Periodic monitoring of physical property changes in a concrete box-girder bridge

The objective of this paper is to quantitatively evaluate the rate of possible structural property changes of a reinforced concrete box girder bridge over a 2-year period using a system identification technique. The structural condition of the concrete box-girder bridge is monitored four times from December 1997 to October 1999 and the physical property changes are estimated using the frequency-based system identification technique. Modal parameters (resonant frequencies and modal amplitudes) for the bridge are extracted from the measured frequency response functions. The validation of the system identification scheme is demonstrated through a numerical study using the finite element model of the same bridge structure.