Fatigue De‐Bonding Analysis of FRP‐Reinforced Concrete Structures Considering Seawater Erosion

ABSTRACT This study experimentally investigates the fatigue behavior of FRP‐concrete structures under marine‐induced corrosion. Three seawater corrosion environments were simulated, with cyclic load ranges of 3901.8 N, 6503.0 N, and 9104.2 N. Three‐stage degradation and three‐stage growth models were identified by bond stiffness and residual slip accumulation, respectively. Fatigue strength decreased with seawater exposure, with more severe degradation under prolonged exposure. For example, under original‐salinity dry‐wet cycle condition with a load range of 3901.8 N, the cycle number of joints cured for 0, 30, 60, and 90 days were 1,763,238, 1,383,336, 1,219,779, and 1,073,708, respectively. The relationship between cycle number ( N f ) and load range (Δ F ) was fitted by a linear logarithmic curve, and a fatigue strength assessment model was proposed. The predicted values showed a maximum relative error of 7%, confirming the model's effectiveness in predicting fatigue strength under seawater corrosion.