Ground-penetrating Radar (GPR) is a non-invasive technique with increasing focus on civil-engineering applications. Referring to existing constructions, the most recent International and National Codes suggest a knowledge-based approach, which is mandatory before any structural assessment or design of interventions. The knowledge-based process includes experimental investigations aimed at the detailed geometrical and structural relief as well as to the evaluation of the materials mechanical properties. However, when dealing with built Cultural Heritage, destructive techniques should be limited or even forbidden. In this context, non-destructive investigations play a key role and their effectiveness should be further studied in relation to specific applications. To this end, Ground-penetrating Radar surveys were performed in the test site of the Laboratory of Applied Geophysics, the University of Salento, Lecce (Italy), with the aim of simulating various real-life practical applications. In particular, several objects of different materials and geometries were buried in the subsurface and a small building was built in the area using different construction techniques, among them, multi-leaf masonry walls, also called sack masonry walls, were constructed. The GPR method can detect both the presence of hidden bodies and different leafs of the walls with a relative efficiency depending on the field context, the dielectric properties of the host material, and the nature and size of the bodies. In this work, a test was planned to verify 900 and 2000 MHz antenna resolutions. The data acquired with the 2000 MHz antenna were used to estimate the mean electromagnetic wave propagation velocity in the sack masonry layers of known thickness and to understand if the inner core was filled with material other than air. The authors propose a high-resolution method to improve the velocity estimation using geometrical optics laws and the sign of the reflection coefficient in order to properly select the arrivals from different interfaces.
High-resolution GPR survey for masonry wall diagnostics
Negri S.
Primo
;Aiello M. A.
2021-01-01
Abstract
Ground-penetrating Radar (GPR) is a non-invasive technique with increasing focus on civil-engineering applications. Referring to existing constructions, the most recent International and National Codes suggest a knowledge-based approach, which is mandatory before any structural assessment or design of interventions. The knowledge-based process includes experimental investigations aimed at the detailed geometrical and structural relief as well as to the evaluation of the materials mechanical properties. However, when dealing with built Cultural Heritage, destructive techniques should be limited or even forbidden. In this context, non-destructive investigations play a key role and their effectiveness should be further studied in relation to specific applications. To this end, Ground-penetrating Radar surveys were performed in the test site of the Laboratory of Applied Geophysics, the University of Salento, Lecce (Italy), with the aim of simulating various real-life practical applications. In particular, several objects of different materials and geometries were buried in the subsurface and a small building was built in the area using different construction techniques, among them, multi-leaf masonry walls, also called sack masonry walls, were constructed. The GPR method can detect both the presence of hidden bodies and different leafs of the walls with a relative efficiency depending on the field context, the dielectric properties of the host material, and the nature and size of the bodies. In this work, a test was planned to verify 900 and 2000 MHz antenna resolutions. The data acquired with the 2000 MHz antenna were used to estimate the mean electromagnetic wave propagation velocity in the sack masonry layers of known thickness and to understand if the inner core was filled with material other than air. The authors propose a high-resolution method to improve the velocity estimation using geometrical optics laws and the sign of the reflection coefficient in order to properly select the arrivals from different interfaces.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
