带约束拉杆矩形钢管混凝土短柱偏压承载力特性研究

Behavior of Rectangular CFT Columns with Binding Bars Subjected to Eccentric Loading

基于带约束拉杆矩形钢管混凝土的本构关系,利用纤维模型法对带约束拉杆矩形钢管混凝土短柱承载力进行数值计算,通过计算结果与试验结果的比较验证纤维模型法的合理性,同时讨论各种因素对带约束拉杆矩形钢管混凝土短柱的单向偏压和双向偏压承载力的影响。带约束拉杆矩形钢管混凝土偏压短柱的参数分析结果表明,随着约束拉杆间距的减少和直径的增大,偏压短柱的极限承载力增大;随着钢管壁厚的增大,偏压短柱的轴力/轴压承载力-抗弯承载力/纯弯承载力(N/Nu-M/Mu)曲线往内收拢;随着混凝土强度和截面高宽比的提高,偏压短柱的N/Nu-M/Mu曲线向外凸出;钢材强度对N/Nu-M/Mu曲线的影响不明显;双向偏压矩形短柱的极限承载力在最大主惯性轴方向达到最大,随着截面高宽比的增大,最小极限承载力的位置从α=45°(方形截面)变化到α=90°(截面最小主惯性轴方向);各参数对单向偏压和双向偏压短柱的N/Nu-M/Mu曲线的影响相类似。

To adopt the constitutive relationship of rectangular concrete filled steel tube (CFT) with binding bars,numerical analysis of the bearing capacity of rectangular CFT stub columns with binding bars subjected to eccentric loading was carried out by using fiber model method.The analysis results are consistent with the experimental ones.The results indicate that the ultimate bearing capacity increases with the reduction of spacing and the increment of diameter of binding bars,N/Nu-M/Mu curves are more interior convex as the tubes are thickened,and more outer convex while the concrete strength and the ratio of high to width of the section are higher,the steel yield strength has no evident effect on N/Nu-M/Mu curves.The maximum value of its ultimate bearing capacities appears at the direction of the maximum principal axis of inertia,and the position of the minimum value is at the direction from α=45°(square section)to α=90° (minimum principal axis of inertia).The influences of parameters on N/Nu-M/Mu curves of stub columns subjected uniaxial and biaxial eccentric loading are similar.