Even though I am a little late with my two cents but here they are anyway.
This is nothing else but a king post truss were the "king post" is a metal rod thus allowing for a long clear span on the first floor with no obstructions like posts. It does nothing for the roof and does not need to. The rod is on tension with the floor practically hanging on it. The braces are on compression and transfer the load to the exterior walls near the post. The tie beam is therefore also under tension. They might have use a rod instead of a post because it is less intrusive. Reminds me of a german build roof systems.
So the only thing different compared to what one finds in most other barns is the fact that tha truss is seperated from the roof/rafter. Not so unusual after all.
