Development of an Alternative Design Method for Aluminum I-Sections Using the Overall Interaction Concept

Aluminum can be successfully used as a structural material as it has numerous positive attributes such as high strength-to-weight ratio, excellent corrosion resistance, and environmental benefits. The current aluminum design provisions are based on simplified approach that does not efficiently consider the effect of strain hardening, local instabilities, and heat reduced properties of aluminum. This results in over-conservative designs which are not desirable from a cost standpoint. Hence, an optimized design approach is needed for accurately predicting the resistance of aluminum sections that can ensure the full economic benefits of having aluminum as a construction material for civil infrastructure. In this study, an attempt has been made to develop an alternative design approach for aluminum I-sections, based on the principles of Overall Interaction Concept (O.I.C.). This O.I.C.-based design approach helps us obtain precise and consistent estimation of buckling resistance as it relies upon the interaction between resistance and stability and considers geometrical and material imperfections in design. In this study, a finite element-based numerical model is developed in Abaqus software to predict the resistance of aluminum I-shaped cross sections. Extensive numerical parametric studies have also been performed to study the effect of geometries (size and thickness of section), alloys, and load cases on the value of resistance. Using the results from parametric studies (nearly 4500 simulations), O.I.C.-based design proposals have then been formulated to obtain the local resistance of extruded and welded aluminum I-sections. Finally, the estimated resistance from the O.I.C.-based design approach has been compared to that from existing design standards. It is found that the O.I.C.-based design proposals are more accurate than current design standards.