverings did not follow the same procedure for all stations. To resolve the special technical requirements demanded by the construction company, two stations were built using traditional methods, from the bottom upwards, while the other two stations were built inversely, first building the vault, fixing it to side piling, and then constructing the lower part of the station. Supporting the covering was a 10.5 m module moved on tracks by use of hydraulic cable hoists, while the modular formwork for the walls and intermediate slabs were moved by crane. The intervention and assistance provided by ALPI helped the company to assure the correct use of the equipment which, purchased by the company, was also used for the construction of the third lot of the underground line.