Design, Optimization, and Management of Cathodic Protection of Rebars in Bridges

Abstract

The future of cathodic protection (CP) as applied to rebars in concrete bridges is strongly dependent upon one important factor, namely the design of CP systems. The design, in turn, determines the effectiveness of CP in minimizing corrosion and the cost of implementation and maintenance. The major drawback of contemporary designs has been excessive flow of CP current in some parts of the bridge, and little or no current at others. The primary objective of our work is to achieve a uniform distribution of current over the entire structure at all times. Our long-term goal is to design expert CP systems controlled by a variety of current and environmental sensors and a dedicated microprocessor. Our short-term goals include: development of numerical techniques that can be used in CP system designs; remote sensing and mapping the distribution of CP currents in bridges; and correlating the effect of micro-climatic changes to the distribution of CP currents. In this work, a Maryland state highway bridge which is presently under CP has been studied using a variety of sensors. Based on that study, a comprehensive approach to design and management of cathodic protection that maintains uniform protection at all times and in all locations in bridges is presented.