Search

This paper proposes a digitally twinned experimental analysis of a scale-reduced laboratory-sized steel cable net subjected to vertical loading. The test is aimed at establishing automated pipelines of information and analysis between the measurements (displacements of nodes) and the numerical model of the cable net, which are seamlessly interconnected through a BIM model. These automated pipelines erect the frame of the development of a digital twin of the cable net with structural analysis purposes. For the sake of measurements, a terrestrial laser scanner is used. Displacements of the nodes are extracted using computational geometry tools. For the sake of analysis, a data-based numerical model is proposed to obtain the tensile state of the cables. Precisely understanding the force distribution along nets is a challenge at design, construction and operation stages. This research belongs to a vaster project related to the development of automated pipelines of information for European infrastructure in the form of digital twins. The outcome of this laboratory test results is of great use when developing similar automated pipelines of information in real sites including cable nets in roofs., All authors acknowledge the funding of ASHVIN, “Assistants for Healthy, Safe, and Productive Virtual Construction Design, Operation & Maintenance using a Digital Twin” an H2020 project under agreement 958161., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

A composite bridge located in the Metropolitan Area of Barcelona represents one of the sites for demonstrating the capabilities of digital twins on maintenance of built assets. Digital twins can be deemed to as digital living replica of the physical one that provides real time information throughout adequate connectivity (sensors, images, remote sensing) and provides automated visualization of the asset for decision-making purposes (performance indicators that are assessed regularly). This demonstrator is an 846 meters long composite bridge with plates and a concrete slab. The plates are tapered along a portion of its length. The bridge is horizontally curved with a bifurcation at its end. One of the challenges in this demonstrator is to reproduce realistically the “as built” shape of the plates using a terrestrial laser scanner for simulation purposes. The outcome of this specific side of the digital twinning (other sides also include many sensor- and image-based methods) is of great interest for maintenance managers. Understanding the real configuration of the asset represents an accurate starting point for subsequent modelling., All authors acknowledge the funding of ASHVIN, “Assistants for Healthy, Safe, and Productive Virtual Construction Design, Operation & Maintenance using a Digital Twin” an H2020 project under agreement 958161., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The main results of the operational modal analysis of a school building are shown. The building has a four-stories framed-reinforced-concrete structure and it was instrumented with 7 triaxial accelerometers, recording along eight days. Also, specific remote measurements were made with an interferometric radar. The purpose was: i) to monitor periods of activity-inactivity, ii) to identify modal frequencies; iii) to validate a numerical model of the structure and iv) to analyse the feasibility of the radar for remote operational modal analysis. This research allowed us: 1) to quantify clear variations in noise intensity, matching the school activities, 2) to identify the fundamental modes and natural frequencies, which were of 4.4 Hz and 5.4 Hz, in the longitudinal and transversal directions, respectively, 3) to observe slight variations of modal frequencies throughout the day, attributed to the loading/unloading of the building, and at night, attributed to variations in temperature; 4) to confirm the usefulness and suitability of frequency experimental measurements to improve the quality and reliability of building numerical models and, 5) to evaluate the potential of radar measurements for operational modal analysis; radar operates better in tall and flexible buildings, than in rigid ones., José Antonio Jara, of the “Institut Cartogràfic i Geològic de Catalunya”, ICGC, was responsible for the instrumentation of the building and for data collection and storage. The help of Meritxell Nicolau and Josep Soler, secretary and administrator of the “Institut Santa Eugènia” of Girona, Spain, is greatly recognized and acknowledged; they both made possible the accurate instrumentation of the building. Antoni Blázquez, from the Association of Structural Consultants (ACE), provided the plans and documentation of the building. This research has been partially funded by the Spanish Research Agency (AEI) of the Spanish Ministry of Science and Innovation (MICIN) through project with reference: PID2020-117374RB-I00/AEI/10.13039/501100011033, and by the European Regional Development Fund (ERDF) of the European Union (EU) through project with reference EFA158/16/POCRISC (INTERREG/POCTEFA. EU)., Postprint (published version)

