基于数值分析的椭圆钢管混凝土柱轴压性能及承载力计算

Axial Compressive Behavior and Bearing Capacity Calculation of ECFST Columns Based on Numerical Analysis

为了研究椭圆钢管混凝土柱的轴压性能和承载力,通过ABAQUS程序建立了轴压作用下椭圆钢管混凝土柱的数值分析模型,考虑了复杂接触问题、材料非线性和椭圆特征。利用试验结果验证了数值分析模型的准确性。开展了轴压作用下椭圆钢管混凝土短柱的诸多参数分析,评价了各参数对组合柱轴压承载力和刚度的影响,揭示了椭圆钢管混凝土短柱的破坏模式和受力机理,基于统一理论提出了椭圆钢管混凝土短柱的轴压承载力简化计算方法。研究结果表明,椭圆钢管混凝土短柱在轴压作用下的破坏模式包括剪切破坏、局部鼓曲破坏和整体鼓曲破坏;椭圆钢管混凝土短柱的轴压受力特征可以分为弹性阶段、弹塑性阶段、塑性强化段和下降段,均与约束效应系数有关。提出的椭圆钢管混凝土短柱的轴压承载力简化计算公式可以用于椭圆钢管混凝土柱设计。

To study the axial compressive behavior and bearing capacity of elliptical concrete-filled steel tube （ECFST） columns, a numerical model of ECFST columns under axial compressive loading is established using ABAQUS software. Complex contact properties, material nonlinearity, and ellipse features are considered in the model. This numerical model is validated through comparing against test results. The parameters affecting ultimate bearing capacity and stiffness of ECFST columns are analyzed, and the working mechanism and failure modes are revealed. A simplified formula on the axial compressive bearing capacity of ECFST columns is proposed based on the unified theory. The research results show the failure modes of ECFST columns are shear failure, local buckling failure, and overall buckling failure. Based on its working mechanism, the behavior of ECFST column can be divided into four stages, namely, elastic stage, elasto-plastic stage, plastic hardening stage and descending stage. These four stages are influenced by the constraining factor. The simplified formula on compressive bearing capacities can be applied to the design of ECFST columns.