Railway track condition assessment at network level by frequency domain analysis of GPR data

The railway track system is a crucial infrastructure for the transportation of people and goods in modern societies. With the increase in railway traffic, the availability of the track for monitoring and maintenance purposes is becoming significantly reduced. Therefore, continuous non-destructive monitoring tools for track diagnoses take on even greater importance. In this context, Ground Penetrating Radar (GPR) technique results yield valuable information on track condition, mainly in the identification of the degradation of its physical and mechanical characteristics caused by subsurface malfunctions. Nevertheless, the application of GPR to assess the ballast condition is a challenging task because the material electromagnetic properties are sensitive to both the ballast grading and water content. This work presents a novel approach, fast and practical for surveying and analysing long sections of transport infrastructure, based mainly on expedite frequency domain analysis of the GPR signal. Examples are presented with the identification of track events, ballast interventions and potential locations of malfunctions. The approach, developed to identify changes in the track infrastructure, allows for a user-friendly visualisation of the track condition, even for GPR non-professionals such as railways engineers, and may further be used to correlate with track geometric parameters. It aims to automatically detect sudden variations in the GPR signals, obtained with successive surveys over long stretches of railway lines, thus providing valuable information in asset management activities of infrastructure managers

Capacitación docente para el ejercicio de la acción tutorial en la modalidad a distancia: una experiencia con anclaje institucional

En la República Argentina la entrada en vigencia de la RM 2641-E/2017 ha establecido que cada institución educativa del nivel superior debe contar con un Sistema Institucional de Educación a Distancia (SIED) validado por el Ministerio de Educación como requisito para el desarrollo de la enseñanza haciendo uso de la opción pedagógico-didáctica a distancia. La formación del plantel docente en aspectos vinculados a dicha modalidad y al uso pedagógico de las TIC es uno de los componentes esenciales del SIED. Este trabajo describe por qué y cómo la Universidad de Morón desarrolló y llevó adelante una experiencia de capacitación con el objetivo de formar a sus docentes como tutores virtuales, aplicando un enfoque participativo institucional y con el fin de desarrollar y potenciar la opción pedagógico-didáctica en la modalidad a distancia en las distintas unidades académicas.In the Argentine Republic, the entry into force of the Ministerial Resolution 2641-E / 2017 has established that each higher education institution must have an Institutional Distance Education System validated by the Ministry of Education as a requirement for the development of teaching using the distance -learning option. The formation of the teaching staff in aspects related to this modality and the pedagogical use of ICT is one of the essential components of the Institutional Distance Education System. This paper describes why and how the University of Morón developed and carried out a training experience with the objective of training its teachers as virtual tutors applying a participatory institutional approach and in order to develop and enhance the pedagogicaldidactic option in the distance modality in the different academic units.Tema: Experiencia Docente.Red de Universidades con Carreras en Informátic

Capacitación docente para el ejercicio de la acción tutorial en la modalidad a distancia: una experiencia con anclaje institucional

En la República Argentina la entrada en vigencia de la RM 2641-E/2017 ha establecido que cada institución educativa del nivel superior debe contar con un Sistema Institucional de Educación a Distancia (SIED) validado por el Ministerio de Educación como requisito para el desarrollo de la enseñanza haciendo uso de la opción pedagógico-didáctica a distancia. La formación del plantel docente en aspectos vinculados a dicha modalidad y al uso pedagógico de las TIC es uno de los componentes esenciales del SIED. Este trabajo describe por qué y cómo la Universidad de Morón desarrolló y llevó adelante una experiencia de capacitación con el objetivo de formar a sus docentes como tutores virtuales, aplicando un enfoque participativo institucional y con el fin de desarrollar y potenciar la opción pedagógico-didáctica en la modalidad a distancia en las distintas unidades académicas.In the Argentine Republic, the entry into force of the Ministerial Resolution 2641-E / 2017 has established that each higher education institution must have an Institutional Distance Education System validated by the Ministry of Education as a requirement for the development of teaching using the distance -learning option. The formation of the teaching staff in aspects related to this modality and the pedagogical use of ICT is one of the essential components of the Institutional Distance Education System. This paper describes why and how the University of Morón developed and carried out a training experience with the objective of training its teachers as virtual tutors applying a participatory institutional approach and in order to develop and enhance the pedagogicaldidactic option in the distance modality in the different academic units.Tema: Experiencia Docente.Red de Universidades con Carreras en Informátic

Using InSAR and GPR techniques to detect subsidence: application to the coastal area of “A Xunqueira” (NW Spain)

