Abu Dhabi Sewerage Services Company (ADSSC) awarded to Impregilo the USD200 million T-03 contract for the third and final lot of the Strategic Tunnel Enhancement Programme (STEP), a 40 km-long hydraulic tunnel in Abu Dhabi. Using gravity, the tunnel will collect wastewater and convey it to a treatment plant in Al Wathba. Under the new contract, Impregilo is to construct 10 km of the hydraulic tunnel, with a 7 m-diameter excavated section, four access shafts to depths between 60 and 80 m, and the links to the main tunnel.
For the first time in Abu Dhabi two TBM EPB for pressures up to 8 bars, will bore and simultaneously line the tunnel with prefabricated concrete segments.
The hydraulic tunnel and the access shafts will be lined with a special membrane to ensure the concrete structures are fully protected from the aggressive environment, for a minimum term of one hundred years. Click ae/16 for tunnelbuilder archive. Visit www.impregilo.it. 49/10.
