Effective length factor for torsional buckling (kz) for column

[Groszni]

sorry to ask this is kind of basic question but im still confused about how to determine the kz (Effective length factor for torsional buckling) because i cant find the value anywhere. is it the larger value of Kx dan Ky determine by using alignment chart? or it depends on the end restrains of the column? or we just take it as 1?

 

[KootK]

Not to worry. I've doing this forever and I still find that stuff a bit confusing at times. Kz represents a purely twisting mode of buckling. It almost never governs for HSS or WF. More of an issue with WT and Cruciform which have very low torsional stiffnesses. Kz x L will represent the distance between points of rotational restraint on the column. Ninety five times out of a hundred that does mean Kz = 1.0.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Groszni]

@KootK thank you! does it apply the same when designing an unbraced frame column and braced frame column

 

[KootK]

It would be the same unless you've got some weird frame that resists sway through member torsion.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.