Since the I have problems installing Robot on my laptop, Glenn helped me showing how to analyze the structure model. I will simply list the 3 samples I selected below and explain the reason why I chose them.
Sample 1 is the longest beam in the whole model. It is located at the front atrium. The result shows that lightest feasible beam is W14*416, which is definitely not applicable in the real life. So I will have to change the geometry there.
Even if the main structure is steel supporting structure, I use concrete for the office part because of cheaper cost and more practical application. The sample above is the typical concrete system in my model.
Sample 3 is a typical steel beam system set in the model. This specific one is supporting the balcony on 2nd floor.