Granite wins Ohio tunnel project

The contract is valued at approximately US$215m (€197m).

The NSIT is a City of Akron project designed to prevent combined sewer overflows (CSOs) from entering the Cuyahoga River during typical storms. It will be funded by the Ohio Environmental Protection Agency’s Water Pollution Control Loan Fund.

The tunnel is the project’s primary structure, collecting overflows at four locations and storing them. It will have storage capacity of more than 37.9 million litres (10 million gallons).

The precast-concrete-segmental-lined rock tunnel will be 2.03km (6,660ft) in length and have an internal diameter of 5m (16.5ft). It will be designed to accommodate both dry and wet-weather sewage flow, as well as to store combined sewage. The project also features control structures, flow drop shafts, connecting sewers and overflow structures.

“Spanning 6,660ft in length and descending over 100ft below ground into rock, NSIT will be a feat of engineering and is set to become a symbol of innovation and environmental stewardship for the entire region,” said Granite vice-president of regional operations Jim Nickerson.

The project is scheduled to begin next month and to be completed in July 2027.

Granite’s subsidiary, Kenny Construction, completed the Ohio Canal Interceptor Tunnel for the City of Akron, designed to reduce CSOs into Little Cuyahoga River The 1.9km (6,240ft) long tunnel has a 8.2m (27ft) internal diameter. It controls CSOs at nine locations and stores more than 95 million litres (25 million gallons).

Tunnelling using a 9m diameter Robbins Crossover TBM was completed in 2018.