Comparative Study of Two Concrete Bridges in Marine Environment

This paper presents the procedure used in assessment, evaluation, diagnosis and design of prestressed concrete bridge structure damaged by steel corrosion on the two bridges on the Adriatic coast. The bridges located in a marine environment have shown severe damages. Today, after 21 years in use, the Krk Bridge from mainland to the island of Krk begins having problems connected with steel corrosion in concrete, caused by chloride ions. That also appeared on the Vir Bridge after 18 years of use. The damages have been investigated in three steps: visual prospecting detailed testing of representative locations and laboratory investigation of microstructure. The question of representative number of tests is discussed. The environmental exposure varies for different parts of the structure and it results with the different degrees of damages This paper reports results of the chloride content in the concrete. The service life of the bridges is calculated based on the chloride content in the concrete. The experimental results were compared to the theoretical values of two different concrete qualities, high one and low one.