A Kiewit-led joint venture is constructing the $368 million Portland Combined Sewer Overflow Phase 2 project for the City of Portland. Phase 2 consists of a network of shallow pipelines that intercept the combined storm and sanitary wastewater, drop it down through shafts and transport it to tunnels for storage until it can be treated. Work includes excavation and lining of a 22-foot-diameter tunnel constructed 85 to 165 feet below ground and seven separate shafts located along the alignment.
The job will precast 48,000 panels that will serve as the tunnel’s lining. This project is the largest public works project in the history of the city and is the final step in the $1 billion clean-up of the Willamette River. Crews completed a 3,055-linear-foot drive, the longest micro-tunnel drive in North American history.
In addition, the City used a best-value process to select the most qualified contractor to build this challenging work.