Optimizing column point brace designs: Balancing strength and stiffness with buckling load equivalence method

This study explores the potential for using smaller braces by increasing strength requirements and reducing stiffness, thereby challenging traditional stiffness-governed design approaches. The buckling load equivalence method (BEM), which assumes that the buckling load of an imperfect column at infinite lateral displacement equals that of a perfectly straight column, was evaluated alongside the Castigliano model (CM) and the Winter model (WM). For fully braced systems, CM and WM produced nonconservative estimates, while BEM yielded more conservative results than finite element analysis (FEA). In partially braced systems, all three models gave conservative estimates compared to FEA, with CM being the least conservative and WM the most. FEA results showed that bracing forces in full bracing scenarios exceeded 1% of column strength and increased with more braces, even when critical stiffness was doubled. This indicates that stiffness alone does not govern brace force requirements. The study highlights the importance of balanced brace optimization, which emphasizes reduced stiffness and increased strength to achieve more efficient designs. By applying an optimal varying amplification factor, smaller brace sizes can meet strength demands per AISC specifications while remaining below linearized stiffness limits. The proposed BEM approach effectively balances strength, stiffness, and efficiency in brace design.