Optimum design of cold-formed steel columns by using micro genetic algorithms

Cold-formed steel members such as beams and columns have the great flexibility of cross-sectional profiles and sizes available to structural steel designers. However, this flexibility makes the selection of the most economical section difficult for a particular situation. In this study, micro genetic algorithm (MGA) is used to find an optimum cross section of cold-formed steel channel and lipped channel columns under axial compression. Flexural, torsional and torsional–flexural buckling of columns and flat-width-to-thickness ratio of web, flange and lip are considered as constraints. The design curves are generated for optimum values of the thickness, the web flat-depth-to-thickness ratio, the flange flat-width-to-thickness ratio for columns. As numerical results, the optimum design curves are presented for various load level and column lengths.