Assessment of vibration-based damage detection for an integral abutment bridge

Vibration-based damage detection (VBDD) comprises a family of nondestructive testing methods in which changes to signature dynamic characteristics are used to track the condition of a structure. Although VBDD methods have been successfully applied to various mechanical systems and to simple beam-like structures, significant challenges remain in extending this technology to complex, spatially distributed structures such as bridges. In the present study, numerical simulations using a calibrated finite element model were used to investigate the use of VBDD methods to detect small-scale damage on a two-span, integral abutment overpass structure located in Saskatoon, Saskatchewan. Five different VBDD techniques were evaluated, as were the effects of sensor spacing, mode shape normalization, and uncertainty in the measured mode shapes. It was found that localized damage to the top concrete cover of the bridge deck could be reliably detected and located if the sensors were located sufficiently close to the damage and if uncertainty in the mode shapes was attenuated through the use of a sufficient number of repeated trials. Furthermore, preliminary studies indicate that it may be possible to detect damage using sensors that are placed well away from the damaged area.