underground concrete water storage tank

[rittz]

I saw a drawing for an underground concrete water storage tank which was approx 20' x 30' x 8' high, The lop of the roof slab was 12" or so above grade. Located 4 or 6 ft to the side of the tank was a 12" dia pipe which extended vertically from a foot above grade down to the level of the bottom base slab (no closure on the bottom of the pipe). It was essentially a deep sump (9ft). What was the purpose of that sump anyone? The tank was in use as a fire pump test facility.

 

[Ron]

You might want to post this in some other forum besides "Wood". You'll probably get more response from either the "Structural Engineering other topics", "Civil/Environmental Engineering other topics", or "Concrete Engineering general discussion".

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The sump might have been an observation well to check for ground water at the tank bottom or to check for tank leaks. If the ground water was higher than the tank bottom, they would want to make sure the tank had water in it to prevent hydrostatic uplift damage to the tank.