Concrete vs Steel is a big debate on lots of projects. Here is a quick rundown on Healthcare related steel vs concrete:
The best way to make a tall building cheap is to use concrete with LOTS of post tensioned steel. This allows you to use less rebar, less concrete. The downside to this is that post tensioned steel is NOT GOING TO MOVE. Once you put tension on it, relocation becomes EXTREMELY expensive.
Healthcare Facilities like to make changes to their buildings. Moving bathrooms, labs, etc happen ALL the time in these buildings. If your slabs or beams are post tensioned then you are going to be extremely restricted in where you can put stuff.
This building is using concrete shear walls in the stairs and elevator tower to help with the rigidity of the structure. This is a hybrid design which helps reduce the amount of cross bracing or moment frame welding required.
There are a bunch of other reasons, but I should probably get back to work so this will have to do for now.......