5-10% of axial load to be applied laterally for steel columns (unbraced)

[TSB-98]

Good day,

I've been told that when designing a steel column (unbraced) that 5-10% of the axial load should be applied horizontally. I understand this for bracing of a structure (generally 2% is the South African code requirement) and the minimum eccentricity applied to concrete columns. I don't know if this requirement is a code requirement as I can't find it in the SANS code and I can't find any research suggesting this claim.

My question is if anyone has come across this to please provide guidance on which code this is stated.

 

[CDLD]

Never heard of 5-10% but I do not practice in South Africa. USA/Canada is generally 2% at ends of column or brace points. That is an old rule of thumb, code requirements for CISC OR AISC may be slightly different, and there are also stiffness requirements. Any eccentricity should also be considered in the column design.

 

[driftLimiter]

Are we talking about a notional type load or a bracing restraint?

It sounds like OP is describing a notional load.

 

[Mark_J]

2% has always been the norm and is very conservative

 

[TSB-98]

Yes it's more a notional load effect. SANS 10162-1 part 10.3 states that the K is to be taken as 1.0 to account for this instead of applying a portion of the axial load horizontally.

Thanks everyone for your time.