Over Head Water Tank
Over Head Water Tank
(OP)
Hi
I have to design a OHWT of capacity 60,000 gal (imperial). shape is octagonal on six RC columns height of the base of tank is 60',dia at 60 Elev. 23',dia at 60+5 Elev. is 37' and with this dia it goes straight up for 9',top is coned with an height of 9'. soil BC is 2tsf.how to start the design, what forces/factors will be most critical.
Regards
I have to design a OHWT of capacity 60,000 gal (imperial). shape is octagonal on six RC columns height of the base of tank is 60',dia at 60 Elev. 23',dia at 60+5 Elev. is 37' and with this dia it goes straight up for 9',top is coned with an height of 9'. soil BC is 2tsf.how to start the design, what forces/factors will be most critical.
Regards






RE: Over Head Water Tank
you've started with a few values - that's good enough for preliminary structural estimating.
But it is not enough.
Wind (adds loads and forces), seismic (adds loads and moments and inertia), corrosion (reduces metal thickness against all forces), sag & overturning moments (as foundations fail, eliminates symetry, increases point loads) -> Get a basic design, look up your local requirements, then apply the local additions to the "theoretically perfect" structure analysis.
RE: Over Head Water Tank
I would suggest that this should come from a more experienced engineer - do you have one in your company?
Not sure we can do that sufficiently on Eng-Tips.
Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies
RE: Over Head Water Tank
RE: Over Head Water Tank
I had seen a code for building them once; I'm going to have to put my thinking cap on...
RE: Over Head Water Tank
@JAE: i have seniors with me at my company. here i posted it to have second opinion, to have latest issues/research/problems that might encounter on the way.Also opening this question may benefit other freshers.
in my company practice is to use SAP2000 , any other software which can be used or should be used to have more realistic results.
Regards
RE: Over Head Water Tank
RE: Over Head Water Tank
RE: Over Head Water Tank
I'll throw out some America-based companies to google.... and this is an incomplete list.....
Phoenix (formerly Universal), Caldwell Tank, Pittsburg Tank, i know there's more
Here is an example of a 60,000 tank. http://www.phoenixtank.com/wp-content/uploads/2013...
RE: Over Head Water Tank
Frankly concrete tanks tend to have very specialised requirements when they get exceptionally large. Also, why elevate with concrete? Seems crazy to choose a brittle material that comes with significant dead load. I can understand using RC columns, but not the tank. If you are designing a steel tank on RC columns, the majority of AWWA D100 will still apply.
RE: Over Head Water Tank
in our area most of housing societies has the practice of concrete OHWT so that its concrete.
i will consider the option of steel tank on RC columns.
RE: Over Head Water Tank
RE: Over Head Water Tank
RE: Over Head Water Tank
Figure out the the worst case force from sloshing, apply it to the inside surface of your tank and work through the load path all the way to the foundation. Remember that the classic load case of dead plus eq plus reduced live should be full live load as it is a storage application.
RE: Over Head Water Tank
Construction and design of elevated steel tanks is a fairly specialized business. If this tank is being built in an area where elevated concrete tanks are the norm, I would expect the same to hold true for them, and it would be prudent to work with designers and constructors of similar tanks.
Serviceability and leakproofing can be major issues, more so with an elevated tank where everyone can see it.