Any Mechanical Engineers willing to a solve a math problem?

Discussion in 'General Technical Questions and Answers' started by WA7F, Jul 12, 2019.

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  1. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Yes, but the snow load, the basic structural load and the load of the added I-beam and any weight it supports will all be supported by the existing end poles. Can they handle the additional load based on the analysis above with sufficient margin? I've done work around bending moments and strengths of wooden telephone poles subjected to wind in their normal application but I'm not sure about the strength in compression of typical pole barn support poles nor what diameter poles the OP has in his barn.

    Seems like the bolded part below is key to the original question.
    N0TZU likes this.
  2. K3RLD

    K3RLD Ham Member QRZ Page

    Just do all your calculations in slugs, then you don't need to use Gc.


    Any ME should remember that from school.....
    AF7XT likes this.
  3. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Good point. OTOH, traditional pole barns are way over “engineered” IF built in the traditional way with stout lumber. Here my county doesn’t require any engineering drawings for them, even in the high snow load areas, if built according to those standards, which they publish. (People hang all sorts of stuff from the rafters too, not that its always a good idea.)

    I still think an hour of a PE’s time for a consultation might yield a very pleasing result, for example, maybe all it would take is to sister two boards to a rafter, or some cross boards to help spread the weight across several trusses.
    K7TRF and KA0HCP like this.
  4. NN4RH

    NN4RH Premium Subscriber QRZ Page

    When I took Mechanical Engineering classes at University of Illinois decades ago, I could not figure out how slugs could support that much weight. For one thing, they're slimy and slippery if you step on them. There's no way a slug could support 32 pounds like the prof said.
    N0TZU and K3RLD like this.
  5. WN1MB

    WN1MB Ham Member QRZ Page

    They tend to disintegrate in salt air environments, too, so fuggetabouit if you're on the left or right coast.
  6. WA7F

    WA7F Premium Subscriber QRZ Page

    Hey guys, I think I’m good at this point. You can carry on if you want.
    W6KCS likes this.
  7. NN4RH

    NN4RH Premium Subscriber QRZ Page

    As for the rest of the thread.... The thread is all over the place because people didn't fully read the OP.

    Yes he starts off talking about barns and snow and stuff (paragraph 2), but then the actual question (paragraph 3) is a simple loaded beam question.
  8. AI3V

    AI3V Ham Member QRZ Page

    Bet you a box of assorted Japanese wavelengths you can't find a I beam made of steel that's not at least a36 steel.

    Pro tip: if you are not buying your beam new, look for the brand on the web, that will tell you who rolled it:

    It'll look something like this....


    Of course if you are buying new steel, your steel merchant will be able to tell you who made it.

    Last edited: Jul 12, 2019

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