Proceedings of the Annual Stability Conference Structural Stability Research Council Grapevine, Texas, April 18-21, 2012 Cross Section Optimization Using Simulated Annealing of Cold-Formed Steel Channel Columns Z.M.Chamberlain Pravia 1 , M. Kripka 2 Abstract Cold-formed profiles has been used in large scale in Building industry, due to the easy way to product them and the wide range of sections feasible to accomplish with the project needs. The search for a maximum performance of structural elements with the low use of material is a challenge of today and future for engineering. This paper presents a numeric study to obtaining minimum weight of cold-formed channel columns, with and without lips, using the prescriptions of AISI 2007. Flexural, torsional and torsional–flexural buckling of columns was considered as constraints. The optimization was made through the method of Simulated Annealing. Several numeric simulations are presented and discussed to validate the proposal and an experimental example that qualifies the implementation. The relations between lips, web width and flange width are analyzed. Finally, the process shows excellent results to reduce the cross section area. 1. Introduction and Background Cold-formed steel structures constitute an alternative for small and medium size steel structures. The great advantage of those sections consists in the possibility of adjusting the form to the needs of the member in the overall group of the structure, obtaining it with the minimum possible weight. In practice that advantage it is not totally explored, therefore the simple search of a section with its maximum relationship of strength versus weight is not a trivial activity of the engineer's day-by-day. In this sense, the present paper integrates a research line that aims to study the optimization of component elements of structures with cold-formed sections. First, is introduced the calculation process for channel sections with or without lips to determine the load capacity. The Simulated Annealing (SA) technique was applied to formulate the optimization of the problem. The relationship between web and flanges width is evaluated for channel section without lips, as well the relations among web, flange and lips in channel section with lips. In the optimization process of the section to get the design load, the method of the effective widths was used. All the calculations were done according the American Standard AISI (2007). Second following that process, each one of the possible elastic loads of buckling (global flexure, 1 Graduate Professor, PPgEng University of Passo Fundo, Brazil, <zacarias@upf.br> 2 Graduate Professor,PPgEng University of Passo Fundo,Brazil, <mkripka@upf.br>