Above screen grab shows Finite Element Analysis model under 30 Kips vertical load and 4 Kips lateral load (theoretical wind drag about 1 Kip).
The model uses 2×2 by 0.188 wall ASTM A500 Gr. B rectangle tube formed into the shape, with ten equal ribs. Rolled channel section collect the loads at the bottom and the middle.
One interesting part is the skin (below the floor plane) which is modeled as a fiberglass layup with horizontal stiffeners every 3’ vertically (approx.). They would lap around and fasten to the the rib tubes, making a very efficient assembly.
This is very preliminary, but the model has 47,000 nodes and is one of the largest computer models of this type that I’ve constructed and operated.