Bond behavior between CFRP and steel structures with random corrosion defects

Steel structures in long-term service are difficult to avoid corrosion and can be reinforced by carbon fiber reinforced polymer (CFRP) bonding method. To investigate the corrosion effect on the bond behavior between CFRP and steel, a modified cohesive zone model was proposed and verified by experiment. Then, a series of random corrosion morphologies controlled by the size and the shape of corrosion pit were generated. Finally, by importing the random corrosion morphologies and the corresponding cohesive parameters distributions into the model, a parametric analysis was executed. Results showed that the ultimate load of CFRP-corroded steel bonding system was sensitive to the size of corrosion pit, while the stiffness had identical sensitivities to the pit size and pit shape. The ultimate load would reach the peak value when the average pit width Wp,avg was 1.0 mm and the average pit depth-to-width ratio (Dp/Wp)avg was between 0.12 and 0.14, whereas the stiffness would reach a high level when the Wp,avg was between 1.0 mm and 1.2 mm and the (Dp/Wp)avg was between 0.12 and 0.14. Moreover, the effective bond length would reach a high level when the Wp,avg was between 1.0 mm and 1.2 mm and the (Dp/Wp)avg was about 0.10.