Effective Length of Framed Columns

The assumption in many structural specifications that the effective length of columns is equal to the actual length may be extremely conservative in some cases and very hazardous in others. Framed columns may have effective lengths even approaching an infinite multiple of the actual length, depending on the end restraints. This paper reviews the current state of knowledge relating to effective lengths, leading from the rigorous, though laborious, procedures to the development of rational approximations using formulae, charts and nomograms, which, together with a proper classification of type of action, permit a rapid selection of the proper effective length for design.