Never argue with Bobby Greif's inventions.  However, a shed I now own (Crushed limestone floor)was converted  by pulling the center post that was rotted off, welding the original bracket to a short I beam, and put back in the hole with cement around it, much like Bobby's pictures, but with an I beam.  I still own the shed, and the whole outfit works a whole lot better than the other sheds I built on the place I used to own.  Takes a bit to level the top piece, but not that hard to do, and still works well.  Last winter I couldn't shut the doors, and was worried about the center piece until I discovered the posts next to the door frame had rotted off.  Put new posts next to old, jacked up the supporting posts, and drilled through both posts to support the doors, problem solved without moving the center.  I had been wondering why the entry door hasn't worked well for the last few years, and my problem with that is solved with replacing the posts by the doors.