Non-Destructive Inspection for Internal Guy Corrosion on Tall Towers

Many of the guys that support several of the Navy’s tall antenna towers are developing severe localized corrosion somewhere along each guy. This corrosion is often occurring on layers deep inside of the up-to 4-inch diameter structural strand that makes up each guy. There is often little correlation between internal corrosion and visual inspections of the often un-corroded outer layers of the strand. With guys as long as 1500 feet, certain strategic Navy antennas have over 250 guys to inspect.

 A non-destructive guy inspection system has been developed to monitor and assess the corrosive condition of each guy. Consisting principally of a guy crawler, a magnetic flux sensor, and a remote control unit, this guy inspection system is capable of determining the loss of metallic area and local faults in the structural strand along each guy.

This paper will present basic magnetic flux sensing concepts, present critical features of the basic hardware, summarize validating test results to-date, and describe the intended program of inspection needed to assess the remaining life and/or risk of failure of guys with varying levels of internal corrosion.