Current AISC Design Provisions Applied to High-Strength Steel Columns – Preliminary Results
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Rolled wide-flange sections fabricated from high-strength steels with a yield strength of 450 MPa or higher offer significant benefits in structural applications. These include enhanced load-bearing capacity, material efficiency, and fabrication cost savings. However, current design provisions (i.e. AISC 360-22; Eurocode 3) may be overly conservative for these high-strength steels when employed as structural steel columns, in part due to assumptions regarding residual stresses. This paper presents results of finite element (FE) investigations focused on the flexural buckling behaviour of hot-rolled I-shaped columns formed from conventional (mild) ASTM A992/A992M steel and A913/A913M Gr. 80 [550] high strength steel. The FE models include initial out-of-straightness imperfections and nonlinear material behaviour, and residual stresses caused by uneven cooling during fabrication. Developed strength curves are compared with AISC and Eurocode results. Comparisons are also made between results obtained using uniaxial and multiaxial residual stress profiles. The findings generally support the use of AISC 360-22, but suggest refinement might be needed for heavier or high-strength rolled shapes in the inelastic buckling range.