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Dr. Ramón González Drigo
Universitat Politecnica de Catalunya, UPC, Barcelona, Spain

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Research Keywords & Expertise

0 Earthquake Engineering
0 Masonry Structures
0 Seismic Risk Assessment
0 Numerical modelling of structures
0 NDT applied to structural damage assessment

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Journal article
Published: 23 March 2020 in Remote Sensing
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In this paper, remote and in situ techniques to estimate the dynamic response of a building to ambient vibration are reported: data acquired through a real-aperture radar (RAR) interferometer and conventional accelerometers are analyzed. A five-story reinforced concrete housing building, which was damaged during the May 11th 2011 Lorca (Spain) earthquake, is used as a case study. The building was monitored using both types of instruments. The dynamic properties of the building are estimated first taking acceleration measurements using a set of 10 high-precision accelerometers installed on the roof of the building. Further, the displacement–time histories, recorded with the RAR device pointing to a corner of the building, are analyzed. Then, the ability and shortcomings of RAR measurements to deal with the fundamental frequencies of vibration of the structure are investigated. The advantages and limitations of from-inside (accelerometric) and from-outside (RAR) measurements are highlighted and discussed. A relevant conclusion is that, after strong earthquakes, RAR may be an interesting and useful tool, as it allows surveying the structural response of mid-rise buildings remotely, without the need to enter the structures, which may be dangerous for inspectors or technicians in cases of severely damaged buildings. Given that the instrumented building suffered significant damage, the ability of these kinds of measurements to detect damage is also discussed.

ACS Style

Rodrigo E. Alva; Luis G. Pujades; Ramón González-Drigo; Guido Luzi; Oriol Caselles; Luis A. Pinzón. Dynamic Monitoring of a Mid-Rise Building by Real-Aperture Radar Interferometer: Advantages and Limitations. Remote Sensing 2020, 12, 1025 .

AMA Style

Rodrigo E. Alva, Luis G. Pujades, Ramón González-Drigo, Guido Luzi, Oriol Caselles, Luis A. Pinzón. Dynamic Monitoring of a Mid-Rise Building by Real-Aperture Radar Interferometer: Advantages and Limitations. Remote Sensing. 2020; 12 (6):1025.

Chicago/Turabian Style

Rodrigo E. Alva; Luis G. Pujades; Ramón González-Drigo; Guido Luzi; Oriol Caselles; Luis A. Pinzón. 2020. "Dynamic Monitoring of a Mid-Rise Building by Real-Aperture Radar Interferometer: Advantages and Limitations." Remote Sensing 12, no. 6: 1025.

Journal article
Published: 11 February 2020 in Sustainability
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The basic input when seismic risk is estimated in urban environments is the expected physical damage level of buildings. The vulnerability index and capacity spectrum-based methods are the tools that have been used most to estimate the probability of occurrence of this important variable. Although both methods provide adequate estimates, they involve simplifications that are no longer necessary, given the current capacity of computers. In this study, an advanced method is developed that avoids many of these simplifications. The method starts from current state-of-the-art approaches, but it incorporates non-linear dynamic analysis and a probabilistic focus. Thus, the method considers not only the nonlinear dynamic response of the structures, modeled as multi degree of freedom systems (MDoF), but also uncertainties related to the loads, the geometry of the buildings, the mechanical properties of the materials and the seismic action. Once the method has been developed, the buildings are subjected to earthquake records that are selected and scaled according to the seismic hazard of the site and considering the probabilistic nature of the seismic actions. The practical applications of the method are illustrated with a case study: framed reinforced concrete buildings that are typical of an important district, the Eixample, in Barcelona (Spain). The building typology and the district were chosen because the seismic risk in Barcelona has been thoroughly studied, so detailed information about buildings’ features, seismic hazard and expected risk is available. Hence, the current results can be compared with those obtained using simpler, less sophisticated methods. The main aspects of the method are presented and discussed first. Then, the case study is described and the results obtained with the capacity spectrum method are compared with the results using the approach presented here. The results at hand show reasonably good agreement with previous seismic damage and risk scenarios in Barcelona, but the new method provides richer, more detailed, more reliable information. This is particularly useful for seismic risk reduction, prevention and management, to move towards more resilient, sustainable cities.

ACS Style

Yeudy Vargas-Alzate; Nieves Lantada; Ramón González-Drigo; Luis Pujades. Seismic Risk Assessment Using Stochastic Nonlinear Models. Sustainability 2020, 12, 1308 .

AMA Style

Yeudy Vargas-Alzate, Nieves Lantada, Ramón González-Drigo, Luis Pujades. Seismic Risk Assessment Using Stochastic Nonlinear Models. Sustainability. 2020; 12 (4):1308.

Chicago/Turabian Style

Yeudy Vargas-Alzate; Nieves Lantada; Ramón González-Drigo; Luis Pujades. 2020. "Seismic Risk Assessment Using Stochastic Nonlinear Models." Sustainability 12, no. 4: 1308.

