Pipe on pylons over creek

[dicksewerrat]

We have a Ductile Iron Pipe carrying domestic sewage supported by pylons over some creeks anbd ravines. We will be lining this pipe with CIPP. What kind of analysis would I be doing to make sure that the pipe does not snap between supports. This is a gravity line, so each support will be lower than the last as you go downstream.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[bimr]

Ductile iron is typically available in 20-foot lengths that allows pipe supports to be located on 20-foot centers.

You have to determine the pipe material, wall thickness, evaluate type of saddles, and determine pipe lengths. The dipra paper outlines the design procedure.

http://www.dipra.org/pdf/pipeOnSupports.pdf

Make some preliminary calculations according to the dipra paper. If you are close to the breaking point, you probably will have to get an professional opinion on the composite lining/ductile interaction.

 

[stanier]

Biggest challenge is flooding in the creek potentially taken the pylons and pipe with it.

Depending on the size of the project you could directionally drill under the creeks using PE. This avoids the issue of contaminating a water course if the worst happens during flooding.

Aerial crossings using plons and cables have been used to cross ravines.

As there is no detail on size of pipe and crossings it is difficult to help.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[cvg]

recommend that if you decide to go over the top, put the carrier pipe in a steel casing designed to handle the structural loading and place it at least a foot above the 100-year water surface elevation. design the pylons to protect against flood loading and the pylon foundations need to be below the estimated scour depth.

 

[bimr]

I believe that disewerrat is attempting to line an existing ductile iron pipe. Interesting project.

 

[dicksewerrat]

Unfortunately, the pipe already exists. I will be getting picture and some more data next week. I will talk to the owner about the 100 year flood.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[TGLG]

This may be a silly question, and it's not related to the original question, but I have to ask: If the pipe is elevated, what keeps the water in the pipe from freezing in winter?

 

[dicksewerrat]

It is in North Carolina. and when you havea 24 inch sewer running over half full, it tends to stay fairly warm. It is exposed in 4 places for about 50 feet each. The rest is underground. Been in service over 25 years.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com