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Integrated geophysical surveys for structural reliability evaluations
by
F. Giannino
(2) Osservatorio Sismologico, University of Messina, Via Osservatorio n°4, 98121 Messina (Italy).
Coauthors: Leucci G., Leucci M.
In order to verify the structural reliability of the main church, geophysical measurements were performed in the site of Botrugno (Lecce, Apulia region, south Italy).
Since the main goal of the evaluation was to highlight the possible presence of voids, fractures or water filling the building and affecting its stiffness, Ground Penetrating Radar (GPR) and 3D Electrical Resistivity Tomography surveys were undertaken inside the sacred building. Some GPR profiles were performed also in the external portion of the church.
Using a 400 MHz antenna in monostatic configuration, 18 profiles were carried out covering a total distance of 244 m.
Although the high attenuation (almost surely due to the presence, for one hand, of water filling the subsoil and the pavement and, for the other, of metallic elements set within the floor) made the processing and interpretation of radargrams rather hard, the presence of voids and fractures were found out after an appropriate processing.
3D ERT surveys, performed using a grid of 10 by 15 m, confirmed the presence of water in the subsoil and allowed to locate the presence of some cave at about 3 m in depth.
Even if the presence of several scaffolds within the building does not allowed to collect the GPR data in order to get a 3D visualization, the comparison between the map of the anomalies obtained with GPR measurements, the 3D ERT measurements and the map of the voids revealed by drillings performed in various points of the building, confirms the effectiveness of the geophysical application presented in this paper and allowed to assess the structural reliability of the building.
Date received: July 19, 2004
Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caon-13.