Indirect bridge damage detection Based on Contact Point of vehicle with bridge

Bridges are pivotal infrastructures in each country, and the maintenance and damage detection in these structures play constructive roles in enhancing road safety and service life. The indirect bridge health monitoring methods, in which sensors are installed on the moving vehicle, become considerably rapid and efficient since there is no need for sensor installation on the bridge elements. However, the responses recorded by the vehicle comprise combined responses of moving vehicle and bridge accelerations, causing further analyses and calculations for decomposing accelerations. The effects of dynamic parameters on acceleration at the vehicle-bridge contact points are considerably lower than that of the acceleration of moving vehicle’s components; therefore, the bridge health condition can be more easily evaluated according to the acceleration at contact points compared to the acceleration recorded by moving vehicle’s components. In this study, the Fourier transform of the vertical acceleration at the contact point of the moving vehicle and bridge was used to assess the bridge health condition. First, the vertical acceleration at the contact point was calculated using the backward procedure for moving vehicle with different speeds crossing over the undamaged bridge. Second, the Fourier transform was applied to acceleration results. Finally, the Fourier transform of the acceleration at the contact point for different speeds of the moving vehicle was predicted and compared against the corresponding accelerations of the undamaged bridge to assess the accuracy of the proposed method in determining damage levels in the bridge. The results indicate that the bridge damage level can be properly determined using the Fourier transform of the responses at the contact point of the bridge and moving vehicle at different speeds. Moreover, the suggested approach leads to accurate predictions of damage levels in the bridge even in the case of noisy data and substantial damage on the bridge pavement surface