Primary Structure Building Analysis

Hi guys.
I`m using SOLIDWORK mainly to sketch simple parts and model, and i came across of Solidwork Simulation lately and feel nice since i can analyze my designs.However, i was wondering how does cad users analyze building structure? I mean the primary structure basically consist of for example concrete and steel rods. Do we need to build a hole feature and insert a rod or just mate the rod with the concrete part? In my opinion these two will give different result, but which is more relevant to the real structure?
I haven't try analyze it yet since i still haven't figured it out which data to use to insert in the custom material list. The data i found gives like for example Compressive strength : 20 - 40 MPa. Should i use the value of 20 or 40? Thanks in advanced