Abstract This paper deals with the numerical investigation aimed to study the axial capacity and the nonlinear deformation response of pin ended cold-formed steel (CFS) built-up columns under monotonic axial loading, applied concentrically. The built-up sections were constructed by adequately spaced channel sections in a back-to-back configuration, connected through webs by means of connecting elements (CFS channels) called spacers. Self-driving screws were used as fasteners to assemble together the lipped channels and spacers. Finite element (FE) models were established and verified against the previously published built-up columns with similar configuration. An extensive parametric study was conducted by varying the key parameters like plate slenderness of the lipped channels, unbraced chord slenderness, and global slenderness in order to investigate their variation on the ultimate compression resistance of these built-up columns. The effective width method was used to determine the design strengths for these built-up columns using the AS/NZ Specifications and European Specification on cold-formed steel structures, which were later compared with the results obtained from the numerical parametric study. This study indicated that the provisions that are given in the current AS/NZS and European Specification in predicting the strengths of the built-up column with spacers had shortcomings. Therefore, new design equations for the reliable design strength predictions of the CFS built-up column composed of lipped channels with spacers were proposed. The incorporation of spacers curtailed the local buckling half-wave length, which improved the buckling resistance, predominantly in the columns failing by local buckling.

中文翻译：

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CFS 组合柱的轴向承载力包括带垫片的唇形通道：非线性响应和设计

摘要 本文进行了数值研究，旨在研究销端冷弯型钢 (CFS) 组合柱在同心施加单调轴向载荷下的轴向承载力和非线性变形响应。组合部分由背对背配置中间隔足够的通道部分构成，通过称为间隔件的连接元件（CFS 通道）通过腹板连接。自攻螺钉被用作紧固件，将唇形通道和垫片组装在一起。有限元 (FE) 模型是根据先前发布的具有类似配置的组合柱建立和验证的。通过改变边缘通道的板细长度、无支撑弦长细度等关键参数，进行了广泛的参数研究。和整体细长，以研究它们对这些组合柱的极限抗压强度的变化。有效宽度方法用于确定这些组合柱的设计强度，使用 AS/NZ 规范和欧洲冷弯型钢结构规范，随后与数值参数研究的结果进行比较。该研究表明，当前 AS/NZS 和欧洲规范中在预测带隔板的组合柱强度方面的规定存在缺陷。因此，提出了用于可靠设计强度预测的新设计方程，该设计方程由带垫片的唇形通道组成。垫片的加入减少了局部屈曲半波长，