I alluded to this earlier.
I've noticed that the typical highway sign supports (i.e. "sign bridges"
etc.) and even the very tall "high mast" lighting structures here in Texas
have base plates that are NOT grouted. The loads into the foundations go
through the anchor bolts for tension AND compression.
The plates rest on the levelling nuts.
Again, no grout.
What if any is the advantage in this? I can sort of see it for big, thick
annular base plates attached to circular or polyhedral columns, which have
only enough "meat" to allow an anchor bolt hole, since the bending is not
likely to be great.
But I can't see the advantage for rectangular base plates, since the bending
and punching forces are likely to be severe. It seems to me that you'd want
a grouted pad beneath them so they'd "behave" more responsibly.
I'd like some comment.