Journal article
Published: 28 November 2019 in Remote Sensing
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In this study the main results of a detailed analysis of an actual building, which was severely damaged during the Mw 5.1, May 11th 2011, Lorca earthquake (Murcia, Spain) are presented. The dynamic behavior of the building was analyzed by means of empirical and numerical approaches. The displacement response of the building submitted to ambient noise was recorded by using a Real Aperture Radar (RAR). This approach provides a secure remote sensing procedure that does not require entering the building. Based on the blueprints and other available graphical information about the building, a numeric 3D model was also set up, allowing obtaining capacity spectra and fragility curves in the two main resistant directions of the building. The main purpose of this study was to check out the feasibility of the RAR-based method to detect the safety state of a damaged building after an earthquake, without the need of entering unsafe structures. A good consistency of the numerical and experimental approaches and the observed damage was obtained, showing that RAR interferometric-based tools may provide promising supplementary remote sensing methods to safely survey and report about the structural health and the operative conditions of buildings in post-earthquake scenarios.

ACS Style

Ramon Gonzalez-Drigo; Esteban Cabrera; Guido Luzi; Luis G. Pujades; Yeudy F. Vargas-Alzate; Jorge Avila-Haro. Assessment of Post-Earthquake Damaged Building with Interferometric Real Aperture Radar. Remote Sensing 2019, 11, 2830 .

AMA Style

Ramon Gonzalez-Drigo, Esteban Cabrera, Guido Luzi, Luis G. Pujades, Yeudy F. Vargas-Alzate, Jorge Avila-Haro. Assessment of Post-Earthquake Damaged Building with Interferometric Real Aperture Radar. Remote Sensing. 2019; 11 (23):2830.

Chicago/Turabian Style

Ramon Gonzalez-Drigo; Esteban Cabrera; Guido Luzi; Luis G. Pujades; Yeudy F. Vargas-Alzate; Jorge Avila-Haro. 2019. "Assessment of Post-Earthquake Damaged Building with Interferometric Real Aperture Radar." Remote Sensing 11, no. 23: 2830.

Conference paper
Published: 01 June 2018 in 2018 17th International Conference on Ground Penetrating Radar (GPR)
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Corrosion is a common pathology in modernist (art nouveau) structures due to the employment of metallic reinforcement in masonry or mortar elements. This pathology can be the cause of important damage. Therefore, detection of corrosion is important in the cultural heritage assessment. Moreover, these cultural heritage structures are usually fragile and must be assessed with the minimum intervention, being non-destructive test (NDT) usually applied to these studies. However, detection of corrosion using NDT is difficult and only specific zones can be analyzed. Therefore, in most cases, results are incomplete. In this study, GPR was applied to obtain information to evaluate of the corrosion damage. The application of this methodology provides results from vast areas with a fast survey acquisition. GPR, as an NDT technique, covers large areas of study while other methods are constrained to a small areas or specific points. In this paper it is presented the study of the mosaic roofs in the Park Giiell, in Barcelona. This park is one of the most key Modernista (Art Noveau) complexes in this city. It is characterized by structures with roofs and banks with tessellation. Some of these structures are most likely supported by metallic elements, and seepage cause significant damage observed over the tessellation. The objective of the study was to define the possible existence of those metallic targets, determining their location. In the case of existence of metallic elements it determines which are the zones more affected by corrosion. Results demonstrate the existence of metallic supports in many parts, as well as some defined areas that could be damaged.

ACS Style

Viviana Sossa Arancibia; Vega Perez Gracia; Sonia Santos Assuncao; Oriol Caselles; Jaume Clapes; Ramon Gonzalez Drigo. Analysis of corrosion in historical heritage structures. The case study of the Park Güell in Barcelona. 2018 17th International Conference on Ground Penetrating Radar (GPR) 2018, 1 -4.

AMA Style

Viviana Sossa Arancibia, Vega Perez Gracia, Sonia Santos Assuncao, Oriol Caselles, Jaume Clapes, Ramon Gonzalez Drigo. Analysis of corrosion in historical heritage structures. The case study of the Park Güell in Barcelona. 2018 17th International Conference on Ground Penetrating Radar (GPR). 2018; ():1-4.

Chicago/Turabian Style

Viviana Sossa Arancibia; Vega Perez Gracia; Sonia Santos Assuncao; Oriol Caselles; Jaume Clapes; Ramon Gonzalez Drigo. 2018. "Analysis of corrosion in historical heritage structures. The case study of the Park Güell in Barcelona." 2018 17th International Conference on Ground Penetrating Radar (GPR) , no. : 1-4.

Journal article
Published: 15 June 2016 in Bulletin of Earthquake Engineering
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In this work, the vulnerability of an unreinforced masonry building, evaluated on the one hand by using the incremental dynamic analysis, and on the other hand by using nine representative non-linear static incremental procedures, is compared. For comparison reasons among the different non-linear static procedures, the obtained incremental dynamic analyses results are used as reference values. The aim of this analysis is to evaluate the applicability and reliability of the diverse non-linear static procedures for unreinforced masonry buildings, and to propose modifications oriented to improve their use in this typology of structures. For this purpose, a fully representative unreinforced masonry building of the dominating building type in the Eixample district of Barcelona, is analyzed. Furthermore, the conditional spectrum approach procedure has been applied with the aim to conveniently define the seismic demand. Regarding the definition of the fragility curves, two different methodologies were used for each non-linear static procedure and incremental dynamic analyzes. Subsequently, the corresponding damage indices as well as the damage curves were calculated and compared for the different considered peak ground acceleration values. The results of this comparison seem to confirm that the damage curves obtained by performing the NSP and by applying the Risk-UE methodology overestimate the damage corresponding to low values of the PGA and underestimate the damage for higher values of the PGA.

