A modified stress-strain model accounting for the local buckling of thin-walled stub columns under axial compression

• A force-based element incorporating local buckling of steel plates is developed.
• A novel stress–strain model accounting for local buckling effect is proposed.
• The accuracy of the obtained predictions has been verified.
• The present element reasonably predicts local and post-local buckling behaviour of thin-walled and CFST stub columns.

A novel stress–strain model accounting for elastic and inelastic local buckling of thin-walled steel plates was proposed in this paper based on an energy method. The proposed model was then implemented in a fibre force-based beam-column element for the advanced analysis of thin-walled and concrete-filled steel stub columns under axial compression. Both geometric and material nonlinearities are included in the fibre model. The obtained results were compared with independent experimental results and those predicted by ABAQUS using shell and solid elements. As shown in the numerical examples, the proposed stress–strain models can reasonably predict the ultimate strength and local and post-local buckling behaviour of thin-walled and concrete-filled steel stub columns under axial compression.