Higher Order Beam-Column Element for Inelastic Analysis of Steel Frames Considering Plasticity Spread

This work presents a beam-column model for advanced analysis of steel frames. Tracing the effect of both geometric and material nonlinearities require much calculation efforts to maintain the accuracy of analysis. The presented element helps in solving the conflict between the accuracy of analysis and the required number of calculations by representing the physical steel member by a single element. Many available researches present one element per member models, but they assumed lumped plasticity at element’s nodes only using plastic hinge analysis. In contrast, the present work is based on distributed plasticity analysis using one element per member, which provides more realistic modelling of the steel frames with fewer number of calculations. A fifth order shape function is adopted to capture and model second order effects. Numerical verifications are presented to assure the accuracy of the proposed element by solving numerous of benchmark frames and other examples under various loading conditions.