I'm a pretty green welder and I'm not sure how to make this stiffer. This is just 1 of 4 racks that will be tied together with 10' long square tubing through the space between the two verticals. This is made from 14g 1-1/4 tube 48" wide, 41" tall, 3'3" between each of the 4 racks to make it 10' long. It will be freestanding. Its made to primarily hold lumber but a couple willl hold some random long steel. When I lean on the top rung/horizontal it deflects about 3/8" which is more than I'd like considering the weight it will have. It's not fully welded yet, just solidly tacked but I don't think that why it's flexing but maybe. I was hoping to avoid gussets and save the space in the rack but I don't want to just keep adding to this thing without really knowing if it will stiffen it. Just haven't worked with steel enough to know. Suggestions?
Welders: How can I stiffen this shelving?
- Thread starter climb.on
- Start date
It's mild steel, it's going to flex. Short of moving the supports that are in the middle currently further towards the outside or using thicker walled tubing there isn't much you're going to be able to do to stop it from flexing. Just make sure your welds fuse well and there's nothing to worry about.
rsanter
Well-known member
Completely under designed for the task
Bare minimum would have been 2” height tubing for the cross pieces
Bob
Bare minimum would have been 2” height tubing for the cross pieces
Bob
Perhaps. I doubt he will be putting 200 lbs per side per rung of load on it. Ot should be just fine. Dont overload it with steel. And keep heavier things closer to the middle.
As far as design only gussetss or taller material would make it stiffer
Yah I should have gone heavier so there is no question. I don't think I'll have much steel on it, but you never know. Oak and maple ain't particularly light either. I have all the steel here and some extra, so I think I will just go to 5 or 6 sections instead of 4. I'll just add gussets if I'm still not comfortable with the the strength. The more I look at it, I think I need to add one to the bottom anyway. There could be a lot of torque on that lowest middle connection.
Even with four posts over ten feet you should be fine. I think you over estimate how.much weight you will put on it. What I was getting at before was your body weight per rung is likely more than it will ever see.
Yes it will deflect and that is why these type of racks sometimes have the rungs at a slight angle. Especially so things wont roll off (tubing). But for a static load it should be fine. Everything deflects. Its the nature of the material.
Yes it will deflect and that is why these type of racks sometimes have the rungs at a slight angle. Especially so things wont roll off (tubing). But for a static load it should be fine. Everything deflects. Its the nature of the material.
b-dog
Well-known member
You could weld a 1/4" (or whatever thickness) x 1 1/4" tall plate to the side of each tube. That would stiffen up the horizontal bars. The taller the plate, the better.
I checked some lumber racks at work and they are sized about the same 1-1/4od pipe instead of square...they deflect about the same and I've never even noticed it before. Been in use for 20 years. I'm going to add one more section just to be sure.
Great idea. Wouldn't take away any shelf space either. Thanks.
tapered-pin
Well-known member
I'd suggest using back to back angles for the shelf supports, personally.
Gusset plates where the cross bars connect to the vertical supports would help with the 'strength' of the welded connection between the pieces.
To reduce the cross bar deflection when you stack stuff (oak, maple, steel, etc) on the shelves, you would need to increase the 'stiffness' of the cross bars.
And the way to do that is to increase the cross bar's "second moment of area" in the vertical direction.
https://en.wikipedia.org/wiki/List_of_second_moments_of_area
Which is engineering speak for 'increase the amount of material in the vertical direction in the bars'.
The general formula for a rectangular shaped beam's second moment of inertia is
I = b * h^3 / 12
where b is the horizontal 'width' of the beam
and h is the vertical 'height' of the beam
Increase h and the value of I increases rapidly (because it is cubed in the formula).
Which you can do by the mentioned method of welding some vertical plates to the sides of your cross bars.
Think of an I-beam. Generally 'smaller' top and bottom flanges and a 'bigger' dimension in the vertical web.
https://en.wikipedia.org/wiki/I-beam
Another relatively quick way to increase the stiffness of your cross bars is to weld another cross bar right underneath and to your existing cross bars.
