The dynamic properties of a full-scale prestressed concrete girder were measured usingaccelerometers and strain gauges as several states of small scale damage were induced. Applying fivedifferent vibration-based damage detection techniques reported in the literature, each relying primarilyupon changes to measured mode shapes, it was found that the damage could be reliably detected andlocated longitudinally using as few as six measurement points equally spaced along each side of thegirder, provided the damage was not located too near a simple support. Only the first mode of vibrationwas required. The most reliable technique was able to determine the longitudinal location of damage witha minimum accuracy of half the spacing between sensors. The accuracy of locating damage wasinfluenced by the proximity of damage to the nearest sensor and spacing of sensors.
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