Investigation of the Rotation Capacity and Flexural Strength of Web Tapered Hybrid High Strength Steel Simple Supported I-Section

Understanding the behavior of structural steel in terms of fabrication and fashioning is an important factor in the design of steel structures. The search for structural steel with capabilities of acceptable responses in seismic regions alongside cost efficiency has led to the investigation of the behavior of high strength steels (HSS), which have a yield strength of 55 ksi (ASTM A572) or higher, as classified by US standards, while their inelastic capacity is less than that of conventional steel. The present research investigates the rotation capacity and flexural strength of hybrid high strength web-tapered I-shaped steel girders using an experimentally verified nonlinear finite element modeling technique. The academic multipurpose software package ANSYS19.2 was used to develop a finite element model, and a mesh convergence study was performed to ensure the accuracy of the results. Geometrical imperfections were applied to conduct a linear eigenvalue analysis and to capture buckling mode shapes to perform a nonlinear analysis. The residual stress was associated in the finite element model for different welding configurations. The numerical model was verified with previous experimental data, and close agreements were achieved. A total of 450 models were used to perform a parametric study with various flange and web slenderness as well as lateral bracing configurations to capture local, overall, and local-overall buckling modes. As results, some equations for direct design of non-prismatic hybrid high strength steel girders were proposed.