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Publication Number:  FHWA-HRT-14-023    Date:  May 2014
Publication Number: FHWA-HRT-14-023
Date: May 2014


Corrosion Monitoring Research for City of New York Bridges

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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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