GPR application to the structural control of historical buildings: two case studies in Rome, Italy

Abstract

Preservation of historical buildings requires particular care, as any intervention must not alter or damage the style, structure or contents of the edifice. In order to properly plan the restoration of a building, non‐destructive techniques can be used extensively to detect structural elements and weaknesses. Ground‐penetrating radar (GPR) is particularly well adapted to this type of work, as the method is non‐invasive, rapid and provides high‐resolution images of contrasting subsurface materials. In the present work we show the successful application of the GPR technique to the investigation of two historical buildings that differ in age, structure and geometry. The first case is the GPR detection of fractures and internal lesions in the architrave of the Porticus Octaviae, a partially restored Roman building. The second case uses GPR in the important Zuccari Palace to determine the internal structure above vaulted ceilings that host a series of 16th century frescos. Both buildings are located in downtown Rome, Italy. These examples show that GPR can give detailed, non‐invasive data that describe the state of conservation of historical buildings. In particular, this technique can produce fundamental information for the restorers (e.g., location, dimension and geometry of the structural lesions) that will help them develop the best possible protection plan, retrieving quantitative information about the location and the dimension of the lesions as well as the thickness of the different layers.

Comparison of GPR and unilateral NMR for water content measurements in a laboratory scale experiment

“…The results show a matching pattern of the physical parameters measured with the two different techniques and a very high degree of linear correlation (r = 0.97) between the radar early-time signal average amplitude and the intensity of the NMR signal, which is proportional to the proton density, i.e., to the water content.This experiment suggests that the early-time approach could be used as a fast and high-spatial resolution tool for qualitatively mapping water content lateral variations in a porous material at shallow depth, using a ground-coupled single-offset antenna configuration and that a quantitative evaluation of the moisture content would require a calibration procedure.In a survey design several factors should be taken into consideration, like the investigation depth, the spatial resolution, the characteristics of the medium (e.g., granular or solid), the physical properties of the material, the site conditions and the reliability of the retrieved physical parameter in terms of water content estimator. If the required investigation depth is limited to a few metres, GPR represents one of the best options in terms of spatial resolution, fast acquisition time, extension of the investigated area and repeatability of the measurements (Annan 2004;Jol 2009;Barone et al 2010). Such a technique is based on radio waves propagating through the medium and the water content value can be indirectly retrieved from the measurement of a signal velocity.…”

Forensic Investigations of Geohazards: The Norcia 2016 Earthquake

“…This type of investigation is well documented in the literature [34][35][36][37][38][39][40], but less used in the post-earthquake situation. The whole house was built in the 1970s, before the new anti-seismic rules and before the modern development of the seismic vulnerability map.…”

The use of ground‐penetrating radar to extend the results of archaeological excavation

“…High‐frequency investigation of standing buildings or important heritage features within such buildings also provides an increasingly interesting sphere of activity [see, for example, Utsi ; Barone et al . ). The uses to which the technique is applied include site detection and site mapping in advance of a survey but understanding the landscape is an equally valid undertaking.…”