I'm writing to you because i have encountered a problem concerning calculations of the characteristics of a steel box girder section. In fact, i have calculated the characteristics through Midas Civil in two different ways. First i have input the section dimensions in Midas and checked the calculation results. Second i have drawn the section in AutoCad and imported it to Midas and then checked the calculation results. What i noticed is the results are different, knowing that the thickness of all components are the same in both method. Thus, i'm wondering if you could help me figure out the reason i have these differences.
PS: You will find here attached the section which was done in AutoCad and the results from Midas calculations for both methods.