Ambient vibration tests of a historical masonry bridge by means of radar interferometry

In this paper, we study the capability of the radar interferometry technique for the ambient vibration tests on very large and massive historical masonry bridges. This innovative contactless technique has been successfully exploited in several works for dynamic identification of concrete and, sometimes, of masonry slender structures, but has been rarely used for large mass masonry constructions. To this aim, we have performed a campaign of ambient vibration tests on a masonry bridge located in Polignano a Mare, a town of southern Italy, using both the ground-based radar interferometry and the traditional accelerometric technique. The comparison of the results obtained from the two experimental techniques highlighted the effectiveness of the radar interferometry in order to identify at least the first natural frequencies of a massive masonry bridge.