An interferometric radar for non-contact measurement of deflections on civil engineering structures: laboratory and full-scale tests

Recent progress in radar techniques and systems has led to the development of a microwave interferometer, potentially suitable for non-contact vibration monitoring of civil engineering structures. The main characteristic of the new radar system, named IBIS-S, is the possibility of simultaneously measuring the (static or dynamic) displacement at several points of a structure with high sensitivity. The paper first describes the technical characteristics of the microwave interferometer and the results of laboratory tests carried out to evaluate the actual displacement sensitivity of the equipment. Subsequently, the application of the sensor to the measurement of ambient vibration response on a concrete bridge is presented and discussed.