Computer Modeling of Offshore Cathodic Protection Systems: Method and Experience

In the absence of protective measures such as paint or cathodic protection systems, steel weldments, immersed in seawater, are expected to corrode freely. This is particularly true for the ice breakers serving the Canadian Coast Guard, where, in the course of operations, paint is scoured from the vessel hulls and cathodic protection systems were not installed. However, the weldments do not corrode uniformly. In some cases, the weld itself corrodes rapidly and requires regular replacement. At the other extreme, the heat-affected zones corrode instead—a potential safety and integrity concern. The morphology of ice breaker weldment corrosion has altered over the last few decades and this has been attributed to changes in welding consumables and processes. The current study is an investigation into the corrosion characteristics of weldments with a particular focus on the compositional differences between weld metal and hull plate steels. A method has been developed for numerically describing the corrosion of weldment regions (plate steel, heat-affected zones, weld cap passes and weld re-heated zones) arising from an accelerated corrosion test. This in turn enabled the development of an equation that predicts weldment corrosion performance based entirely on material composition. This permits selection of welding consumables that are anticipated to give good corrosion performance, avoiding the extremes of rapid weld metal corrosion and preferential heat-affected zone attack.

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Operation and maintenance of Impressed Current Cathodic Protection systems on concrete civil structures

IABSE Conference, Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future ◽

10.2749/copenhagen.2018.219 ◽

2018 ◽

Author(s):

Jacob Brink Jansson ◽

Ruth Sørensen ◽

Kirsten Riis

Keyword(s):

Service Life ◽

Cathodic Protection ◽

Protection System ◽

Civil Structures ◽

Correct Operation ◽

Operation And Maintenance ◽

Number Of Factors ◽

Protection Systems ◽

Cathodic Protection System

Cathodic protection is a very well-known method of preventing or stopping reinforcement corrosion and thereby extending the service life of reinforced concrete civil structures. However, a number of factors, which among others are design, materials and components, installation methods, quality of workmanship, and operation and maintenance of the cathodic protection system, have influence on the functionality and effectivity of the cathodic protection system. The optimum design that fulfils the Client''s requirements to cost, traffic disruption, service life, etc. shall be determined in accordance with the structure layout and the ability of the Client''s organisation to conduct operation and maintenance. It is critical to ensure that all components are installed properly to achieve the expected service life of the system. Regular and correct operation and maintenance is also crucial to ensure the functionality and effectivity system.

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