Vibration

El Masri E., Waters T. & Ferguson N.

Many engineering structures must be inspected or monitored throughout their serviceable life to ensure their safe operation. In the case of reinforced concrete structures, the most common cause of failure is corrosion of the steel reinforcement bars. However, the latter are not accessible to sensors. This paper proposes a non-invasive technique based on guided waves for detecting localised abnormalities in reinforcement bars embedded in concrete beams. Certain guided waves are strongly reflected by damage just at the cut-on frequencies at which they start to propagate. No model or historical measurements of the intact structure are required.