Environmental Services has completed construction on a project to repair about 900 feet of public sewer pipes in downtown Portland that were 100 to 140 years old and in deteriorating condition. The sewer pipes were showing signs of cracks, breaks, holes, offset pipe connections, and obstructions, putting the pipes at risk of structural failure. Urgent repairs completed at three locations shown on the map below will protect the public and the environment by reducing the possibility of sewage releases to buildings and streets.
Repairs were made in three locations (see map).
Construction began mid-February 2018 and continued through July 2018.
This project included both trenchless and trench excavation construction methods. To repair the main line sewer pipes, the city employed a process called Cured-in-Place-Pipe Lining (CIPP). This process inserted a liner to strengthen and reinforce the pipes, making them last for many years. This work occurred at night, after 6 p.m. and before 7 a.m., when flows in the pipes were low. Doing this work at night reduced traffic congestion, created a safer work zone, and allowed time for the new sewer pipe lining to harden. Some setup and pipe cleaning work occurred during the day.
The CIPP sewer pipe lining process occurred in phases:
- One day to set up the bypass service to provide uninterrupted sewer service to adjacent buildings
- One night to line the sewer pipe and cure the lining so it could harden 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
The spot repair in SW Oak Street just west of SW 1st Avenue required digging a trench to relocate a water line and repair the sewer pipe.
This project also required some sawcutting and jackhammering to install cleanouts in multiple locations. This noisier work was done during the day. 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.
Click here for more details about the construction methods.
This project had the following traffic impacts:
- Accessing the sewer line through manholes required temporary street closures of one-to-two-block segments on SW Alder, SW Oak, and SW Taylor streets.
- Where needed, local access was provided by flaggers.
- Access to and from driveways may have been delayed.
- Staging areas for materials and construction vehicles were on cross streets and required some lane closures and parking removal.
- Bypass pumping to maintain sewer service during construction required temporary crosswalk closures and pedestrian detours with local access provided by flaggers.