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Thread: Angle iron stand strength for a fish tank stand

  1. #1
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    Angle iron stand strength for a fish tank stand

    Hi all,

    I do not have any engineering background so pardon my ignorance.
    I am interested in build a stand for my big fish tank (8'x2' dimensions with wet weight of 3750 lbs).

    Thinking of using 1 1/2" (1/8" thick) angle iron for building a stand for it (instead of using 2x6" wood framing).
    Stand dimensions: 8' x 2' (length x width); and 2.5' tall.

    Want the final product to look something like this (not my pic)



    1) Would 1 1/2" (1/8" thick) angle iron would be sufficient to hold about 3750 lbs of dead weight?
    2) Would one vertical support between the corner legs be sufficient (so one every 4')?
    3) Is there a certain simple formula giving stress values by putting size of angle iron & weight capacity over various lengths?

    Thanks again for all help.
    Attached Images Attached Images
    Last edited by Kelly_Bramble; 07-23-2016 at 07:05 AM.

  2. #2
    Technical Fellow Kelly_Bramble's Avatar
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    Quote Originally Posted by nostradamus View Post
    1) Would 1 1/2" (1/8" thick) angle iron would be sufficient to hold about 3750 lbs of dead weight?
    2) Would one vertical support between the corner legs be sufficient (so one every 4')?
    3) Is there a certain simple formula giving stress values by putting size of angle iron & weight capacity over various lengths?

    Thanks again for all help.
    Classic over the top question. Without creating a 3D model, importing into FEA software or doing hand calculations I can't be sure..

    To be sure the effort would probably take a little over a week (40+ hours).

    The best answer I can give you... Buy a table that is certified at or above the loading requirements you need...
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  3. #3
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    stand update

    Well, I'm thinking of using 1 1/2" square tubing for the stand. Hope it works, as far as the structural integrity.
    Can anybody tell me how much weight a this type of stand can hold?
    Stand dimensions: 8' x 2' x 2.5' (L x W x H)

    Here is an image of something I am envisioning...
    Attached Images Attached Images
    Last edited by Kelly_Bramble; 07-24-2016 at 06:38 AM.

  4. #4
    Principle Engineer Cragyon's Avatar
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    are you wanting to hire somebody to do an analysis? I think that's against the forum rules..

  5. #5
    ghostdigital
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    If the tube a a36 structural steel - it will support a bunch...

    Quote Originally Posted by nostradamus View Post
    Well, I'm thinking of using 1 1/2" square tubing for the stand. Hope it works, as far as the structural integrity.
    Can anybody tell me how much weight a this type of stand can hold?
    Stand dimensions: 8' x 2' x 2.5' (L x W x H)

    Here is an image of something I am envisioning...

  6. #6
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    Crayon, I am not looking to hire anyone. I am member in woodworking forums and have received lot of help with formulas stating the tolerance values for 2x4s, etc of different tree species. I was just curious if there was something simple like that for regular iron square tubing (1 1/4 size). That way, I know how much a my stand to the described specs would hold without giving way.

    ==## did not mean to undermine anyone's work, all I want to know is if my stand would hold ~4000 lbs without issue ##==

  7. #7
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    Found some info. on this website - but not sure if I understand it right...


    **** Commercial links Not Allowed Link Removed ****
    Last edited by Kelly_Bramble; 07-25-2016 at 07:13 AM.

  8. #8
    Technical Fellow Kelly_Bramble's Avatar
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    I am not looking to hire anyone. I am member in woodworking forums and have received lot of help with formulas stating the tolerance values for 2x4s, etc of different tree species.
    Here's what I think... Your original post seemed to ask for an analysis of the entire frame... Like I ***d - not trivial for somebody that knows what they are doing.. This is a lot of work to ask an engineer or designer on a volunteer forum.

    I was just curious if there was something simple like that for regular iron square tubing (1 1/4 size)
    Yes the tools do exist but not simple if you are not trained in simple stress and deflection analysis but here is the most comprehensive links to equations and calculators available on the web ..

