圆端形椭圆钢管混凝土长柱偏压受力性能研究

为了获悉圆端形椭圆钢管混凝土偏压长柱的理论计算模型和受力性能,考虑了圆端形椭圆截面特征,提出了圆端形椭圆钢管混凝土本构关系等效方法;基于有限元法建立了圆端形椭圆钢管混凝土长柱在偏压作用下的理论分析模型。对钢材强度、混凝土强度、偏心距、径厚比、长短轴比和长细比等诸多参数进行了系统分析,评价了各参数对圆端形椭圆钢管混凝土长柱偏压承载力的影响,揭示了其破坏模式。研究结果表明:圆端形椭圆钢管混凝土偏压长柱的承载力随着混凝土强度和钢材强度的增大而增大;随着偏心率、径厚比、长短轴比和长细比的增大而减小。最后,基于统一理论提出了圆端形椭圆钢管混凝土长柱偏压作用下的承载力设计方法。研究结果将为建立圆端形椭圆钢管混凝土结构的设计和应用提供参考。

Study on the Eccentric Compressive Behavior of Round-Ended Elliptical Concrete-Filled Steel Tubular Slender Columns

In order to investigate theoretical calculation model and mechanical behavior of round-ended elliptical concrete-filled steel tubular(RECFST)slender column under eccentric load,an equivalent constitutive method of RECFST is proposed based on the characteristic of round-ended elliptical cross-section.A numerical model of RECFST slender column subjected to eccentric compression is built based on finite element(FE)method.The parameters such as steel strength,concrete strength,load eccentricity,diameter-to-thickness ratio,aspect ratio and column slenderness are analyzed.The influence of these parameters on the eccentric compressive strength of RECFST slender column is evaluated.The failure modes are discussed and the calculation formulas for predicting the ultimate eccentric compressive strength of RECFST members are proposed.The results show that the eccentric compressive strength of the RECFST slender column increases with the increase of concrete and steel strength,but it decreases with the increasing of load eccentricity ratio,diameter-to-thickness ratio,cross-section slenderness ratio and slenderness ratio.The results will provide a useful reference for the design and application of RECFST columns.