Abstract The present study is focused on the local stability of concrete-filled and partially-encased stainless steel sections, fabricated from duplex and lean duplex plates, under axial compression. A total of 34 specimens with box, circular, and I-shaped sections are investigated. Geometrical imperfections of the fabricated stainless steel specimens are measured prior to testing. Following the experiments, a comprehensive parametric study is conducted using finite element method. Results of the experiments as well as the parametric study are then synthesised to recommend axial slenderness limits for the investigated section types. The recommended limits are compared with those stipulated by current design specifications for carbon steel-concrete composite sections. The findings are also compared with the previous data available in the literature for austenitic composite sections and the similarities and differences are highlighted and discussed. The experimental and numerical results are further investigated to calibrate effective width relations to exploit the post-local buckling reserve strength of the studied sections. To facilitate the comparison of the findings with current codified requirements and other studies, the recommendations are presented in three notations used typically by the Australian, American, and European standards.

中文翻译：

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双相和精益双相不锈钢-混凝土组合柱的轴向细长限制

摘要 本研究的重点是在轴向压缩下由双相和精益双相板制成的混凝土填充和部分包裹的不锈钢截面的局部稳定性。总共研究了 34 个具有箱形、圆形和 I 形截面的试样。在测试之前测量制造的不锈钢样品的几何缺陷。在实验之后，使用有限元方法进行了全面的参数研究。然后综合实验结果和参数研究，为研究的截面类型推荐轴向细长限制。推荐的限值与碳钢-混凝土复合材料截面的现行设计规范规定的限值进行了比较。还将这些发现与文献中有关奥氏体复合材料截面的先前数据进行了比较，并强调并讨论了相似之处和不同之处。进一步研究实验和数值结果以校准有效宽度关系，以利用研究部分的局部屈曲储备强度。为便于将研究结果与当前的编纂要求和其他研究进行比较，建议以澳大利亚、美国和欧洲标准通常使用的三种符号表示。进一步研究实验和数值结果以校准有效宽度关系，以利用研究部分的局部屈曲储备强度。为便于将研究结果与当前的编纂要求和其他研究进行比较，建议以澳大利亚、美国和欧洲标准通常使用的三种符号表示。进一步研究实验和数值结果以校准有效宽度关系，以利用研究部分的局部屈曲储备强度。为便于将研究结果与当前的编纂要求和其他研究进行比较，建议以澳大利亚、美国和欧洲标准通常使用的三种符号表示。