allowable settlement for tank with big diameter

[alireza1348]

what is maximum settlement for oil tank with big diameter i.e. 125m

 

[MiketheEngineer]

As much as it wants -----

Sorry - just had to do that!!! You know - the 800 lb gorilla problem....

 

[MintJulep]

I would not be worried so much about total settlement, as by differential settlement- at least as far as the tank itself is concerned.

Total settlement will obvioulsy affect any piping connected to the tank.

 

[vpl]

alireza1348

Is this a concern about ground settlement or oil sedimentation settlement? When I saw MintJulep's answer I realized that I might have been about to respond to the wrong question.

If it is indeed ground settlement under the tank, then it depends on factors such as the soil stabilization and weight of the tank. If it's oil sedimentation settlement then it depends on amount of mixing, flow from the tank, time, and probably temperature and quality of the oil.

Please clarify.

Patricia Lougheed

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.

 

[JStephen]

API-653 has criteria for evaluating settlement of tanks. I would try to keep settlement much lower than it allows if feasible.

In general, uniform settlement all over isn't a big problem. Uniform tilting isn't a big problem. out-of-plane settlement is. If the tank has a supported roof, then differential settlement between the shell and interior will affect the roof structure.