Applying floor loads to displace the location of the CG?

Question

Hi, 
 I am modelling a steel structure for which the weight and center of gravity are known. The objective is to check the reactions on the supports and to verify the overall structural integrity. 
 I have finished the model now, I used a factor on the self-weight load to obtain the known weight, but now I need to shift the location of the CG in model to match the actual location in the real structure (it differs from my model because of miscellaneous equipment present in the structure, for which the weight is unknown). 
 Can you suggest an approach to this? I was thinking of applying live loads on the floor, close to where this miscellaneous equipment is located, until I get an CG close enough to the one I need. But this seems to be a trial/error method which might be very time consuming and inaccurate. 
 Any ideas? 
 Kind regards.

Sye · Answer

To calculate the CG correctly and also to find out the correct support reactions, you need to know the weight of the equipment and it’s location in the structure. If there is a single equipment and you know the location of that, your job is easy. You can find out its weight by subtracting the self weight of the structure from the total weight (including the equipment). You can subsequently follow the procedure described in the wiki below to include imposed loads as part of the CG calculation 
 
 communities.bentley.com/.../28648.how-can-i-find-out-the-cg-of-my-structure 
 
If you have multiple equipment, then you can do a trial and error but the calculation will only be approximate. Finding out the actual weight and location of EACH equipment would be the way to go to get an accurate estimate.