La idea de magnitud de un fenómeno de ladera parece muy evidente, pero sometida a análisis no resulta tan simple. Además, carecemos de una escala de referencia para su valoración cualitativa. Esta indefinición en la magnitud se traslada al concepto de peligrosidad, lo cual dificulta la comunicación, incluso entre técnicos, y más aun con públicos más amplios, quienes resultan imprescindibles aliados para la implementación efectiva de estrategias de mitigación del riesgo. Esta preocupación por la comunicación de la idea de peligrosidad ha orientado en todo momento la elaboración de la guía técnica para la elaboración de Estudios de Identificación de Riesgos Geológicos (EIRG) por parte del ICGC. Esta figura resulta una pieza clave para la consideración de los riesgos geológicos en el urbanismo en Cataluña y hacer efectivo el mandato legislativo en la materia. A raíz de estos trabajos se ha desarrollado una escala de magnitud que pretende ser de la máxima simplicidad y claridad para lograr una comunicación adecuada del riesgo. En esta comunicación pretendemos realizar un test de viabilidad de la escala mediante una encuesta participativa a las personas participantes al simposio., Postprint (published version)

The version of record of this article, first published in Natural Hazards is available online at Publisher's webside: https://doi.org/10.1007/s11069-022-05282-2, The fragmentation phenomenon has a significant effect on rockfall risk assessment. This information is difficult to obtain, but it is key to improving rockfall modelling. For this reason, the RockModels team has gathered data on the fragmentation of several natural events since 2014 that nowadays wants to share them with professionals, academics and stakeholders. The best way for the dissemination of this information is the use of standard or data specifications in order to be interoperable. A fragmentation rockfall database has been created using all the gathered information, according to the INSPIRE Natural Hazard Area Data Specification currently in force. However, new tables have had to be added, since this specification does not consider fragmentation data. There are currently 6000 records of geometries of source areas, envelopes, deposits and mostly individual blocks. A web mapping application, with an automatic function for coordinate reference system transformation, has been created to facilitate access to the spatial database information. All that was developed on open-source software such as OpenLayers JavaScript library, database (PostGre-PostGIS) and the map generating Web Map Service (GeoServer). As more data are collected, the database can be easily updated and the new information will be published. Moreover, to improve data interpretation, a future task is to incorporate 3D models on the web application. The existence of this public database will facilitate research and advance in knowledge of this kind of natural hazards., Peer Reviewed, Postprint (published version)

This paper presents a procedure for tracking rockfall trajectories and extracting kinematic parameters from both the impacts and the resultant fragments. A set of full scale rockfall experiments was performed in a quarry located in Vallirana, Barcelona (Spain). The study site was chosen due to the presence of a rigid discontinuity surface, inclined at 42° in the middle of the slope, whose configuration was expected to favor the breakage of the blocks. The trajectories of the blocks released and of the resultant fragments were recorded with three video cameras. A C++ program was specifically developed to track the 3D trajectory of blocks and fragments, and measure velocities before and after the impact. Two different modules were implemented, one for the blocks that break and one for those that do not. The trajectory of a non-fragmented block is obtained by comparing it to its 3D model. In this way, both the center of mass position and the orientation of the block are tracked. For fragmented blocks, the local coordinates of the fragments determined from the images are converted to terrain coordinates using the program we developed. A total of 16 blocks and 36 rock fragments after impact were tracked. The parameters obtained were georeferenced and linked to a common system of 3D terrestrial coordinates. The captured parameters allow obtaining the velocity distribution of fragments, the coefficient of restitution, and energy balance for the blocks that break. To our knowledge, this is the first attempt to capture kinematic parameters of rock fragments that result from the impact and breakage of rock blocks in full-scale tests. Although the analysis of the rockfall fragmentation phenomenon is beyond of this work, we have compared the performance of the fragmented and unbroken blocks. To this purpose, we have built 3D models of the rock fragments generated using images captured with a drone. The results indicate that blocks that fragment show higher rebound velocities an, Peer Reviewed, Postprint (published version)

There are personal and institutional decisions that can increase the seismic resilience of the buildings in a city. However, some of these decisions are possible if we have basic knowledge of buildings’ seismic risk. The present document describes the main results of a detailed study of seismic vulnerability and seismic risk of residential buildings of Ciutat Vella (the ancient district of Barcelona) and Nou Barris (one of the newest districts of Barcelona). In this study, we assessed seismic risk according to the Vulnerability Index Method-Probabilistic named as VIM_P. Moreover, we analyzed the influence of basic buildings’ features in the final vulnerability and seismic risk values. For instance, we assessed the seismic vulnerability and the seismic risk of groups of buildings defined according to the number of stories of the buildings. Findings of this research reveal that the annual frequency of exceedance of the collapse damage state in Ciutat Vella buildings is, on average, 4.7 times higher than for the buildings in Nou Barris. Moreover, according to the Best vulnerability curve, 70.31% and 2.81% of Ciutat Vella and Nou Barris buildings, respectively, have an annual frequency of exceedance of the collapse damage state greater than 1 × 10–5., The present research has received partial funding from the European Union’s Horizon 2020 research 826 and innovation program (grant agreement Nº 823844, ChEESE CoE Project)., Peer Reviewed, Postprint (author's final draft)

