增强纤维约束混凝土轴压应力-应变关系试验研究

本文通过不同增强纤维包裹的混凝土圆截面短柱的轴压试验,并结合国内外同类试验结果分析,认为纤维约束混凝土根据约束刚度比βj或约束比ξ的不同,可分为强、弱约束两种不同情况,分别讨论了它们在弹性、弹塑性及强化或退化不同阶段核心混凝土所处的状态和应力-应变曲线的特点,认为约束刚度比决定了强化或退化段的直线斜率,约束比决定了强约束混凝土的强度。文章给出了适用于纤维强、弱约束混凝土统一函数形式的应力-应变曲线方程及特征点和相应系数的确定方法,其结果与试验值吻合较好。

Research of stress-strain curve of concrete confined by fiber reinforced plastics under axial compression

Based on the experimental studies on short concrete round section columns wrapped with different types of fiber reinforced plastics (FRP) and the analysis of the same by experiments, the confined concrete wrapped with fiber can be divided into two kinds, i.e. the strong confined concrete and weak confined concrete according to the confinement stiffness ratio βj or confinement ratio ξ. The paper discussed the characteristics of the stress strain curve and the state of the core concrete in three stages,namely the elastic, elastic plastic and strengthening or degenerating stages. The paper points out that the confinement stiffness ratio βj determines the slope of strengthening stage (degenerating stage),and confinement ratio ξdecides the ultimate strength of confinement concrete. The stress strain curve equation, latent point and the method of ascertaining corresponding quotiety applicable to the unitive function form of strong confined concrete and weak confined concrete are given, and the results appear to be in good agreement with the testing results.