GPR Survey of Historic Masonry Arch Bridges Ponte de San Antonio, Cerdedo, Galicia (2006)

Ground Penetrating Radar (GPR) has been in use for archaeological purposes for more than two decades. Nowadays it has evolved into a powerful non invasive method to detect underground anomalies. The great advantage compared to other geophysical prospection methods, as i.e. magnetics, is that the data displays information about the depth of the found anomaly as well and this with a much better resolution than seismics can offer. With the appropriate software and knowledge about the ground composition, the object can be displayed 3-dimensionally. Monitoring of Masonry Bridges with GPR is a relatively new subject in cultural heritage. Most of the work has been done so far in Great Britain (Colla et al., 1997, Flint et al. 1999, Jones, 2004), mainly to determine load-carrying capacity of 19th century railway bridges. GPR in cultural heritage focuses on the detection of defects and inhomogenities in the structure, and to find out more about its composition. The overall goal is to determine the state of conservation to provide information in aspect of conservation and restoration.