Hello Richard,

In API 650 11th Edition under section 5.11.2, MF is the moment about the shell-to-bottom joint from liquid where weight of liquid is Wa. where:
Wa = 4.67tb square root(FbyH). What is Fby? Is tank software using this formula?.Fby not specified in API 650 11th Edition.

Thanks

Rob

"Fby" is the yield strength of the bottom plate material. You can specify this value in the "Seismic Input". If you leave this value blank, then TANK uses the yield strength of the bottom shell course.

thank you Richard. This will help.

Rob