Spliced Center Columns

[yosamitysamm]

I am having trouble sourcing a center column for a 50' tall tank that is long enough in one piece(24" std wt pipe). I have heard that our old tank expert did not allow splicing of the tank center columns. I would think that with proper testing of the weld and insuring the column remains straight this shouldn't be a problem. Does anyone have any experience with splcing tank columns? Is this a no-no in the industry?

Thanks for any responses.

 

[JStephen]

It's not uncommon. The main concern is straightness, not so much weld inspection.

 

[yosamitysamm]

Are there any Codes that give guidlines on straightness of the columns? AISC?

 

[IFRs]

Splice away - it is very common. Be wary of splcing with a plate (some might think that two fillet welds are easier to do than a butt weld) since it creates trouble for cleaning in the future.

 

[UTDude]

If you are concerned with the straightness, consider the deviation of the column axis from the compression axis at the ends as inducing a bending moment with the deviation being the moment arm. Then combine the axial and bending stresses by addition or sum of squares and compare to allowable. For a column to need splicing, it should be long enough for buckling to be the failure mode and the resulting stress reduction enough to overcome weld efficiency at the splice.