Eastbound SR-312 bridge repairs will last a year


400-SPALLING-312-PILINGSFor the next year, Historic City News readers will notice workers with Orion Marine Construction, Inc. of Tampa, who will be installing a cathodic protection system to defend the piers beneath the eastbound side of the Mickler O’Connell Bridge on SR-312 from the debilitating effects of concrete spalling.

Cathodic protection is a widely used form of corrosion control that sends a small, but continuous, electric charge that prevents corrosion and protects the steel within the concrete structure of the bridge piers. The electricity is carefully adjusted using devices that are placed on the bridge to monitor performance. In turn, protecting the steel helps protect the concrete.

“Barges and work boats will be around the area beneath the bridge, so we are asking boaters to use caution around the bridge supports as work crews and divers will be in the Matanzas River,” a construction spokesman told Historic City News this morning. “While the channel beneath the bridge is not currently scheduled to close during the project, the width of the channel may be restricted at times; however, the Florida Department of Transportation will coordinate any restrictions with the U.S. Coast Guard.”

Minimal motorist traffic disruption is expected during the project, but a traffic shift or lane closures may be necessary to accommodate construction equipment. Orion Marine Construction says that their plan is to work Monday through Friday from approximately 7:00 a.m. to 5:30 p.m. and on Saturday from 7:00 a.m. to 3:00 p.m. A night schedule may be added later during the project and adverse weather conditions could extend the completion of the project.

Spalling is usually caused by corrosion of the steel reinforcement bars embedded in the concrete matrix. Modern construction standards generally call for at least one inch between the outer concrete surface and any rebar. Exposure to moisture, as in the case of marine concrete installations, can cause the metal inside to corrode, expand, and eventually force the concrete to chip and split away — exposing the rebar and weakening the structure.

The Florida Department of Transportation is paying $2.5 million to complete the project.