Climate change represents an important cause of subsidence, especially in coastal cities affected by changes in surface water level and water table. This paper presents a complementary study of Interferometric Synthetic Aperture Radar (InSAR) and Ground Penetrating Radar (GPR) for the early detection of subsidence and sinkhole phenomena. The methodology was applied to a coastal urban area in Galicia, northwest Spain (humid region), showing apparent signs of subsidence and building settlement during the last two years. Two different InSAR methods are compared for the period from June 2021 to March 2022: PSI (Persistent Scatterer Interferometry) and SBAS (Small Baseline Subsets), and the average deformation velocities obtained resulted in −3.0 mm/yr and −4.1 mm/yr, respectively. Additional GPR data were collected in January 2022 to validate the InSAR results, which detected subsidence in agreement with the persistent scatters obtained from the PSI method. This is crucial information to plan preventive maintenance.Xunta de Galicia | Ref. ED431F 2021/08European Commission | Ref. 101036926European Commission | Ref. 101021714Ministerio de Ciencia e Innovación | Ref. RYC2019–026604–IMinisterio de Universidades | Ref. CAS21/00241Ministerio de Ciencia e Innovación | Ref. TED2021-130183B-I0

Review of InfraRed Thermography and Ground-Penetrating Radar applications for building assessment

The first appearance of concern for the good condition of a building dates back to ancient times. In recent years, with the emergence of new inspection technologies and the growing concern about climate change and people’s health, the concern about the integrity of building structures has been extended to their analysis as insulating envelopes. In addition, the growing network of historic buildings gives this sector special attention. Therefore, this study presents a comprehensive review of the application of two of the most common and most successful Non-Destructive Techniques (NDTs) when inspecting a building: InfraRed Thermography (IRT) and Ground-Penetrating Radar (GPR). To the best knowledge of the authors, it is the first time that a joint compilation of the state-of-the-art of both IRT and GPR for building evaluation is performed in the same work, with special emphasis on applications that integrate both technologies. The authors briefly explain the performance of each NDT, along with the individual and collective advantages of their uses in the building sector. Subsequently, an in-depth analysis of the most relevant references is described, according to the building materials to be studied and the purpose to be achieved: structural safety, energy efficiency and well-being, and heritage preservation. Then, three different case studies are presented with the aim of illustrating the potential of the combined use of IRT and GPR in the evaluation of buildings for the purposes defined. Last, the final remarks and future lines are described on the application of these two interesting inspection technologies in the preservation and conservation of the building sector.European Union Next GenerationEU/PRTRAgencia Estatal de Investigación | Ref. PDC2021-121239-C32Agencia Estatal de Investigación | Ref. RYC2019-026604-

Characterization of volcanic structures using ground penetrating radar and additional inverse modelling: Multidisciplinary geophysical investigation in the Timanfaya National Park (Spain)

—A ground penetrating radar survey is presented over a recent lava flow at the volcanic area of Timanfaya National Park (Canary Island, Spain). The purpose was to locate lava tubes into the lava flow through the combination of field and simulated data. Different modelling strategies were used for the analysis and knowledge of the signal behaviour. Finite-difference time-domain algorithm was considered for simulations, and the pattern of reflections generated from previously known volcanic structures were characterized. After the characterization of the radar-wave response, the interpretation achieved was applied over the field data acquired at other non-studied area in which different lava tubes were recognized.Authors thanks to the financial support of the National Parks Network of the Spanish Ministry of Environment and Rural and Marine Affairs (320/2011 – project “Caracterización estructural del Parque Nacional de Timanfaya mediante uso combinado de técnicas y métodos geodésicos y geofísicos”. The staff of National Park of Timanfaya is also acknowledged, as well as the Applied Geotechnologies research group from the University of Vigo for providing the RAMAC/GPR equipment. Additionally, this study is a contribution to the EU funded COST Action TU-1208.Peer reviewe

Ground Penetrating Radar applied to monumental stone conservation: application to the Rock Necropolis of San Vítor de Barxacova in NW Spain

This paper deals with the application of the Ground Penetrating Radar (GPR) method in the assessment of stone monuments. Compilation of published works and a discussion of their main findings are first addressed. Next, to show the potential of the method, a case study is presented aiming to assess the state of conservation of the rock necropolis of San Vítor de Barxacova (Ourense, Spain) consisting of 56 anthropomorphic graves carved into the natural rock. Fieldwork was carried out using a GPR system equipped with a 2.3 GHz central frequency antenna. The main goal of this study is to provide an effective approach for the detection and localization of internal damages such as fractures and voids. New amplitude-based 2D and 3D imaging strategies are presented aiming to improve damage detection. A new approach was also developed to digitize the extracted information into a point cloud format, thus improving the possibilities for 3D visualization with the surrounding environment. Although a total of 39 graves were surveyed, only 13 graves are included in this paper due to their singularity and relevant results. The potential of using GPR tests for the assessment of the conservation state of monumental stone structures is also discussed.Xunta de Galicia | Ref. ED431F 2021/08Ministerio de Ciencia e Innovación | Ref. RYC2019-026604-IAgencia Estatal de Investigación | Ref. RTI2018-095893-B-C2

