Originally Posted by
Bruce Breedlove
I don't think the fire protection provided by grouting the beam in the beam pocket makes any difference whatsoever. Assuming a simple beam (no rigid end connections), the stresses at the ends of the beam are very small compared to at mid span. If there is a fire hot enough to cause the steel beam to lose strength it will fail at mid span long before it fails at the end supports.
I'm thinking more along the lines of fireblocking. Fill the beam pocket with grout and you've fireblocked that open area up into the wall (at least as I am envisioning the way it would be configured).
As far as rotation goes, I am envisioning a standard flange ("I") or wide flange ("H" on its side) beam which is not that tall, the ones I've seen did not have a large height/width aspect ratio, thus rotation would not be an issue.
Without a photo, who knows.