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For slabs where bending is always in the out-of-plane direction, modifiers m11, m22 and m22 m12 are required to model cracking behavior.
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Walls are generally not designed for out-of-plane bending to avoid excessive longitudinal reinforcement. In this case, use a small modifier say 0.1 for m11, m22 and m12 so numerical instabilities could be avoided. However, use m11, mm2m22, mm12 m12 = 0.70 (or 0.35) when considering the out-of-plane bending in wall.
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Flat Plates & Flat Slabs....0.25*Ig modeled as membrane – f11, f22, f12 = 0.25 / modeled as shell – f11, f22, f12, m11, mm2m22, mm12 m12 = 0.25 (for both cases fxx is not important if rigid diaphragm is assigned)
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