Indirect damage detection for bridges using sensing and temporarily parked vehicles

Due to the influence of many factors such as vehicle properties, road roughness, and external noises, accurate indirect identification of the bridge’s frequencies is challenging. Further, given the insensitivity of the bridge’s frequencies to damage and limited acquired modal information, damage detection is often difficult to be implemented in practical engineering. This paper proposes an indirect approach to localize and quantify bridge damage using sensing and parked vehicles. First, equations for back-calculating residual contact-point responses of the sensing vehicle with suspension and tire damping and sensor-installing errors are newly deduced to eliminate its self-frequencies and suppress the negative effects of road roughness. Second, another temporarily parked truck is introduced to increase the amount of modal information about the bridge and its sensitivity to local damage. Third, a novel modal assurance criterion-based objective function using indirectly identified frequencies is proposed to enhance the robustness of damage detection. Numerical simulations utilizing a half-car model and a simply supported bridge verify the effectiveness of the proposed strategy. It is found that the new objective function improves the robustness of damage detection when the parked truck is employed at different positions. In addition, a higher speed of the sensing vehicle can negatively affect damage detection, while the ongoing traffic can help to resist the negative impact of environmental noises and bridge damping. By considering possible influence factors and model updating errors in practical applications, the damage can be located and quantified with acceptable precision.