T形钢管混凝土柱轴心受压稳定承载性能研究

Behavior of Concretefilled Tshaped Steel Tube Intermediate Long Columns Subjected to Axial Loading

摘要:

基于9根T形钢管混凝土中长柱的单向、双向偏心受压试验的结果，建立了T形钢管混凝土柱用于纤维模型程序分析其承载力的本构模型.在验证纤维模型程序合理性的基础上，对T形钢管混凝土柱轴压稳定性能进行了参数研究.研究参数包括：钢材屈服强度、混凝土抗压强度、管壁宽厚比、截面肢宽厚比、长细比以及加载角度.理论结果表明： 长细比是影响T形钢管混凝土柱轴压稳定承载力的主要因素，混凝土工作承担系数和加载角度也对钢管混凝土柱的承载力有一定影响.纤维模型计算的柱子曲线与钢结构规范的a, b, c, d类曲线之间的比较表明：不同参数截面的T形钢管混凝土柱的柱子曲线会在一个较宽带宽范围内变化.最后，在大量参数分析基础上，考虑长细比和混凝土工作承担系数的影响，提出了T形钢管混凝土轴压柱的稳定承载力系数的实用计算方法.理论公式计算结果与已有试验结果吻合良好，可为工程设计提供理论参考.

Abstract:

A fiber element analysis method was proposed and verified according to the experimental results of 9 concretefilled Tshaped steel tube (CFTST) columns subjected to uniaxial eccentric loading or biaxial eccentric loading. The behavior of concretefilled Tshaped steel tube intermediate long columns subjected to axial loading was investigated. The parameters in the analysis included the yield strength of steel, the compressive strength of concrete, the depth to thickness ratio of steel plate, the cross sectional depth to width ratio, the slenderness ratio of the specimens, and the angle of the loading. The results of theoretical analysis show that the loadcarrying capacities of the CFTST columns under axial load were obviously influenced by the slenderness ratio of the specimens and to some extent the load ratio carried by core concrete and the load angle. A comparative study of the normalized slenderness ratio vs. stability reduction ratio curves of the CFTST columns (λnφ) predicted by the fiber element analysis method and Code for Design of Steel Structures in China shows that the curves with different section parameters wave in a larger range. Finally, based on the extensive parametric analyses, the simplified calculation method of normalized slenderness ratio vs. stability reduction ratio curves (λnφ) was proposed with a considerction of the effect of the slenderness ratio and the load ratio carried by core concrete. Good agreements between the values predicted by the simplified calculation method and the experiment results were achieved, and the simplified calculation method may be referred for practical engineering design.