Detecting changes in the structural behaviour of a laboratory bridge model using the contact-point response of a passing vehicle

Abstract

Drive-by bridge condition monitoring, using in-vehicle sensors to monitor bridges, represents a potential solution for network-scale monitoring of bridge structures. This paper presents a proof of concept for using the vehicle contact-point (CP) response for drive-by condition monitoring of bridges. An expression is presented which allows the vibration response at the point of contact between the tyre and the bridge surface to be inferred from the in-vehicle measurements. Following a simple numerical demonstration of the concept, laboratory tests are undertaken to verify that the CP response can be used to detect the fundamental frequency of the bridge. Results show that the CP response can be used to identify the bridge frequency with greater certainty than the signals measured directly on the vehicle. It is also shown, for two simulated damage cases, that changes in bridge frequency can be detected. The CP response is seen to be more sensitive to changes in bridge frequency than the measured signals. It is also observed that the detected frequency is sensitive to the vehicle speed and mass, which is an important consideration when combining results from multiple vehicle passages. Overall, the results verify that the CP response can be used to enhance drive-by bridge monitoring regimes.