Sorry, but I very much doubt it was "close to structural Failure".
Instantaneous -1.6g against a normal operating limit of -1g isn't a particular structural drama. Severe turbulence encounters can put unsecured occupants on the ceiling without the aircraft falling apart. Obviously very distressing for the passengers and crew but some way off from the aircraft disassembling itself.
The subsequent investigation should make for interesting reading though. I'll be interested to see what particular autoflight/component failure would allow the protection limits to be exceeded like this....
If it ain't Boeing I ain't going.......