effective lenght factor

[beamblanck]

Hi all guys,
I need some help about a frame I’m trying to calculate, in particular the dimensioning of the columns.
The loads on the box are really heavy and dynamic, and can also be different each one. The step between the loads is about 285 mm.
In your opinion, how is the effective length factor I have to use to calculate these columns?
I suppose a coefficient of “2” for both the two axis of inflections 2-2 e 3-3, is it too much precautionary?
I can’t add any kind of brace or other reinforcement. The structure has to remain as I schematized, I can only use a bigger profile for the columns (ø168.3mm)

Many thanks for your suggestions, if you need more information to better understand my problem let me know, I’ll reply as soon as possible.
I don’t know where find some support to my problem.

Thank so much again and again.

Claudia

 

[lae007]

Yes "2" for effective length factor is reasonable since you can't brace the system.

 

[IJR]

beamblank

buckling may not govern in your problem, having so closely spaced columns.

Do not forget to check deflections, though this too is not likely given close spacing of columns.

Is your dynamic load continuous kind(rotating machinery etc)? If yes, check the frequency first before anything.

 

[HalimWardag]

i think the coeffeciant you have choosen is Ok, even you can choose 2.1, because the frame seems to be fixed in the bottom and free at the top (neglect the interaction between Beam-Col)

the attached is a table you can use

Hope it will help you

tnx