I want to build a custom power rack to safely perform heavy barbell exercises in my home. Commercial racks are too tall for my basement.
Others have done this before: http://www.home-gym-bodybuilding.com/homemade-power-rack.html
One aspect I'm unsure about is how much space between holes in the upright posts I need to safely support the weight.
For those unfamiliar, a set of safety bars (1" solid steel bars) goes through the holes on each side. If you fail to complete a lift, you set the barbell on the safety bars and wriggle out from underneath.
500lbs would be a generous upper limit for the combined weight of the barbell and weight plates. It's fathomable that this weight may be dropped from let's say a foot above the safeties. Generally, I expect to be able to set the bar down gently, but that might not always be the case.
Placing the holes closer together allows for better placement of the safety bars and barbell holders. Several people will be using the rack, so I cannot simply place holes where they are best for just me.
I threw together a SketchUp model of what I'm planning. The holes will be 1 1/8" diameter (need to check actual diameter of some pipe to be sure). Currently, I have them spaced 3" on center. The holes are also be a bit off center, moved out towards the edges of the uprights, so that they are spaced far enough apart.
Can anyone help me to understand how I could calculate if this is structurally solid?
I understand wood is rated in compressive strength by psi. I'd be grabbing the best 2x6's I can find at a big box store, which looks like top choice hem-fir. I find some calculators, like this - https://courses.cit.cornell.edu/arch264/calculators/example7.1/index.html. That shows 840lbs for a 2x6, but 3846lbs for two 2x6's (I will be gluing two 2x6's together for each upright).
I'm not totally sure how to calculate the surface area. Obviously it's 3" through the board, but with a round pipe in a round whole, would I use half the diameter of the hole (3"*1&1/16*π = 10 sq in), or less? What's the effective area in contact with the pipe to determine the psi applied to the uprights?
I also don't know how the holes in the board affect the compressive strength.. I would assume it lowered it, but when I search about it I don't see length/height of board taken into account.
Any help would be greatly appreciated. Here's the sketchup