Decks, Patios, Porches and Docks - Deck Piers

I planning to build a free standing deck around an above ground pool. I was considering sinking the PT posts directly into the concrete to avoid the need for bracing the posts. This seems to be a good way to secure fence posts but is this a good practice for decks, not to mention code requirements.

Also, since it's a free standing deck, can I avoid digging the holes down to 42 inches, say only 24 inches instead? I considered using the floating piers but the plans on freedecking.com shows 30 piers for a 27 foot deck.
Thanks...

That's not the way you want to do it!

First, you mention 42" footing depth. That tells me that you are in an area where frost is an issue. Dig the hole 42" deep. At the bottom of that hole, pour a footing that is 16" to 18" square and a foot deep. While that concrete is still wet, add a length of 10" or 12" Sonotube to the top of the footing that extends at least 6" above grade and fill the Sonotube with concrete. Backfill around the outside of the Sonotube with dirt as you come up. When the Sonotube is full, insert a Simpson PBS44, CBS44, or similar. (My preference is CBSQ's.) Give the concrete a day or two to cure, then start building your deck. Your 4X4 posts will sit in the post base or column base.

Lastly, your holes HAVE to be 42" deep if that's what the frost line in your area is -- the inspector won't pass them if they aren't!