Sounds a good candidate for a pivot, in lieu of requested hinge. Hinge infers load transfer to frame elements, and a pivot transfers most of axial load to floor, and radial load to frame elements.
45,000 pound is a pretty hefty load... powered open and closed? Missile resistant assembly? Watertight assembly?
Labyguy is correct... without more complete info, none here can guide you very well.
B: Not bothering to acknowledge assistance offered
C: Not bothering to finish this particular homework question
I have heard many members opine that they do not respond to guest questions for these reasons, or any of another hundred possible reasons guests do not appear to return. Perhaps I shall give that position some thought...