Global buckling prevention of multi-celled corrugated-plate CFST walls under pure in-plane bending loads

Abstract

The multi-celled corrugated-plate concrete-filled steel tubular (MC-CFST) wall system is a novel structural solution featuring an alternating arrangement of corrugated cells and interval elements. This design offers high flexibility and is well-suited for prefabricated construction. Horizontally placed corrugated steel plates provide excellent confinement for the infilled concrete, significantly reducing steel consumption and wall thickness. This study systematically investigated the stability performance of MC-CFST walls under pure in-plane bending loads through theoretical analysis and numerical simulations. Based on the theory of thin-walled elastic structures, formulas for torsional and warping rigidities were derived, along with a theoretical formula for calculating the critical moment. A refined finite element (FE) model was developed to simulate the global flexural-torsional buckling behavior of MC-CFST walls and was validated against the theoretical formulas. The model was further used to analyze failure modes during elastic and elastoplastic stages and to assess the effects of wall height and width on stability performance. The results revealed that as wall height and width increase, the failure mode transitions from strength-controlled to stability-controlled. When the normalized slenderness ratio does not exceed 0.4, the composite wall is unlikely to experience global flexural-torsional buckling. However, comparisons showed that existing design codes fail to provide conservative predictions of the stability performance of MC-CFST walls under pure in-plane bending loads. Therefore, a new stability design curve was proposed and proved to be capable of providing design results with reasonable accuracy and safety margin, demonstrating its validity for practical designs of MC-CFST walls.