Vessels on support legs
Vessels on support legs
(OP)
When analyzing the support legs on a vessel shouldn't one consider the loading
from the attached nozzles?
Thanks in advance.
from the attached nozzles?
Thanks in advance.
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RE: Vessels on support legs
Regards,
Mike
On Edit: Expecting some different opinions :)
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Vessels on support legs
It's not a 100 perfect solution (are the loads e.g. primary or secondary loads, do they act together, what other combinations are possible, etc.) but it works out very well in most cases. With this document the vessel fab therefore has a theoretical upper limit (i.e. nozzle loads) to which he could check the supports. However, chances are the nozzle loads will never act in the most worst case situation but more likely in a situation where one cancels the other, or where the resultant vector is negligible wrt to the supports.
This is my experience, but my scope of vessels is usually rather limited in size (small volumes of a few millilitres to maybe a few cubic metres). Not sure what would happen with a 60 mtr column where the top nozzle loads gives a side load. Think of that (for a) moment ...
RE: Vessels on support legs
For example, small vessel, with big pipe attached. Is that pipe going to push the vessel over? Or does it hold the vessel up?
RE: Vessels on support legs
We need to consider all the loads and load combinations for design of any component of pressure vessels as per code.
But as SnTMan, XL83NL and JStephen explained through their experience, you need to check how much impact it will have on the lug design. Here engineering judgment and logic will play key role(if one has no experience). Which is why I often say code is just guidebook but use your own logic and judgment to consider the best possible scenario of loading.
Another thing to note is the forces and moments due to Wind and Seismic will be much much higher than the nozzle loads acting on the vessel which will govern the design of leg supports. Also I think the piping loads acting on nozzles will impact locally rather than globally provided the size of nozzle is less or not big enough compared to vessel size.
RE: Vessels on support legs
The difficulty with including nozzle loads in the support design is that piping connection loads are not generally known at the outset, and as noted above, the loads generally counteract each other anyway. Assumptions need to be made to ensure the vessel shell can handle reasonable loadings, and checked once piping design is firmed up. Such procedure could be used to check support design for unusual nozzle arrangements, but I find it difficult to believe this would be an issue.
RE: Vessels on support legs
Regards
r6155
RE: Vessels on support legs
RE: Vessels on support legs
RE: Vessels on support legs