To reduce the cross bar deflection when you stack stuff (oak, maple, steel, etc) on the shelves, you would need to increase the 'stiffness' of the cross bars.
And the way to do that is to increase the cross bar's "second moment of area" in the vertical direction.
https://en.wikipedia.org/wiki/List_of_second_moments_of_area
Which is engineering speak for 'increase the amount of material in the vertical direction in the bars'.
The general formula for a rectangular shaped beam's second moment of inertia is
I = b * h^3 / 12
where b is the horizontal 'width' of the beam
and h is the vertical 'height' of the beam
Increase h and the value of I increases rapidly (because it is cubed in the formula).
Which you can do by the mentioned method of welding some vertical plates to the sides of your cross bars.
Think of an I-beam. Generally 'smaller' top and bottom flanges and a 'bigger' dimension in the vertical web.
https://en.wikipedia.org/wiki/I-beam
Another relatively quick way to increase the stiffness of your cross bars is to weld another cross bar right underneath and to your existing cross bars.
rsanter
Well-known member
On a storage rack, 200 pounds happens faster than you know it
penright
ALLIANCE MEMBER
This may be overkill....
I was going to say anytime you have a round tube that needs to be stiffen after the fact, is to lay some angle iron across it. I have seen it used in gantries a lot. I think this is what @tapered-pin was describing. It would not exactly be a piece of square tubing, since you have your round tube also.
@MoonRise Question, so looking at the web page you posted.
I am guessing the 'I' is how much bend, the more 'I' the less bend.
"An annulus of inner radius r1 and outer radius r2" would be the tubing.
"An equal legged angle" would be the angle iron.
So, if one piece of angle iron was added to the bottom or top of the round tube so the direction of Ia would be vertical, would the two 'I's (tube and angle iron) add? Or would it be some percentage of the sum of 'I'?
The other option .... did not come close to understanding what you were saying.
I was going to say anytime you have a round tube that needs to be stiffen after the fact, is to lay some angle iron across it. I have seen it used in gantries a lot. I think this is what @tapered-pin was describing. It would not exactly be a piece of square tubing, since you have your round tube also.
@MoonRise Question, so looking at the web page you posted.
I am guessing the 'I' is how much bend, the more 'I' the less bend.
"An annulus of inner radius r1 and outer radius r2" would be the tubing.
"An equal legged angle" would be the angle iron.
So, if one piece of angle iron was added to the bottom or top of the round tube so the direction of Ia would be vertical, would the two 'I's (tube and angle iron) add? Or would it be some percentage of the sum of 'I'?
The other option .... did not come close to understanding what you were saying.
Lelandwelds
Well-known member
Wood racks flex a bit. Install it where it will not hurt anyone if it fails. Add another upright if it worries you.
If you build a steel rack, avoid the issue by building it from steel purlins with spacers. No arm to flex.
If you build a steel rack, avoid the issue by building it from steel purlins with spacers. No arm to flex.
@MoonRise Question, so looking at the web page you posted.
<snip-snip-snip>
The other option .... did not come close to understanding what you were saying.
Last option I mentioned (since the OP said he had some more square tube available):
Basically taking two pieces of 1.25" square tube and welding them together to turn it into rectangular tube that is 1.25" wide and 2.5" tall. Install it with the 2.5" dimension in the vertical direction.
penright
ALLIANCE MEMBER
I did not mean other option to OP, I ment if what I was asking did not make sense, then it (other option) means I did not understand what you explaining in the website ("second moment of area"). I was asking a technical question. I was trying to explain, using the terminology on the website, why adding angle iron to round tube would increase it stiffness. Or I was asking the question a different way to see if I understood what the you/website was saying.
Sorry for confusion. My bad ...
strutaeng
Well-known member
I did some racks some time ago using 1x2 tube (I think like 12 gauge.), but the "arms" were only like 12"
You could weld them at a small angle upward (2-4 degrees) such that when you load them they wouldn't deflect downward.
