Damped test vehicle for scanning bridge frequencies: Theory, simulation and experiment

By the vehicle scanning method, an instrumented test vehicle is used to scan the frequen-cies of vibration of the underlying bridge. In this paper, a realistic theory is proposed considering the damping effect of the test vehicle, which was not well studied previously. Bridge damping is ignored since the bridge vibration sensed by the moving vehicle is tran-sient in nature. The vehicle response was criticized for the presence of vehicle frequency, which renders scanning less effective. In contrast, the response of the vehicle's contact point (CP) with the bridge is free of the vehicle frequency and enables us to extract more bridge frequencies . For the model adopted, closed-form solutions are firstly derived for both the vehicle and CP responses, with their transmissibility discussed. Through the numerical simulations and field test, the following are concluded: (1) The improved procedure for the CP response is reliable for scanning the first few bridge frequencies; (2) the effect of vehi-cle damping on the CP response can be ignored; (3) the performance of the CP response is always better than the vehicle response for each scenario studied; and (4) ongoing traffic is a positive effect that can outbalance the negative effect of surface roughness. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The vehicle scanning method uses an instrumented test vehicle to scan the frequencies of bridge vibration, with a proposed realistic theory considering the damping effect of the test vehicle. The improved procedure for the contact point response is reliable for scanning the first few bridge frequencies, outperforming the vehicle response in each scenario studied.