The springs on this monster are two big torsion springs about 4" in diameter and 3 feet long. They are wound up 7.75 turns each. On the end of an 18" rod it is a pretty good push.
If these babies ever let go it won't be safe to be in the room. Chips of the concrete tie beam will be missiles.
I did anchor the bracket with 5/8" read heads in the tie beam so it should stay there.
This is probably a 400 pound door. It is 150 MPH without supplimental bracing.
