Fire Moose, is that 2700 psf? Thanks for the info.
UD, yes and no. If you scroll down on the blog to "Why this will work", there is a five-ton ball inside a metal frame, and a similar ball with all the metal works inside.
I've also constructed an eight-foot cube in stone, its about 2/3 down on this blog:
I love heavy work! But this will be a stretch for me, no mistake. Friday morning I go into pre-engineering meetings to decide details on the beam sizes and foot sizes, so we can get an engineer to ok initial specs, so we can get fabrication and shipping budgets started.
It is seriously exciting.