Long-range Inspection of Suspender Ropes in Suspension Bridges Using the Magnetostrictive Sensor Technology

The applicability of a long-range guided wave inspection technique called “magnetostrictive sensor (MsS) ” for inspection of suspender ropes was field-evaluated on the George Washington Bridge (GWB) in New York City. From a test location above the sidewalk of the bridge, a pulse of 10-kHz longitudinal guided waves was launched along the length of the suspender and the reflected signals from geometric features and defects in the suspender were detected without requiring any paint removal. The test results showed that, from a single test location and without scanning the sensor along the rope, the MsS technique could examine the entire length of the suspender rope (from the socket to the main cable including the region over the main cable band) that was up to more than 100-meters (330-feet) long. The field tests indicated therefore that the MsS technique has good potential for providing a very cost- and performance-effective method of inspecting suspender ropes including areas that are remote and difficult to access, such as the socket end of the rope below the sidewalk and the region over the main cable band