HyrdrostaticUplift force on buried pipes
HyrdrostaticUplift force on buried pipes
(OP)
Hello everone.
I have a pipe buried at 3 ft below river bed at stream crossing. The water level is 10 m above river bed. When checking if the pipe is going to be uplifted under hydrostatic water pressure, I noticed that in literature when calculating upward hydrostatic force under pipe, only water height under river bed is considered. I meant that in the literature the water height above river bed is not counted to the upward hydrostatic force. Should not the uplift hydrostatic force be computed for the full water height (including the water height above river bed). (Gamma Water * height of water) ? Thanks for help
I have a pipe buried at 3 ft below river bed at stream crossing. The water level is 10 m above river bed. When checking if the pipe is going to be uplifted under hydrostatic water pressure, I noticed that in literature when calculating upward hydrostatic force under pipe, only water height under river bed is considered. I meant that in the literature the water height above river bed is not counted to the upward hydrostatic force. Should not the uplift hydrostatic force be computed for the full water height (including the water height above river bed). (Gamma Water * height of water) ? Thanks for help





RE: HyrdrostaticUplift force on buried pipes
A sketch would help.
Remember - More details = better answers
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RE: HyrdrostaticUplift force on buried pipes
RE: HyrdrostaticUplift force on buried pipes
force up : weight of water volume calculated with the external diam of pipe (Archimede)
PS : with concrete pipe, generally speaking, to avoid buoyancy, it is enough one meter of ground above the pipe
RE: HyrdrostaticUplift force on buried pipes
Roby eng has it nailed. The uplift force is the volume of the pipe times the density of the fluid, in this case water.
Down forces are the weight of pipe and coatings plus soil weight and soil shear strength. Initially soil strength is often ignored unless it becomes important.
Usually you aim for a minimum of 1.1 for forces down vs forces up.
This idea of hydrostatic forces under the pipe is not the way to think about this issue. Start thinking differently.
Depth of the river will affect the external pressure on the pipe, but that's something completely different.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: HyrdrostaticUplift force on buried pipes
RE: HyrdrostaticUplift force on buried pipes
RE: HyrdrostaticUplift force on buried pipes
RE: HyrdrostaticUplift force on buried pipes
If your pipe is exposed on the surface then yes there is a force from the flowing water.
If this stream can get to a high flood state then 3ft burial is looking rather low.
Scour and washout become your issue, especially if you've open cut this and then just dumped the soil/gravel back in.
All depends on your "stream".
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: HyrdrostaticUplift force on buried pipes
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