Design of interface between slab and ring foundation of water tank

[Berniedog]

I need help. I have searched through various posts but have not found out how to design the interface between the slab and frost wall of a water tank. See attached PDF. We have seismic and wind shear and overturning.

 

[Sawbux]

Looks like the slab is poured monolithic around the "starter plate".
Ring foundation poured first with anchor/leveling bolts. Plates and starter plates of tank wall put in place and levelled, then floor slab and exterior ring of concrete poured.

 

[WARose]

Looks like you have your loads and your load path.....just a matter now of crunching the numbers.

If you are thinking about the differential forces of heave on the slab and the "frost wall".....with such a shallow frost depth, I would think you could improve the ground underneath the slab to eliminate heave (or have it be minimal and not generate much force).

 

[Berniedog]

Can you reference something to show us how to design?

 

[WARose]

Outside of a reinforced concrete text and maybe a foundation design handbook.....I can't think of anything. Not sure if API has anything on this.

If the lateral force can all be taken out by friction in that slab.....then about the only forces at the interface to think about are the (previously mentioned) heave issue......and some vertical and moment forces from the differential settlement between the slab and the ring. (From the downward forces.)

 

[oldestguy]

To eliminate heave at the edge, substitute the supporting soil at least four feet thick and four feet ouside (at bottom) with granular soil less than 5 percent P-200 sieve. Of course high compaction 95% Mod.Poctor.