Advanced analysis of steel-concrete composite beam-columns by refined plastic hinge method

Based on the second-order inelastic analysis, this paper presents a practical method of design for steel-concrete composite beam-columns that satisfies code performance requirements. The concept of second-order inelastic analysis for structures is to consider both geometric and material nonlinearities and their imperfections so that the real structural behavior can be captured and the assumption for effective lengths is not required. The refined plastic hinge approach proposed herein traces the gradual material yielding and simulates full plasticity of a cross-section. The definitions of the initial and full yield surfaces (which are used to initiate the yielding and to indicate the full plastic stage) for steel-concrete composite cross-sections, based on the cross-section analysis, are presented. The proposed method is verified in examples of isolated composite columns and frames.