Experiment study on vehicle-bridge dynamics characteristic of a new thin-walled girder bridge

A new thin-walled trough girder bridge was recently adopted for urban rail transit in China. Field test was conducted on this type of bridge to investigate its vehicle-bridge dynamic behavior. The measured data include natural frequencies, dynamic deflections, dynamic strains and accelerations of the girder. The test results are compared with those obtained by vehicle-bridge dynamic interaction analysis. Both test results and numerical results demonstrate that the fundamental frequency, maximum deflection and maximum acceleration of the girder are within the limit values regulated in related codes, the new trough girder is proved to be suitable for urban elevated rail transit. The dynamic factors for global longitudinal bending of the girder is found to be much less than the design value, whereas the dynamic factors for local transverse bending of the carriageway slab, which are not specified in the codes, are found to be a maximum value of 1.38. The test results can be applied in further structure design and special attention may have to be paid to the local vibration of the carriageway slab of the thin-walled trough bridge.