Optimization of RC structure performance in marine environment

Abstract

As a result of extensive research work performed on durability design and long-term performance of concrete structures in marine environments, new procedures for probability-based durability design have been shown to provide a more realistic basis for the analysis. This approach has been successfully applied to several new concrete structures, where requirements for a more controlled durability and service life have been specified. It is commonly assumed that the dominant degradation mechanism for reinforced concrete structures in a marine environment is the corrosion of the reinforcement due to the presence of chlorides. A design approach based on the verification of the serviceability (durability) limit states has been suggested, examples of which are depassivation of reinforcement, cracking and spalling due to corrosion, and collapse due to cross section loss of reinforcement. With this design approach the probability of failure, i.e. the probability of not verifying the limit state, can be determined as a function of time. In the present paper, a probability-based durability performance analysis is used in order to demonstrate the importance of the durability design approach of concrete structures in marine environments. In addition, the sensitivity of the various durability parameters affecting and controlling the durability of concrete structures in a marine environment is studied. Results show that the potential of this approach to assist durability design decisions making process is great. Based on the procedure shown, it is possible to prolong the service life of structures while simultaneously optimizing the final design solution.