Column Size

What is staad work?

Are you a civil engineer?

It depends on material and style....

http://en.wikipedia.org/wiki/Column

It depends on 1) the load on the column, 2) length of the column, 3) strength properties of the column's size, shape, and material, 4) how the ends of the column are attached to adjacent components, and 5) intermediate bracing, if any.

Too complex for any simple forum thread answer.

STAAD is a structural engineering program utilizing FEM. It's pretty good and been around for some time now (about 25 years)....if you know what you are doing it's a good platform, otherwise for the unexperienced it may cough out erroneous answers. "Garbage-in, Garbage-out"! All too often, young inexperienced engineers employ design and analysis software without fully comprehending engineering basics by just "winging it", or knowing the limitations of the program. This type of approach will burn the uninitiated every time.

I'm afraid that this is the case here, as the OP appears to have no clue what they're doing....

Some good answers by some regarding what conditions are used to design a column. Additional information that is required: knowing the end restraints (top & bottom), any eccentricities of the induced axial load that can result in applied bending moments, and applied moments due to lateral forces such a lateral wind and seismic loads derived from a the Portal Frame Analysis. And don't forget about thermal stresses and Delta-P effects either!

I wonder if the OP is using STAAD III, or an older (and possibly pirated) version????

Don't 'ya just love it? OP has provided NO units of measure, as is the usual case around here.

300 x 600 WHAT? We can only assume they are in millimeters.....

I give the poor student (OP) an "F" grade on his homework assignment, which this surely is. the assigned grade by moi is based on the fact that these units were not provided by him/her. Call me a tough SOB, but attention to details is what engineering is all about.