A Wireless Embedded Sensor System to Monitor and Assess Corrosion in the Tendons of Prestressed Concrete Girders

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

The nation's civil transportation infrastructure of structural concrete bridges is aging and deteriorating - principally as a result of the corrosion of the steel reinforcement tendons that give these structures their strength. Current estimates place the total cost of inspection, rehabilitation, and replacement of existing corroded structures in the US at $210 billion. Assessing the condition of the steel reinforcement is still based primarily on qualitative visual inspections and anticipated design lives, since the steel is typically buried beneath 1 to 2 inches or more of concrete. A multi-disciplinary team of three researchers, with expertise in the areas of non-destructive evaluation (NDE), wireless communication, and structural modeling have joined with bridge designers and managers from their state department of transportation to develop a wireless embedded sensor system to examine corrosion of tendons in prestressed concrete girders. The results of this project have the potential to deliver advanced, accurate information about the internal condition of steel reinforcement as well as the efficacy of new materials and rehabilitation methods and could save the nation billions of dollars annually. The research plan consists of three thrust areas and a demonstration project. In Thrust 1, a corrosion detection and monitoring method will be developed that uses embedded sensors. Thrust 2 will integrate the internal sensors with wireless systems for the harsh, embedded environment of a concrete girder. Thrust 3 involves the development of a software program for relating embedded sensor data to changes in significant structural characteristics. Finally, in cooperation with the Illinois Department of Transportation, the embedded sensor system will be installed in a prestressed girder during fabrication so that in-field measurements can be taken over an extended period of time to validate the effectiveness of this new embedded sensor system. This research will illustrate the importance of integrating technologies and expertise from several fields in solving complex information flow problems, not only for the structural health-monitoring and assessment community, but also for other areas where the link between any kind of sensor data and decision-making is not well-defined. The development methodology implemented in this project can also be applied to other problems to produce sensor systems that provide cost-effective and useful information to resource managers.