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verticality problem

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zhEngineer

Petroleum
Dec 21, 2014
2
dear,
please i need some help, i'm looking verticality tolerance of column erected on foundation,
i found in some document 1mm/1000mm max 25mm is it true
thanks for help
 
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In my opinion it is not so much the vertical alignment of the Column shell but the Level tolerance allowed for the Trays. The Trays must be absolutely level so the fluid maintains the same pressure across the whole tray.

Sometimes its possible to do all the right things and still get bad results
 
There are many specifications for erection and installation tolerances, sometimes the levelness of trays could be the prevailing factor. I am using for general guidance the PD 5500, Annex L: Guidance on structural tolerances.
Cheers,
gr2vessels
 
1:1000 is what AISC requires as a 'basic tolerance' for steel structures. And yes, that would be a good limit to include in a tower specification. But pennpiper and gr2vessels, the critical tolerance for proper performance is the as-installed levelness of the trays. With the trays level, the tower can look like the Leaning Tower of Pisa and still work well.
 
If out-of-plumbness is severe enough, it'll add to the overturning moment due to wind or seismic loading.
 
JStephen, I was thinking the same thing. It is doubly concerning since the weight of the liquid on the trays will contribute to additional p-delta moment.
 
Good point, gr2vessels. I suppose it could be a packed column instead of the trayed column that we assumed.
 
dears
thanks alot for your answers very helpful,
for tray we have only two, the vendor ensure to adjust it.
using 1mm/1000mm we found that colone out tolerance 33mm
 
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