Damaged pre-stressed ocean outfall pipe
Damaged pre-stressed ocean outfall pipe
(OP)
Hi everyone
I am working on a project to stabilize an ocean outfall pipe ( 72 inch Dia.)constructed in 1980 and has cathodic protection system. A study has been completed by Pure Technologies to monitor the condition of the pre-stressed outfall pipe (section of the pipe about 2.5 miles under water) The recent results indicated that the section of the pipe in the water has a high number of wire breaks.
The outfall can not be shut dawn because there is no storage capacity in the waste-water treatment plant and temporary pipe(bypass)is not going to be allowed be environmental department besides the heavy boats traffic at the bay, therefore the slip-lining solution to stabilize the pipe is not considered. The pipe is buried about two feet below the bed level of the bay. The recommendation based on the high rate of wire breaking (717 wire breaks in 130 days) is to replace the outfall. We are trying to stabilize the pipe for the time being and until a new outfall is constructed. Any ideas about other restoration options!
Thank You
I am working on a project to stabilize an ocean outfall pipe ( 72 inch Dia.)constructed in 1980 and has cathodic protection system. A study has been completed by Pure Technologies to monitor the condition of the pre-stressed outfall pipe (section of the pipe about 2.5 miles under water) The recent results indicated that the section of the pipe in the water has a high number of wire breaks.
The outfall can not be shut dawn because there is no storage capacity in the waste-water treatment plant and temporary pipe(bypass)is not going to be allowed be environmental department besides the heavy boats traffic at the bay, therefore the slip-lining solution to stabilize the pipe is not considered. The pipe is buried about two feet below the bed level of the bay. The recommendation based on the high rate of wire breaking (717 wire breaks in 130 days) is to replace the outfall. We are trying to stabilize the pipe for the time being and until a new outfall is constructed. Any ideas about other restoration options!
Thank You





RE: Damaged pre-stressed ocean outfall pipe
You could get a fiberglass or steel jacket made up in two pieces.Bolt them together around the pipe and grout if necessary.
What you need depends on the pressure differential. Fiberglass might need to be concrete wrapped. If so there are concrete mats that can be made up around the fiberglass.
If you are worried about internal blockage .Cut the section out and make the jacket overlap the gap.It may be possible to jet excavate around the pipe as its not too deep below the seabed.
If you cannot stop the flow, to reduce work time make the jacket hinged. Install the bottom part of the jacket, lift out the cut section and flip over the second half of the jacket and bolt.
Intrusion Prepakt /marineconcrete.com
RE: Damaged pre-stressed ocean outfall pipe
Do you think jet grouting the soil around the pipe would work as it might stop the water from penetrating the concrete and cause the corrosion in the wires besides it would increase the pipe resistance to external pressure
RE: Damaged pre-stressed ocean outfall pipe
Thank you
RE: Damaged pre-stressed ocean outfall pipe
Thank you
RE: Damaged pre-stressed ocean outfall pipe
Intrusion Prepakt /marineconcrete.com
RE: Damaged pre-stressed ocean outfall pipe
The pipe is 2 feet deep below the seabed and the length of the pipe underwater (the bay section) is about 2.5 miles.
RE: Damaged pre-stressed ocean outfall pipe
Intrusion Prepakt /marineconcrete.com
RE: Damaged pre-stressed ocean outfall pipe
Do you think jet excavation would be the best option to install the jacket and without causing other problems in the bay.
RE: Damaged pre-stressed ocean outfall pipe
Intrusion Prepakt /marineconcrete.com
RE: Damaged pre-stressed ocean outfall pipe
RE: Damaged pre-stressed ocean outfall pipe
If it is a short term solution that is needed and assuming that the concrete is still intact, then steel jackets or bands tightened around the pipe could replace the broken wires as reinforcement.
Stephen Argles
Land & Marine
www.landandmarine.com