Hochtief Solutions Middle East Qatar W.L.L., together with Al Sraiya Strabag for Roads and Infrastructure W.L.L. and Petroserv Limited, signed a contract for construction of the central section of the new sewerage network IDRIS (Inner Doha Resewerage Implementation Strategy) under the capital of Qatar. The client is the Public Works Authority (ASHGHAL).
The construction contract is part of an extensive refurbishment and expansion of the overloaded sewerage system in the historic south of Doha. The system, which serves an area of 680 km² is required as the result of rapid population growth. The overall project includes several smaller connections to the existing sewer system.
For constructing the 14.7 km long tunnel, two tunnel boring machines will be used. After installation of the tunnel’s outer shell an inner lining will be added to protect the concrete from the aggressive gases by means of an HDPE membrane, ensuring a planned project life of 100 years.
The sewer tunnel will have an interior diameter of 4.5 m. In addition to the tunnel, shafts up to 45 m deep will be built, some of which will serve as connectors to other IDRIS construction contracts. The joint venture is responsible for the execution planning for this demanding project which is scheduled to be completed by the beginning of 2019, after a construction period of 45 months. The contract has a value 265 million euros, with a Hochtief share of 45 %.