钢筋混凝土柱轴心受压性能及尺寸效应的细观数值研究

钢筋混凝土构件的尺寸效应行为根源于两个方面:(1)混凝土材料本身的非均质性导致的尺寸效应;(2)钢筋/混凝土相互作用力学行为的高度复杂性导致的尺寸效应。考虑混凝土细观结构非均质性的影响,假定钢筋与混凝土之间完好粘结,建立了钢筋混凝土柱轴心受压加载下力学特性及破坏行为研究的细观尺度力学分析模型。首先通过对混凝土试件受压力学特性试验的模拟,采用反演法确定了各细观组分的力学参数;进而,对某钢筋混凝土柱轴心受压损伤破坏行为进行了宏/细观尺度数值模拟,并初步探讨了钢筋混凝土构件名义轴心压缩强度的尺寸效应规律。本文细观数值结果与试验结果的良好吻合,验证了建立的钢筋混凝土构件层次尺寸效应研究的细观分析方法的合理性。

Mesoscopic simulation of the mechanical properties and the size effect of reinforced concrete column subjected to axial compressive loading

The size effect behavior of reinforced concrete (RC) components is caused mainly by 1) the heterogeneity of concrete itself,and 2) the complex mutual effects between concrete and steel rebar. Considering of the mesoscopic heterogeneity, it is assumed that the steel rebar and concrete is well bonded. A series of meso-scale mechanical analysis models of RC columns subjected to axial compressive loading are set up. First, the mechanical parameters of the meso components are confirmed by an inversion method based on the simulation of compressive mechanical properties test of a concrete specimen. Then, the damage process of RC column subjected to axial compressive loading is simulated at macro- and meso-scale. The size effect of the nominal compressive strength of RC components is discussed. The mesoscopic simulation results of this work follows closely the test results. The rationality of the established mesoscopic analysis method for the research of size effect of RC components has been verified.