buried cast iron pipe
buried cast iron pipe
(OP)
Could anyone offer your opinion on the responsibility in ensuring the buried cast iron pipe underneath a structural footing would not fail?
Geotechnical engineers don't think they are the ones, the cast iron pipe manufacturers think it's the responsibility of the structural engineer, and on and on..
Thanks.
Geotechnical engineers don't think they are the ones, the cast iron pipe manufacturers think it's the responsibility of the structural engineer, and on and on..
Thanks.






RE: buried cast iron pipe
If you're the one building the structure over it, it's your problem. It's probably not anyone's contractual responsibility, but someone's got to deal with it. The pipe manufacturer probably isn't the one to be bugging, though. If you have to load it, underground pipe analyses aren't too bad and you could probably whip through it pretty quickly, especially with geotech support.
RE: buried cast iron pipe
RE: buried cast iron pipe
How deep is the pipe and what's the diameter?
If it's deep, it shouldn't be a problem. If it's small (4"?), it shouldn't be a problem.
Otherwise, compare you footing load to a vehicle load (is it way less, way more or something in between?) and check the load tables provided by the pipe manufacturer. They should give a buried depth that the pipe works for a vehicle load.
And if you're still at all worried, uncover it and concrete encase it. Better than losing any sleep.
RE: buried cast iron pipe
RE: buried cast iron pipe
To clarify a bit further:
This is a new construction. The 15" diameter cast iron drainage pipe will be buried at about 6 or 7 feet below the bottom of a large retaining wall footing. The overall width of this tall retaining wall footing is about 25 feet and the pipe is running parallel to the footing width. The highest soil pressure at the footing is about 3500 to 4000 psf.
The most sure way to handle this situation is of course to step/lower the footing at the crossing of the pipe to allow the pipe to run through the wall stem. However, that means a lot of concrete when stepping such large footing up and down simply for couple pipes.
On the other hand, I'm not sure if 6 or 7 feet is deep enough for the soil between the footing and the pipe to act in arching. Hence the question.
Curious to see what my fellow engineers would do in this situation.
Thanks.
RE: buried cast iron pipe
RE: buried cast iron pipe
RE: buried cast iron pipe
RE: buried cast iron pipe
Ductile iron pipe is actually considered flexible. It's just that DIP is a whole lot stiffer than the various plastic pipes in use today. Concrete, vitrified clay, and asbestos cement are examples of rigid pipes.
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RE: buried cast iron pipe