Load bearing capacities of cold formed steel sections subjected to axial load

Abstract

The paper describes a test program on cold-formed axially compressed steel members. Research has been conducted in order to explain how cold working technology causes considerable enhancement of the material properties in finished element, comparing to the base material. In analysis, we have used results obtained with experimental and numerical methods. "PAK" software, designed for nonlinear finite element analysis of structures, derived results for ultimate bearing capacity with corresponding force-deflection graphs and buckling curves. These results are compared with those obtained in experiments on built-up members. Experiments were conducted on five series each with six specimens with global slenderness values of 50, 70, 90, 110 and 120. Compressed members were analyzed on Amsler Spherical pin support with unique electronically equipment and software. As well as force-deflection curves stress values for several cross sections along the height of the members were also determined. Both groups of results (numerical and experimental) were compared with European buckling curves. These give the value for the reduction factor of the resistance of the column as a function of the reference slenderness for different kinds of cross-sections (referred to different values of the imperfection factor). © 2013 RILEM.