A. To output the center of rigidity

To instruct the program to include the center of rigidity of each rigid diaphragm in the analysis output, use the following procedure.

The lateral force at each floor, as generated by earthquake and wind loading, acts at the center of rigidity of each floor which is modeled as rigid floor diaphragm. The center of mass of each floor is defined as the mean location of the mass system of each floor. The mass of the floor is assumed to be concentrated at this point when the floor is modeled as rigid diaphragm. The distance between these two is the lever arm for the natural torsion moment for seismic loads when that option is used.

Select the Post Analysis Commands tool in the Analysis Data group on the Analysis and Design ribbon tab.

The Analysis/Print Commands dialog for post-analysis commands opens.
Tip: If the dialog does not immediately open, click Define Commands on the Post Analysis Print - Whole Structure dialog.
Select the Dia CR tab in the Analysis/Print Commands dialog.
Check the After Current option to insert the print command following the currently selected command within the Post Analysis Print - Whole Structure dialog. Otherwise, the print command will be added to the end of the STAAD input file.
Click Add. The command is added to the STAAD Input file.
Click Close.