变幅反复荷载作用下变形钢筋与混凝土间的黏结退化

Bond Degradation between Deformed Reinforcement and Concrete under Variable Repeated Loads

反复荷载下钢筋与混凝土间的黏结滑移本构模型是震后钢筋混凝土结构整体性能评估及加固修复的重要依据。由于黏结应力主要由变形钢筋与混凝土间的机械咬合力所组成,黏结区域侧向约束状态会对其黏结性能产生影响。基于此,研究了在侧向压力作用下变幅反复荷载对钢筋与混凝土黏结性能的影响,定量分析了黏结参数随变幅反复荷载的退化规律,并利用数字图像技术分析了钢筋与混凝土间的黏结破坏机理。研究表明,在混凝土保护层充分约束条件下,钢筋与混凝土间的黏结退化主要与反复荷载控制位移有关,而侧向压力对其影响可忽略。

The bond-slip constitutive model between reinforcement and concrete under repeated loads is an important basis for the assessment of the overall performance of reinforced concrete structures and reinforcement repair after earthquakes.Since the bond stress is mainly composed of the mechanical occlusion force between deformed reinforcement and concrete,the lateral confinement state in the bond region will affect its bond performance.On this basis,this paper investigated the effect of variable repeated loads under lateral pressure on the bond performance between reinforcement and concrete,quantitatively analyzed the degradation law of bond parameters with variable repeated loads,and studied the bond damage mechanism between reinforcement and concrete by using digital image technology.It is shown that under the condition of sufficiently restrained concrete protective layer,the bond degradation between reinforcement and concrete is mainly related to the displacement controlled by repeated loads,while the effect of lateral pressure on it is negligible.