Hey guys I found this forum and very informative i must say. My question is i found a similar thread but i am wondering. I am building a punching bag frame for 14 punch bags between the weight of 100-120lbs. The span is 23' by 20'. The span of 23' will be broken up with a support in the center. My question is that having 20' 4x4 tube steel with a wall thickness of 3/16" will it be able to support 300-360lbs of this span. My other question is if 2 people were to jump on this say 500lbs would this support the weight. Inclosed is some drawings. Apprechiate the help. This is the side brackets witch will be used on the corners towards the centre post side. I have not done the 20' side yet. The centre post brace will be on both sides and the bolt holes will be sleeved.