Partially Buried API 650 Tank
Partially Buried API 650 Tank
(OP)
I was wondering how I go about designing a partially buried welded steel tank. I can't find any reference in API 650 regarding this. I can perform a finite element analysis to determine the stresses, but what allowable do I use? Anyone know of any references? I've designed 100's of Aboveground Storage Tanks, but partially buried is a first for me.
Thanks in advance.
Thanks in advance.





RE: Partially Buried API 650 Tank
RE: Partially Buried API 650 Tank
Is it actually an oil tank? If so, highly recommend not partially burying it, due to inspection difficulties.
RE: Partially Buried API 650 Tank
Wouldn't you use the same allowables as for any tank, above ground or buried for both internal AND external pressure design ?
Soil pressures are well documented or you could ask for advice at the Civil Engineers forum.
I would have thought the issue to be more one of what corrosion allowance to select and how to protect the tank once it's buried. For that, try the Corrosion engineering forum.
David
RE: Partially Buried API 650 Tank
Steve Braune
Tank Industry Consultants
www.tankindustry.com
RE: Partially Buried API 650 Tank
FYI, I spoke to John Lieb from your company who authored the future Appendix V in API 650. He said that the appendix would not apply for buried tanks because it is only meant to address uniform pressures (not linearly varying pressures like soil).
What I ended up doing is using a Roark's formula (5th Edition), Table 35, Case 19b. which is the Formulas For Elastic Stability of Plates and Shells. This allowed me to back-calculate the allowable height between stiffeners given a certain soil pressure.
I compared the values to AWWA D100's wind girder calc and calculated that D100's equations are based on a factor of safety of 1.96 compared to Roark's formulas. I chose a factor of saftey of 2.00 and off I went.
RE: Partially Buried API 650 Tank
Steve Braune
Tank Industry Consultants
www.tankindustry.com