ACS Style

R. Gonzalez-Drigo; J. Avila-Haro; L. G. Pujades; A. H. Barbat. Non-linear static procedures applied to high-rise residential URM buildings. Bulletin of Earthquake Engineering 2016, 15, 149 -174.

AMA Style

R. Gonzalez-Drigo, J. Avila-Haro, L. G. Pujades, A. H. Barbat. Non-linear static procedures applied to high-rise residential URM buildings. Bulletin of Earthquake Engineering. 2016; 15 (1):149-174.

Chicago/Turabian Style

R. Gonzalez-Drigo; J. Avila-Haro; L. G. Pujades; A. H. Barbat. 2016. "Non-linear static procedures applied to high-rise residential URM buildings." Bulletin of Earthquake Engineering 15, no. 1: 149-174.

Journal article
Published: 20 November 2014 in International Journal of Architectural Heritage
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The main objective of this work is to assess the vulnerability and seismic risk of typical existing modernist unreinforced masonry (URM) modernist buildings and aggregates situated in the Eixample district of Barcelona, part of the architectural heritage of the city. The context of the analysis is the methodology proposed by the Risk-UE project. The buildings are characterized by their capacity spectrum and the earthquake demand is defined by the 5% damped elastic response spectrum, considering deterministic and probabilistic earthquake scenarios. A discussion addresses the basis of the seismic damage states probabilities and the calculated damage index. An important research effort has been focused on the buildings modeling. All the architectural elements and their mechanical properties have been studied and evaluated accurately. It has been evidenced that a detailed and complete knowledge of all the structural elements existing in this type of buildings influence directly their behavior and hence the calculations and the results. The analysis of the isolated buildings and of the aggregate building has been performed for both mentioned seismic scenarios. Finally, a complete discussion of the results is included.

ACS Style

Ramon Gonzalez-Drigo; J. A. Avila-Haro; Alex H. Barbat; L. G. Pujades; Y. F. Vargas; S. Lagomarsino; S. Cattari. Modernist Unreinforced Masonry (URM) Buildings of Barcelona: Seismic Vulnerability and Risk Assessment. International Journal of Architectural Heritage 2014, 9, 214 -230.

AMA Style

Ramon Gonzalez-Drigo, J. A. Avila-Haro, Alex H. Barbat, L. G. Pujades, Y. F. Vargas, S. Lagomarsino, S. Cattari. Modernist Unreinforced Masonry (URM) Buildings of Barcelona: Seismic Vulnerability and Risk Assessment. International Journal of Architectural Heritage. 2014; 9 (3):214-230.

Chicago/Turabian Style

Ramon Gonzalez-Drigo; J. A. Avila-Haro; Alex H. Barbat; L. G. Pujades; Y. F. Vargas; S. Lagomarsino; S. Cattari. 2014. "Modernist Unreinforced Masonry (URM) Buildings of Barcelona: Seismic Vulnerability and Risk Assessment." International Journal of Architectural Heritage 9, no. 3: 214-230.

Journal article
Published: 13 September 2014 in Bulletin of Earthquake Engineering
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A parametric model for capacity curves and capacity spectra is proposed. The capacity curve is considered to be composed of a linear part and a nonlinear part. The normalized nonlinear part is modelled by means of a cumulative lognormal function. Instead, the cumulative Beta function can be used. Moreover, this new conceptualization of the capacity curves allows defining stiffness and energy functions relative to the total energy loss and stiffness degradation at the ultimate capacity point. Based on these functions, a new damage index is proposed and it is shown that this index, obtained from nonlinear static analysis, is compatible with the Park and Ang index obtained from dynamic analysis. This capacity based damage index allows setting up a fragility model. Specific reinforced concrete buildings are used to illustrate the adequacy of the capacity, damage and fragility models. The usefulness of the models here proposed is highlighted showing how the parametric model is representative for a family of capacity curves having the same normalized nonlinear part and how important variables can be tabulated as empirical functions of the two main parameters defining the capacity model. The availability of this new mathematical model may be a powerful tool for current earthquake engineering research, especially in seismic risk assessments at regional scale and in probabilistic approaches where massive computations are needed.

ACS Style

Luis G. Pujades; Yeudy F. Vargas-Alzate; Alex H. Barbat; José R. González-Drigo. Parametric model for capacity curves. Bulletin of Earthquake Engineering 2014, 13, 1347 -1376.

AMA Style

Luis G. Pujades, Yeudy F. Vargas-Alzate, Alex H. Barbat, José R. González-Drigo. Parametric model for capacity curves. Bulletin of Earthquake Engineering. 2014; 13 (5):1347-1376.

