I’ve been toying with sinking a pair of ‘telegraph pole’ type timbers vertically, about 3m apart, then having a metal bar spanning the pair (like a crossbar) About 11ft up..
This will create a structure to have a swing/Olympic ring/Arial hoop hanging from.

I’ll probably get some rings (for fixing) welded into the bar, and either have the bar ‘passing through’ the timbers, or have a fixing plate fitted to the end do it can bolt into place (11 feet up).

Ignoring the fact I’m likely to need about 16 feet of timbers to make the uprights (twice!), would scaffolding pipe be strong enough to span the 3m and have family P swinging from it like some over eager but underachieving cirque du solero wannabees??!!

DrP

Scaffolding pole is more than strong enough.
It might be easier & cheaper to use the narrow-gauge tubing that hand-rails and kids climbing frames are made of, for that and the uprights. I can’t remember the trade names offhand.

Scaffold tube is strong stuff, bloody heavy too.

I will follow this one with interest as i do a bit of rings stuff myself, think i’ll have a fiver on shoulder/ rotator cuff injury.

I have been looking at a similar project and was wondering on the diameter to use, I actually have some scaffold tubing in the garden, and it seems to be the correct diameter however it is pretty rusty so I am not going to use it.

Some googling would suggest that the thicker the diameter the harder the exercise will be.

My problem will be integrating the pull up bars into a pergola.

There are some interesting builds on Youtube to give you inspiration

somewhere that supplies Galvanised pipe