Probabilistic Lifetime Assessment of Prestressed Concrete Structures Exposed to Chloride Environment

In order to study the durability behavior of marine prestressed concrete structures exposed to chloride environment, the structural service life is defined as the corrosion initiation of prestressing steel bars. For the chloride ingress in prestressed concrete, a calculated model used to predict the lifetime is developed. Based on the definition of durability limit state, a probabilistic lifetime model and its time-dependent reliability analytical method are proposed by considering the random natures of influencing factors. Then, the probabilistic lifetime prediction models are applied to a PC bridge located in Hangzhou Bay with Monte Carlo simulation. It is found that the time to corrosion initiation t0 follows a lognormal distribution. With the permitted failure probability of 5.0%, it is also observed that the structural durability lifetimes are 25.6, 107.4 and 224.2 years for c=40mm, c=60mm and c=80mm, respectively.