GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.2 627 with 2 GHz antennas. A positioning system has been set-up so to follow the observation line in a precise way with regard to the height of the antennas from the ground. The photo on the left of Fig. 1 shows the test site comprising two columns while the drawing on the right depicts internal scheme of the anomalies displaced within the column considered for the experiments. Fig. 2 illustrates the scattered field radargram related to a circular GPR profile gathered at a height of 136 cm above the ground. A clear diffraction hyperbola originated by the void cylinder (see right picture in Fig. 1) appears in the image. The tomographic reconstruction corresponding to the dataset in Fig. 2 is reported in Fig. 3. This last confirms the effectiveness of the considered data processing algorithm in detecting the presence of defects in the structure. In conclusion, an ad-hoc test site has been built and an algorithm for the data processing aiming to investigate circular structures has been implemented and some first experimental results have been reported. The work is in progress and future developments will regard the possibility of gathering and processing data with more antennas, as well as the development of a more practical positioning equipment. Acknowledgements The GPR measurement system was implemented within the research project PROdotti, MEtodologie e TEcnologie Originali e Sostenibili per la diagnosi, la conservazione e la comunicazione dei beni culturali PROMETEOS, funded by the Puglia Region. References J. R. Butnor, M. L. Pruyn, D. C. Shaw, M. E. Harmon, A. N. Mucciardi, M. G. Ryan, Detecting defects in conifers with ground penetrating radar: applications and challenges, For. Path. vol. 39 pp. 309–322, 2009, doi: 10.1111/j.1439- 0329.2009.00590.x G. Leucci, R. Persico, F. Soldovieri, “Detection of Fracture From GPR data: the case history of the Cathedral of Otranto”, Journal of Geophysics and Engineering, vol. 4, pp. 452-461, 2007. N. Masini, R. Persico, E. Rizzo, A. Calia, M.T. Giannotta, G. Quarta, A. Pagliuca, “Integrated Techniques for Analysis and Monitoring of Historical Monuments: the case of S. Giovanni al Sepolcro in Brindisi (Southern Italy).” ����Near Surface Geophysics, vol. 8, n. 5, pp. 423-432, 2010. Fig. 2 - Scattered field B-scan related to a profile taken at a height of 136 cm above the ground, in correspondence of the cylindrical anomaly visible in Fig. 1. Fig. 3 - Tomographic reconstruction related to the dataset shown in Fig. 2.