Tank Shell Buckling Check for Wind

[xema77]

Line 9 on the standard API 650 datasheet in Appendix L gives the option to "Check buckling in the Corroded Condition". I would have thought this to be a manditory calculation. Why is it an option?

Thanks

 

[JStephen]

The stiffness of the shell for this kind of buckling depends on the aveage thickness. A localized thin spot wouldn't significantly affect it. API is apparently assuming that corrosion is somewhat localized, rather than a uniform loss of metal on the entire tank. This also enters in on some of the weight calculations, which are not always handled uniformly.