Theoretical analysis of low-frequency noise radiated from bridge vibrations

The vehicle-bridge coupling vibration theory and the propagation principle of air wave are applied to establish a numerical method for calculation of low-frequency noise induced by bridge vibrations. A simply supported steel bridge in service is simulated as a lattice girder model as a case study. Dynamic responses of the bridge due to vehicles are calculated and the sound pressures of low-frequency noises are obtained by using the numerical method, and the results are compared with the experimental data to validate the probability of the theoretical approach to sound pressure computation. Further studies on the effects of parameters such as road surface roughness and parameters of vehicles have been conducted. According to the analysis, smoothing road surface may decrease low-frequency noise produced by bridge vibration, the simulation method for vehicles has certain effects on the calculation of sound pressures, and in order to increase the calculation accuracy, the calculation for bridge vibration in high frequency range, the non-stationary signal analysis, the boundary absorption and reflection of sound wave need further improvements.