AC Pipe Joint Restraint

[FLdrain]

I am looking for suggestions of methods to provide joint restraint on an existing 14" AC watermain. The watermain currently transitions from AC to PVC by a transition coupling which is approxiamately 10' from an existing gate valve on the AC side. The PVC portion of the watermain must be removed so a stormwater pond can be constructed. The pond will be over 15' deep. Since there is an existing tee prior to the valve and that AC pipe must remain in service during construction the restraints need to be in place prior to removing the PVC pipe.

Does anybody have any suggestions of how to accomplish this? I would like to use Stellar Clamps connected by all thread rods but haven't had any luck in locating a manufacturer.

 

[rconner]

If this installation is somewhere in the USA or other regulated countries, you are perhaps already aware that there are multiple issues involved (OSHA, state regulatory, and others etc.) in addition to questions related to self-restraint etc. in dealing with existing asbestos cement (AC) water and even some other service AC pipelines. I do not profess to be an expert in these AC issues (other than being aware of some of them!), and if you have not done so I would strongly suggest you carefully read all governing regulations and maybe even seek out some actual experts/authorities etc. for dealing with and/or disturbing etc. this pipe.
However, I can see some of these issues as potential obstacles to the number of "takers" you might get to help you out with merchantable restraint devices to work on this pipe (at least on the list so far this appears to be zero!)
If you don't find same or if it is not possible for some reason to parallel or otherwise replace enough of this piping with some other suitable contemporary piping (for example a suitable restrained length of contemporary piping now listed suitable for carrying potable water, as is apparently being done in many parts of the world), perhaps you could consider e.g. some sort of "external anchorage" of all pressure thrust foci (such as a valve that might be closed with pressure against the closed gate?)involved. What exactly this external anchorage could be may be limited some by the configuration(s) of the actual thrust foci involved, the pressure, available space, soil conditions, constructability, the fragility (with regard to construction support and digging around/under etc.) of the existing AC, and of course the structural/mechanical imagination/experience etc. of the designer.
Perhaps something else that might be considered is sliplining or pipebursting the existing pipe with some length of near the same size or smaller self-restrained line, if this is allowed in the area by regulatory folks and can be tolerated by hydraulic conditions etc. While I have no specific experience with sliplining of AC pipe either, I wonder that if a length of new piping can be slid up inside the end of an existing buried, I suspect maybe long undisturbed, AC pipeline, might that new restrained piping even be somehow grouted in place to aid in the anchorage you seek?

 

[dicksewerrat]

Can you leave a small portion of the pvc in place? then use thrust blocks and threaded rods back to the gate valve? Then look at removing all your AC pipe.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[JStephen]

My idea: Dig down on the pressurized side of the valve, pour concrete blocking around or next to the pipe, run anchor rods from this blocking back to the valve.

 

[MPENN]

A/C water pipe is like the office curmudgeon. They generally do not like to be disturbed, least of all when uncovered and under pressure.

Can the water line be valved off for the "short" duration of closing the valve, capping the PVC pipe and restraining the cap/placing new dead end thrust block? Work could be schduled off peak; if the main services only commercial/ industrial area perhaps paying premium time for weekend or holiday work may solve the problem.

With due respect to the danger of working in a trench with any fluid line under pressure, be it water or sanitary or storm sewers under head, no one will be happy if a joint opens or a weak spot in the line fails at an "inconvenient" time. It is always better to program a water shut down rather than dealing with Aunt Edna in the shower, covered in suds and no water to rinse.

Is the water line owned by a water company or municipal authority? If so, ask for help; you would not presume to work on their line with out their approval of your plan and permission. The local water company workers may share their knowledge of the A/C pipe and be willing to open their bag of tricks. Does the pipe have a history of joints opening (or later leaking) after being worked on? Perhaps there are rodded restraints in place along with thrust blocking.

If this is a privately owned water supply, well . . . perhaps you should discuss with a competant water contractor with deep experience with A/C pipe repairs.

Consider hiring this experienced water contractor to perform this work in advance of the general construction contract.