retaining dike for cisterntank in russia

huangyhg

retaining dike for cistern/tank in russia
hi all
a colleague of mine has asked a question. he is designing a cistern/tank in the western part of russia. the question is regarding the retaining dike/pit.
are there any codes or recommendations for this type of "structure"? is anybody familiar with for example requirements regarding size (50/100/100% of tank)?
should there be some kind of emergency walkway between the tank and the retainging pit?
since requirements vary in dirrerent countries any hints for western russia (european part) would be greatly appreciated.
thanks in advance
thomas
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you might want to take a look at aci 350-01 code requirements for environmental engineering concrete structures (aci 350-01)and commentary (aci 350r-01).
we do those regularly in our office.
our cases usually involve some sort of hazerdous fluid, oil, ethanol and the like.  we follow state and federal requirements for containing spills so the fluids won't get away and pollute waterways.  if you are in russia, i have no clue about codes, but, if it were in the states, and if it contains such a "hazardous" fluid, here's some guidelines.  
look into nfpa, there are requirements for containments.  
briefly, you contain 100% of the largest tank within the containment dike.  also include enough containment volume to contain the largest amount of rainwater likely (or specified by code, usually something like 25-year, 24-hour storm, for us there are charts to give this in inches of rain, and for russia, who knows?).  if there are multiple tanks in the containment remember that only the largest one ruptures, the other ones don't & therefore reduce the containment volume by this amount:  area unruptured tank(s) x height of fluid.  (this is not as confusing as it first sounds, think about it).  for hazardous materials in the us, the dike usually is lined, with a clay or membrane liner.  (many things to deal with here, material specs, anchor details, installation qa/qc, etc.)  but size it for 100% of the volume of the largest tank.
the emergency walkway may or may not be required.  it depends on the fluid contained, operating procedures.  if the fluid is something you don't want to walk through elevated walkways may be a good idea.  i don't think any us codes require them though.  also consider how to drain the spill and also any rainater that collects.  containment probably should be sloped to a sump, that can either be pumped out manually (they come in with a pumper truck and stick the suction hose down into the sump and pump it out), or you could put in a drain pipe to a oily water separator, or other holding pond.  in the us, you probably have to put a valve in that pipe, so you can hold the rainwater for testing, if it tests clean you can just let it go or dump it, if it tests dirty, you need to do special handling of it.  but you'd probably need the valve.
hope this is of some help.
regards,
chichuck