Chicago/Turabian Style

Luis G. Pujades; Yeudy F. Vargas-Alzate; Alex H. Barbat; José R. González-Drigo. 2014. "Parametric model for capacity curves." Bulletin of Earthquake Engineering 13, no. 5: 1347-1376.

Original articles
Published: 11 July 2013 in Journal of Earthquake Engineering
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Microzonation is widely used in seismic risk evaluations to define the predominant period values, which are usually associated with extended areas of a few hundred meters. However, the representative values corresponding to these areas are obtained from few measurements in each area. Thereby, results are accurate only in the case of depth-dependent soils. However, not detected narrow and sharp lateral changes in soil are potentially the cause of imprecision and could be a source of specific errors. This article aims to present several tests conducted in order to emphasise the importance of accurate selection of points, to underscore the necessity of more precise and detailed evaluations, and to suggest a possible methodology to select the most appropriate data acquisition points. Results highlight the need to divide microzonation areas into smaller zones for a precise evaluation in locations where sudden changes in soil characteristics exist. Therefore, in such sites the requirement of nanozonation appears; defining zones with the same soil response. Distance between vibration measurements could be the main problem for nanozonation; data acquisition in areas with irregular geology can be time consuming when a precise analysis is required. In the most complicated environments or in dense cities, it could even be unfeasible. Consequently, it is necessary to establish a functional methodology to adequately distribute the measurement points throughout the area. On this occasion, three sites in Barcelona city were studied. This city is surrounded by mountains at NW, W, and S, and by the Mediterranean Sea at N and E. As a consequence, the shallow geology is characterized by many paleochannels and streams that are currently buried. These geological structures most likely affect the soil response. Several tests were carried out to determine this dependence. The tests were based on Ground Penetrating Radar (GPR) surveys to define the paleochannels position and on vibration measurements in order to define properly the soil response. The results from both methods were compared to the known geology to accurately define the effect of the shallow geological structures in the predominant period and in the GPR images. Areas with the same geological unit but different materials were identified in the GPR images, allowing the selection of the most appropriate distance between vibration measurements in each place. As a final result, predominant periods that were measured over the same geological unit but over different material showed changes higher than the 40% in short distances. This procedure could improve the soil response maps, including nanozonation.

ACS Style

V. Salinas; J. O. Caselles; Vega Pérez-Gracia; Sonia Santos Assuncao; J. Clapes; L. G. Pujades; Ramon Gonzalez-Drigo; J. A. Canas; Joan Martinez Sanchez. Nanozonation in Dense Cities: Testing a Combined Methodology in Barcelona City (Spain). Journal of Earthquake Engineering 2013, 18, 90 -112.

AMA Style

V. Salinas, J. O. Caselles, Vega Pérez-Gracia, Sonia Santos Assuncao, J. Clapes, L. G. Pujades, Ramon Gonzalez-Drigo, J. A. Canas, Joan Martinez Sanchez. Nanozonation in Dense Cities: Testing a Combined Methodology in Barcelona City (Spain). Journal of Earthquake Engineering. 2013; 18 (1):90-112.

Chicago/Turabian Style

V. Salinas; J. O. Caselles; Vega Pérez-Gracia; Sonia Santos Assuncao; J. Clapes; L. G. Pujades; Ramon Gonzalez-Drigo; J. A. Canas; Joan Martinez Sanchez. 2013. "Nanozonation in Dense Cities: Testing a Combined Methodology in Barcelona City (Spain)." Journal of Earthquake Engineering 18, no. 1: 90-112.

Journal article
Published: 01 November 2012 in Key Engineering Materials
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Barcelona, as well as a large number of cities in the Mediterranean basin, has a housing stock composed of a large number of unreinforced brick masonry buildings. Motivated by different factors, the enlargement of the city (Eixample in Catalan) was held from the second half of the 19th century and the beginning of the 20th, a period in which a large number of buildings of this type were built, many of which are still used as dwellings. Although the buildings were built individually, some of them are linked to adjacent buildings by the side walls. This feature leads to the analysis of the buildings as isolated structures and also as an aggregate. Barcelona is located in a seismic region of low to moderate hazard, with macroseismic intensity between the grades VI and VII of the European macroseismic scale EMS'98. Based on the deterministic and probabilistic response spectra for the different types of soils present in Barcelona obtained in the work of Irizarry (2004), the seismic risk of four individual buildings and an aggregate is evaluated. The buildings are modeled and analyzed using the TREMURI program and MATLAB routines under the guidance of RISK-UE project.

ACS Style

Jorge Arturo Avila-Haro; Jose Ramon González-Drigo; Yeudy Felipe Vargas; L.G. Pujades; Alex H. Barbat. Deterministic and Probabilistic Earthquake Scenarios for the Seismic Risk Analysis of URM Buildings. Key Engineering Materials 2012, 525-526, 537 -540.

AMA Style

Jorge Arturo Avila-Haro, Jose Ramon González-Drigo, Yeudy Felipe Vargas, L.G. Pujades, Alex H. Barbat. Deterministic and Probabilistic Earthquake Scenarios for the Seismic Risk Analysis of URM Buildings. Key Engineering Materials. 2012; 525-526 ():537-540.

