I've built a pergola using Redwood out of 4x4's (posts), 2x6's (beams), 2x6's (joists) and 2x2's. The pergolas is 4 feet wide and approximately 26 feet at the longest dimension, it's shaped like a large U -- looks something like the attached picture (top view)
The posts are set on top of concrete filled sonotubes and attached via U-brackets. There are knee braces which are set down from the top of the posts approximately 18". Longest span between posts is approx 11 feet. The whole structure wobbles when I grab a post and shake it with one hand. Any ideas on how I can decrease the wobbling?
Drill/dowel rebar into post footings - sticking up 18"
Pour additional concrete around the posts - 2' tallx12" diameter
The two sets of 4 posts on the long side - it looks like the posts are 4' apart there. Run full height X-bracing between the posts (from bottom of one post to top of other - on both the set next to the house and the set 4' away from house)
Add another set of 2x2 purlins on a 45º angle on top of existing 2x2 purlins - run screws in at every connection
How thick are the knee braces? How are they attached to post and beam?
They could probably be beefed up to stiffen structure.
Do any combination or all four of the above...
there are also other options...