Monitoring Bridges Vibration Using a Ground Based Radar

Abstract

Monitoring the stability of bridges under heavy traffic conditions is of paramount importance. Surveyors are interested in quantifying the amount of short-term vertical displacement due to traffic loads. A common way to measure the vertical oscillation of a bridge is by deploying reflectors/prisms on the bridge and using a total station. Alternatively lasers can be used to measure vibrations, but these are generally expensive. In this work, we are testing the use of relatively inexpensive technology based on a Stepped Frequency Continuous Waveform radar. We have acquired radar backscattering under bridges in Milton Keynes, UK and validated the results using a video camera synchronised with the radar acquisitions. Every time a truck was crossing the bridge an oscillation of around a millimetre was observed. Different trucks provided slightly different oscillations.