Hello 66mynd, in the Pacific Northwest we are considered to be seismically challenged, thus after the Northridge quakes in California and the subsequent fall-out from it, there was a major shift in engineering and welding specifications.
Allowable self-shielded wires changed, the engineering and weld procedures for much of the structural steel being erected changed, and a host of other things were implemented. I believe that is the time when FEMA 353 was put into place as a supplement for governing welding practices on structural steel erection and welding.
Not all work is under FEMA 353 and likely there are exceptions based on size and application of a structural project as well. Geographically I am of the understanding that the West coast and possibly a few other locations in the continental United States utilize FEMA 353 in conjunction with AWS D1.1 or similar codes with regard to seismic conditions where and when they apply.
In our classroom we have a mock-up steel structure with a number of different connection examples. I need to update and expand it again, there are just so many different combinations that are in use and have been used. We try to give students the opportunity to visually see, touch, smell, these things and allow them to have some recognition of what they may become involved with when they end up in a fab-shop or on a field-erection crew.
Thank you for continuing this conversation as some of the folks looking in on this might appreciate the subject and it's discussions and content. Best regards, Allan