偏压下椭圆钢管混凝土短柱力学性能研究

Study on the Mechanical Behavior of Elliptical Concrete-Filled Steel Tubular Short Columns Under Eccentric Compression

为了考察椭圆钢管混凝土短柱的偏压性能,通过ABAQUS有限元程序建立了椭圆钢管混凝土短柱在偏压作用下的数值分析模型,并利用试验结果验证了数值分析模型的准确性。进行了偏压作用下椭圆钢管混凝土短柱的参数分析,研究了各参数对椭圆钢管混凝土短柱最大轴压承载力、最大弯矩和延性的影响,揭示了偏压下椭圆钢管混凝土短柱的破坏模式,通过数值分析拟合了轴力-弯矩相关曲线。研究结果表明,椭圆钢管混凝土短柱在偏压作用下的破坏模式包括半高截面鼓曲破坏、半高以下截面鼓曲破坏、加载柱端双褶鼓曲破坏和柱两端双褶鼓曲破坏;影响椭圆钢管混凝土短柱最大轴压承载力和最大弯矩的主要因素为偏心距、径厚比和长短轴比,影响延性系数的主要因素为径厚比、长短轴比和混凝土强度。研究结果将为建立椭圆钢管混凝土短柱设计方法提供参考。

In order to find the eccentrically compressive behavior of elliptical concrete filled steel tubular（ ECFST） short columns,a numerical model of the ECFST short columns under eccentric compression is built using finite element（ FE） software ABAQUS,and the accuracy of FE model is verified using test data. This paper focuses on the influence of various parameters on the ECFST short columns under eccentric compression. The paper also studies the failure modes of the ECFST short columns under eccentric compression. The measured axial pressure-bending moment correlation curves match well with the numerical analysis results. The results show there are four failure modes of ECFST short columns under eccentric compression,including buckling at mid-height,buckling below mid-height,double-fold at loading end and double-fold at both ends. Three factors influencing the ultimate bearing capacity and ultimate bending moment are eccentricity,diameter thickness and long short axis ratio. The ductility is mainly influenced by concrete strength,diameter thickness and long short axis ratio. These results can be used as a reference for the design methods of ECFST short columns.