Installing Pergola support beams

Looking at building a 20' x 12' pergola, I'd like your opinion: When my 10' horizontal support beams meet at the midway (6 x 6) post, there's only half of the width of that post to share with each horizontal support beam ... and not enough area (IMO) for proper use of lag screws. Would it be a better plan to notch all my 6 x 6 posts in order for the horizontal support beams to have a platform on which to rest?

 

I'm missing something - how does notching the 6x6 make more area for the beam to sit on?

 

I think the OP's first option is lagging the beams to the face of the post. We know this is not legal or recommended.

Notching would give more support. Someone will follow with code specifics on this.

 

That makes sense - I thought we were talking about resting on top, then resting on the cut edge after notching....

 

Check out your local real lumber yards, I know mine carry's up to 20' long pressure treated 2 X's.
The 2 X 6's need to be notched.

 

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Don't notch anything. Far more effective to just use a short, thick "spreader" beam (3'+/- long) on top of the center post, making a support platform for the beam ends to rest on.

 

Do you mean adding something like a jack stud along side the post to rest the 2X beam onto?

 

No. I mean making a capital "T" with the spreader beam on top of the existing column; obviously, the column will have to be shortened by the thickness of the spreader. It (the spreader) has to be thick enough to resist the shear forces it will be subject to, meaning something like a 6 x 6, 3' long. I haven't crunched the numbers, but I don't think a 2 x 6 would work, being too thin.

I'm a licensed professional engineer, but only licensed in Colorado at the present time. That's why I'm reluctant to perform engineering calculations for anyone from another state.