Torsion problem

[marty494]

I am designing a new pipe support to be supported on top of an existing steel first floor beam. The new pipe support is a 152UC, approx 2.5m tall and has an eccentric load at approx 500mm (like a hangman support). I have calculated the torsional load for the horizontal eccentricity but i am not sure if i need to allow for any additional torsion on the support beam due to the height of the 152UC. I would think there is potential for twisting due to slenderness etc....

 

[ishvaaag]

If there is some possibility of the pipe forcing the loaded flange to some side, better to gauge in what extent. Temperature? Hydraulic Inertia? If no movement is expected, you can go along without any imposed displacement and the ordinary assumptions. Otherwise impose some rotation, of or force a sliding support, or brace the tip of your cantilever etc. The pipe itself may need be restrained against unwanted movement.

 

[marty494]

Thanks ishvaaag, pretty much what i was thinking but only worried about any unknown forces that would have an effect being quite a tall lever arm.

Thanks for the info.

 

[Ussuri]

Is the existing beam an open or closed section?

If it is an open section, and you are relying solely on the beams torsional resistance to provide support I think it would be wise to check how much angle of twist you would expect to see. It is possible that the beam displacement may force your pipe to adopt a different deflected shape, altering the forces in the pipe. The pipe ends up 'supporting' the beam and not the other way round. Just a thought.

 

[marty494]

Open section so i am reliant on the torsional resistance. I am going to go with restraining the top of the cantilever or tying together two beams that are adjacent, therefore increasing the torsional resistance. Visit site tomorrow to see.