Manufacturing limitations in hollow concrete-filled steel tube (HCFST) structures often lead to significant void ratios, which can result brittle failure after reaching the peak load. To address this issue, this study proposes a novel structural solution: reinforced hollow concrete-filled square steel tubular (RHCFST) columns. These columns integrate the benefits of hollow concrete-filled steel tubes (CFST) and prestressed high-strength concrete (PHC) tubular columns. The research includes experimental testing and finite element simulations on five full-scale, thin-walled RHCFST under axial compression. Experimental results reveal that the column specimens predominantly failed with mid-section buckling, including local buckling of steel tubes and shear or cleavage failures in the sandwich and core concrete. Increasing steel tube wall thickness (e.g., from 5 mm to 8 mm) enhanced peak load by up to 13.66 %, while adding conventional reinforcement increased it by up to 6.97 % and significantly improved post-peak behavior. Finite element analysis conducted on the ABAQUS platform, demonstrated superior composite behavior during loading, with coordinated deformation between the sandwich and core concrete. Internal reinforcement significantly enhanced the mechanical performance of the tubular column. Parametric analysis indicated that for width-to-thickness ratios exceeding 60, additional conventional reinforcement substantially improved the mechanical performance of the members. This study also assessed the applicability of design models from GB 50936–2014, AISC 360–16, and Eurocode 4 in predicting the load capacity of RHCFST short columns. The AISC 360-16 model predicted a high accuracy, with an average prediction ratio of 0.976, and the proposed adjustments to the partial section factors in GB 50936-2014 significantly improved accuracy, achieving average prediction ratios of 0.989.

中文翻译：

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全尺寸加筋空心高强混凝土填充薄壁方钢管柱的轴向抗压性能

空心混凝土填充钢管 （HCFST） 结构的制造限制通常会导致很大的空隙率，这可能导致在达到峰值载荷后发生脆性失效。为了解决这个问题，本研究提出了一种新的结构解决方案：钢筋空心混凝土填充方钢管 （RHCFST） 柱。这些柱子集成了空心混凝土填充钢管 （CFST） 和预应力高强度混凝土 （PHC） 管柱的优点。该研究包括对 5 个全尺寸薄壁 RHCFST 在轴向压缩下的实验测试和有限元模拟。实验结果表明，柱子试件主要以中段屈曲为破坏，包括钢管的局部屈曲以及夹层和芯混凝土的剪切或解理破坏。增加钢管壁厚（例如，从 5 毫米增加到 8 毫米）使峰值负载提高了 13.66%，而添加传统加固使其增加了高达 6.97%，并显著改善了峰值后的行为。在 ABAQUS 平台上进行的有限元分析表明，夹层和芯混凝土在加载过程中具有优异的复合材料性能，夹层和芯混凝土之间具有协调的变形。内部加固显著提高了管状柱的力学性能。参数分析表明，对于超过 60 的宽厚比，额外的常规加固大大提高了杆件的机械性能。本研究还评估了 GB 50936-2014、AISC 360-16 和欧洲规范 4 的设计模型在预测 RHCFST 短柱负载能力方面的适用性。 AISC 360-16 模型预测精度高，平均预测率为 0.976，GB 50936-2014 中对部分截面因子的建议调整显著提高了准确性，平均预测率达到 0.989。