Time-varying characteristics of the durability and lateral bearing behaviour of FRP bar-reinforced concrete piles in marine environments

Abstract In this paper, the time-varying characteristics of the durability and lateral bearing behaviour of fibre reinforced polymer (FRP) bar-reinforced concrete piles in marine environments are studied. A diffusion model of chloride ions in FRP bar-reinforced concrete piles is established based on Fick's second law. The failure probability of the corrosion initiation time of FRP bar-reinforced concrete piles induced by chloride attack is evaluated. The stiffness degradation model of FRP bar-reinforced concrete piles with different replacement ratios of FRP bars is established based on the time-dependent reinforcement corrosion model. The lateral bearing behaviour of FRP bar-reinforced concrete piles under lateral loading is obtained by the finite difference method. The Monte Carlo simulation method is used to generate random parameters to evaluate the failure probabilities of FRP bar-reinforced concrete piles under the failure criteria of bending moment and lateral displacement. The analysis results show that for the same FRP replacement ratio, the bending stiffness of FRP bar-reinforced concrete piles decreases with increasing exposure time, and the decreasing range of bending stiffness of FRP bar-reinforced concrete piles decreases with increasing FRP replacement ratio. For an exposure time of 50 years, the lateral displacement of the pile top increases with an increase in the replacement ratio of the FRP bars but decreases with an increasing replacement ratio of the FRP bars for exposure times of 100 years and 150 years. Before an exposure time of 75 years, the failure probability of FRP bar-reinforced concrete piles under the two failure criteria increases slightly with the increase in the replacement ratio of FRP bars but decreases significantly with the increase in the replacement ratio of FRP bars after an exposure time of 75 years.