    Section Properties Equations and Calculators

    Beam Stress and Deflection Equations and Calculators

    Engineering Materials

    Machine design and Application

    all I want to know is if my stand would hold ~4000 lbs without issue
    If you put enough wood in it probably, but who knows? are you putting this thing upstairs in a frame house? How are you going to attach different members to each other? Nails? Clips? What is the actual wood made from? Can you verify the engineering characteristics of the wood? What happens over time?

    Engineering and design is about understanding the problem before you and applying science to be sure about the design.. "Gut feel" can and does work with experience however either the creation is very expensive $$$$ or a failure occurs - which again is $$$$.
    Last edited by Kelly_Bramble; 07-25-2016 at 07:46 AM.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  9. #9
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    As Kelly has stated it not a simple question and one additional issue is that, due to the lack of any diagonal stiffeners, the deflection of the frame under load will also substantially depend upon the rigidity of the base upon which the stand is setting.

  10. #10
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    Quote Originally Posted by JAlberts View Post
    As Kelly has stated it not a simple question and one additional issue is that, due to the lack of any diagonal stiffeners, the deflection of the frame under load will also substantially depend upon the rigidity of the base upon which the stand is setting.
    Thanks for the info on diagonal stiffeners - I will make sure to add that to the square tubing stand.

    I put the following info. in the removed website:
    Steel Tube: Ends Fixed
    tube size in inches = 2
    decimal gauge = 0.25
    length of beam in inches = 48 (as there will be vertical support every 48" to the stand)
    center load in pounds = 2000 (I put 2000 lbs assuming the wt of the tank will be distributed throughout the stand on 4 sides).

    And, this is the output I got
    :

    type = steel ends = fixedest.
    weight = 5.9461# per foot
    OD = 2" ID = 1.5"
    Moment of Inertia = 0.9011
    Deflection = 0.043"

    In your opinion, does the 0.043" deflection fall in the acceptable range? Also, after I add the diagonal bracing, it should have added support.Just want to know what your thoughts are ...

    Important Caveats:
    This calculator may give you a rough idea of the deflection of metal tubing, but it's not accurate enough to do any more than estimate it. If the deflection is large enough to permanently bend the tube, then all bets are off.
    Last edited by Kelly_Bramble; 07-27-2016 at 09:53 AM.

  11. #11
    Technical Fellow Kelly_Bramble's Avatar
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    1, a single point loading is NOT the loading configuration that a "fish tank" will exert on the frame.

    2, the ends of your frame will NOT be Free to pivot.

    3, the calculator assumes an E of 29,700,000 - which does not include a FOS.

    4, using EE calculator at https://www.engineersedge.com/beam_b...flection_2.htm

    I get a deflection of 1.034" and a maximum stress of -40,000 which means that the beam will fail under loading.

    Wrong calculator, giving you the wrong answer using the wrong data..

    See my post above for the right calculator, etc...

    Quote Originally Posted by nostradamus View Post
    Thanks for the info on diagonal stiffeners - I will make sure to add that to the square tubing stand.

    I put the following info. in the removed website:
    Steel Tube: Ends Fixed
    tube size in inches = 2
    decimal gauge = 0.25
    length of beam in inches = 48 (as there will be vertical support every 48" to the stand)
    center load in pounds = 2000 (I put 2000 lbs assuming the wt of the tank will be distributed throughout the stand on 4 sides).

    And, this is the output I got
    :

    type = steel ends = fixedest.
    weight = 5.9461# per foot
    OD = 2" ID = 1.5"
    Moment of Inertia = 0.9011
    Deflection = 0.043"

    In your opinion, does the 0.043" deflection fall in the acceptable range? Also, after I add the diagonal bracing, it should have added support. Just want to know what your thoughts are ...

    Important Caveats:
    This calculator may give you a rough idea of the deflection of metal tubing, but it's not accurate enough to do any more than estimate it. If the deflection is large enough to permanently bend the tube, then all bets are off.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

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