Hollow, rectangular structural sections, due to the even distribution of the material around their longitudinal axis, represent an efficient structural form. They are often used as compression members in high-rise buildings. The load-carrying capacity of these sections can be significantly reduced by the interaction between the local buckling of the component plates and the overall buckling of the compressed columns. Recently, the use of box-column has became increasingly popular in tall building because of these structural merit. But many structure designer is perplexed with the absence of special design codes such as H-section column. The greater part of high-rise building analysis is carried out by using computer program, in which the analysis algorithm for box-column is not included.
The main aim of this paper is to develop the sub-program for optimal design of box-column by initial constraints which are the two sides of section and, thickness. Object of optimize is section area, because of section area determine the unit weight.
