engineerding:
That's different from what I inferred from your first post... Obviously it's not what you expected to imply, but I (and I'll hazard to guess BAretired et al as well) though you meant naked driven column shafts as the foundation...
If you cast the column into the soil an pour concrete around it, I wouldn't call that direct embedment. I would agree, however, that it is an excellent solution and a good way to go. The solution is predicated on the ability to source and handle long enough columns to get the embedment required.
At 30ft out of the ground, and I'm guessing about 6ft into the ground, we're just about pushing for length. Also this commits the project to field work on site unless you can get the fabricator to deliver the fully assembled sign (not out of the question, but I've seen and heard of trouble in this regard).
A star for your excellent idea, now that I actually see what you meant! lol
Regards,
YS
B.Eng (Carleton), P.Eng (Ontario), MIPENZ (Structural-New Zealand)
Working in Canada, and missing my adoptive New Zealand family... at least I brought the little Kiwi with me!