I was running a design for a WT vertical brace and found what I believe to be a mistake in the calculation of the shear lag factor, U, for tensile rupture. I have (7) rows of bolts connecting the WT flange to the gusset. From AISC Table D3.1 I would expect my shear lag factor to be the larger of Case 2 (U=1-x_bar/L) or flange portion of Case 7 (U=0.9).
However, it appears that for Case 2, the x_bar being used in the program is not the distance from the faying surface at the flange to the centroid of the member as expected. Rather, it is using the distance from the geometric center (depth/2) of the section to the centroid. Unless I am missing something, the distance from the geometric center to the centroid is arbitrary in this case and the distance from the faying surface to the centroid should be used.
For Case 7 it also appears that it is using the web connected case (U-0.7) instead of the flange connected case (U=0.9).
Is there any guidance on how I should interpret these results? Has anyone else run into this issue?
Note: I am using Connection Standalone Version 10.0.0.177