Radar investigation of masonry structures

Maierhofer, Ch.; Leipold, S

doi:10.1016/s0963-8695(00)00038-4

Cited by 73 publications

(33 citation statements)

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“…In order to account for those impact motions that can potentially cause damages on manufactured and urban structures, PS outliers derived from ascending and descending datasets and characterized by V SLOPE > |10| mm/year were firstly selected, according to the damage threshold proposed by Mansour et al (2011) [63]. Furthermore, these outliers were clustered by deriving the PS buffers from the 3 m CSK spatial resolution and grouped by amount of at least 4 PS [64][65][66]. Results permitted to derive 19 "active clusters" of PS with V SLOPE > |10|, defined as the most moving and potentially hazardous sites over the Volterra study area at the large scale ( Figure 6).…”

Section: Persistent Scatterer Interferometry (Psi) Analysis and Resulmentioning

confidence: 99%

Detecting Slope and Urban Potential Unstable Areas by Means of Multi-Platform Remote Sensing Techniques: The Volterra (Italy) Case Study

2016

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Volterra (Central Italy) is a town of great historical interest, due to its vast and well-preserved cultural heritage, including a 2.6 km long Etruscan-medieval wall enclosure representing one of the most important elements. Volterra is located on a clayey hilltop prone to landsliding, soil erosion, therefore the town is subject to structural deterioration. During 2014, two impressive collapses occurred on the wall enclosure in the southwestern urban sector. Following these events, a monitoring campaign was carried out by means of remote sensing techniques, such as space-borne (PS-InSAR) and ground-based (GB-InSAR) radar interferometry, in order to analyze the displacements occurring both in the urban area and the surrounding slopes, and therefore to detect possible critical sectors with respect to instability phenomena. Infrared thermography (IRT) was also applied with the aim of detecting possible criticalities on the wall-enclosure, with special regards to moisture and seepage areas. PS-InSAR data allowed a stability back-monitoring on the area, revealing 19 active clusters displaying ground velocity higher than 10 mm/year in the period 2011-2015. The GB-InSAR system detected an acceleration up to 1.7 mm/h in near-real time as the March 2014 failure precursor. The IRT technique, employed on a double survey campaign, in both dry and rainy conditions, permitted to acquire 65 thermograms covering 23 sectors of the town wall, highlighting four thermal anomalies. The outcomes of this work demonstrate the usefulness of different remote sensing technologies for deriving information in risk prevention and management, and the importance of choosing the appropriate technology depending on the target, time sampling and investigation scale. In this paper, the use of a multi-platform remote sensing system permitted technical support of the local authorities and conservators, providing a comprehensive overview of the Volterra site, its cultural heritage and landscape, both in near-real time and back-analysis and at different scales of investigation.

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Section: Persistent Scatterer Interferometry (Psi) Analysis and Resulmentioning

confidence: 99%

Detecting Slope and Urban Potential Unstable Areas by Means of Multi-Platform Remote Sensing Techniques: The Volterra (Italy) Case Study

2016

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“…Since moisture is influencing this parameter, radar can also be applied to detect an enhanced moisture content and to determine the moisture distribution. With radar, reflection measurements from one surface as well as tomographic measurements from both sides are usually performed to obtain information about the internal structure of the structural element under investigation [5][6][7].…”

Section: Columns Of the Entrance Hallmentioning

confidence: 99%

Non-destructive investigation of structural elements of the “Altes Museum” in Berlin

Maierhofer

Köpp

Hamann

et al. 2008

WIT Transactions on the Built Environment

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Strategies and methodologies for the assessment of historic masonry structures based on non-destructive and minor-destructive testing methods were developed in the European Research Project ONSITEFORMASONRY and were successfully applied to assess the structure and material properties of selected structural elements in the Altes Museum in Berlin-Mitte. For the planning of a broad reconstruction within the framework of a master plan concerning the whole of Museum Island in Berlin, several questions arose which are also typical for other historic structures in general, thus the Altes Museum was chosen as a pilot site for the validation of non-destructive testing methods.

