Damage Detection In Laboratory Concrete Beams

The aim of the investigation reported in this paper is to clarify to what extent damages in reinforced concrete can be detected by estimating changes in the vibrational properties. A series of damages were introduced by applying static load cycles of increasing magnitude to two concrete beams: a beam with a typical reinforcement ratio, and a beam with a small reinforcement ratio. The modal properties of the beams were found exciting the beams by a series of pulses and identifying the properties using ARMA and ARMAX models. It was found, that extremely small damages could be detected, that the significance of detection was only slightly improved using the measured input signal, and finally that it was easier to detect damage in a normally reinforced beam than in a lightly reinforced beam.