load capacity of square steel tube

A deliberately vague answer-it depends on the length and the assumption of the end restraint conditions....

Best answer is "whatever the structural engineer specifies and inspector approves"

8' lengths

This is one of those questions that lots of guys would hesitate to answer. What if one of us said 10k pounds and you built it and it fell down in a storm?

I suggest you look this up in Machinery's Handbook and if I were you I would suggest being conservative. Build it once to last forever. Steel is cheap compared to rebuilding.

And the thing you're worried about here is crumple mode. So your end design may well have stiffeners welded to the sides of the tube.

GWE

I've scanned and posted column analysis here:

Sorry, but this is something you don't want to fool around with. Take your plans to a certified Structural Engineer and get him/her to review them. The engineer will make recommendations and provide you with the necessary calculations for the building permitting process. Should cost around $250, a small investment to avoid unnecessay worry and headaches with the inspector.

Most of the standard round posts I see in the building centers have rated capacities well in excess of 8,000 pounds. Round post, 4" of adjustment. Check them out.

I had some posts and beams special made at my local steel yard. I certa> I am building a house and the draftsman says that standard 3" round steel

I think Marks Handbook has values for steel pipe filled with concrete. The concrete keeps the pipe from buckling as well as supporting load.

Dan

Anyway I ordered 4 X 4 X 1/4" wall square tubing and I think it will be way overkill but anyway still much cheaper than the local engineering/steel erectors want.

I designed and built the steel columns that support the glue-lam beams in our basement. Without more detail, all I can tell you is my

3"x3"x3/16" square tube columns, 7.2' in length were ssomewhat overkill in my house but that was fine with me and the steel was available locally.

Ted

After you reach a certain length, buckling is the critical element.

John

Do think about filling them with concrete. It will increase the amount they will support, and also help a little with increasing the life if there is ever a fire. Steel columns fail rather quickly in a fire.

Dan

and only the elastic modulus matters not the tensile or compressive strength if the column is long enough.

Ted

replying to Ted Edwards, Mr chrome wrote: Ah man what a bunch a sissys. What if what if. Sir if I had to translate the answers... Well I don't have a clue in hell how much they support...because we have never tested that particular product for that circumstance.