Detection of the Presence of Broken Wires in Cables by Acoustic Emission Inspection

Abstract

Safety of suspension or stay cable bridges depends on the durability of their cables; stay cable bridges may present a healthy aspect on observable lengths but may be damaged in the nonvisible parts (anchorages). It is important to be able to detect as early as possible the defects affecting them. In this study, the acoustic emission (AE) technique is employed to detect the presence and location of broken wires in anchorage. Allowing a cable to vibrate can induce AE from interwire fretting. The study of the behavior of a broken wire during bending contributed to the understanding of the origin of the AE, that is, interwire fretting and the definition of the most suited bending conditions. For the identification of interwire friction, the main parameters of the acoustic signals are the number of events, their energy, and frequency distribution. These parameters are very dependent of roughness, lubrication, contact strength between wires, and recovery length. Several cables were studied with various surface conditions including corroded, dry, and oiled.