precast concrete water storage tank
precast concrete water storage tank
(OP)
I am looking for information on the construction of precast concrete water tanks. I have a 6000 gallon tank constructed using three, 4-foot high sections(7'x17'x 12' deep). Cracks have developed at the corners of the tanks and the long walls bulge upon filling the tanks with water (no backfill present when water placed in tank). I am interested in gathering any industry-accepted code information that may be out there; specifically can anyone point me to code references regarding backfilling prior to filling tanks with water? thanks.






RE: precast concrete water storage tank
There's no code prescribing backfill procedures. But a water tank should not need backfill to resist internal pressures. A correctly designed tank can resist soil pressures without liquid and liquid without soil pressures.
RE: precast concrete water storage tank
I agree with Jed. Bulging visible to the eye suggests a fundamental problem.
RE: precast concrete water storage tank
RE: precast concrete water storage tank
the precast sections were connected shiplap style with conseal joint sealant. I have no detail from precaster at all, no engineering design drawings, specs, etc. I don't even know f'c.
RE: precast concrete water storage tank
to be more specific about the cracks: the cracks are vertical and are typically located at the ends of the long wall at the shorter return wall. I do not have a measurement of crack widths, some are filled with sealant. The cracks are only located at the middle panel and I can only see a small amount of the top portion of the cracks for the tank walls are partially backfilled. The cracks are near the tank corners and located on the intersecting shorter wall. cracks resulting from bulging? I could not measure bulging due to backfill soil.
RE: precast concrete water storage tank
The precaster either didn't know or could care less that this is being used to hold liquid. Hopefully he was told this when this was ordered. I'd call him up, tell him his tank is failing, and ask him what he's going to do to make it right.
A lot of times these sections are not used to hold water, but for vaults and low pressure manholes. So they mostly resist outside (soil) pressures. And those are much easier to design for.
RE: precast concrete water storage tank
RE: precast concrete water storage tank
Absolute gem. It took me a while to work out this seems to be three rectangular boxes stacked one on top of another.
No idea how thick or what re-inforcement etc, but looks like a disaster in the making to me....
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: precast concrete water storage tank
I do not believe repair is a viable option.
Listen to Jed, Hokkie, and LittleInch. Cuddos to Brad for answering the actual question, but you've asked the wrong one OP. There is no need for technical information beyond fundamental design theory: It may not have collapsed yet, but to satisfy SLS the structure must be fit for use.
For once I think we are all signing from a common hymn book for very good reason.