Multi-objective optimization-based model calibration of masonry bridges

Multi-objective optimization-based model calibration can be an intermediate solution between the computationally expensive probabilistic approaches and the single-objective optimization strategies that do not allow uncertainty quantification of the obtained solutions. This work addresses the multi-objective model calibration of two historic stone arch bridges using high-fidelity computational FE models. To implement the methodology, a five-step approach is proposed: experimental characterization through non-destructive testing techniques, non-parametric asbuilt geometric modeling, macro-finite element modeling, sensitivity analysis, and multiobjective optimization. The preferred solution among the Pareto front solutions is selected based on two different classical criteria, and the set of optimal solutions is further statistically analyzed to assess the validity of the identification process. The results show an average frequency error of 0.97 % and 0.70 % and an average MAC of 0.97 and 0.96 for each case study, respectively, thus highlighting the adequacy of the proposed methodology.Agencia Estatal de Investigación | Ref. PID2021-124236OB-C33Agencia Estatal de Investigación | Ref. PRE2019-087331Agencia Estatal de Investigación | Ref. RYC2019-026604-IXunta de Galicia | Ref. ED431F 2021/08Universidade de Vigo/CISU

Combined use of GPR and Other NDTs for road pavement assessment: an overview

Roads are the main transportation system in any country and, therefore, must be maintained in good physical condition to provide a safe and seamless flow to transport people and goods. However, road pavements are subjected to various defects because of construction errors, aging, environmental conditions, changing traffic load, and poor maintenance. Regular inspections are therefore recommended to ensure serviceability and minimize maintenance costs. Ground-penetrating radar (GPR) is a non-destructive testing (NDT) technique widely used to inspect the subsurface condition of road pavements. Furthermore, the integral use of NDTs has received more attention in recent years since it provides a more comprehensive and reliable assessment of the road network. Accordingly, GPR has been integrated with complementary NDTs to extend its capabilities and to detect potential pavement surface and subsurface distresses and features. In this paper, the non-destructive methods commonly combined with GPR to monitor both flexible and rigid pavements are briefly described. In addition, published work combining GPR with other NDT methods is reviewed, emphasizing the main findings and limitations of the most practical combination methods. Further, challenges, trends, and future perspectives of the reviewed combination works are highlighted, including the use of intelligent data analysis.Xunta de Galicia | Ref. ED431F 2021/08Ministerio de Ciencia e Innovación | Ref. RYC2019–026604-

Reliability-based structural assessment of historical masonry arch bridges: The case study of Cernadela bridge

Nowadays, several historical masonry arch bridges present a deficient state of conservation due to degradation processes induced by natural or human actions. Usually, these constructions have significant economic, cultural, and heritage value. Therefore, they shall be thoroughly assessed to verify their structural integrity and safety condition. For this purpose, reliability-based structural assessments are typically performed. However, the associated outcomes (i.e., reliability index and probability of failure) highly rely on the accuracy of the structural parameters uncertainty quantification. This work presents a study regarding the influence of the scattering of the arches' thickness dimensions in the load-carrying capacity assessment of the Cernadela Bridge, a historical stone bridge located in Galicia, Spain. The study first involved a comprehensive experimental campaign to characterize the outer and inner bridge geometry through geomatic techniques, i.e., terrestrial laser scanning and ground penetrating radar. Subsequently, a limit analysis model was developed, considering only the arches' outer (visible) data. From this initial structural assessment, a reliability index of 2.38 was obtained. The influence of the uncertain structural parameters, both geometric features and material properties, in the collapse load was investigated through a global variance-based sensitivity analysis (i.e., Sobol' indices) complemented by a surrogate modeling strategy based on the Kriging approach. Finally, the measured inner geometry of the arches was introduced in the computational model through Bayesian inference procedures. Thus, two new structural assessments were performed: first, by considering the updated distributions of all arches thicknesses, and second, by considering only the updated distributions of the non-influential ones. Reliability indexes of 1.51 and 2.33 were derived, thus highlighting the importance of a proper uncertainty quantification process and the relevance of the sensitivity analysis outcomes to identify the critical parameters on the bridge mechanical response.Ministerio de Ciencia e Innovación | Ref. TED2021-130497A-I00Ministerio de Ciencia e Innovación | Ref. RYC2019-026604-