Moving force identification using an existing prestressed concrete bridge

Field measurements were carried out for a moving force identification study using an existing prestressed concrete bridge. A two-axle heavy vehicle was hired for the calibration test of the field measurements. The dynamic bending moments of the test bridge deck brought about by both hired and in-service vehicles were acquired. Dynamic axle forces were identified by means of the time-domain method. Results show that the axle forces can be identified with acceptable results for both hired and in-service vehicles. Therefore the method is valid for identifying dynamic axle forces. Gross weights were obtained by summing up the equivalent axle load of each axle. The fundamental frequencies of the vehicles were obtained by converting the corresponding axle loads identified in the time domain to the frequency domain by using fast Fourier transformation.