BEAM-COLUMN MODELING

Two beam-column element models are compared for nonlinear planar problems in structural engineering using steel members. These problems deal with moment amplification in a slender column, hysteretic buckling and tensile yield of a brace, cyclic loading of a cantilever beam, and response of a frame to a harmonic ground motion of increasing amplitude. The models studied include one of the plastic-hinge type and one of the fiber type. The former is more computationally efficient than the latter, but the fiber element includes residual stresses and better represents features of the yielding process. These additional features of the fiber element proved to be most important when modeling collapse of a slender column, hysteretic brace behavior, and cyclic flexure under large axial load. Agreement between the two models for the frame problem was reasonably good, including the level of ground motion at which collapse occurred.