Repair of failing interceptor sewer 2

[sscokid11]

A client has recently completed cleaning and videoing of 15-,18-21" interceptor sewer. The sewer pipe is RPM installed in the 1970's and shows cracking along the crown of the pipe for extended lengths which allows leakage and gives concern about potential failure of the pipe.

Anyone have experience with failure potential of the pipe and best repair options for RPM pipe? Sliplining may be possible as existing sewer has excess hydraulic capacity.

 

[bimr]

Several technologies are available. Historically, the most common repair/replace method has been by open cut, as the work can be undertaken with the existing sewer in operation.

The second most common method of repair/replace has been cured-in-place pipe (CIPP). CIPP is one of several trenchless rehabilitation methods that can be used to repair existing sewers. CIPP is a jointless, seamless, pipe-within-a-pipe with the capability to rehabilitate sewers ranging up to 110-Inch diameter.

The third most common method of replacement has been sliplining. Sliplining involves the insertion of a new pipe with a smaller outside diameter than the inside diameter of the pipe to be rehabilitated. Pipe lengths can be fused together to create a long continuous string, frequently done with PE and fusible PVC, which is then pulled into the pipe. Slip lining will be more difficult if you have services that must be reconnected.

Pipe bursting involves the breaking up of the old pipe and pushing it into the surrounding soil by passing a bursting or splitting device through it, while pulling a replacement pipe in behind the bursting head. The replacement pipe is usually high density polyethylene, PVC, or DI. In some cases, the process can be used to expand the void created thus upsizing with the insertion of a larger diameter. Pipe bursting has now been accomplished in diameters up to 60 inches.

Offline replacement simply involves the installation of a new pipe without regard to the line and grade of the existing pipe. Normally, the existing deteriorated pipe being replaced is kept in service while the new replacement pipe is being installed.

You can use any of these technologies to repair/replace the pipe.

 

[dicksewerrat]

We do CIPP all the time on pipes this size. Check the yellow pages or one of ther online Trenchless magazines for contractor/ installers in your area.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[rconner]

You have gotten good response(and I’ve given bimr another well-deserved “star”). I noticed you had started your inquiry with the question, “Anyone have experience with failure potential of the pipe…” In that regard, I think with a few key words and a brief internet search you will quickly be assured you are not the “Lone Ranger” when it comes to problems with fiberglass composite pipe. I am aware there have also been multiple lawsuits concerning such issues, many of which mention remedial approaches to those problems as well (including some as discussed so far on this thread) that could be examined. Some of these problems go as far back e.g. as the matter of a failure of a substantial then quite new line of I believe 30” RPM pipe that was sliplined with 24” ductile iron pipe roughly thirty or so years ago (and litigation surrounding recovery for the plastic problems that thereafter went on for years e.g. per accounts at

http://touchngo.com/sp/html/sp-4940.htm,

http://www.bizjournals.com/sacramento/stories/2005/11/14/story6.html

and also

http://www.sdbar.org/Federal/2000/2000dsd028.htm

etc).

It probably bears mentioning as well that while any sort of construction involves risk, there are some rather unique potential pitfalls and hazards to various sorts of remediation attempts as well, as I’ve noticed at

http://www.marinij.com/rosskentfieldgreenbrae/ci_18099442

etc. (and of course some more recent reports of the San Bruno pipeline disaster, that appear to now most implicate adjacent pipe-bursting with polyethylene pipe in that event).