Maximum Pipe Deflection

[engg9009]

I'm working on a project where we're exposing a pipeline while it is in service to repair some damaged coating. I'm wondering how to figure out the maximum allowable stress due to the bending of the pipe, so that I can decide how much pipe to excavate at one time. Any help would be greatly appreciated.

Thanks

 

[BigInch]

Wondering is not the thing to be doing at this time, and deflection may not be the right criteria to be worried about.

Do a stress analysis of the pressured line while "virtually" removing restraining soil and "virtually" increasing the unsupported length until you are nearing maximum allowable stress, then shorten that unsupported length by a safety factor, and/or support the pipe with sand bags at intermediate locations. Be sure to replace any underlying soil removed with sand cement bags that will guarantee adequate support in the future.

If its a gas pipeline see allowable stress clauses of ASME B31.8, liquid line see B31.4

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