Nicholson Construction has been awarded a support of excavation contract for two diaphragm walls as part of the Westerly Storage Tunnel project in Cleveland, Ohio.
The $135M (£100M) project, which is owned by the Northeast Ohio Regional Sewer District (NEORSD,) includes approximately 9,600l of combined sewer overflow (CSO) storage tunnel excavated in rock and three shafts.
The Westerly Storage Tunnel is part of NEORSD’s Project Clean Lake, which is a 25-year programme designed to reduce pollution in Lake Erie by 15bn litres per year.
Nicholson’s contract includes the construction of a 1m thick, 46m deep unreinforced diaphragm wall shaft for support of excavation at the drop shaft, as well as a 60cm, 21.6m deep steel reinforced diaphragm wall for support of excavation of the connecting gate structure and a 90cm thick, 53m deep unreinforced diaphragm wall for support of excavation for the 6m diameter drop structure vent shaft.
Nicholson Construction executive vice president Luca Barison said: “It’s great to be working with the Northeast Regional Sewer District again here in Cleveland.
“Our team has been all over the country working on CSO projects and we’re happy to bring that experience back for another project in Ohio.”
Project Clean Lake is scheduled to be complete in 2036. At that time, over 98% of wet weather flows in the new CSO system are predicted to be captured and treated.