Research on Vehicle-Induced Vibration of Pedestrian Bridge and Its Application in Comfort Evaluation

The vibration responses of pedestrian bridges are mainly caused by two transmission routes of ground and airflow under vehicle excitation. In order to clarify the action mechanism and influence degree of ground excitation and airflow excitation on pedestrian bridges, based on stochastic theory and flow field analysis method, the calculation models of vehicle-induced ground excitation and airflow excitation considering the influence of vehicle length, vehicle width and bridge deck width are established respectively. Considering the effects of vehicle speed, road grade, and vehicle mass, the vibration response of a continuous steel box girder pedestrian bridge under the two transmission routes was analyzed in this study. The laws of vibration acceleration and stress were summarized, and the accuracy of the finite element model and the laws were verified by field-measured data. Results show that road grade and vehicle mass are the main factors causing the vibrations of pedestrian bridges under vehicle excitation. Vehicle speed has a great influence on structural vibration under airflow excitation. The vibration response is the largest at mid-span along the pedestrian bridge-length direction. When the vehicle speed is less than about 60 km/h, the influence of the airflow excitation on the structure may not be considered. On this basis, the comfort level of the pedestrian bridge was evaluated using the British Standards Institution. The given evaluation criteria of the pedestrian bridge complement the design regulations of the pedestrian bridge.