Decks, Patios, Porches and Docks - Pergola footings - California

I am wondering what size footings I need for a 12'x12' wood pergola, with four 6x6 vertical posts, topped by two paired 2x10 or 2x12 headers on two sides, then most likely by 4x4s running perpendicular on top of the headers at 16" or 24" on-center spacing. Should I sink a U-bracket into the concrete for through-bolts or sink the wood in the concrete? I live in Nevada County, California, at 1500' elevation (Frost depth looks to be about 5" from the frost depth chart). I have heard that builders in the area pour concrete footings 2'x2'x2' for pergolas, but I'm not sure what the code says. A couple more questions: Would I definitely need knee bracing in the corners? Should the 4x4s be attached with hurricane brackets? Thanks in advance!

Go with the 2' cubes and embed Simpson column bases (CBSQ or similar) in them to mount your posts in. Frost in Nevada County is there, but not deep enough to be much of an issue, especially with your footings being 24" deep.

You are relying on the footings to prvide all of your lateral support -- the pergola won't be attached to anything. Make them large enough to do the job.

Thanks for the reply. A couple more questions: I plan on painting the wood (to match the style of the house/decks); does paint protect pine from rot? Or should I definitely use cedar or redwood, despite the fact that it would be painted?

And in the footings, how much if any rebar? I'm thinking that'd be a big chunk of cement not to put any rebar in.

Thanks!

You're in CA -- the only 6X6 you are going to find is doug fir. That's what you want to use anyway because that's what will give you the most span at any given size.

No, the footings don't need any rebar.