Dynamic properties of a full-scale bridge using forced vibration testing

Forced vibration testing has been used for condition assessment of bridges in the past. To be considered a valid method of condition assessment, forced vibration testing must be reproducible. Nine tests were performed on a three span bridge on Interstate 15 using forced vibration. Velocity transducers were used to acquire the response of the bridge. Three test parameters were altered for four of the tests. These parameters were temperature, the amount of forcing and the direction of forcing. Forced vibration testing was repeated and analysis was performed to determine the variability in both testing and analysis. Dynamic properties investigated include natural frequencies, mode shapes, and modal damping.