This research focused on demonstrating the effectiveness of a new inelastic material model, τBTR, and was compared with an existing modified tangent modulus model, τTM, at matching the limit load response of detailed finite element models of steel frames. The influence of stiffness reduction was studied on seven W8x31 columns and eleven benchmark frames. The column study considered minor axis bending with L/r ratios of 40, 60, 80, 100, 120, 180, and 200. Limit load analyses were conducted on steel frames with major-axis and minor-axis bending. The extent of yielding and lateral displacements were evaluated for all benchmark frames at the collapse condition. Discussion is given regarding the two material models and their ability to match the limit load responses of the finite element models. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection