Overall stability of steel web-tapered frame members

Abstract

The solution to the problem of fully nonlinear stability analysis of web-tapered I-shaped members is presented in the paper. In order to accelerate the analysis, an analytical- numerical approach was applied in the solution. Nonlinear stability analysis in the elastic range is carried out by the use of the analytical procedure (so-called “Member” procedure) which is based on the combination of the results of buckling and linear analyses. The growth of the plastic deformations is taken into account by adding extra displacements in the “Member” procedure. These displacements are determined numerically in the process of incremental loading (so-called “Section” procedure). The proposed approach allows the calculation of all displacements at each load step and the estimating of the member’s overall stability capacity, rapidly (up to 20 times faster than using shell-FEM) and accurately enough. The overall stability calculation results, depending on the different variables (slenderness, load eccentricities and their ratios, rigidity variations) under different load cases, are given in the paper. The stability capacity comparison between tapered and prismatic members is presented. Also the comparison with existent experimental researches’ results is provided in the paper.