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“…В большинстве случаев её использование направлено на выяснение структурной информации: оценку толщин конструктивных элементов [2,9], обнаруже-ние и выявление местоположения стальной арматуры или труб, перекрытых цементным слоем [17]. Кроме того, с помощью метода георадиолокации решаются задачи оценки присутствия влаги в бетоне [9,10] и выявле-ния крупных пустот [12]. Распространенной модификацией георадио-локации является модификация с совмещён-ным источником и приёмником.…”

Section: Introductionunclassified

Searching and Measurement of Functional Voids by Means of GPR Tomography by the Example of Two Columns

Sudakova¹,

Terentieva²,

Kalashnikov³

2017

IJCCSE

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1 Московский государственный университет имени М.В. Ломоносова, г. Москва, РОССИЯ 2 Институт Криосферы Земли Сибирского отделения Российской академии наук, г. Тюмень, РОССИЯ Аннотация: В статье приведены результаты исследования, целью которых является оценка возможности обнаружения и оконтуривания конструктивных пустот, размеры которых превышают длину волны для используемой частоты. Описываются два примера применения георадиолокационного томографического просвечивания: 1) квадратной бетонной колонны с гранитной облицовкой, полой внутри, и 2) цилиндри-ческой гранитной колонны с конструктивной полостью круглой формы с железными стенками. Рассмат-риваются вопросы методики, структура получаемых данных, выделение полезных волн на фоне помех, анализируется результат томографического обращения, который сравнивается с результатом георадио-локации в традиционной модификации с совмещёнными источником и приемником. В результате проде-ланной работы было доказано, что задача поиска, оконтуривания и определения размеров пустот внутри строительных конструкций уверенно решается при помощи георадарной томографии. С высокой точно-стью было определено распределение скорости электромагнитных волн в твёрдой части колонн (бетоне и граните), которое может быть использовано для пересчёта в физические свойства, такие как влажность, пористость и пр. Был получен количественный результат, лишенный обычной неоднозначности, свой-ственной косвенным методам исследования, и является более качественным и достоверным по сравне-нию с результатами георадиолокационного зондирования с совмещенным источником и приёмником.Ключевые слова: неразрушающий контроль, электромагнитные методы исследования, прямая и обратная задачи, математическое моделирование, георадар, томография. Abstract: The present article focuses on GPR tomography method potential aimed at the search of functional voids and estimation of their sizes in engineering structures. The size of voids is assumed to be greater than the wavelength for usable frequency. Two examples of the GPR tomographic survey are examined: 1) a square concrete pillar with granite coating and a square void in the center, 2) cylindrical granite column with functional spherical void which has iron walls. The following issues are considered in the article: the method, the structure of the acquired data, the picking of wanted waves, the analysis of tomographic inversion result, compared with the result of commonly used single-fold antenna geometry GPR. As a result of the research performed it was demonstrated that GPR tomography represents a good solution for the problem of detection, delineation and characterization of voids inside engineering structures. The velocity of electromagnetic waves propagated within the solid part of the column (concrete and granite) was accurately measured. The measured velocity can be considered to the basis for physical properties estimation, for example humidity, voids ratio etc. The acquired quantitative results are characterized by high quality and are more reliable compared to the...

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Radar investigation of masonry structures

Cited by 73 publications

References 1 publication

Detecting Slope and Urban Potential Unstable Areas by Means of Multi-Platform Remote Sensing Techniques: The Volterra (Italy) Case Study

Detecting Slope and Urban Potential Unstable Areas by Means of Multi-Platform Remote Sensing Techniques: The Volterra (Italy) Case Study

Non-destructive investigation of structural elements of the “Altes Museum” in Berlin

Searching and Measurement of Functional Voids by Means of GPR Tomography by the Example of Two Columns

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