Chicago/Turabian Style

Jorge Arturo Avila-Haro; Jose Ramon González-Drigo; Yeudy Felipe Vargas; L.G. Pujades; Alex H. Barbat. 2012. "Deterministic and Probabilistic Earthquake Scenarios for the Seismic Risk Analysis of URM Buildings." Key Engineering Materials 525-526, no. : 537-540.

Journal article
Published: 01 February 2012 in Near Surface Geophysics
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High-resolution methods are required in the non-destructive study of historical buildings, archaeological sites and cultural heritage structures in general. Ground-penetrating radar (GPR) is widely used in such studies. However, radar images of archaeological sites and cultural heritage architecture tend to be unclear and are difficult to interpret. Knowledge of the antenna’s behaviour and the optimum expected resolution could help to interpret radar data and define a limit of the real resolution in field surveys. Laboratory tests could provide information about the optimum resolution for each specific antenna. The main goal of this study was to obtain experimental data under lab conditions and thus define the optimum resolution expected in radar surveys. This could then be considered as a limit in field surveys. All of the lab tests were performed using homogeneous media (water and sand) to avoid interference and clutter. As a result, simple images were obtained. The optimum resolution was defined from radar data acquired under these favourable, controlled conditions. In all cases, resolution was defined as the distance (considered as a function of wavelength) between two targets (in the vertical or horizontal axis) that were needed to obtain separate anomalies. All the optimum values were considered to define the limits of the survey resolution in the different cases presented in this paper. In each case, the optimum values were compared with the result and with the radar images to define the best approach to the expected resolution in architectural heritage surveys. To conclude, we define some experimental values of the optimum resolution, described in terms of wavelength. These experimental data are likely to provide a better approach than theoretical estimations.

ACS Style

Vega Pérez-Gracia; Ramon Gonzalez-Drigo; Roger Sala. Ground-penetrating radar resolution in cultural heritage applications. Near Surface Geophysics 2012, 10, 77 -87.

AMA Style

Vega Pérez-Gracia, Ramon Gonzalez-Drigo, Roger Sala. Ground-penetrating radar resolution in cultural heritage applications. Near Surface Geophysics. 2012; 10 (1):77-87.

Chicago/Turabian Style

Vega Pérez-Gracia; Ramon Gonzalez-Drigo; Roger Sala. 2012. "Ground-penetrating radar resolution in cultural heritage applications." Near Surface Geophysics 10, no. 1: 77-87.

Original articles
Published: 08 April 2011 in International Journal of Architectural Heritage
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This article presents the characterization of a mediaeval bridge located in Fillaboa, Galicia (northern Spain). The study of this bridge involves data acquisition about the structure (geometry, visual inspection of damages, and nondestructive testing), the evaluation of the possible damage mechanisms compatible with the observed cracks and fissures, and the dynamic evaluation of the structure. This bridge is a masonry four-lancet arches bridge, with damage on the piers and abutments. Two non-invasive methodologies are applied to obtain information about the bridge: ground-penetrating radar (GPR) survey and ambient vibration noise measurements. The drawings of the structure were created using close-range photogrammetry (CRP). A finite elements model of the structure was obtained prior to the vibration field measurements, as a preliminary evaluation. Data obtained from GPR and the geometry determined with CRP were the information used in this preliminary model of the bridge. This model was improved using the dynamic field test to compare model behavior and to validate the numerical results. A second and more accurate model was then obtained by using finite elements according to the experimentally measured modal frequencies (the possible first three transversal vibration modes of the bridge).

ACS Style

Vega Pérez-Gracia; Daniel Di Capua; Oriol Caselles; Fernando Rial; Henrique Lorenzo; Ramón González-Drigo; Julia Armesto. Characterization of a Romanesque Bridge in Galicia (Spain). International Journal of Architectural Heritage 2011, 5, 251 -263.

AMA Style

Vega Pérez-Gracia, Daniel Di Capua, Oriol Caselles, Fernando Rial, Henrique Lorenzo, Ramón González-Drigo, Julia Armesto. Characterization of a Romanesque Bridge in Galicia (Spain). International Journal of Architectural Heritage. 2011; 5 (3):251-263.

Chicago/Turabian Style

Vega Pérez-Gracia; Daniel Di Capua; Oriol Caselles; Fernando Rial; Henrique Lorenzo; Ramón González-Drigo; Julia Armesto. 2011. "Characterization of a Romanesque Bridge in Galicia (Spain)." International Journal of Architectural Heritage 5, no. 3: 251-263.

