Extracting bridge frequencies from the dynamic response of a passing vehicle

The frequencies of vibration of bridges represent a kind of information that is most useful for many purposes. Traditional vibration tests aimed at measuring the bridge frequencies often require on-site installation of the measurement equipment, which is not only costly, but also inconvenient. As a first attempt, the idea of using a vehicle moving over a bridge as a message carrier of the dynamic properties of the bridge is theoretically explored in this paper. In order to identify the key parameters dominating the vehicle-bridge interaction response, while illustrating the key phenomena involved, assumptions that lead to closed-form solutions are adopted in the analytical study. For instance, a vehicle is modelled as a sprung mass, and a bridge as a simply supported beam considering only the first mode of vibration. The concept of extracting bridge frequencies from a passing vehicle, however, is not restricted by the aforementioned assumptions, as will be demonstrated in an independent finite element study, which do not rely on any particular assumptions. Concluding remarks are given concerning the feasibility of extracting the bridge frequencies from the dynamic response of a passing vehicle, along with directions for future research identified. (C) 2003 Elsevier Ltd. All rights reserved.