Measuring Dynamic Impaction Aged Timber Bridges: Some Experimental Options

Abstract

There are thousands of aged timber beam bridges on local roads in New South Wales (NSW) and because of deterioration their safety levels are unknown. To identify a bridge safety level requires a structural performance measurement, preferably with a Structural Health Monitoring (SHM) system, so that any significant temporal change can be quickly identified. There is a need, however, to identify sensors and systems that can be used to monitor the dynamic impact of loads moving at highway speeds that are of adequate performance and of a cost that is a small fraction of the structures' value. Three measurement systems are considered: a high speed camera system to enable the establishment of base-line performance; a laser sensor system to enable accurate validation of other measurement systems on in-service structures; and a system comprising accelerometers to provide a relative motion record of components compared to the motion of a main girder.