This month will see the start of TBM excavation on the 4km long, 7.2m diameter Mill Creek II Sanitary Sewer Storage tunnel in Cleveland, Ohio, the largest diameter tunnel to be undertaken by the client, the North East Ohio Sewer District.
The contractor JV of The Kassouf Co/Mole Construction/Murray Hill Construction/Kenny Construction won the $50M contract in October 1999 and will build the tunnel using an extensively modified Robbins Model 234-280 TBM. The drive will primarily be through Cleveland shales of approximately 100 Mpa with a primary lining consisting of a three piece, 360 degree ring beam, wire mesh for crown support and invert stability provided by wood lagging. A final lining of in situ reinforced concrete will leave the tunnel with a 6m id.
The TBM was previously used on the 12.4km long Abda Doukala tunnel in Morocco and has been converted from single to double shield. Robbins is also supplying a backup system with horizontal and vertical conveyors for the contract.
The contract is the second of three on the Mill Creek Sewer job. Contract 1, a 4.3km long, 2.7-3m id tunnel, was completed in October 1999 by the Kassouf/Murray Hill & Mole JV using a 3.8m diameter Lovat TBM. The third and final contract will be bid in early 2001 and involves a 4.6km long, 6m id tunnel with five access and flow drop shafts. The estimated price of construction is $50M.
