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Thread: Help needed in determing the tip load capacity of a particular pole type

  1. #1
    Associate Engineer
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    Help needed in determing the tip load capacity of a particular pole type

    I am trying to determine the max horizontal tip load capacity that can be rated to a pole used for overhead transmission lines.

    The horizontal tip load is specified at 0mm from the tip of the pole. The tip load should be calculated with a vertical (compressive) load of self-weight + 200kg of additional weight. In addition, the pole is erected with an embedment depth of 1.5m

    All of my efforts to contact the supplier in china have been in vain as the 2nd party distributor hasnít been forthcoming with the name of the supplier. The only specifications that I have been able to obtain from the distributor is as follows.

    ASTM A53 Plain End Galvanized Pipe
    Outer Diameter: 114.3mm or 4Ē
    Thickness: 5mm
    Length: 9m
    Weight/m: 13.88 kg/m

    It is obvious that the material described above is not developed for overhead transmission pole applications but unfortunately thatís whatís being utilized.

    I would appreciate it if anyone could provide some assistance in solving this problem.

    Thank you in advance.

  2. #2
    Lead Engineer Cake of Doom's Avatar
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    So you need to check it for a combination of loads; both horizontal for bending and compression? Something also sounds a bit off about the information they have provided you. But anyways, as you have the grade of steel and some vertical load, all you need now are your variables (like wind loading) and you should be able to run quick second order analysis on your column. Other considerations: assuming this just being driven, you'll do yourself a favour to check the ground conditions are suitable to support all reactions. Never take anyone's word that it's all "OK".

  3. #3
    Associate Engineer
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    Thanks for the reply. What I need to determine is the max horizontal tip load capacity for the said pole type. Once I am able to put a rating to that I will then be able to compare it to horizontal components of external loads the pole is subject to such as conductor tension and wind induced loads etc.

    Typically with poles designed for overhead transmission applications, a max horizontal tip load capacity is prescribed. Unfortunately, the pole type that I have to work with is more of a general purpose pipe used more for piping applications (as dictated by my employer). I have been searching but I am not able to get any design capacity information relevant to the said type of circular hollow section of that particular grade of steel.
    Last edited by khknima86; 06-12-2019 at 06:38 PM.

  4. #4
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    Do you know the Grade of your pipe? There is a wide variance in the min yield strength between the various grades of a53.

  5. #5
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    No, that is something that I have been questioning the distributor about as well. I understand that there are grades A and B.

  6. #6
    Lead Engineer
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    Is your pipe seamless, if so, it is likely Grade B with a yield strength of 35ksi.

  7. #7
    Lead Engineer
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    Since you cannot get any help from your supplier of your pipe how about seeing if you can get/find the data for a standard pole i.e. O.D.,wall thickness or I.D., material spec and tipping strength. If so then it may be possible to determine the limit for your pipe using some calculations and ratios between the your pipe and the standard pole.

  8. #8
    Associate Engineer
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    Yes it is seamless. Ok, yes I think I'll have to just resort to that. Thanks for the advice.

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