From a strength standpoint they are probably okay.
Also, my racks had full height verticals from floor to ceiling. That way the forces go into the floor and ceiling, instead of the studs.
I hope this helps.
You could weld them at a small angle upward (2-4 degrees) such that when you load them they wouldn't deflect downward.
From a strength standpoint they are probably okay.
Also, my racks had full height verticals from floor to ceiling. That way the forces go into the floor and ceiling, instead of the studs.
I hope this helps.
strutaeng
Well-known member
I took a look at your photo and I'm not sure how this is working. I thought they were racks bolted to a wall.
metalmagpie
Well-known member
Put two more posts on the outside. That will enormously stiffen the horizontal members, which as is would be loaded in cantilever.
metalmagpie
metalmagpie
EVOLVO
Well-known member
I just did something similar for my steel rack, although it isn't as wide as yours. I would suggest putting in trusses about 4-6" below each cross bar at the uprights that go about 2/3 rd of the way out towards the cross bar ends forming a long triangle. You lose a bit of stacking height inside at the uprights, depending on how far down you anchor the trusses but it will make the cross bars very stiff. Hope that's a clear explanation!
b-dog
Well-known member
Gummi Bear
Well-known member
When in doubt, I add a gusset.
I don’t have a bandsaw or a plasma, so cutting them is kind of a pain.
I really like to buy from A&A, they have a ton of neat stuff in their catalog
https://www.aa-mfg.com/gussets?limit=all
The last material rack I built, I used Unistrut. It bolted together, and as far as I know, is still being used. It was for holding GRC conduit, and was always full.
I went to the woods because I wished to live deliberately...
Henry David Thoreau
I don’t have a bandsaw or a plasma, so cutting them is kind of a pain.
I really like to buy from A&A, they have a ton of neat stuff in their catalog
https://www.aa-mfg.com/gussets?limit=all
The last material rack I built, I used Unistrut. It bolted together, and as far as I know, is still being used. It was for holding GRC conduit, and was always full.
I went to the woods because I wished to live deliberately...
Henry David Thoreau
There is a lesson for you here OP...steel is fairly cheap. Find a supplier, buy all your material there, tip the yard guys that write it up...you will learn why.
Buy a bit heavier than you may think you need for earlier projects until you start to figure out the characteristics of the various types of stock...
Buy a bit heavier than you may think you need for earlier projects until you start to figure out the characteristics of the various types of stock...
b-dog
Well-known member
So much truth to this - even if you're familiar. I design machinery and if it's something for mass production then cutting material costs is important. However, for anything that is a 1-off, I take what I think will be good enough, then double or triple it. Too many times I have a thought, "This size should be good enough" then after the fact wished I had gone bigger.
EVOLVO
Well-known member
That's called a gusset, the idea was shot down in the OP.
True, but it's either a gusset/truss or a failed rack. OP can take his pick!
So much truth to this - even if you're familiar. I design machinery and if it's something for mass production then cutting material costs is important. However, for anything that is a 1-off, I take what I think will be good enough, then double or triple it. Too many times I have a thought, "This size should be good enough" then after the fact wished I had gone bigger.
I like that approach. And I should know better and have trusted my instinct to go heavier. One definition of an "expert"...a guy who's made more mistakes than anyone else
...and learned from them. I guess I'm on my way.Oh give me a break.
Yah wow they do have some cool stuff - thanks!
Thought I would follow up with pics of the finished product. As I stated above, I decided to add one more set of arms, which turns out was good since most of the material is 8' long and it would have been resting 3 arms instead of 4. Now most is on 4 arms, and some on 5. It's very very solid. I bolted it to the floor as well. I have no concerns. It holds way more than I thought and I'm already thinking about what I can fill it up with.
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hefnerconstructionlc
Well-known member
Real nice. Heck yeah!