I have designed a 80m box truss with StaadPro. For the top chords that are in compression, do I need to specify their Lz to be equal to 80m? If I do that, the top chords will fail terribly due to slenderness. Is it a valid assumption to default the Lz for the top chords to the member length between nodes in this circumstance?
I have attached the relevant file; will appreciate some advices.
Hello,
As given in the help manual, the LZ parameter is :
" Length in local z - axis to calculate (KZ)(LZ)/Rzz slenderness ratio."
Lets take top chord 27 for example, this member is restrained in between nodes 28 and 30. So for slenderness calculation, the length should be 4m (member length is this case).