U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|This report is an archived publication and may contain dated technical, contact, and link information|
|Publication Number: FHWA-HRT-14-023 Date: May 2014|
Publication Number: FHWA-HRT-14-023
Date: May 2014
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Cable suspension bridges are essential components in the transportation networks of large metropolitan areas, such as the City of New York, and their serviceability is extremely important for economic and societal growth. The safety of such structures is closely linked to the safety performance of the cable supported system and, in particular, of their main cables. Currently, all State and local agencies base their maintenance plan mainly on previous experience and on limited visual inspection of the exterior and sometimes the interior of the cable. This report presents the results of a study aimed at developing a corrosion monitoring system for main cables of suspension bridges. Direct and indirect sensing technologies were reviewed, tested, and integrated in a redundant system that is able to monitor quantities like temperature, relative humidity, and corrosion rate. All these technologies were tested on a 20-ft (6.1-m)-long, 20-inch (508-mm)-diameter cable mockup before the field installation on two panels of one of the main cables of the Manhattan Bridge in New York, NY. The sensor system developed for this project recorded measurements of the temperature, relative humidity, and corrosion rate from inside the main cable for a period of almost 1 year, providing valuable information on the internal environment of an in-service main cable. This report will be of interest to highway managers; engineers involved in design, construction, and operations; and researchers.
Jorge E. Pagán-Ortiz
Director, Office of Infrastructure
Research and Development
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