Second-Order Analysis for Steel Frame Structures with a Distributed Plasticity Numerical Model

TLDR: The model is accurate and provides benchmark solutions of steel frames using second-order distributed plasticity analysis and is useful for the verification of various simplified second- order inelastic analyses.

Abstract: This paper provides an efficient numeric model of steel frames using second-order distributed plasticity FEM (finite element method). Details of the modeling including element type, mesh discretization, material model, residual stresses, initial geometric imperfections, and boundary conditions are presented. Its validity is verified by several numerical examples. Case studies of Vogel’s portal frame and space steel frames are performed. The ultimate loads obtained from the proposed analysis and Vogel agree well within 2% error. Therefore, the model is accurate and provides benchmark solutions of steel frames using second-order distributed plasticity analysis. The benchmark solutions of the steel frames are useful for the verification of various simplified second-order inelastic analyses. It is observed that the load carrying capacities calculated by the Code for design of Steel Structures (GB50017-2003) method are 20%∼30% conservative when compared with those of the proposed analysis. and using this model the study was carried out on the effects of the nonlinear factors on the behavior of steel frames.