FW: Urgent Beam Stress calculation incorrect

Question: Urgent Beam Stress calculation incorrect

There seems to be a beam stress calculation error or something the program is doing that I cannot figure out. For example, for element 70013 in Stage 3-6 wind, the SY stresses corresponding to MZ are approximately twice what they should be if you took the MZ forces and divided by the weak axis section modulus. I have verified that the Moments are correct and the section properties are correct. Can you please clarify what the discrepancy is? I have attached the file.

Sby stress is equal to Mz/Izz*Cyp. So it seems that there isn't any error.
I attatched .xlsx and .ppth files. In .xlsx file, I calculate stresses using Mz and compared with stress output data.
And you can understand how program calculates stresses by viewing .pptx file.
Thanks & Regards.
Jihoon Kang
Creation date: 10/23/2017 12:34 AM      Updated: 2/2/2018 3:15 PM