Vertical pipe support load

[ttoonnyy]

Hi Guys

I got this question for a vertical pipe, hundreds meter deep for underground mine dewatering.
I'll need to work out the weight to support for the hanger design. No piping engineer to provide the load, unfortunately...
The total pipe weights about 5t and content weights 7t. vertically positioned, lateral controlled every 6 meter.
No expansion, dynamic, water hammer load considerd for now.
For the vertical load, there are 2 supporting options
Option 1
1 hanger hung the pipe from very top, the pump is connected at very bottom.
Therefore will generates a 12t weight for the hanger.
If this is the case, assuming the pipe is strong enough..can the pipe carry 7t content vertically?
Does the content pass whole gravity to the pipe wall through pressure and friction?
I see the reference from Peng engineering ASME mentioned the pipe line load should consider content as line load, not sure if it fits here.
Option 2
1 hanger hung from the very top, and another hanger/support from the very bottom before connecting to pump.
If this is the case, should bottom hanger undertake 60%+ of the total (pipe+content load); the top hanger undertake minimum 50% of the total (pipe+content load)?
Or bottom hanger undertake 7t content + 50% of the pipe load (5t)?


Would appreciated for any comments.
Cheers, Tony

 

[GBTorpenhow]

Need a sketch.

If open to the fluid at the bottom I have a hard time imagining how the weight of the contents could show up as tension in the pipe. Usually the weight of the contents appears as hydrostatic pressure only.

Production/injection well strings are typically supported only at the wellhead as I recall and hang freely into the well so yes, the entire weight of the pipe string can possibly be supported as tension at the top of the string assuming the pipe is strong/thick enough.

Bottom support might be tricky, any compression loads would be probably be undesirable as such a long string would have very low buckling resistance

 

[LittleInch]

It all goes on what is happening at the base of the pipe and the flexibility of the connection to the pump.

I would normally have thought that the end cap force from the weight of the fluid in the pipe would be taken by base support with some sort of fixed support, but maybe not.

contents will not cause a force on the pipe from friction and pressure, but end cap force will have an impact if the pipe is free to move at the base of the shaft.

If you have two supports then it all starts to get a bit complex depending on the level of either thermal expansion between installed condition and operating or strain expansion of the pipe.

In theory the top hanger could then be a spring hanger sized for the weight of the pipe, with a vertical force of 5 tonnes, with the base support being responsible for the fluid weight. But any failure of the top hanger or too much expansion or contraction of the pipe outside the range of the spring hanger could leave the base support supporting it all.