Probability-based approach to service life analysis of concrete harbour structures

Title: Probability-based approach to service life analysis of concrete harbour structures
Author(s): M. Ferreira, S. Jalali, O. E. Gjørv
Paper category : conference
Book title: 2nd International RILEM Workshop on Life Prediction and Aging Management of Concrete Structures
Editor(s): D.J. Naus
Print-ISBN: 2-912143-36-5
e-ISBN: 2912143780
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 319 - 328
Total Pages: 10
Nb references: 13
Language: English

Abstract: Along the Norwegian coastline there are more than 9.000 harbour structures, most of which are concrete structures, where the durability has typically been specified in the form of some prescriptive requirements to maximum w/c-ratio and minimum cement content and concrete cover. Even for relatively new concrete structures, where the durability requirements have been in accordance with the new European Concrete Code EN 206-1, the concrete structures are typically showing chloride-induced corrosion within a period of 10 years. In recent years, extensive research has been carried out in many countries in order to obtain a more controlled service life of concrete structures in chloride containing environments, and based on this, a probability-based service life design has proved to be very valuable. Although there is a lack of relevant data, this methodology has been successfully applied to several new concrete structures, where strict requirements to durability and long-term performance have been specified. In order to provide more data and experience with probability-based service life analysis of concrete harbour structures, three relatively new concrete structures in Norwegian harbours were selected for field investigations and subjected to service life analysis. For each structure, the investigation included a large number of chloride penetration measurements, surface potential mapping and concrete cover measurements. In addition, accelerated chloride diffusivities were determined based on drilled out concrete cores. For the modelling of the chloride ingress, Fick's Second Law of diffusion in combination with a time dependent diffusion coefficient was applied. For the reliability analysis, a Monte Carlo simulation was performed. For all the concrete structures investigated, the service life analysis showed that the probability of failure in the form of onset of steel corrosion exceeded 10 % within a period of 10 years, and the field investigations revealed that onset of steel corrosion within a period of 10 years had already taken place. These results indicate that the durability requirements according to the new European Concrete Code EN 206-1 are not adequate for assuring appropriate durability of concrete structures in a marine environment. For all new concrete structures in a marine environment, therefore, a probability-based durability design should be carried out.

Online publication: 2003-04-02
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143780.031