Axial load on partially buried wall

[Fr109]

Hi,
Not having a lot of experience, I'm looking for a simple approach for the following situation:

I need to design a prestressing bed foundation consisting of 2 parallel concrete walls 128 ft long, 8ft high x probably 16" thick, 7 ft apart. The walls will be buried up to 16" from the top on the outside, and 40" from the top in the center with compacted gravel/sand. Maybe considering a plain concrete floor in the center if necessary.

On top the walls, and perpendicular to them, is welded a light metal structure consisting of a 6" channel on edge, at 4 ft o.c. On top of these, in the center, running parallel to the walls is a plate 1/8" thick x 13" wide whose edges are supported by 4" channels on edge.

Loads: A moment at each end, tending to uplift the ends of the walls, 1,630,000 lbs-ft, situated at 13.5 ft from each end.
Plus a 243 kip axial load compressing towards the center, applied at the top of each wall also at 13.5 ft from each end.

QUESTION: Can these walls be considered as having continuous lateral bracing, so that I can provide reinforcement only for the uplifting moment, and not have to worry about the axial loading?

Any advice would be very much appreciated.
Thanks!

 

[ishvaaag]

Quite likely yes, but one would have to go about the numbers to prove it. Of course and to help in that intent the channels should be welded to plates anchored to the top of the walls.

Anyway you can model the thing, the prestress trough the equivalent loads in FEM, even with some degree of initial imperfection, and assuming some degree of lateral spring reaction of the soil on the walls, include P-Delta and see about the general stability of the outfit.