Dear Sir
Is the Brownell and Young Method
checking required for All vertical vessels? when I change the base ring design option from "Analyze" to "Brownell and Young Method" , the skirt locally stress error will be appeared for some vessels. but I Do not know really . should I correct this error or not?
Can I use the "analyze" option instead of "Brownell and Young Method" and trust it?

Hello Vahid_mahdavinasab,

Both anaylse and B&y Analyse calculate bolt area requirement by same method.

Analyse option-considerations:

1) Bolts are preloaded to 100%
2) concrete is subjected to load based on the assumption that bolts are preloaded to 100%
3) there is no explicit differentiation of stresses of steel bolts between downwind and upwind side. Bolt stresses are considered same throughtout as they are on the upwind side.same is true for concrete also.

Result:

Both analyse and B&Y Analyse use the same formula for calculation of basering thickness, but the bending moment for analyse option is greater than B&y analyse.
(Since concrete stress at the outer edge of baseplate will come out to be lesser than allowable in B&Y analyse, while anaylse option will consider bolt preloading to be 100% which result in higher concrete load than B&Y analyse.)

Also B&Y calculates iteratively to calculate actual stresses of bolt and of the concrete at the PCD and at the outer edge.

For Large columns it is conservative to use analyse and simplified (steel on steel) approach.(where assurance of joint strength between steel and concrete cannot be verified)

Also for Skirt thk calculation anaylse option refers to Javad and farr while B&Y analyse refer to chapter 6 (shell attached to flat plate basis)

Formula by B&y analyse is more conservative as compared to Javad and farr.

Please go through brownell and young book.

Hope this helps.
Regards
ASD23789

Dear ASD23789
Thanks for attention.
Best regards
Vahid