Proper Reading A Concentric Load of Pipe

[Herbrata]

Dear All

I found a chart in this site:
https://www.engineeringtoolbox.com/load-steel-pipe-columns-d_1348.html

Can we describe it like in these pictures attached.

I select 3 inches pipe and length of 6 Feet.


Thanks all.

 

[Herbrata]

I confuse since I have a real world problem.

My contractor propose me a lattice boom of 3,5 inch pipe sch 40 (0.226 inch thickness). 20 feet / 6 meter length with load force (P) of 98 kN.


From this site:
https://www.engineeringtoolbox.com/load-steel-pipe-columns-d_1348.html

Max safety load of that pipe is only 53.4 kN.


But compare to this video:
[ame="https://www.youtube.com/watch?v=-VrAinXULUc"]Calculate if a column can can support a load - YouTube[/ame]


After calculation, I get:

- The Compression acting is 56.7 kN/m2, which is less than 200,000 kN/m2 (for standard steel allowed). OK Good

- P Critical (Buckling) is 114.5 kN which is more than force P applied (98 kN). OK Good.


Now which one is right?

Do I make mistake in calculation?