Shell Plate Buckling

[ayaan5739]

Dear Experts,
we are constructing a self supported cone roof tanks,there by mistakes we are getting 32mm buckling(inside)
so i want to know what is the waiveness allowed for the shell according to api650 as banding allowed 13mm.if anyone have idea how to fix this buckling please give us your idea,we already use a stiffener inside to fix this problem but we are getting same result.
Regards,

 

[ahmadsalah]

Hello:

Can you send a picture of the roof and the defect that you are getting? a drawing would even be better

 

[tankSnvessels]

First of all, I don't think it is buckling as you term it. Second as you've added stiffener, would you like to re check your top shell thickness? Third: Hope you do not have external pressure, applicable to App. V. If so , refer App. V and try to follow else you may have to use Sec VIII Div 1 only for the buckling case.

 

[Syahar1975]

Ayaan 5739,

Please refer to ASTM A 20 or A 6. Depend on your material group. If your material under API 650 group I, II, III you may refer to A6.

Group IV, V, VI you may refer to A20.

API 650 under "Plumbness tolerance section" allow us to refer to those standards for waviness and flatness.

Based on plate thickness and width you could find allowable waviness and flatness in those 2 standard.

Give more detail about material specs, thickness and with on that plate in question.

Syah