Expansion is a serviceability issue, not a strength issue, so for that reason most codes are silent on expansion requirements. The amount of expansion allowed mostly depends on how much your structure can tolerate which is very difficult if not impossible to codify. About all you will find are recommendations in code commentaries, white papers, etc.
We hardly ever use expansion joints in foundations or grade beams. The foundation itself does not need to be designed for expansion because the temperature is relatively constant since it is buried in soil. As for expansion of the superstructure, the resulting expansion forces are simply resisted by the foundation at the base of the column.
In your case, I am assuming you have a 6' or 8' high chain link fence. Any expansion of the fence mesh will simply cause it to buckle between the fence posts. No need for an expansion joint.