Dynamical test and vehicle-bridge coupling analysis of LaSa River Bridge

In order to inspect the dynamic responses of a bridge structure, dynamical tests were made on LaSa River Bridge, a beam-arch combined bridge with the span of 108 m. The frequencies and modes of natural vibration were tested. The vibration excitation was made to test the dynamic responses of strains, displacements, swings and accelerations of the structure by dynamic loads of the train passing through bridge with different uniform velocities and braking at a specifical point on the bridge with some required uniform velocities. The test results were compared with the calculated results of the vehicle-bridge coupling analysis, and indicate that the combined system has favorable vertical and transverse stiffness; the passing train has some impacting effect on the bridge but not obvious; it is of good safety and comfortable performance. The design theory and the analysis method of the new combined structure are rational. It provides theoretical and technical reference for designing this type of bridge in the future.