I'm about to build a 14 x14 ft pergola using 4 4x6 post, 15 2x8x16 PT wood. I'm concerned the overall weight. I want to attach 4 2x8x16 to the posts and notch the other 11 2x8x16 and attach 2x2 on top. Will the 4 4x6 post hold the weight or do I need to add more post.
If the the pergola is going to be attached to another structure, like the one pictured above, then you're good. If its not attached then I would have some concern about the overall structure racking. However this is easy to fix by adding 4x6 knee braces at 45 degree angles to each post (example below). They'll only need to be a couple feet long to add a great amount of lateral stability to the structure.