Buckling parameter for multi-level RC column with beams framing in only one orthogonal direction

[stroxy]

Hi, how does one model a column and set the buckling parameters for a column that is spanning over multiple beams that frame into the column in only one orthogonal direction? Does one model it as single elements between levels or as a continuous element.  As single elements you can easily consider the connecting beams but then in the other direction where it is acting as a cantilever column over multiple levels, the buckling coefficient for the single elements then becomes a bit of a challenge, especially for the upper levels due to defining the bottom restraint condition.  Screenshot attached.

[Simau]

Hi @stroxy 

Does one model it as single elements between levels or as a continuous element

It's better in several elements (between floors or main beams). Each element will have its own buckling settings.
It's hard to say without an example

[stroxy]

Hi @Simau 

In one direction the column is behaving as a cantilever column.  Would you divide a cantilever column into several elements with each element having it's own buckling settings?  

The example is shown on the attached image

[Simau]

@stroxy 

There is nothing attached

[stroxy]

Hi @Simau 

The attachment (image) is in my first post.  Unless you're looking for something else

[Simau]

Hi @stroxy 

The screenshot is too general

As requested in post 2, could you share an example with a model

[stroxy]

Hi @Simau 

This is actually a general question and not because I am having any problem with a model.

[Stephane.kapetanovic]

hi @stroxy 

I agree with @Simau. The design parameters (member types) are often specific to the bar element in question, and it is much easier to answer your question based on a specific case that requires a model.

If you have a bar made up of several segments, you can use a superbar for sizing. This allows you to recombine it, for example, in the case of broken shapes or bars with variable cross-sections along the length of the bar.If the buckling and torsional buckling lengths do not directly depend on the bar length, you need to select the type of internal bracing.

Since managing uninterrupted bar types in multiple directions will be challenging in your case and does not align with the manufacturing objective, it is better to opt for segmentation.

Best Regards

[stroxy]

@Stephane.kapetanovic  Sorry I didn't make it clear, but I am referring to reinforced concrete members, where I believe you cannot combine bars to apply a buckling coefficient and also no internal bracing.  Think of a concrete column say 6m long with beams framing in at mid height (3m) along one orthogonal direction with a buckling length of approx.  2.4m (fixed at base and restrained by beam) in the direction of the framing beams and say 12m (cantilever column) in the direction without framing.  Now if you were modelling this element and had it divided into 2 x 3m columns because of the framing beams and you want to model the upper column, how would you set the buckling length for the direction where the column is behaving as a cantilever?

[Stephane.kapetanovic]

hi @stroxy 

so, after many messages, to avoid confusion, please share your model.

Best Regards