Api 650 11th Ed. Addendum 1 Anchorage Ratio calculation 1

[CDiaz]

In the Addendum 1 of the API 650 11th Edition there is a change in the calculation of the Anchorage Ratio J. There is a new parameter wint (calculated design uplift load due to product pressure per unit circumferential length).

Can anybody explain me what does this term means and how can I calculate it?

 

[rwaterguy]

See AWWA D100-5 Welded Steel Tank For Water Storage. J is a simple idea but the emperical formula requires the the AWWA code. It is probably related to the API 650 Stability Ratio.

J = Ms/(D2{wt*(1-0.4*Av)+wl}.

Ms is the overturning moment.

See page 147 & 148 AWWA D100-S

 

[chicopee]

I don't keep up with API 650 however I believe that the "J" factor that you are refering to deals with the effects of overturning loads on the base of tanks and the related effects on tensionn on bolts and compression on the footing. I have included a .JPEG attachment of a page on tubular steel structures for you review. There are three more pages about this article so if you think that you are interested,I'll include them as attachments

 

[JStephen]

"calculated design uplift load due to product pressure per unit circumferential length"

If the tank is an atmoshperic tank, then it would be zero.

If the tank is an Appendix F tank, then it would be internal pressure times cross-sectional area of the tank divided by circumference, all with consistent units of course. Final number in lbs/ft to match the rest of the equation.