^^ Concrete posts or concrete footings?
I don’t see how there’d be a lateral stability problem with a screw pile vs a concrete footing. They’re both sunk down into the earth. I’m sure it depends on soil composition and stuff, but if properly engineered there should be no problem.
I wouldn’t be surprised if there were certain soil conditions where screw piles were actually preferable over a concrete footing/foundation, even for a house.
Neither one provide any lateral stability. They footings only provide a stable base to rest on and the post just sit on top. The only reason the posts are bolted to the bracket is so that they don't get knocked out of position if they get hit, or run into with a mower,
or something. Neither one provide any lateral (side-to-side) stability. Below is a picture of one of the new posts on the screwpile and next to the old concrete piling. There is nothing there to prevent lateral movement for the posts. When i went to remove the old post from its concrete mount, after i removed the old support beam, i simply pushed it over and ripped out the nails holding it to the mounting bracket. Same for the new ones mounted on the screw piles. I had to use lots of temporary bracing until I got the joists and diagonal bracing in place.
No problem setting anything on screw piles AFAIC as long as the lateral bracing is addressed.
As far as applications are concerned, screw piles are far superior for avoiding frost heaving than concrete piles in my experience. I know a contractor friend of mine installed screw piles for his deck and some fence posts almost 15 years ago and he has never had an instance of heaving since. The freeze-thaw cycle has gotten a lot worse in the last several years and last year my deck heaved more than ever and was really noticeable. Last winter the front rim joist of my deck looked to be elevated at least a few inches above the ledger board.
