Originally Posted by justmehere
the scallops that you were mentioning is called "camber" in engineering terms.
the beams will straighten when all the load is factored in.
I think everyone who referred to the scallops was referring to the ends of the steel spandrel beams seen here:
source - from NewYorkSkyline117's post #22179
That's not camber at all. I'm not sure of what the "scallops" are exactly exactly, but my theory is that they are "fuses" that allow the ends of the beam near the connections to fail via ductile failure. In my theory, they are designed to fail at a load that's less than the failure load of the connections. That way, any potentially catastrophic loads would only damage the beam at these "scallops"/"fuses", and the damage to the rest of the connection area would be minimized or eliminated (this also means minimized or eliminated damage to the column as well).
EDIT: After doing some research, it turns out my theory is mostly correct: