The maximum axial load that a column can support, when it is on the verge of buckling, is called critical load. normally the load is applied through the centroid of the cross section.
This will calculate the critical force in column. either force is applied at centroid of the cross section or at some distance (eccentric distance) from centroid of the cross section.
e = eccentricity of the load P, measured from the centroidal axis of the column’s cross-sectional area to the line of action of force.
c = distance from the centroidal axis to the outer fiber of the column where the maximum compressive stress ?max occurs.
A = cross-Sectional Area of the column.
r = radius of gyration