O.I.C.-based design of extruded and welded aluminum I-sections

Current standards rely on simplified approaches to predict the resistance of aluminum structural elements that can be shown to inadequately account for the effects of strain hardening, instabilities, and heat reduced prop-erties. This paper summarizes investigations towards the development of an alternative design method for aluminum open cross-sections, based on the Overall Interaction Concept (O.I.C.). This innovative design approach relies on the interaction between resistance and stability, and also allows to consider geometrical and material imperfections. Moreover, it allows to obtain direct, precise and consistent resistance predictions using continuous buckling curves.A numerical finite element model was developed to accurately predict the resistance of aluminum cross -sections. Its efficiency was validated by comparing its numerical predictions of resistance to available experi-mental test data. Extensive parametric studies were then conducted, allowing to study the impact of varying geometries, aluminium alloys and load cases on the resistance. Using the results from more than 2 300 numerical simulations, O.I.C.-type design proposals were formulated for the local resistance of extruded and welded aluminum sections.The performance of the design equations was evaluated by comparing their resistance estimates to the reference numerical results and to resistance predictions from the Canadian, European, and American aluminum design standards. The comparisons showed that the O.I.C. design proposal leads to much more accurate and consistent results than these standards, while remaining simpler and more efficient.