In the past I've used plane stress elements to model shear walls, but that wasn't using ANSYS. The first thing to mention is that I assume it's a masonry structure? If this is the case then in ANSYS you need to be looking at the SOLID65 element, which is the only element capable of handling the concrete (TB,CONC) material model (and it is a 3D brick). On the other hand, if you're not interested in cracking/crushing/tension softening/secant moduli/etc. then you could possibly use one of the plane elements:
(42, 82) -> all things being equal, I would choose this method (less computation burden and a simple model)
(63, 93) -> would be concerned with the large thro-thickness and whether this influences the result
(182, 183) -> as per 42/82 but with better non-linear formulations
This all depends on your structure and whether it's symmetric, or whether it has rebar or other localised embedded stiffeners. The beauty of using the SOLID165 is that you can easily define these stiffners. If I had a nice simple linear structure with no rebar, and I had to choose, I'd go for the plane82 (as a plane stress option). (Just in case I'd do a simple correlation of the results with a simple 3D brick model as well.)
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