Damping Detection for Periodic Bridge Health Monitoring Using a Moving Vehicle

In the past decade there has been a considerable increase in the number of bridges being instrumented for the purposes of vibration based monitoring, typically to monitor dynamic parameters such as frequencies and mode shapes. This type of approach using direct measurements can be very accurate and provide valuable information about a bridge structure. However, drawbacks of this approach include the time and expense associated with the installation of sensors and data acquisition equipment on the bridge. Also, although short to medium span bridges form the greatest proportion of transport networks worldwide, a large percentage of these are not instrumented. Therefore, more recently, a number of researchers have investigated the use of an alternative low-cost approach to monitor bridge dynamic parameters which involves the use of a moving vehicle fitted with accelerometers on its axles. By taking measurements on the vehicle only, this type of indirect method reduces the need for direct installations on the bridge. It is therefore aimed at providing an efficient alternative for the preliminary screening of the condition of short to medium span bridges in a transport network. In this paper, the feasibility of use of the instrumented moving vehicle to detect changes in bridge damping is investigated in a laboratory experiment. The damping of the bridge is used as a damage indicator in this paper as it has been shown to be damage sensitive. Furthermore, it has been found in numerical investigations that it is possible to detect changes in bridge damping from the acceleration response of an instrumented vehicle.