@hopetobereborn Wow, the pic helps put in to context why that thing failed. Glad you’re ok man
From looking quickly the lack of cross brace at the bottom probably didn’t help your joints. With the verticals sitting a little “toe out” the 90degree joints would be taking a lot more load that if it was perfectly perpendicular to each other, a brace at the bottom would help with this and keeping the frame in shape
If I was to build that thing again I would build a simmilar structure out of wood and mount a 3” diameter (scaffolding pole) between the uprights.
When building like this you need to think triangles too. Making an inverted “T” shape for each side is good, but then brace the upright to the foot of the T with a 45degree brace on either side and then connect both sides via a beam between them at the bottom. I would have thought 4x4” fence posts would be sufficient and would allow you to mount the pull up bar between them by drilling a whoppping big hole and then capping off the bar either side to ensure it secure (no joints to break)
Good luck my dude
Edit - like this but without the fancy top bits and also central to the base
https://www.google.co.uk/imgres?img...sXaAhXDDMAKHfm6Ds4QMwhwKAswCw&iact=mrc&uact=8