GPR analysis of a masonry arch for structural assessment

Many of masonry arch bridges are ancient structures still in use within the transportation infrastructure, and they require a constant diagnosis of their structural integrity. In the last decades, non-destructive testing has been recommended for evaluation in order to preserve their historical character. In this work, a multidisciplinary approach to assess masonry arches is presented. A GPR survey of the Cernadela bridge was carried out using the 250, 500 and 800 MHz antennas. The main goal was to obtain relevant unknown parameters such as the inner ring stone thickness of arches for later structural analysis by analytical modelling. Photogrammetric methods were also employed in order to provide the precise external geometry of the bridge. Results show that it is possible to determine the ring stone thickness, which can be valuable information for engineers in order to perform an exhaustive assessment of the load carrying capacity of the bridge.