Aah okay
You say tensile strength and not tensile stress like in appendix V of API650.
Can you explain why they use a very low f in the example of V10 (f=21600 lb/inē)

An other question
Which Nē (number of waves) use TANK or where can I find the value in the calculation?
I have a other value than TANK.

The radial load on stiffener is not the same if I calculated with formula of V.8.2.2.3.
Radial Load on Stiffeners Ps = 27.059
Stiffener Spacing (ft) Load (lb/in)
1 16.814 18.495
the load is not Ps*Ls/12!!

I send you also the job file (.tki).

Thanks!

Regards,