Beam-column element for nonlinear seismic analysis of steel frames

This paper describes a beam-column element intended to model steel members with flexural yielding, as well as members with yielding under combined fle xure and axial force in frames subject to earthquake ground motions. The el ement has the capability to model plastic axial deformation and changes in axial stiffness, and it employs hardening rules to handle monotonic, cyclic , or arbitrary loading. When compared with experimental results and fiber m odel predictions, the element shows significantly better performance than t ypical bilinear hinge models. The developed element can more accurately pre dict local deformation demands and the overall response of structural syste ms under earthquake loading than the bilinear hinge element.