Behaviour of circular concrete-filled lean duplex stainless steel–carbon steel tubular short columns
Behaviour of circular concrete-filled lean duplex stainless steel–carbon steel tubular short columns
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DOI：
10.1016/j.engstruct.2013.04.016
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发表时间：
2013-11
影响因子：
5.5
通讯作者：
M. Hassanein;O. Kharoob;Q. Liang
中科院分区：
文献类型：
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作者：
M. Hassanein;O. Kharoob;Q. Liang
最近，奥氏体不锈钢-碳素钢管混凝土柱被引入作为一种新的组合构件形式。该柱由外部不锈钢管和内部同心放置的碳素钢管组成，整个管段均填充混凝土。然而，这种复合柱的优异性能还可以通过使用低成本的贫双相不锈钢材料来实现。本文利用通用有限元分析程序ABAQUS，研究了圆形双相不锈钢-碳素钢管混凝土短柱在轴压作用下的受力性能。提出了一种新的同时受外不锈钢管和内碳钢管约束的混凝土芯材本构模型，并将其纳入有限元模型中。采用精确的两阶段应力-应变关系对冷弯薄双相不锈钢进行了数值模拟。有限元计算结果表明，该混凝土模型与试验结果吻合较好。然后进行了参数研究，以研究混凝土抗压强度、碳钢屈服应力和截面几何形状对钢管混凝土柱性能的影响。研究发现，ACI规范严重低估了钢管混凝土柱的极限轴压强度。为此，提出了钢管混凝土短柱的一种新的设计模式。结果表明，所提出的设计模型可以很好地预测钢管混凝土圆柱轴向极限承载力。
Recently, a concrete-filled austenitic stainless steel–carbon steel tubular column has been introduced as a new form of composite members. This column is composed of an external stainless steel tube and an internal concentrically placed carbon steel tube with concrete filling in the whole tubular section. However, the excellent performance of such composite columns can additionally be achieved by utilising the low-cost lean duplex stainless steel material. In this paper, the behaviour of circular concrete-filled lean duplex stainless steel–carbon steel tubular (CFSCT) short columns under axial loading is investigated by using the general purpose finite element analysis program ABAQUS. A new constitutive model for the concrete core confined by both the external stainless steel tube and the internal carbon steel tube is proposed and incorporated in the finite element model developed. The accurate two-stage stress–strain relationships are employed to model cold-formed lean duplex stainless steels. The finite element results obtained by the proposed concrete model are shown to be in good agreement with test results. Parametric studies are then conducted to investigate the effects of concrete compressive strength, carbon steel yield stress and cross-section geometry on the behaviour of CFSCT columns. The ACI code is found to significantly underestimate the ultimate axial strengths of CFSST columns. Therefore, a new design model is proposed for CFSCT short columns. It is shown that the proposed design model provides excellent predictions of the ultimate axial strengths of circular CFSCT columns over a wide range of diameter-to-thickness ratios of the stainless steel tubes.