fuel tank foundation design
fuel tank foundation design
(OP)
My company is working on a military project with a 45' diameter fuel storage tank as part of the design. This is the first time we have encountered a fuel storage tank foundation design. The tank will bear on a concrete foundation around the perimeter of the tank and on grade within the ring foundation. Can someone lead me in the right direction as far as designing the perimeter concrete tank ring foundation, checking for overturning during a seismic event, and whether anchorage is required. The only material that has been mentioned so far is the API-650 and our office does not have a copy.





RE: fuel tank foundation design
As I recall, the design is fairly straightforward. But I haven't done one in over a decade. There's a design guide you need to find and review; perhaps someone will provide the citation for you...
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: fuel tank foundation design
ASCE " Wind Loads and Anchor Bolt design for Petrochemical facilities" would be two places to start. The 45' diameter will probably prclude overturning. Design the width of the ringwall/ring beam to have approximately the same pressure as the soil loading at the center of the tank. Backfill the interior of the ringwill with a granular material. Design the hoop stress of the ringwall for the surcharge loading of the fuel filled tank.
Check with some of your peers, see if any of them does standpipe design. If he does, he probably has a spread sheet for the seismic and anchor bolt design,
best, tincan
RE: fuel tank foundation design
Good luck.
RE: fuel tank foundation design
RE: fuel tank foundation design
Suggest you hire a consultant civil engineer who is knowlegable in soils engineering and concrete foundation design. This is not "cook book" engineering.
RE: fuel tank foundation design
RE: fuel tank foundation design
I don't think the use of ringwalls has increased so much as many new tanks are being built. I suspect it's a combination of the life cycle and (hopefully) reviving economic conditions. And we should remember that many of the engineers who used to perform these designs are probably retired, so the cumulative knowledge about this kind of design is severely reduced in comparison to the design environment of the 1970's and 1980's.
Crushed stone ringwalls can also work, but can have problems with lateral spread - which can result in damage to the floor of the tank. And the viability of a crushed stone pad diminishes as the height of the tank increases. Imagine a 40 ft (12.2m) high tank filled with a fluid with GS of 2.2 ...
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: fuel tank foundation design
Best regards and
RE: fuel tank foundation design
My experience goes with Focht3. There are two methods; one with a concrete ring beam and the other is simply a thick layer of crushed stone overtopped by a layer of bitumen sand mix.
I don't think there is any particular reason why one is better than the other but the footprint of the former should be slightly smaller than the latter. Without a ring beam the crushed stone has to be extended wider than the tank in order to spread the load. What most people do not realise is that large settlments of a fuel tank is tolerated and the magnitude could cause a heart attack to an engineer who only designs buildings (in feet instead of inches). The materials used in the two designs are similar but their quantities are not and so a direct comparison is not on a like to like basis.
Any structural engineer can confirm that a RC ring beam can provide a stronger and more uniform support for the vertical wall of the tank.
An important consideration is to prevent contamination of the soil by the fuel in case of a leak and it is sometimes necessary to cast the tank farm area with a concrete slab to form an imprevious layer with a high bund wall along the perimeter. Thus the ring wall beam solution fit neatly into this application.
RE: fuel tank foundation design
RE: fuel tank foundation design
RE: fuel tank foundation design
There is no question about the bunds being needed in tank farms for the spill protection - but to say that RC ringwall is a positive measure in case of rupture when the area is underlain by clay . . .
I still say that your choice of a concrete ring wall or crushed stone ring wall or no ring wall under the tank edges is dependent on the site conditions and the tank under consideration. I wouldn't put in the ring walls unless it was absolutely necessary.
RE: fuel tank foundation design
A large majority of petroleum tanks where the diameter >> height have no footings, the overturning due to wind and or seismic is << that the dead load resisting moment and require no tie-downs.
RE: fuel tank foundation design
I bring to our attention paper by Bjerrum on Edge Failure of large oil storage tank - International Conference on Soil Mechanics and Foundation Engineers, London, 1956. It's an oldie but a classic.