How much weight will it hold?

[bad_idea]

I want to build a metal rack similar to Mike_C's to store 2x4's and other lumber and also various metal. I have enough 2x3/4x1/16" rectangle steel tube to build the rack. My question is how much weight do you all think it will hold? I plan on doing a weight test to see if it bends or flexes, but I was hoping maybe someone had some first hand knowledge on the strength of the tube. Thanks.

Here is a picture of Mike_C's rack for reference.

 

[Regnar]

I dont think the tube will be your weak point. More then likely it will be the wall that is mounted to. Now if you run the tube all the way down to the ground the wall would only be used to counter react the off balance.

 

[mike13u]

Wall stress only. That tube isnt going anywere.

 

[bad_idea]

cool. I am figuring 1/4"x2" lag screws should hold. Should I use longer?

 

[DirtyWhiteBoy]

I was worried about mine pulling out of the studs, so I ran legs to the floor. It's most likely overkill, but I like it that way. I still need to install loops and chain to make sure nothing falls on my melon.

 

[BD1]

Hi, what's the wall look like ?? is it finish drywall and finished ceiling?? Can the steel go to the floor ??. my wall was 2x4 studs, no drywall. Besides lag screwing to face of stud I welded steel square plates to side of vertical uprights with holes in them to through bolt to stud. Worked out well and will not pull out. you may be able to run up to the ceiling joist too depending on construction or have a ninety at top of steel upright that would rest on top of wall plate. a picture would help.

 

[duffman1278]

If you really want to know send me or post up the dimensions of your storage rack and I can run a stress analysis and see.

 

[bad_idea]

Thanks duffman. Here is a sketch of the rack.

Wall studs are spaced 24" OC. Four of these brackets, one per stud.

 

[duffman1278]

Let me just say that I'll run more test tomorrow.

Anyways I ran this test using just a single beam as the rest would be equivalent so keep in mind that the loads and stresses I am giving you are PER beam.

Now based off a cantilever beam, applying a single load at the very end while making the opposite end (nearest the wall) rigid yielded me 291 pounds of force at a factor of safety of 2 from hand calculations. The computer also got about the same as shown below.

Moving on though, I placed the 2"x.75"x1/16" tubing on the overhanging tube as shown below. This turned out to give out much worst result at 25.5psi applied to the top of the beam which results in a vertical center load of 291 pounds producing 256,000 psi of stress which is obviously immediate fail.

In the end though, your looking at about 4.7psi of loading PER BEAM, or 50 pounds at the center to give a max stress of 47,000 psi which is cutting it kinda close to the yield

 

[bad_idea]

Wow. That is a lot of talk way over my head. What I gather from that is the square tube is good for 291 pounds per beam safely. But the same square tube is no good for the vertical piece. What is a better material for the vertical pieces then? Thank you for taking your time to work on this for me.

 

[duffman1278]

Actually, I wouldn't exceed about 50 pounds. Would help though if you put a gusset under.

 

[metaldad]

very nice work, Duffman.
1/4 x 2 lags is a bad idea. 3'' are more better, as will 3/8. pilot drill lag locations. gussets will add strength

 

[Hephaestus29]

I made a rack for stock, that I mounted on the wall out of old bed rails that works pretty good for light stuff. Each level probably has about 100 lbs on it right now and could really benefit from small gussetts.
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