Description
To ensure the structural stability of large infrastructure systems like concrete bridges, a range of measurement techniques are needed to identify and detect various types of damage or decay, including rebar corrosion, cracking, tendon failure, or alkali-silica reactions.
In an experimental study, a progressively increasing point load was applied at the centre of a flipped-T-shaped concrete sample, inducing a reduction in mechanical stiffness. During the loading process, structural deformation and acoustic emission resulting from concrete crack formation were measured. Between the load steps, the unloaded structure was excited with an impulse hammer for a modal analysis. Therefore, accelerometers were attached at 24 sensor locations.
At first, we assess the suitability of the individual methods in detecting, localizing and quantifying possible damage. As a second step we show correlations in the number and intensity of identified crack events, the change in eigenfrequencies of correlating mode shapes of the specimen and the size and location of optically identified cracks on the concrete surface.
We conclude that the combination of different methods increases the reliability and quality of damage detection and localisation required for real-world application.
