I used a steel framing system to allow for longer spans/less columns/more open space. All columns are located along walls to prevent any interruption in the space. I used W12x26 for girders, and W10x12 for purlins. I made sure to frame the openings (skylight and stairwell) and added columns at grids C4 and F4 to help with load transfer from the opening to the girders along grids C and F.