Journal article
Published: 17 September 2010 in Bulletin of Earthquake Engineering
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Between the late nineteenth century and the early twentieth century, Barcelona was expanded, occupying the terrains connecting the old walled city and the nearby towns of the plateau of Barcelona. At that time, a large number of unreinforced masonry buildings were constructed and nowadays many of them are still used as dwellings. Though built individually, these buildings are connected to adjacent buildings, forming blocks composed of aggregates. In order to analyze the seismic behavior of isolated buildings and aggregates, two typical central buildings and one typical corner building have been chosen. The two central buildings and the corner building are referred as C1, C2, and E buildings. Two corner buildings and two central buildings have been connected in order to simulate a block side. This aggregate is referred as AGG and it is composed by the following sequence of individual buildings: E-C1-C2-E. Original plans and drawings of existing buildings are then used to model these buildings. The modeled buildings have five stories. Standard pushover analyses lead to evaluate their seismic performance by means of capacity spectra and fragility curves. The analysis has been carried out in the parallel (Ux) and transversal (Uy) directions to the street. Then, a capacity spectrum based method is used to analyze the seismic behavior of these buildings considered as individual buildings and as an aggregate. Two earthquake scenarios are considered. The first one is a deterministic scenario which is based on a historical earthquake occurred in 1,824, 25 km away from the city and the second one is a probabilistic scenario, which represents the ground motion with a probability of occurrence of 10% in 50 years. The soil local effects have been also considered and both scenarios have been used to assess the expected damage. Four non-null damage states are considered: slight (1), moderate (2), severe (3) and extensive-to-collapse (4). For the type of soil where most of the buildings are, and in the Ux direction, the four buildings show a similar behavior. The mean damage grade is 2.3 for the deterministic scenario and 2.7 for the probabilistic one. This means that moderate to severe damage is expected in both cases; furthermore, in the case of the deterministic scenario more than 10% of the buildings would suffer extensive-to-collapse damage and nearly 20% for the probabilistic scenario, confirming the high vulnerability of such buildings. The differences in the expected damage are due to the significant different characteristics of the response spectra of the earthquake scenarios in the range of the fundamental periods of the buildings.

ACS Style

L. G. Pujades; Alex H. Barbat; Ramon Gonzalez-Drigo; J. Avila; S. Lagomarsino. Seismic performance of a block of buildings representative of the typical construction in the Eixample district in Barcelona (Spain). Bulletin of Earthquake Engineering 2010, 10, 331 -349.

AMA Style

L. G. Pujades, Alex H. Barbat, Ramon Gonzalez-Drigo, J. Avila, S. Lagomarsino. Seismic performance of a block of buildings representative of the typical construction in the Eixample district in Barcelona (Spain). Bulletin of Earthquake Engineering. 2010; 10 (1):331-349.

Chicago/Turabian Style

L. G. Pujades; Alex H. Barbat; Ramon Gonzalez-Drigo; J. Avila; S. Lagomarsino. 2010. "Seismic performance of a block of buildings representative of the typical construction in the Eixample district in Barcelona (Spain)." Bulletin of Earthquake Engineering 10, no. 1: 331-349.

Conference paper
Published: 01 June 2010 in Proceedings of the XIII Internarional Conference on Ground Penetrating Radar
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The non-destructive study of historical buildings, archaeological sites and other Cultural Heritage structures requires high resolution methodologies and a good knowledge of the potential of the different methods. Laboratory measurements provide valuable information about the ability to detect different targets and to determine structural problems, but these data must be compared to the results obtained in real and complex structures. In this work, we present experimental GPR measurements made in order to determine the spatial resolution under laboratory conditions. These results were compared to the data obtained in different GPR surveys applied to Cultural Heritage. The information obtained in drillings, in visual inspections and in old documentation about the historical buildings and archaeological sites is used to determine the resolution in each case.

ACS Style

Vega Pérez-Gracia; Daniel Di Capua; Ramon Gonzalez-Drigo; O. Caselles; L.G. Pujades; V. Salinas. GPR resolution in cultural heritage applications. Proceedings of the XIII Internarional Conference on Ground Penetrating Radar 2010, 1 -5.

AMA Style

Vega Pérez-Gracia, Daniel Di Capua, Ramon Gonzalez-Drigo, O. Caselles, L.G. Pujades, V. Salinas. GPR resolution in cultural heritage applications. Proceedings of the XIII Internarional Conference on Ground Penetrating Radar. 2010; ():1-5.

Chicago/Turabian Style

Vega Pérez-Gracia; Daniel Di Capua; Ramon Gonzalez-Drigo; O. Caselles; L.G. Pujades; V. Salinas. 2010. "GPR resolution in cultural heritage applications." Proceedings of the XIII Internarional Conference on Ground Penetrating Radar , no. : 1-5.

Conference paper
Published: 01 January 2010 in 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010
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Ground penetrating radar has been converted in one of the most common non-destructive geophysical surveys applied to civil engineering and the evaluation of structures. However, required resolution in these kind of studies use to be elevated. In this paper, experimental measurements under controlled lab conditions and in plain media are presented. Using these data, values of the possible resolution obtained with a high-frequency antenna are provided. Notwithstanding, in civil engineering studies, resolution must be enough to determine the most important features, but it is also desirable not detect small and unimportant anomalous targets that only produce noise in the radar data. Several measurements in different structures provides information about the resolution obtained in real studies. Results are compared to those obtained in laboratory, and seem to indicate that even radargrams from the structures evaluations are highly complex and provide less resolution than radargrams from plain media studies, GPR data is enough revealing to be used as main preliminary information about the structural elements in buildings and other civil engineering constructions.

ACS Style

Vega Pérez-Gracia; L. G. Pujades; Daniel Di Capua; Ramon Gonzalez-Drigo; O. Caselles; V. Salinas. GPR Resolution – Lab Data Compared to NDT Evaluations of Structures. 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010 2010, 1 .

