Monitoring System to Provide Assurance for Maintenance of Structures

Abstract

Repair costs of reinforced concrete structures exponentially grow with the time from construction to the onset of corrosion and deterioration, up to inspection, evaluation, repair, and rehabilitation. Therefore, the planning of an automated-monitoring system, which is able to reveal the corrosion risk of steel reinforcement and other embedded items in concrete structures would be a critically important issue. If concrete structures such as a highway bridge are ignored from regularly planned structural condition surveys, inspections, and evaluations then it could lead to catastrophic failure and loss of life and commerce. Such failures of structures also may lead to significant financial liability. The corrosion potential of steel, whose change could indicate the onset of conditions favorable for corrosion initiation, can be monitored by embedding electrodes in the structure, either for measuring the start of corrosion or simply as a baseline reference for future inspection and evaluation. Judiciously selected suitable locations of these embedded electrodes depend on the type and geometry of the structure, as well as on the exposure condition of each of its critical structural elements. A computerized system has been in use in Italy for few years. The applications described here are for concrete structures, including one steel structure that is exposed to the sea-breeze on the Adriatic Coast of the City of Ancona, Marche, Italy. The system monitors and documents by means of the embedded electrodes and sends the records to a computer via a communication line data points both for the structure and the weather. The collected data on the computer are saved on backup files, analyzed, and finally sent via modem to a monitoring station for further processing and dissemination to the architect, engineer, and owner. This structural monitoring procedure has been applied to several concrete structures that are continuously controlled and managed from the monitoring station. These experiences show the effectiveness of the continuously monitored computer system for inspections and evaluations, as well as for scheduling repairs and rehabilitations. It is important to evaluate the installation of such a structural monitoring system on any infrastructure to minimize the impact of its disruption on public safety, daily commerce, future liability, and maintenance.