Practical implications of GPR investigation using 3D data reconstruction and transmission tomography

Topczewski, Lukasz; Fernandes, Francisco Manuel Carvalho Pinto; Cruz, Paulo J. S.; Lourenço, Paulo B.

doi:10.1057/palgrave.jba.2950060

Cited by 29 publications

(22 citation statements)

References 12 publications

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“…The latter effect is a result of the antenna radiation pattern emitting waves in all directions and the reflected energy being recorded before and after the GPR is directly over the feature (Huisman et al, 2003). Three‐dimensional radar records can be directly acquired or reconstructed by performing a linear interpolation between successive two‐dimensional radar records (Topczewski et al, 2007). See Daniels (2004), Conyers (2004), Neal (2004), and van der Kruk et al (1998) for more detailed discussion of GPR fundamentals and operation.…”

Section: Methodsmentioning

confidence: 99%

Identification of Underground Karst Features using Ground‐Penetrating Radar in Northern Yucatán, México

Estrada‐Medina

Tuttle²,

Graham

et al. 2010

Vadose Zone Journal

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Northern Yucatán is a dry tropical area where limestone karst terrain supports a subdeciduous forest that is critical for sustaining the local economy of Mayan people. The 5‐ to 10‐m‐deep vadose zone is characterized by shallow soils (<30 cm thick) with frequent rock outcrops overlying limestone bedrock, which contains the aquifer. This limestone has two important characteristics: (i) lithologic properties that change with depth and (ii) numerous dissolution cavities ranging from small pores to caves, some of them filled with soil (soil pockets). Due to soil shallowness, differences in rock properties are relevant because they restrict or favor root growth; in particular, caves, crevices, and soil pockets allow preferential movement of soil, water, and roots. These features may be important for water and nutrient availability, especially for tree species, but they have not been investigated within an ecological context. We studied the capability of ground‐penetrating radar (GPR) for identifying various limestone layers—the laja (0.3–2.5 m), the sascab (2.5–5 m), and the coquina (5–9 m)—and dissolution cavities. Research was conducted in a limestone quarry so that radar records could be compared with karst features revealed as blasting and rock extraction advanced. Radar records obtained using a 200‐MHz antenna were generally of good interpretative quality; observation depths ranged from 3 to 5 m. In areas that lacked a soil mantle, the interface between the laja and the sascab was clearly identified by GPR at about 2 m. However, the sascab–coquina, and coquina–aquifer boundaries could not be identified. Areas of deep soils (>1 m), microrelief (mounds and plains), and large soil pockets within the limestone matrix were also identified. Main sources of GPR signal attenuation were suspected to be the higher clay and water contents of soil material contained in underlying cavities. As a noninvasive tool, GPR can help to determine properties of the limestone and its dissolution features that are critical to vadose zone–forest interactions.

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Section: Methodsmentioning

confidence: 99%

Identification of Underground Karst Features using Ground‐Penetrating Radar in Northern Yucatán, México

Estrada‐Medina

Tuttle²,

Graham

et al. 2010

Vadose Zone Journal

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“…The information from the travel time or the amplitude from many transmitter-receiver pairs is then used to reconstruct the hidden structure through the use of special inversion algorithms. In general terms, the radar velocity tomography technique has already been successfully applied to the inspection of masonry structures (Binda et al 2003, Topczewski et al 2006. In concrete, tomographic research has been primarily based on acoustic waves (Olson 2004), while the radar technique has not previously been reported according to our knowledge.…”

Section: Transmission or Tomography Measurementsmentioning

confidence: 99%

Application of radar techniques to the verification of design plans and the detection of defects in concrete bridges

Cruz

Topczewski

Fernandes

et al. 2010

Structure and Infrastructure Engineering

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Non-destructive tests (NDT) are an essential tool used in special inspections to gather detailed information about the condition of a bridge. The inspection of bridge decks is a critical task, and, currently, can be successfully carried out using a wide range of NDT techniques. Nevertheless, some of these techniques are excessively expensive and time consuming. One of these techniques, the ground penetrating radar (GPR), has been used for some decades in the non-destructive inspection and diagnosis of concrete bridges. GPR is useful to find general information about the true position of reinforcement and tendon ducts, and check the quality of the construction and materials. A significant number of reinforced and prestressed concrete bridges are deteriorating at a rapid rate and need to be repaired and strengthened. During these rehabilitation processes, designers are often faced with a lack of original design plans and unawareness of the real position of reinforcement and tendon ducts. In this paper, three case studies of the use of GPR techniques for the inspection of concrete bridges are presented and analysed. The main aim of this research is to show the strong need and usefulness of these techniques, which can provide non-visible information about structural geometry and integrity required for strengthening and rehabilitation purposes.

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“…For example, simulation and laboratory tests in simple and flat masonry samples have been carried out with the purpose of enhancing the GPR processing data for the detection of unfilled joints [12], highlighting the difficulty in recognizing reflections caused by voids in real data, but without obtaining realistic images of the media. More complex walls were also evaluated to define irregularities by means of GPR tomography [13]. Other structures, such as masonry arch bridges, were also tested in laboratory and simulated in order to define the crack size range that could be detected with GPR [14] and evaluated in different applications [15,16].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Complex Masonry Structures with GPR Compared to Other Non-Destructive Testing Studies

et al. 2014

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Columns are one of the most usual supporting structures in a large number of cultural heritage buildings. However, it is difficult to obtain accurate information about their inner structure. Non-destructive testing (NDT) methodologies are usually applied, but results depend on the complexity of the column. Non-flat external surfaces and unknown and irregular internal materials complicate the interpretation of data. This work presents the study of one column by using ground-penetrating radar (GPR) combined with seismic tomography, under laboratory conditions, in order to obtain the maximum information about the structure. This column belongs to a "Modernista" building from Barcelona (Spain). These columns are built with irregular and fragmented clay bricks and mortar. The internal irregular and complex structure causes complicated 2D images, evidencing the existence of many different targets. However, 3D images provide valuable information about the presence and the state of an internal tube and show, in addition, that the column is made of uneven and broken bricks. GPR images present high correlation with seismic data and endoscopy observation carried out in situ. In conclusion, the final result of the study provides information and 3D images of damaged areas and inner structures. Comparing the different methods to the real structure of the column, the potential and limitations of GPR were evaluated.

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Practical implications of GPR investigation using 3D data reconstruction and transmission tomography

Cited by 29 publications

References 12 publications

Identification of Underground Karst Features using Ground‐Penetrating Radar in Northern Yucatán, México

Identification of Underground Karst Features using Ground‐Penetrating Radar in Northern Yucatán, México

Application of radar techniques to the verification of design plans and the detection of defects in concrete bridges

Assessment of Complex Masonry Structures with GPR Compared to Other Non-Destructive Testing Studies

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