Optimization of Cold-Formed Thin-Walled Cross-Sections in Portal Frames

• Published in: Buildings (Basel) 2024-08, Vol.14 (8), p.2565
• Main Authors: Stulpinas, Mantas, Daniūnas, Alfonsas
• Format: Article
• Language: English
• Subjects: Algorithms; Analysis; Cold; Cold working; cold-formed steel; Cross-sections; Design optimization; Design specifications; Eurocodes; Finite element analysis; Frames; Genetic algorithms; global buckling; local buckling; Mathematical optimization; Optimization; Parametric analysis; portal frames; Stiffeners; thin-walled structures
• ISSN: 2075-5309; 2075-5309
• DOI: 10.3390/buildings14082565

Portal frames with built-up cold-formed cross-sections hold significant potential; however, there is a notable gap in the analysis of cross-section types and connections. In this study, an optimization algorithm was developed for the closed cross-sections of portal frame members. An optimization algorithm was tested against optimized open cold-formed cross-sections. The results indicated a portal frame volume up to 38% lower where members were assembled of optimal closed cross-sections when compared to frames with optimal open cross-sections. Parametric analysis was carried out, where two types of cross-sections were examined: Type A, with four web stiffeners bent inwards, and Type B, with four web stiffeners bent outwards. The optimization was conducted using a Genetic Algorithm in MATLAB R2022b. Portal frames with optimal Type B cross-sections had a volume that was up to 22% lower when compared to frames with optimal Type A cross-sections. Significant differences were noted between the optimal beam and column cross-sections, with the optimal column cross-section thickness being on average 74% greater, but the optimal beam cross-section height being on average 81% greater than those of the respective counterparts. In this article, a practical assembly solution for the connection of the frame members was proposed for the optimized novel closed cross-section types in portal frames. However, the strength and stiffness of these connections were not analyzed in this research.