Optimizing material use in modern structural engineering is essential for achieving sustainable and cost-effective development. Conventional structural steel design methods, although reliable and widely adopted, are often limited by simplified assumptions, such as the use of elastic–perfectly plastic (bilinear) material models and the isolated evaluation of structural members. These simplifications neglect nonlinear material behavior, strain hardening, corner enhancements in cold-formed sections, and the redistribution of internal forces within the structure, potentially leading to conservative designs and suboptimal material efficiency.

Advances in computational modeling have enabled the development of Advanced Design Methods (ADM) capable of addressing these limitations. Within this framework, Finite Element (FE) analysis, referred to as Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA) in Eurocode 3, presents as a powerful tool for performing sophisticated nonlinear simulations of entire structural systems. ADM approaches can incorporate different modeling techniques, as the Effective Material Model (EMM) and the Direct Design Method (DDM). The EMM provides a more realistic representation of the stress–strain distribution within a cross-section, accounting for strain hardening, residual stresses, and corner enhancements, whereas the Direct Design Method (DDM) enables the evaluation of the global nonlinear behavior of the entire structural system.

This study proposes to extend the application of the Effective Material Model (EMM) to the entire SSAB catalogue of square and rectangular hollow sections (SHS and RHS), covering material grades from S355 to S700. Furthermore, the Direct Design Method (DDM) will be applied to structures composed of cold-formed slender members (Classes 3 and 4 as defined by Eurocode 3), thus contributing to the development of lighter, safer, and more sustainable structural systems in modern construction.