Publication
Current experimental studies on the seismic behavior of steel wide-flange columns under multi-axis cyclic loading reveal that these members, depending on their geometric characteristics, may be susceptible to axial shortening, out-of-plane deformations and lateral-torsional buckling coupled with local buckling. In that respect, simulation models have intrinsic value to generalize the previous experimental findings in a wider range of member sizes and aid the further development of our seismic design and assessment standards. Prior work on continuum finite element (CFE) modeling of steel wide-flange columns stressed the importance of the proper consideration of local and member imperfections within the CFE model. The assumptions underlying the steel material model, particularly its hardening laws, along with the methodology for obtaining its input parameters, have been overlooked. The main issue explored in this paper centers on the fact that commonly used nonlinear isotropic/kinematic plasticity models within CFE simulation platforms were originally developed for stainless steels. Therefore, they do not represent the discontinuous yielding phenomenon present in typical structural mild steels. Nonlinear analyses conducted in this paper underscores that the predicted buckling modes are sensitive to the choice of material model for a class of steel wide-flange columns.