Galvanic Corrosion Protection for Bridge Structures

Impressed Current Cathodic Protection (ICCP) system has been installed in bridges to protect bridges from corrosion since 1970s. When ICCP systems are properly monitored and maintained, corrosion is minimized or virtually stopped. However, many installed ICCP systems are not working to their full potentials due to lack of qualified personnel and maintenance budgets.

Galvanic anodes have been included in patch repairs of steel reinforced concrete structural elements suffering from corrosion since the mid-nineties. Drilled Galvanic anodes are used in many concrete structures where corrosion potentials are high and/or chloride level is high but corrosion does not progress to the extent causing concrete damages. These two types of anodes has been included in the recently published ACI RAP Bulletin 8 ‘Installation of Embedded Galvanic Anodes’ (1).

Recognizing the inadequate monitoring and maintenance of impressed current cathodic protection that will make it in-effective, with the successful experience of galvanic anodes in patch repairs, a new galvanic cathodic protection system was developed in 2003, a trial using this distributed galvanic anodes was conducted in bridge deck overlay to address the global corrosion issues in the structure in Canada in 2003. The trial had been monitored for 12 years and was considered a success. The newly developed distributed galvanic anode system has been used in various bridge applications, including abutment overbuild, concrete deck overlay, concrete jackets for columns, piers and marine piles around the world since its inception.

This paper first introduces some corrosion basics and cathodic protection, then discusses the levels of galvanic corrosion protection and its applications.