Steel Joist bottom chord extension 3

[honat]

Can one safetly use joist bottom chord extensions to provide adequate lateral bracing requirement for a beam column in a roof or a floor diaphragm? If so what is the magnitude of axial forces to provide the joist manufacturer?
Is there also any code provision that deal with this situation? Which one and where?

 

[civilperson]

What is a beam column that supports a joist? The top chord of a joist can be used to brace the compression flange of a beam if the other end is attached to a wall or a stable member.

 

[honat]

OOPS.
I meant Girders in a diaphragm system that see both flexural and axial loads in the analysis.

 

[MiketheEngineer]

Seems to be done all the time.

OLD rule of thumb says you need 2% of the column axial load to brace it?? So use 5% and you should be good to go.

 

[bjb]

Bottom chord extensions result in continuity moments that have to be accounted for in the design of the joist.

 

[darthsoilsguy2]

I see joist bottom chords used to stabilize joist girders at ~1/3 and the ~2/3 span region of the JG almost every time i see joist and joist girders together. i inspect steel and rarely design it however.