Probabilistic durability design method for marine concrete structures based on characteristic subdomain model

Traditional methods for durability design of marine concrete structures usually select and estimate durability design parameters according to engineering experience due to lack of quantitative design model. In order to deal with this problem, a probabilistic durability design method was developed to determine the allowable values of durability design parameters for marine concrete structures. The characteristic subdomain model was proposed at first to provide an efficient and accurate way to describe the concentration profile of chloride ions within the large concrete structures with complex geometry. Then a deterministic three-parameter design model was presented to estimate the durability design parameters of marine concrete structures, including the chloride diffusion coefficient, concrete cover thickness, and aging factor. Finally, a probabilistic durability design procedure was developed by taking into account the probabilistic durability limit state function and the predefined target reliability index rationally. A 150,000 ton wharf in the Beibu Gulf was taken as an example to demonstrate the validity of the proposed method. Results show that the proposed method reflects accurately the influences of geometry, material properties, and environmental conditions as well as their uncertainties on the durability performance, satisfying the requirement of service life of marine concrete structures under chloride environment.