Non-destructive Assessment of Damaged and Repaired Concrete Beams

Nowadays, much civil concrete infrastructure is experiencing problems of ageing and deterioration after decades of use and abuse by humans and the environment. This study aims at using modal testing, as a global non-destructive assessment method, to generate the vibration characteristics of incrementally loaded laboratory-scale reinforced concrete (RC) beams. The work was done on a series of RC beams of dimensions (2,0 x 0,14 x 0,09)m. The testing procedure included measuring the natural frequencies, modal damping and mode shapes of the intact then successively damaged beams. The study employs the collected vibration data to discriminate between types of damage, locate damage and estimate its extent. In addition, the tested RC beams were repaired by using carbon fibre reinforced polymer CFRP layers, and the regenerated vibration parameters were utilised to evaluate the impact of the subsequent repair. In this study, all common modal parameters and their derivatives were shown to be reliable as a means to distinguish between beams with different damage scenarios and to locate the position of the damage. Also, it is clearly possible to estimate the enhanced properties of repaired RC beams.