This paper presents the results of a health monitoring study, carried outduring the destructive load testing of a prototype reinforced concrete (RC)bridge. The bridge was made up of cement-concrete reinforced with steel rods,and represented a popular class of road bridges in which regular healthmonitoring is a very important issue during the service life. The bridge wasinstrumented with piezoceramic transducer (PZT) patches, which wereelectrically excited at high frequencies, of the order of kHz, and the realpart of admittance (conductance) was extracted as a function of the excitingfrequency. The patches were scanned for the acquisition of this signature atvarious stages during the loading process. The signatures of the patcheslocated in the vicinity of the damage were found to have undergone drasticchanges, while those farther away were less affected. Damage wasquantified in non-parametric terms using the root mean square of the deviationin signatures with respect to the baseline signature of the healthy state.This non-parametric index was found to correlate well with the damageprogression in the structure.