Be more specific. I have never heard of using light gauge steel members to make a portal frame. Are you thinking about the portal frames that are used in pre-engineered metal building construction?
I have seen on some websites either single or double 'C' Shape Member back-to-back. The beams and columns were attached by steel plates and bolts to create the building shape similar to PEMB Frames. They were used on garage, sheds, and barn size structures.
