Dissapating corner moments in a rectangular underground tank

[Infinitybyzero]

This is a conceptual question based on a project I and a few other engineers finished at work. We are replacing the roof of a concrete tank that is part of a larger pump station for a river. Unfortunately, the roof is very integral in this structure, which means that once it's removed, the walls need to be braced.

The tank is roughly 60x20x22' deep and the long direction will have continuous shoring across mid height. The tank is integral on 3 corners with the rest of the station, but there is a corner that's unrestricted. From a theoretical standpoint, the soil, surcharge, and hydrostatic conditions on the outside of the walls cause a very large moment around that corner. The walls are close to 100 years old with no indication of corner steel/dowels, which obviously means that a large corner moment will crack the concrete quickly. There's no cracks in any of the tank right now and we certainly don't want to create any during construction.

Our solution was to provide corner struts to redirect some of the stresses, but realistically it won't go down that much because the walls are infinitely stiff compared to some 3" pipe. I'm not looking for a design recommendation, but more rather what you would do to dissipate excessive moment at the free standing corner of a tank (or wall intersection in a building) that is subject to significant lateral loading.

 

[Nidum]

The great cathedral builders and the later millwrights knew all about this sort of problem .

Many problems were solved using buttresses and other masonary reinforcement .

For example :

Two buttresses one on each face near but not on corner . Plain taper or flying

Groin buttresses wrapped around corner .

Castellated corners .