In-Service Performance Deterioration Analysis of FRP-Reinforced Concrete Structures Exposed to Natural Marine Environments: A Theoretical Approach and Application

This paper proposes a theoretical framework for analyzing the in-service performance degradation of fiber-reinforced polymer (FRP)–reinforced concrete structures exposed to natural marine environments, focusing on the deterioration of concrete and its FRP reinforcements. First, multiscale physicochemo-coupled modeling was employed to evaluate the moisture transport, heat transfer, chloride penetration, and carbonation in concrete structures exposed to marine atmospheric environments. Subsequently, based on the dynamic internal concrete environments (i.e., temperature, RH, pH, and chloride concentration) obtained previously, a chemical etching–based model and the gas–liquid state shift theory were applied to calculate the erosion depth and horizontal shear strength of FRP bars embedded in concrete. Finally, based on the periodical weather data, the long-term performance degradation of FRP reinforcements within concrete was projected over decades of service. The proposed approach offers significant potential for evaluating the time-dependent service performance of FRP-marine concrete infrastructures, with validations by a case study, the glass FRP–reinforced concrete dry dock in Hawaii using field data after 18 years of service.