Golden Valley, MN is a 1st ring suburb of Minneapolis with a local population of approximately 20,000, and with more than 30,000 people actually working in the city. As Golden Valley is contracted with the Metropolitan Council Environmental Services to pay by volume to treat its wastewater, Golden Valley is highly incentivized to pursue every opportunity to limit infiltration & inflow (I&I) into their system; this has led to an extensive I&I mitigation program. Every leak in the system is an unnecessary additional cost to Golden Valley.
Whereas Trelleborg’s DrainPacker System is more typically used as a complete structural repair for a damaged section of pipe, this project called for achieving a leak tight seal to close off abandoned service connections.
As part of a site redevelopment project, three existing services on a high traffic county road were being abandoned where four buildings were removed to make way for new construction; the community impact made roadway excavation to remove the abandoned services impractical.
The DrainPacker System provided a cost-effective and minimally disruptive solution for establishing a leak tight seal over the abandoned services.
Products: Trelleborg’s DrainPacker System
Contractor: Central Iowa Televising of McCallsburg, Iowa (CIT)
Agency: City of Golden Valley, MN / Utility Engineer: Richard (R.J.) Kakach
In the past, Golden Valley has completed manhole to manhole cured-in-place pipe (CIPP) lining while reinstating only the active services as a practical means of sealing off abandoned laterals. For this project, however, the 1960s era 9” sewer main had already been renewed with a CIPP liner back in 2011 and all of the then active services had been reinstated and sealed with brim (hat) style connection liners.
Golden Valley was seeking to seal off these recently abandoned services while limiting community and system disruption.
A local consulting engineer, with extensive experience working with Trelleborg’s pipe rehabilitation solutions, suggested the installation of CIPP Point Repair (CIPP-PR) liners over the existing lateral connection brim-style liners.
Central Iowa Televising (CIT) was contracted to complete the work using Trelleborg’s DrainPacker System; 3 ft long CIPP-Point Repairs were installed directly over the lateral brim connections in order to seal the sewer main against infiltration from the abandoned service laterals.
Fast & Minimally Disruptive Installation:
CIT was able to: pre-inspect with CCTV; clean & prep; install the 3 CIPP point repairs; and post-inspect with CCTV – all within the same day.
Because of the small jobsite footprint, traffic disruption was kept to a minimum.
The 1,000,000 psi flexural modulus enables a thinner structural wall to limit flow impact; this was of particular benefit in an already lined main.
Zero shrinkage resins, such as Trelleborg’s silicate resins used on this project, provide a more resilient water tight seal by establishing a tight frictional interface across the full length and full area of the point repair.
A proper creep retention factor in the wall thickness design is used to ensure that the liner can both handle loads and maintain a water tight seal for the 50 year design life