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Closet Rods or Structural Engineering of a "L" Bar

Discussion in 'Question of the Day' started by ship, Nov 14, 2006.

  1. ship

    ship Senior Team Emeritus Premium Member

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    So I had a thought while in the car today. (No I'm not going to do it, but simply theorizing about it.) Dextron, that slotted angle steel often used for mounting garage doors. Slots in it every say 1" on center of various types of slot or hole with a "L" shape of 14 to 16ga high carbon steel in having 1.1/4" to 1.1/2" legs to it.

    Given the spacing, it might make in some ways a decent closet rod - not that I’m considering such a ting at home but for a debate topic, consider it as this. What if you were to use such a thing for closet rod. Dispersed but at times very heavy weight to it.

    So now the real question, structurally is it stronger for the 1.1/2" strut to be leg down in hanging from the part of it in a vertical position, leg up in hanging from the horizontal portion of it, or legs folded together in hanging from both legs? If legs folded, is it best for the fold portion to be up or down?
     
  2. Van

    Van CBMod CB Mods Premium Member

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    Personally, I think using Buckminster Fuller as your guide to this would be best. I would instal it with the both of the legs facing down at 45 degree angles. The meeting point of the two legs would then from the apex of a right triangle, Mr. Fullers Ideal form for weight and load bearing structures. This would also most lateral dynamic forces to which a closet rod might be subjected, eg, pushing too hard on the rod while trying to force one more tweed jacket between those newly pressed tuxedos. :mrgreen:
     
  3. ship

    ship Senior Team Emeritus Premium Member

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    Ah' an angle I didn't think of. Given this would be a good angle, will the clothes hanger that hangs the tweed and especially Tux (neither of which I own) by shape with closed hook at the end assuming - a wooden hanger with 12 or 10ga wire hook span both holes than given the holes in the legs are ninety degrees apart say for a assumed 1.1/2" bar? If such a hanger can't (under question by way of the radius of the hook as compared to the slot of the angle steel,) this for something sufficient in hanger type to hang a tux, what will be the effects of hanging it off one leg? This by way of dispersed or single point source loading overall given say 25# load over a 4' span to one leg of the angle shape?

    Just wondering in this theory/discussion. Kind of a curious engineering thing that has other applications. Debate and plucking one's mind is useful later always for such things. I am plucking your brain to learn. I hope that all also learn from our musing and or theorizing about something very simple in engineering concept but getting very complex in explination and understanding by way of further refining the question/s.

    Will if at an angle and only putting a point source on one of the two legs be stronger than leg up, down or bent together as one? (This bent together of course being not so bent together to be flat but more like 1/4" apart in retaining some amount of angle but not it's origional shape any longer.)

    Side bar, if one were to hang a whailer across some flats on stage, is it best leg up, down or at an angle? (Term here, what's a whaler - given a certain also disqualification from Van to answer this specific part of the follow up question.)
     
    Last edited: Nov 15, 2006
  4. Van

    Van CBMod CB Mods Premium Member

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    Hmmm Ok, I'm going to have to R&D this tomorrow now ! You may have pierced my Buckminster Fuller theory. Given that there is no actual third side to this proposed triangular structure and that you are going to be point loading through the holes, it warrants further investigation. No wait, I'm going to stand on my original theory. I don't think that, given the thin gauge of the steel, it would hold up to the compression, or torsional stresses that would be present in any other configuration. If you are going to use the holes as the load points ( to keep hangers from sliding back and forth I presume ?) I think the only way It would work would be in the "Inverted V" format. In any other configuration I think the compression would simply cause the steel to "fold" over the top of itself causing bending then collaspe. If you were dead set on using one of the legs in an up or down configuration I would think that an inverted "L" would be the best canidate. The tension forces would be better aligned with the bottom edge of the steel and the compression forceswould be spread along the wider ,curved surface of the "corner". the inverted L would also reduce torsional forces to a minimum as the load would be pulling more directly down than if you were to use a standard "L" orientation. In a standard "l" the down force would be located away from the center point of the structure therefore and necessarily increasing the torque on the entire structure.
    Stop asking interesting quetions I need to go play Starcraft ! Oh yeah and I've got to go catch up on some drafting too !
     
  5. ship

    ship Senior Team Emeritus Premium Member

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    Laughing out loud!!! you and me both. Thanks for the mind twist. I agree and laugh that you were able to put into words what is very sensible about a closet rod. Thanks, great stuff. Curious question is also a good thing adding spice to life.

    Later thoughts

    What if instead of doing the reverse "V" you were to do the V hanging on it - assuming TBA the hanger would not work in the reverse "V" position. Would this be more structurally benevolent than the other L or reverse L options or that of the bent V?

    Dynamic loading of course becoming a factor to consider in balance with the live load.
     
    Last edited: Nov 15, 2006
  6. jwl868

    jwl868 Active Member

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    Without something tying the ends of the "V" together, it will just start to open up the V or close it, leaving a thin flat piece of metal that will bend and fail. But if you tie the end of the V togther, you no longer have a structural "L", but something of a box beam.

    I don't know whether it matters if the L points up or down because the load is borne mostly by that long arm. The shorter arm stiffens the beam.

    The only other way to look at it is to look at all the railroad bridges. "I" beams vertical and horizontal, with diagonal braces.


    Joe
     
  7. kingfisher1

    kingfisher1 Active Member

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    now lets remember that most closet rods are cylindric (cylindrical, cylinderstic?) what would the structuaral implications be if i took a drill, and for the purpose of the segragation of tuxes from tweeds, drilled through the rod at the chord to the circle that is nearest teh diameter, but still allows a hanger hook (approx. 10 gauge wire, 1 inch radius...) to go through?
     

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