How can I find out the CG of my structure ?
You can use the command PRINT CG in your input command file as shown below
PERFORM ANALYSIS PRINT STATICS CHECK
The software would then calculate the CG based on the selfweight of the structure. It must be clearly understood that imposed loads like joint loads, member loads, floor loads etc. are not included in the CG calculation. The section 5.42 of the technical reference manual contain details on this command.
If one needs to calculate the CG for part of the structure, one has to define a member group consisting of the structural elements belonging to that part and then use the command below
PRINT CG (_group_name)
The software prints the CG as part of the analysis output file ( File > View > STAAD Analysis Output ) as shown next
If one needs to include the imposed loads as part of the CG calculation ( for example, if one needs to include some heavy equipment sitting on the structure ), one has to define the self weight and all imposed loads in global Y as part of a primary load case. Subsequently one should use PERFORM ANALYSIS PRINT STATICS CHECK command and then the center of force for that primary load case will be printed in the analysis output file as shown below