I am trying to understand if RAM Frame takes into account the effect of openings in concrete shear walls on their stiffness when distributing story shears in a rigid diaphragm due to wind loading. To determine this I have modelled a square building, one side of which has shear walls with very large openings and on the opposite side of which it does not have openings. It has 3 floors all with rigid diaphragms. I then evaluate the shear induced on the walls by wind load in the direction of the shear walls with openings and without openings. Unfortunately, I have been alarmed to see that the shear forces are the same on each side... if there are 3 shear walls on 3 sides of the building. However, if I add a 4th shear wall, the walls with openings take on less shear than the walls without openings as expected! It is very strange. Adding another level of confusion is that the Center of Rigidity is very clearly in the right place and is taking into account this change in stiffness for both the 4 walled system and the 3 walled system. But, unless I specify a special load case for the CR, the button does not turn on, which indicates to me that RAM Frame does not compute torsional forces about the center of rigidity. Is it computing them about the COM? Essentially, I have two questions:
1. Does RAM Frame account for the change in stiffnesses due to wall openings when distributing lateral forces due to wind in systems with rigid diaphragms?
2. How does RAM Frame compute torsion for these systems? If not about the COR, why not?