In STAAD.Pro y-y is the minor axis and z-z is the major axis for cross sections. These are local axes of members which are different from the global axes. All unsupported lengths are specified with respect to the local axes. So LY and LZ would be unsupported…

Assuming you have a concrete deck on top of steel beams and the fact that the deck will restrain the top flange of the beam laterally, it is fair to use a very small value of LY and UNT. Using the spacing between shear studs is fine as that is a small…

First you should look at the default values for each design parameter and if you think the default value is going to work for your structural member, you do not need to add/assign a design parameter explicitly. However if that is not the case, you would…