重复荷载作用下CFRP布-混凝土界面黏结滑移模型

he bond-slip relationship between CFRP and concrete is the base of stress analysis of concrete structure strengthened by CFRP. In this paper, considering the influences of load level, concrete strength, CFRP-to-concrete width ratio and bond length of CFRP sheet, the CFRP-concrete interface characteristics tests were performed using hinged beam specimens to investigate the bond-slip constitutive relationship of CFRP-concrete interface under monotonic load and cyclic load. The results showed that as load cycles increased, the bond-slip curve of CFRP-concrete interface degenerated continuously, and the slope of the ascending section of the curve and the bond strength also decreased continuously, but the change of the slip corresponding to the bond strength was very small. Based on the existing constitutive bond-slip model under static load, considering the influences of load level, concrete strength, CFRP-to-concrete width ratio and so on, a bond-slip degradation model and a degradation formula of the slope of the ascending section of the model curve were proposed for a certain position of CFRP sheet-concrete interface under repeated load. In addition, a degradation formula of bond strength during the debonding process of CFRP sheet-concrete interface under repeated load were proposed.