50x75 steel frame foundation questions

[loweredd]

I'm getting everything together now for a 50x75x16 in NW Iowa. It will be a steel frame building with 3 bays. I was thinking of doing 8 6'x2.5' piers for the columns and then a 2'x8" grade beam for the perimeter. Our frost line is around 4' everywhere I've looked online. I was planning on pouring the floor later in 3 sections to be able to use cash when I had it.

Does this sound fine?

 

[healing]

If your concrete for the columns are below frost line and you don't skimp on rebar I believe that will work.