circular concrete tank-hinged wall base 1

[bjb]

for a circular concrete tank not prestressed, how do you detail a hinged base between the walls and the base slab? The tank I am dealing with is 40' in diameter and 27' tall. The details that I see in ACI 350.3-01 and "Design of Liquid-Containing Concrete Structures for Earthquake Forces" by PCA seem a little cumbersome.

Instead, I propose that you could provide straight dowells centered in the tank wall between the wall and base slab. The curtains of vertical steel at each wall face would stop at the top of the wall.

All comments are greatly appreciated

 

[JedClampett]

I usually design these tanks for both cases and provide vertical dowels for the fixed case and circumferential bars for the hoop stresses for the hinged case. It's probably less confusing to build with the two curtains of reinforcing continuing into the slab and a waterstop centered in between these bars. It never hurts to have a belt and suspender design for liquid contining structures.
Don't forget that there needs to be circumferential or radial bars in the foundation to carry the shear transfer into the base.

 

[AlohaBob]

The foundation ring can have a raised cast concrete curb to control shear and limit translation. There are graphite or other material pads that allow limited translation with a low coefficient of friction.