It became clear that the calculation of such structures in the program is not supported. If I wish to add to the list, is there any chance that in the future this type of calculation to be realized?
I suggest you to (workaround) by using two panels (Vertical as wall and Horizontal as footing). But you have to do your own manually stabilities checks such as ( overturning , sliding … etc)
You can download from French Forum (Expert tool 2012). Returning wall model is existing module and using French and polish codes only.
