Submerged Tank 6

[dik]

I've got a 6' dia tank X 20' long tank submerged vertically in soil. The x-section of the tank is about 28 ft^2 and the conc base I'm proposing is about 10'X 10'. How do other engineers address this type of problem. I've got a bit of a discussion going on at the office. Assuming the entire system is submerged, is it reasonable to assume that the concrete base has a density of 150-62.4 psf and the included weight of soil is (100 - 28) * (gammasoil-62.4)*20' (assuming no angle and no friction) to resist floatation? or would you neglect the weight of the soil?

Dik

 

[midvill]

I have a 72" diameter 10'depth with 8 inch walls precast pump station that will be installed under a pressure slab that is 15inch thick. their are no slab tie downs in the area. I was following the threads on this and found this setup verry similar to what you guys are dealing with. what would the uplift force be on this structure to the slab and will this "pop" the slab. Assume 100% saturation with out the widened base as pictured above. 1 foot of stone under base and # 7 at 6" radial tied back itno slab.

 

[JStephen]

For a vertical tank, the uplift is just the pressure at the bottom end times the cross-sectional area, less the dead weight. Or if fully submerged, the volume times density of fluid less the dead weight. You'd probably need to check with the slab designer to see if that kind of load was figured in the slab.