...
SAP2000 does not evaluate warping directly for frame elements and it does not explicitly calculate or use the warping moment of inertia, Iw.
...
FAQ
How can I obtain warping stresses from SAP2000?
Open Question
Use shell elements to create a detailed model of the beam.
Can I evaluate warping stresses using only frame element, or do I need to create more detailed model using shell elements?
Open Question
...
Modeling by shell elements is required.