AMA Style

Vega Pérez-Gracia, L. G. Pujades, Daniel Di Capua, Ramon Gonzalez-Drigo, O. Caselles, V. Salinas. GPR Resolution – Lab Data Compared to NDT Evaluations of Structures. 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010. 2010; ():1.

Chicago/Turabian Style

Vega Pérez-Gracia; L. G. Pujades; Daniel Di Capua; Ramon Gonzalez-Drigo; O. Caselles; V. Salinas. 2010. "GPR Resolution – Lab Data Compared to NDT Evaluations of Structures." 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010 , no. : 1.

Journal article
Published: 30 June 2009 in NDT & E International
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High-resolution ground-penetrating radar (GPR) evaluations of structures are usually carried out using antennas with high nominal centre frequencies (between 1 and 2 GHz). A comprehensive characterization of such an antenna would make it possible to determine the capabilities of a system and obtain accurate data interpretations. This paper describes the experimental determination of the radiation pattern of a commercial 1.6 GHz antenna, which forms part of a comprehensive experimental characterization. Radiation patterns are closely related to spatial resolution, so the horizontal and vertical resolutions are evaluated first. The footprint of the antenna is then measured in air using simple devices at different distances. The final result is the approximate spatial radiation pattern of the emitted energy, measured in air. Finally, these measurements are also taken in sand to obtain the radiation pattern and footprint of the antenna in this medium.

ACS Style

Vega Pérez-Gracia; Daniel Di Capua; Ramón González-Drigo; Lluís Pujades. Laboratory characterization of a GPR antenna for high-resolution testing: Radiation pattern and vertical resolution. NDT & E International 2009, 42, 336 -344.

AMA Style

Vega Pérez-Gracia, Daniel Di Capua, Ramón González-Drigo, Lluís Pujades. Laboratory characterization of a GPR antenna for high-resolution testing: Radiation pattern and vertical resolution. NDT & E International. 2009; 42 (4):336-344.

Chicago/Turabian Style

Vega Pérez-Gracia; Daniel Di Capua; Ramón González-Drigo; Lluís Pujades. 2009. "Laboratory characterization of a GPR antenna for high-resolution testing: Radiation pattern and vertical resolution." NDT & E International 42, no. 4: 336-344.

Conference paper
Published: 01 January 2009 in Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design, Construction, Workforce and Public Acceptance
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In the design of seismic category 1 buildings in nuclear power plants (NPP) or, outside the nuclear domain, in the conventional structural design of buildings, the seismic evaluation of these buildings may be done. In the occurrence of an earthquake in a NPP or in the case of changing the use of a conventional building, the seismic levels are modified. Then a new analysis need to be performed. This paper focusses on the situation where reinforcing the concrete building is needed and it also analyses how an extern reinforcement performed using polymers can be carried out to fulfill the new seismic requeriments. We present two main results: a) the resulting momentum-curvature diagrams obtained reinforcing standard segments embraced with polymers; b) the evaluation of the structure capacity on the basis of the modified diagrams. Finally, a modal pushover analysis is selected to perform the seismic evaluation of two types of concrete columns, those having a polymer reinforcement and those without it. This paper presents the basis of the subject in a theoretical form.

ACS Style

Ferran Prats Bella; Ramón González-Drigo; Adrina Bachiller Saña. Contribution to the Design of Concrete Columns Reinforced With Externally Fiber Polymers. Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design, Construction, Workforce and Public Acceptance 2009, 161 -169.

AMA Style

Ferran Prats Bella, Ramón González-Drigo, Adrina Bachiller Saña. Contribution to the Design of Concrete Columns Reinforced With Externally Fiber Polymers. Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design, Construction, Workforce and Public Acceptance. 2009; ():161-169.

Chicago/Turabian Style

Ferran Prats Bella; Ramón González-Drigo; Adrina Bachiller Saña. 2009. "Contribution to the Design of Concrete Columns Reinforced With Externally Fiber Polymers." Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design, Construction, Workforce and Public Acceptance , no. : 161-169.

Journal article
Published: 31 December 2008 in NDT & E International
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This paper summarizes various approaches to determine the spatial resolution (SR) in non-destructive ground-penetrating radar (GPR) studies and compares the results obtained in these approaches to experimental data acquired in two different media. In one of the experimental measurements, we used 0.4 mS/m conductivity water, which is a low-attenuating medium. In the other case we used sand. Due to the water content in the sand, we obtained velocities similar to the usual velocities in concrete. Experimental radar data showed two different zones: first, the zone in which the recorded anomalies indicate the presence of more than one target; and second, the zone in which the recorded anomalies are related to the existing targets and the interference effects are minimized. We associate the first zone with the antenna's ability to detect two close targets buried at the same depth, and we associate the second zone with the path of the antenna, which is usually estimated as the first Fresnel zone. All of these estimations were carried out using the nominal frequency of the antennas and the dominant frequency obtained from the spectra of the reflected waves.

ACS Style

Vega Pérez-Gracia; Ramón González-Drigo; Daniel Di Capua. Horizontal resolution in a non-destructive shallow GPR survey: An experimental evaluation. NDT & E International 2008, 41, 611 -620.

