Using two connected vehicles to measure the frequencies of bridges with rough surface: a theoretical study

Measuring the bridge frequencies indirectly from a test vehicle is a potentially powerful technique for its advantage of efficiency and economy. However, the existence of road surface roughness may excite the vehicle-related frequencies to a higher level of amplitude than the bridge-related ones, making it difficult to identify the bridge frequencies. In order to overcome this drawback, this paper proposes the use of two connected vehicles to remove or reduce the blurring effect of road surface roughness, so as to ensure the successful identification of bridge frequencies. Underlaid by this idea, a Fourier-based algorithm for extracting the bridge frequencies is presented. Numerical studies are conducted for several different combinations of vehicle masses and stiffnesses, as well as for vehicle spacing. Through such a study, the feasibility of using two connected vehicles to extract the bridge frequencies is confirmed.