Stability analysis of stiffness reduction models on rotary- and non-rotary straightened W-shapes

Abstract

This paper presents a parametric study of stiffness reduction models on rotary- and non-rotary straightened hot-rolled steel W-shapes to examine if the models for non-rotary straightened sections are appropriate for stability analysis of rotary-straightened members. Four stiffness reduction models were investigated, which include (1) a conventional model adopted by AISC 360, which is known as the CRC model, (2) a model fitting the column strength curves provided in Eurocode 3, and models fitting cross-section distributed plasticity curves incorporating (3) the ECCS residual stress pattern and (4) a residual stress pattern of rotary-straightened sections. Beam finite element models were created and second-order inelastic analyses were conducted. A range of different cross-section geometries typically used for beam–columns was investigated, which includes various aspect ratios and flange-to-web area ratios. Columns and beam–columns were investigated with uniaxial bending about the major and minor axes with several axial utilization ratios. The effects of the stiffness reduction models on the stability limit state are discussed. The results of the parametric study are presented along with comparisons of the stiffness reduction values for hot-rolled steel members, which provide further understanding of the stiffness reduction model’s influence on the stability analysis of rotary straightened hot-rolled steel members.