纵向初应力作用下圆钢管混凝土轴压短柱受力机理

应用连续介质力学,确立钢管在纵向初应力作用下的圆钢管混凝土同心圆柱体钢管和混凝土受压时的计算模型,推导了初应力作用下的钢管混凝土组合弹性模量计算公式和组合应力-应变关系全曲线的表达式,分析了不同初应力系数下钢管混凝土加载过程中的钢管轴向应力-应变关系、环向应力-应变关系以及核心混凝土的轴向应力-应变关系、径向应力-应变关系的变化情况,探讨了初应力系数对钢管混凝土力学性能的影响。分析结果表明:随着钢管纵向初应力的增大,核心混凝土的纵向刚度、径向压应力、纵向强度与钢管环向拉应力也有所降低,而相应的钢管纵向压应力有所增加,套箍约束作用和极限承载力也有所降低,但对组合弹性模量影响不大。

Mechanical behavior of concrete filled circular steel tubular stub columns with axial pre-stress in steel tube

Based on continuum mechanics,the calculation model for concrete filled circular steel tubes of concentric cylinders of circular steel tube with concrete core of entire section loaded with axial pre-stress in steel tube was determined,the theoretical calculation formulas for composite elastic modulus and composite stress-strain relationship of concrete filled circular steel tubular(CFST) stub columns with axial pre-stress in steel tube were presented,the axial stress-axial strain relationship of steel tube,the perimeter stress-strain relationship of steel tube,the axial stress-axial stain relationship and the radial stress-axial strain relationship of concrete core were analyzed,and the influence of the axial pre-stress ratio on mechanical behavior of columns was discussed.Analysis result indicates that the axial stiffness,radial stress, and axial strength of concrete core and the perimeter stress of steel tube decrease with the axial pre-stress increasing of steel tube,but the axial stress of steel tube increases,the confinement effect and ultimate capacity decrease,but the composite elastic modulus is hardly influenced.5 figs,9 refs.