As part of a consortium, Bessac and Soletanche Bachy Fondations Spéciales, have recently been awarded their first contract by SIAH (the Croult and Petit Rosne Valleys Intercommunal Water Development Agency). Being a design and build contract, Setec Hydratec joined the team as designer.
The works, carried out in Bonneuil-en-France in the north of Paris, will include the construction of a discharge pipe for treated water from the wastewater treatment plant to its connection to the Garges-Épinay sewer, including 920 m of 1.6 m ID reinforced concrete pipes in one single drive with microtunnel boring machine. The programme also includes two deep secant pile shafts to be built by Soletanche Bachy Fondations Spéciales, as well as civil engineering works and the laying of a section of pipe in a trench.
The technical solution provided by the Bessac / Soletanche Bachy Fondations Spéciales / Setec Hydratec JV, consist in the construction of a very long microtunneling drive without an intermediate shaft. This proposal won over the owner because it greatly limits the impact of the works on the sensitive natural area and neighbours while optimizing costs.
Piles works have just started and the microtunnel works are scheduled for the beginning of January.
Finally, this project will be the subject of a world first since the microtunnel lining will consist of ultra-low carbon concrete pipes. The first pipes were cast at the end of July at our partner’s precast plant and the first results are excellent.