Acoustic Emission Monitoring and Localization Method for Broken Wires in 13 In-Service Stay Cables Connected by a 165-m-Long Waveguide Rod

The stay cable is one of the crucial structures of a cable-stayed bridge, and the occurrence of broken wires in cables may endanger the safety of the entire bridge. Currently, the acoustic emission (AE) monitoring method for detecting broken wires of cables requires a significant number of sensors, which leads to high monitoring costs. To reduce the monitoring cost and the number of sensors for cable monitoring, this study used a 165-m-long waveguide rod to connect 13 cables on the Yellow River Super Bridge of Anluo Expressway in Henan Province, China, and carried out experiments on the acoustic emission attenuation of the waveguide rod and the arrangement of sensors. The acoustic emission attenuation law of rigid and flexible waveguide rods with a length of 165 m was studied, the difference in the AE sensor arrangement on the side and cross section of the waveguide rod was analyzed, and the arrangement of AE sensors was optimized. Two AE sensors were arranged at both ends of the waveguide rod to locate the cable with broken wires. The results indicate that the acoustic emission amplitude of the 165-m-long rigid waveguide rod is the characteristic parameter with the smallest attenuation compared with duration, ringing count, and energy. The attenuation of the acoustic emission amplitude of the 165-m-long flexible waveguide rod is greater than that of the rigid waveguide rod under the same length, while the attenuation rates of time duration, ringing count, and energy are less than those of the rigid waveguide rod. Under the comprehensive comparison, the two types of waveguide rods show lower attenuation in different characteristic parameters and are suitable for various application scenarios; therefore, one can reasonably choose the type of waveguide rods according to the actual structure of the cable, monitoring needs, and the installation environment. The AE sensor arranged on the cross section of the waveguide rod is more conducive to monitoring the broken wires of the cables. A 165-m-long waveguide rod is used to connect 13 cables, and a sensor arranged at both ends of the waveguide rod can determine cables with broken wires.