Advantages of radar interferometry for assessment of dynamic deformation of bridge

Bridges during exploitation are often subjected to external forces. Arising vibrations can affect the quality of usage and the safety of structure. Studying the dynamics of building is a major problem because of the need to describe fast-changing movements. Measurement technique should provide the high accuracy and high frequency of displacement observation. In addition, it must be independent on weather conditions to carry out field tests. Reliable description of the behaviour of the bridge under load requires the use of method, which enables observation of many points simultaneously. No need for direct access of the measuring device to the observed object is also a desirable feature. The authors present the possibility of use the novel ground-based radar interferometer for measuring displacement of the structure. The instrument used for dynamic testing enables displacement measurements of 0.1 mm accuracy and up to 200 Hz sampling frequency. Moreover, it allows the observation of the entire bridge simultaneously and does not require any elements on the structure. The results obtained were compared with other measuring devices.