New calculator for buckling strength of EMT pipe

[WaWaWeeWa]

Can anyone comment on this calculator I found for the buckling strength of EMT pipe

http://www.atc-mechanical.com/calcul...al-properties/

1. Enter length of tube (6 feet for me)
2. Enter load (I just put 400lbs)
3. Pick "select tube based on column buckling property"
- the subset confused me. It gives you options for one end fixed/ one end pivoted, both ends fixed, etc
- I just selected one end fixed/ one end pivoted because my design is a single vertical EMT pipe with 2 guylines on one side and the hammock on the other
4. Pick "use any size"
5. Pick "every gauge"
- 1" EMT has a wall thickness on 0.057"

This calculator says the buckling force for 1" EMT with 0.058 wall thickness is 817 lbs. Does this sound right? If it is I would think it would be fine for my stand since ive seen other threads around here talking about maximum compressive force being ~400lbs for average individuals.

[AA2FD]

It's been over 35 years since my college class in mechanical engineering. Here's my take:

The end in the air would be 'pivoted/pinned'. Is the end on the ground driven into the ground (like a 8-foot length with 2 foot in the ground, and 6 foot above)? That would be a fixed end. if it was just a 6-foot length with the bottom able to pivot around, then it would be 'both ends pivoted/pinned'.

If I were doing the calculations, I would run all 4 options, pick the lowest number, and then use half (or less) of that as a safety factor.

...Bob

[WaWaWeeWa]

Its basically the classic Alamosa stand. and the bottom of the pole resting on a piece of wood on the ground.

[DylanC]

If you're worried about it just go up to 1.5" EMT and call it good. I think that's what I used as an 8' ridge pole on my "stand." If I remember my mechanical design courses (also an engineer) minimum safety factor is three for almost anything you can imagine... Even higher for dynamic loads.

[G-Rat]

In the situation you describe both ends of the pipe are free to rotate, thus are "pinned" not "fixed". An example of fixed would be setting the pole into a deep hole in the ground filled with concrete, which would prevent the lower end from rotating. Running the calculator with both ends pinned should result in the lowest buckling strength.