基于随机开裂理论的钢筋混凝土粘结损伤拉伸弹性性能

Tensile elastic performance of reinforced concrete bond damage based on the random cracking theory

为了研究钢筋混凝土构件在界面脱粘后导致的宏观力学性能的变化,考虑混凝土随机开裂和界面脱粘两种损伤机制,建立了钢筋混凝土单胞的拉伸损伤分析模型,基于单胞模型的拉伸损伤分析给出了界面粘结强度、界面脱粘长度、平均裂缝间距与模型等效拉伸弹性模量的函数关系。基于模型分析把钢筋混凝土的损伤过程分成3个阶段,推导得到各个损伤阶段的等效弹性模量,并分析单胞分析模型中钢筋体积分数和混凝土体积分数,混凝土轴心抗拉强度标准值和弹性模量,Weibull分布参数m对等效弹性模量的影响。分析表明:等效弹性模量的变化趋势与实际钢筋混凝土损伤状态相符,可为钢筋混凝土构件的宏观力学性能劣化与细观损伤形态之间的双尺度理论分析提供依据。

To study the macroscopic mechanical properties of reinforced concrete members after debonding at the interface,the damage analysis model of steel bar-concrete was established considering random concrete cracking and interfacial debonding.The relationship between debonding length,final average crack spacing,interfacial bonding stress and model elastic parameters were given with the model.The tensile damage process of the unit cell model was divided into three stages,and the equivalent elastic moduli expressions of three damage stages were derived.The effect of main model parameters on equivalent elastic moduli during three stages were evaluated such as the volume fractions of steel bar and concrete,tensile strength and elastic module of concrete,and Weibull distribution parameter m.The results show that the variation of equivalent elastic modulus is consistent with the actual damage state of reinforced concrete,which can make it more possible to establish the relationship between the macroscopic mechanical damage properties of reinforced concrete members and the mesoscopic damage mechanisms.