WORKSHOP ITEM Jon Haukaas, Public Works Director
Title
93rd AVENUE UTILITY BREAK UPDATE
Background
The repair to the sanitary sewer collapse under the I35W West Service Drive at 93rd Ave is progressing well. The contractor has stopped the ‘pipe-jacking’ process and is beginning to connect the various segments back together with the goal of returning the regular gravity operation by the end of the week.
Work to date includes:
- Bypass pumping of 93rd Ave neighborhood. This requires 24 hour monitoring of the pumps.
- Pipe extension bypass of forcemain.
- Dewatering to level of pipes at 35 feet deep.
- Temporary removal of 18” water main
- Relocation of gas main
- Temporary removal of storm sewer culvert
- Pipe-Jacking of 24” HOBAS fiberglass pipe into the deteriorated 27” CMP.
o Able to insert liner pipe through 335 feet of the 505 foot length
o Grouting pipe ends and sealing any leaking joints
- Installed intersection manhole
- Reconnect 93rd Ave sewer
- Reconnect forcemain sewer (continuing to use bypass temporarily)
- Backfilling site
Staff will present a picture gallery of the work so far to help Council understand the scope of the repair work.
Upcoming work:
- Complete manhole construction and backfill
- Restore watermain and storm sewer culvert
- Spray-line intersection manhole to seal and protect from future corrosion
- Restore forcemain connection
- Pave roadway
Additional projects are necessary to prevent future deterioration of the existing sewer mains. These projects will be completed through a design and open bid process. This work would involve cured in-place pipe (CIPP) lining of the remaining section of 27” CMP sewer, CIPP lining of the next two downstream stretches of sewer, CIPP lining of several sections of sewer in the industrial areas upstream of the lift stations leading to this, spray lining of several manholes. Funding has been appropriated in the Sewer Fund to complete the majority of this work. Projects are planned to be bid out and brought back to Council for final approval later this summer.