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  1. UofIgrad17

    Stiffening HSS Column

    GC_Hopi, yes, the design is quite different as mine is above the top ladder rung, but same basic idea.
  2. UofIgrad17

    Stiffening HSS Column

    dcornelius, to clarify, the ladders are primarily installed in plants where they will be fixed to walls or large tanks essentially making them rigid. The client is dealing with all of the OSHA guidelines. I am strictly checking the design strength. Unfortunately, I'm the only one here with a...
  3. UofIgrad17

    Stiffening HSS Column

    CANPRO, I'm determining the maximum angle from the drop test (Edit: middle of the ladder rung, maximum of half a foot on either side). Real-life application will be different, I'll admit. However, in real-life application, there will be a device between the person and the post that is...
  4. UofIgrad17

    Stiffening HSS Column

    JStephen, I'm pretty sure the standard HSS material is A500 Gr. B and not really sure where to find higher grades anywhere else that are readily available without significant cost increase. I think I'm going to take the rectangular HSS approach, but trying to determine the best way to calculate...
  5. UofIgrad17

    Stiffening HSS Column

    HotRod10, as far as I know, channels typically are only made of A36 steel correct? I'd be taking a hit on strength there. I think rectangular HSS is the best route to take. The smallest size that would work that I could find online was a 3 x 1 1/2 x 1/8. Thinking now to CANPRO's comment however...
  6. UofIgrad17

    Stiffening HSS Column

    MotorCity, please see my response to CANPRO for testing criteria. I definitely see the flaw in logic of installing this device, but that is how the client that's selling them sees it best to install them I guess. I'm sure he has some sort of harness himself with carabiners or something similar...
  7. UofIgrad17

    Stiffening HSS Column

    Thanks CANPRO! I'm not sure exactly why they require 5000 pounds for a simple ladder safety device that probably will never see more than 500 pounds on it. The funny thing to me is that the device withstood the dynamic drop test, but failed the static test. Since the dynamic drop test passed, so...
  8. UofIgrad17

    Stiffening HSS Column

    Size is of some importance simply because he'll be carrying it up the ladder so it can't be too bulky (it's already 8'3" long). From a cost standpoint, I also doubt he'd want to go the aluminum route. I calculated that a 3 x 1 1/2 x 1/8 tube will handle the forces and is only adding 0.43 lbs/ft...
  9. UofIgrad17

    Stiffening HSS Column

    I also played with reducing the eccentricity, but you'd have to essentially be at the face of the post to pass combined flexure and axial loads, which isn't an option. I like the idea of using a rectangular 2 1/2 x 2 x 1/8 as the difference is less than half a pound per foot, but I can't find a...
  10. UofIgrad17

    Stiffening HSS Column

    I had a "duh" moment where I realized that it's just treating it as a built-up member. I don't suppose there's a way to calculate the length that the bar needs to be however. Since the axial force and moment is essentially uniform throughout the tube I'd imagine the bar would have to span the...
  11. UofIgrad17

    Stiffening HSS Column

    Please see the sketch above. Unfortunately, the connection plate cannot come down any further. There are two iterations to the design, one short and one long. The long one is giving the issues.
  12. UofIgrad17

    Stiffening HSS Column

    I've attached a sketch. The dashed area is where I was thinking of welding the bar on. The thought of it having to be a composite section crossed my mind, but I wasn't sure exactly where to find the spec calculations for this as the composite section mostly refers to concrete and steel together.
  13. UofIgrad17

    Stiffening HSS Column

    This is my first thread on here so I wanted to say hello to everyone and how much I appreciate the community. I'm currently a structural engineering intern so I'm learning where real life and academia tend to clash. I'm working on a device that is going to be used to prevent falls from ladders...

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