Column Design 2

[jcoots]

I am trying to design a simple support structure involving one column and a horizontal member at the center elevation of the column to keep it from buckling. The other end fo the horizontal member is tied into an existing structure, its end will be considered fixed. What I can't figure out is what axial force is transfered into the horizontal member from the axial load placed on the column. Please advise.

 

[warrenw]

You have a column that is braced at the top and bottom and there is a horizontal member at the center to reduce the unbraced lenght of the column. If that is the case, then the horizontal bracing member is usually designed to carry about 2% of the axial load in the column. I thought it was stated in the AISC manual, but I can't find it.

 

[UcfSE]

In the 3rd edition AISC LRFD spec in chapter B there are requirements for strength and stiffness of bracing. The 2% rule is a typical rule of thumb that probably has no rigorous derivation. It's been used for a long time though and many people use it.