AMA Style

Vega Pérez-Gracia, Ramón González-Drigo, Daniel Di Capua. Horizontal resolution in a non-destructive shallow GPR survey: An experimental evaluation. NDT & E International. 2008; 41 (8):611-620.

Chicago/Turabian Style

Vega Pérez-Gracia; Ramón González-Drigo; Daniel Di Capua. 2008. "Horizontal resolution in a non-destructive shallow GPR survey: An experimental evaluation." NDT & E International 41, no. 8: 611-620.

Short communication
Published: 30 June 2008 in Journal of Cultural Heritage
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ACS Style

Ramon Gonzalez-Drigo; Vega Pérez-Gracia; Daniel Di Capua; Luis G. Pujades. GPR survey applied to Modernista buildings in Barcelona: The cultural heritage of the College of Industrial Engineering. Journal of Cultural Heritage 2008, 9, 196 -202.

AMA Style

Ramon Gonzalez-Drigo, Vega Pérez-Gracia, Daniel Di Capua, Luis G. Pujades. GPR survey applied to Modernista buildings in Barcelona: The cultural heritage of the College of Industrial Engineering. Journal of Cultural Heritage. 2008; 9 (2):196-202.

Chicago/Turabian Style

Ramon Gonzalez-Drigo; Vega Pérez-Gracia; Daniel Di Capua; Luis G. Pujades. 2008. "GPR survey applied to Modernista buildings in Barcelona: The cultural heritage of the College of Industrial Engineering." Journal of Cultural Heritage 9, no. 2: 196-202.

Journal article
Published: 01 January 2008 in Journal of Cultural Heritage
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ACS Style

Vega Pérez-Gracia; Francisco García; Lluis G. Pujades; Ramón González Drigo; Daniel Di Capua. GPR survey to study the restoration of a Roman monument. Journal of Cultural Heritage 2008, 9, 89 -96.

AMA Style

Vega Pérez-Gracia, Francisco García, Lluis G. Pujades, Ramón González Drigo, Daniel Di Capua. GPR survey to study the restoration of a Roman monument. Journal of Cultural Heritage. 2008; 9 (1):89-96.

Chicago/Turabian Style

Vega Pérez-Gracia; Francisco García; Lluis G. Pujades; Ramón González Drigo; Daniel Di Capua. 2008. "GPR survey to study the restoration of a Roman monument." Journal of Cultural Heritage 9, no. 1: 89-96.

Journal article
Published: 31 December 2007 in Engineering Failure Analysis
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Traditional architectonic heritage elements are fragile and irreplaceable resources, signs of the ancient ways of life and the history of the modern societies, and essential valuable elements of the own landscape of a region. Accurate updated documentation might be the basis for any conservation or restoration intervention over architectonic heritage in order to ensure the conservation in its original appearance and in a collapse risk-free state, with the minimum intervention. This paper shows a multidisciplinary approach to heritage documentation involving close range photogrammetry and ground penetrating radar techniques, as well as the development of finite elements based structural models. Specifically this study is focused on the documentation of a mediaeval bridge concerning the geometric shape, the building material and the current damages and its causes. The usefulness of close range photogrammetry techniques in the accurate 3D modelling, cracks detection and mapping and exterior material characterization is analyzed. Further, a non-destructive test through GPR is employed for the interior material and zones description. For both techniques, the methodology followed for data collection and data processing aimed at minimisation of time consuming and optimisation of results is described in detail. Advantages and limitations of these techniques are displayed and the accuracy of the obtained results is also estimated. Resulting information related to the whole bridge geometry is taken as basis to develop a numerical analysis using the finite elements methods (FEM). Linear finite analysis provides useful information for diagnosis although non-linear methods should be used when the properties and geometry of the internal and external elements are well known. Photogrammetry provides the exact geometry needed to perform the FEM pre-process. Radar data provide approximate information about the different internal zones of the bridge. Finally, the FEM analysis leads to obtain a stress distribution compatible with the detected damages, allowing identifying its possible causes. Close range photogrammetry, ground penetrating radar techniques and the FEM analysis are proposed to perform a complete survey of the stability of the bridge and its accurate geometry.

ACS Style

Pedro Arias; Julia Armesto; Daniel Di Capua; R. González-Drigo; Henrique Lorenzo; V. Pérez-Gracia. Digital photogrammetry, GPR and computational analysis of structural damages in a mediaeval bridge. Engineering Failure Analysis 2007, 14, 1444 -1457.

AMA Style

Pedro Arias, Julia Armesto, Daniel Di Capua, R. González-Drigo, Henrique Lorenzo, V. Pérez-Gracia. Digital photogrammetry, GPR and computational analysis of structural damages in a mediaeval bridge. Engineering Failure Analysis. 2007; 14 (8):1444-1457.

Chicago/Turabian Style

Pedro Arias; Julia Armesto; Daniel Di Capua; R. González-Drigo; Henrique Lorenzo; V. Pérez-Gracia. 2007. "Digital photogrammetry, GPR and computational analysis of structural damages in a mediaeval bridge." Engineering Failure Analysis 14, no. 8: 1444-1457.