Is there a setting somewhere that allows the horizontal members importing from the ISM Repository to place at Top of Steel vs the Centroid?
Horizontal steel members are getting imported at the Centroid placement point and are not at the correct elevation.
There is no setting in AECOsim Structural that allows you to change the Placement Point of members when they get imported from STAAD.Pro or in the ISM import. Open the ism file in Structural Synchronizer Viewer, which is in the Start menu with a shortcut in the Bentley Engineering folder, before it gets imported into AECOsim. Then double click on any member and it should show you the properties on it, which includes the Placement Point. If it is not the placement point that you want, then the issue shifts back to the Staad program where it may be set before it gets exported out of STAAD.Pro.