Concrete Beam Ratios

[northward]

I am working on the design of some insulated concrete form walls (Rastra walls ER-4203). These walls are only 6" wide (that is the concrete width not including foam). The wall needs to act as a beam to support loads at window/door headers. However, with such a small width I was wondering if there are limits to the depth of the beam? (ie Depth to thickness ratio?) I did find a reference to lateral buckling for a length to thickness ratio of 50 in the ACI. Also, are shear ties useful/possible in such a small section of concrete? The ICBO report does indicate ties are possible, but for only one bar of reinforcing, I need two bars side by side for some of the longer spans. Also with two bars and ties the clearances are tight, but I would assume that foam would act as a barrier to allow for a clear concrete cover of 3/4".
I am also looking for hints how to analyze this for vertical/axial loads. There are several places where girder trusses are bearing down on the wall (12,000#). This work is being done under the California Building Code.

 

[RiBeneke]

I am not familiar with the detail of your code.
In general the depth-width ratio will determine whether the member falls under the 'beam' or 'wall' design rules.
I do not see a problem with 2 bars and vertical ties (by ties I think you mean what I would call stirrups) in a 6'' width, as long as you get 1) required cover 2) passage for 1.5x aggregate size between the bars 3) concrete poker vibrator (if used here) between the bars.