正方形断面钢管混凝土短柱轴心受压极限承载力的研究

本文根据钢管混凝土柱轴压实验及有限元分析的结果，首次提出正方形断面钢管混凝土短柱轴心受压极限承载力计算模型．该模型将钢管视为平面应力状态，将核心的混凝土划分为双轴受压区与三轴受压区，利用Ｍｉｓｅｓ屈服曲面以及复杂应力状态混凝土的强度理论，可将钢管混凝土柱的承载力表示为钢管模向应力的函数．根据塑性理论中的下限定理，即可确定钢管混凝土柱的极限承载力。

ANALYSIS OF ULTIMATE AXIAL LOADS OF CONCRETE-FILLED STEEL COLUMNS WITH RECTANGULAR SECTION

A method to predict the ultimate loads for short concrete-filled steel columns with rectangular section is proposed. The behavior of steel tubes is assumed as plane stress states and the filled concrete is divided into biaxial and triaxial compression regions based on stress analysis by using finite element method. Therefore,the axial load of the column can be represented as a function of hoop tensile streess in the steel tube.The stresses of the steel tube are evaluated by Mises's yield condition and the strength of filled concrete are estimated by Kupfer's envelope for biaxial regions and Richart's criterion for triaxial regions. Based on the lower bound formula in the theory of limit analysis, the maximum value of axial loads,which is regarded as the ultimate load,can be determined by using stationary conditions. Inaddition,twelve specimens were studied by this model and very good results have been gaven.