Pergola Build - Freestanding i.e. No Post Holes

I'd worry about that much wood in contact with the ground. How about building a deck on something like this? I'd worry about wind, if that's a problem in your area.

What I did many years ago might be similar. Approximately 36 years ago I built a 10x12 deck with 2x12 around the perimeter. Posts sunk approximately 12~18" and surrounded with concrete.

About 4 years later I built a cover over the deck using 10, 4x4 posts on the perimeter. The posts are anchored to the top of the deck with Simpson post anchors. Basically a U shaped bracket anchored to the deck and the post sitting in the U and screwed to the bracket. I added rails with pilasters between the posts except on the front center entrance and back center entrance. The top is corrugated galvanized steel panels

During hurricane Ike, I added 3, 1x4 diagonal cross braces to stiffen the structure. With out the cross braces there was always a little wiggle in the cover structure. BUT the wiggle was never enough to worry about until the hurricane, approximately 21 years later. Immediately after the storm I removed the cross braces.

Today, some 30 years after I added the cover to the deck it still has just a little bit of wiggle but is as sound as the day I erected it. Our son has been enjoying the structure for the past 9 years, since he bought the home from us.

If you are not anchoring to the ground you should be concerned about the overhead structure possibly catching the wind and lifting the structure. Granted a pergola is mostly open but you never know.

No, but you might consider putting it on skids. The frame for the skids would strengthen the overall structure.

I'm not sure what you mean. Could you explain further?