Environmental Services is designing a project to repair approximately 6,500 linear feet, over one mile, of public sewer pipes, and construct 270 feet of new pipe in downtown Portland. These pipes are 50 to 140 years old, in deteriorating condition, and are showing signs of cracks, breaks, holes, offset pipe connections, and root and grease obstructions. The project will also repair or replace 29 manholes. These improvements will protect the public and the environment by reducing the possibility of sewage releases to buildings and streets.
The Project is in the Portland State University (PSU) area and is generally bounded by SW Mill Street to the north, I-405 to the south and west, and SW Harbor Drive to the east. The project also includes work on W Burnside and SW Columbia streets.
Construction is anticipated to begin in the fall of 2018 and take a year to complete.
This project will include both trenchless and trench excavation construction methods:
- Cured-in-Place-Pipe Lining (CIPP) to repair the main line sewer pipes
- Sawcutting and jackhammering to install cleanouts in some locations
- Digging trenches to replace some sewer service lateral connections to buildings
The CIPP process will insert a liner to strengthen and reinforce the pipes, making them last for many years. Pipe lining work will occur after 6 p.m. and before 7 a.m., when flows in the pipes are low. Doing this work at night will reduce traffic congestion and allow time for the sewer pipe lining to harden. Some setup and inspections will occur during the day.
The CIPP sewer pipe lining process will occur in phases:
- One day to set up the bypass service that will provide uninterrupted sewer service to adjacent buildings
- One night to line the sewer pipe and cure the lining so it hardens in place
- One day or night to reinstate the sewer service lateral connections to adjacent buildings
- One day or night to line the service laterals and remove the bypass service
This project will also require sawcutting and jackhammering to install cleanouts in multiple locations. Cleanouts are typically installed near the curb, but may also be placed in the sidewalk or near the building. They will be used to maintain sewer service during repairs and to provide access for future maintenance. This noisier work, along with any trench excavation, will be done during the day.
The spot repair in SW Oak Street will require digging a pit to relocate a water line and replace a section of the sewer pipe. This work will occur during the day.
The project may also require some sawcutting and jackhammering to install sewer cleanouts in multiple locations. This noisier work will be done during the day.