How does STAAD.Pro compute the Ky and Kz when Calculate option is chosen from within Design Parameters for AISC ASD code ?
STAAD.Pro can calculate the effective length factor for steel members when design is carried out as per the AISC 9th edition code ( invoked by the command CODE AISC ). The procedure is documented as part of the software online help as shown next.
The calculation of the effective length factor is carried out as per a paper titled “Compression Members” by George Tsiatas which can be downloaded from:
Automatic calculation of effective length factors - A paper by George Tsiatas