Experimental investigation into flexural buckling of double-limb built-up plate members under compression

Abstract

Planar steel plates have many advantages, including high precision, flexible outline shape fabrication, and convenient transportation and storage, which make them suitable for various steel structures (e.g., reticulated shell structures). However, the steel plates are not commonly used as structural members, because they have a relatively low out-of-plane flexural stiffness. To improve the flexural buckling resistance, a novel type of built-up plate member comprising two longitudinal plates is proposed in this study. Additionally, the flexural buckling behavior of the novel built-up members is investigated. A series of compression tests on 42 specimens of built-up plate members is conducted to determine the elastic and ultimate critical loads. Flexural buckling about the minor axis is observed to be the failure mode of the specimens. The equivalent slenderness ratio method is used to determine the theoretical elastic critical loads of the specimens. With consideration of the measured material properties, geometric imperfections, and residual stresses of the specimens, a refined finite-element model is developed to simulate the flexural buckling behavior. Furthermore, the applicability of two representative specifications (American and European) to the novel built-up member is discussed. The results indicate that the design strengths calculated using these specifications are generally conservative for determining the ultimate loads of the built-up plate members. Design curve “c” in Eurocode 3 is found to be the most suitable among the specifications of interest for determining the design strength. This study provides valuable guidance for the design of built-up plate members.