Calculation Of Columns : A Practical Application Of The Theory, BY THEODOR NIELSEN. EXPERIMENTS and calculation show that the centre line of a column will, if deflected, assume a wave line, and the free length will be cotisidered as the distance between two consecutive points of contraflexure, this being the length of a column with ideal pin ends. The first step in all column calculations is to deduce the free length from the actual length, and it is also the weak point of such caIculations, as the Bee length depends upon the nature of the fixing of the ends which may even cause some eccentricity of the loading. In case where any doubt exists it is better to assume a greater free length, say full length, of the column even if the ends are held. As a guide the following will prove useful, but much depends upon individual judgment. Both ends free the free length G L is purely ideal, but very often allowed.