镀锌铁丝约束混凝土应力-应变本构研究

为给复杂高层、大跨混凝土结构小缩尺比模型试验中常采用的铁丝约束混凝土的本构模拟提供依据,该文设计了素混凝土、铁丝约束混凝土、钢筋约束混凝土共计13个圆柱,对其进行轴压试验,对比研究铁丝约束混凝土的破坏历程、应力-应变曲线与钢筋约束混凝土的区别,并分析铁丝与普通钢筋对核心混凝土约束作用的区别。结果表明:模型试验中常采用的镀锌铁丝弹性模量仅钢筋的60%左右;与素混凝土相比,铁丝约束混凝土的强度和变形能力均得到显著提高;对于螺旋配箍的钢筋约束混凝土,按Mander模型模拟更为准确;对于螺旋配箍的铁丝约束混凝土,Park模型能很好地估计其峰值压应力,但过低估计其峰值压应力对应的应变和极限压应变;修正后的Park模型能很好地模拟铁丝约束混凝土的应力-应变行为。

Research on stress-strain constitutive model of concrete confined by galvanized iron wires

To provide a reference for the constitutive model of galvanized iron wire (GIW) confined concrete often used in the small-scale model test of high-rise and long-span concrete structures, thirteen circular columns including three plain concrete columns, three reinforced concrete columns and seven GIW confined concrete columns were designed and tested. The failure processes and stress-strain curves of GIW confined concrete columns under uniaxial compression loads were compared with those of the reinforced concrete columns. The confinement effect of GIW on core concrete was also compared with that of reinforcement bars. Results show that the elasticity modulus of GIW often used in model tests is only about 60% of that of reinforcement bars. Compared with the plain concrete, the peak strength and deformation capacity of GIW confined concrete are significantly improved. Mander model is more accurate in representing the stress-strain behavior of reinforced concrete with spiral hoops. Park model can estimate the peak compressive stress of the concrete spirally-confined by GIWs well, but may underestimate its ultimate compressive strain and the strain corresponding to the peak stress. The modified Park model can simulate the stress-strain behavior of GIW spirally-confined concrete better.