Florida DOT Substructure Protection in Marine Environment

Uncontrolled corrosion of reinforcing steel and prestressing strands in marine structures can decrease the life expectancy of a structure to a fraction of its design life. Structures in direct contact with coastal waters experience corrosion activity around the tidal splash zone areas.

Many of Florida's coastal structures suffer from premature deterioration of substructure elements. The reinforcing steel or prestressing strands do not have a protective coating and overdriving of concrete piles during construction caused hairline cracks in the concrete that serve as a direct path for moisture, oxygen, and chlorides to reach the reinforcing steel.

For many years the Florida Dept. of Transportation (FDOT) has combated the deterioration from corrosion on the piles with conventional patching. They have also placed fiberglass jackets around the piles and backfilled with grout in an attempt to keep moisture and oxygen out of the pile. These repair procedures were found to have a short life with jackets failing after as little as 3 years. Further, the pile jackets were only hiding an increasingly dangerous condition as many prestressing strands were found to be completely severed by corrosion.

Through FDOT's Corrosion Research Lab in Gainesville, cathodic protection was introduced and developed into a standard repair procedure for existing substructures suffering corrosion damage. Cathodic protection has been used to control corrosion in bridge elements since 1974.

The FDOT standard requires an impressed cathodic protection system utilizing ELGARD™ anode mesh attached to the inside of a fiberglass jacket. The jacket is placed around all piles (or other members) and the annular void is filled with grout. This method, using the ELGARD™ anode mesh has a life in excess of 50 years. Further, the system can be safely designed to protect prestressed concrete members. Since 1991 FDOT has protected over 400 piles with this system.

Project Data
Location:  Jacksonville, Melbourne, and Tampa, FL
Owner:  Florida Department of Transportation
Owner Contact:  Mr. Rod Powers
Telephone:  (352) 372-5304
Anode Type: ELGARD™ 300 Anode Mesh w/ FRP Jackets

Installation Date - Size 
1991 - Rt. 115 0ver Ribault River (44 piles)
1992 - Howard Frankland Bridge (12 piles)
1995 - Rt. 111 over Moncrief Creek (112 piles)
1995 - Rt. 105 over Dunns Creek (113 piles)
1997 - Rt. 520 over Banana River (105 piles)

1998 - Rt. 105 over Broward River (57 piles)

Leading governmental and independent trade organizations have monitored, tested, and reported on corrosion control strategies over the past three decades. These groups include the American Concrete Institute, National Association of Corrosion Engineers, and Federal Highway Administration. They advocate CP as the only rehabilitation technique that effectively stops corrosion in salt-contaminated structures, regardless of the chloride content of the concrete.

ELGARD™ is a trademark of Eltech Systems Corporation.