The cross-shaped concrete-filled steel tube (CFST) is a new shape of column, which avoids convex corners and increases the interior area of the room. Cross-shaped CFSTs possess high bearing capacity, good seismic performance and efficient construction speed. In this study, cross-shaped stub CFSTs under axial loading were tested. The key parameter is the width/thickness ratio of the cross-section. Experiments revealed that local buckling could be delayed and section capacity enhanced by reducing the tube width/thickness ratio. Moreover, a finite-element model was established using the commercial program Abaqus to simulate the compressive performance of the specimens. The results were used to confirm the precision of the finite-element model. Further, a parametric study was completed to inspect the effects of the tube width/thickness ratio, concrete strength and steel yield strength on the mechanical properties of specimens. Relying on the constitutive theoretical model of restrained concrete, an equation is recommended to calculate the section capacity of cross-shaped CFSTs. Finally, the practical outcomes and the calculated outcomes obtained from different design codes (AISC, AIJ, EC4, CECS and GB) were compared. The comparison results revealed that all recommended design codes underrate the section capacity of cross-shaped CFSTs.

中文翻译：

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轴向压缩下十字形短管CFST的实验和数值研究

十字形钢管混凝土（CFST）是一种新的柱形，避免了凸角，增加了房间的内部面积。十字形钢管混凝土承载力高，抗震性能好，施工速度快。在这项研究中，对轴向载荷下的十字形短管 CFST 进行了测试。关键参数是横截面的宽厚比。实验表明，通过降低管宽/厚比可以延迟局部屈曲并提高截面容量。此外，使用商业程序Abaqus建立有限元模型来模拟试件的压缩性能。结果用于确认有限元模型的精度。此外，还完成了参数研究以检查管宽/厚比的影响，混凝土强度和钢筋屈服强度对试件力学性能的影响。依托约束混凝土的本构理论模型，推荐了一个计算十字形CFST截面承载力的公式。最后，比较了从不同设计规范（AISC、AIJ、EC4、CECS 和 GB）获得的实际结果和计算结果。比较结果表明，所有推荐的设计规范都低估了十字形 CFST 的截面承载力。CECS 和 GB）进行了比较。比较结果表明，所有推荐的设计规范都低估了十字形 CFST 的截面承载力。CECS 和 GB）进行了比较。比较结果表明，所有推荐的设计规范都低估了十字形 CFST 的截面承载力。