Los deslizamientos superficiales desencadenados por precipitaciones intensas pueden causar daños importantes en diferentes tipos de infraestructuras e incluso provocar pérdidas de vidas humanas. La ocurrencia de estos deslizamientos está directamente relacionada con futuros cambios (climáticos y de usos de suelo). Por ello es necesario disponer de herramientas para planificar el territorio y de esta manera contribuir a la reducción del riesgo asociado a estos procesos. En este estudio, se presenta un nuevo modelo de susceptibilidad llamado FSLAM basado en la teoría del talud infinito. El modelo calcula las presiones de agua en el suelo mediante dos modelos hidrológicos que incorporan la lluvia antecedente y la lluvia desencadenante. FSLAM es un modelo de código abierto que se ha implementado en un plugin de QGIS para su uso. El modelo FSLAM se ha aplicado y validado en cuatro áreas de centenares de kilómetros cuadrados del Pirineo (Andorra y Val d’Aran), del Pre-Pirineo (Berguedà) y de la Cordillera Prelitoral Catalana (Montseny). Se ha evaluado su eficiencia mediante el análisis ROC (Receiver Operating Characteristic) mostrando unos valores de precisión (accuracy) altos y satisfactorios a pesar de las incertidumbres de muchos parámetros de suelo. Mediante FSLAM se ha analizado la influencia de los efectos del cambio climático y de futuros cambios en los usos y cubiertas del suelo en la susceptibilidad a generar deslizamientos en la zona de la Val d’Aran. Los resultados indican que los cambios en las cubiertas del suelo, especialmente la transformación de prados y arbustos a bosques, aumenta la estabilidad global en la zona de estudio. Por el contrario, el aumento de precipitación diaria para un periodo de retorno de 100 años provoca una reducción de la estabilidad. Sin embargo, el efecto del cambio de las cubiertas del suelo es más importante que el cambio en las condiciones pluviométricas y, por ello, la estabilidad global en esta zona de estudio aumentará en el f, El presente estudio ha sido financiado por dos proyectos nacionales: SMuCPhy (BIA 2015-67500-R) y EROSLOP (PID2019-104266RB-I00/AEI/10.13039/501100011033)., Postprint (published version)

La revolución experimentada por el uso creciente de la geoinformación 3D en la ingeniería geológica, gracias a los avances tecnológicos, que progresivamente han facilitado una disponibilidad de técnicas de adquisición de datos y de herramientas para su análisis. Junto a los avances experimentados en la disponibilidad de recursos de computación y almacenamiento en la nube, han impulsado la expansión de numerosas aplicaciones que permiten la difusión de la geoinformación 3D en la web. A pesar de estos avances científico-técnicos, es común ver los datos 3D simplificados en imágenes estáticas 2D, perdiendo parte su potencialidad comunicativa. El objetivo de esta comunicación es presentar el diseño y las funcionalidades de unos visores web 3D de código abierto como una herramienta de sencilla utilización con la que interactuar y visualizar los resultados. Así mismo, estamos ensayando las posibilidades de la realidad mixta como una experiencia plenamente inmersiva para lograr una mejor comunicación de la geoinformación 3D., Peer Reviewed, Postprint (published version)

La fragmentación en desprendimientos rocosos es un fenómeno complejo y poco comprendido que afecta a la evaluación del peligro y del riesgo. Sólo algunos modelos de simulación de caídas de rocas lo consideran explícitamente. RockGIS es un programa de simulación numérica de desprendimientos rocosos que considera la fragmentación, empleando una aproximación puntual de la masa y un modelo de rebote mediante coeficientes de restitución. Su principal innovación es la implementación del modelo de fragmentación fractal (Rockfall Fractal Fragmentation Model, RFFM) para distribuir la masa al romper los bloques. Los parámetros del modelo de fragmentación se calculan según las condiciones cinemáticas de cada impacto para reproducir diferentes escenarios de fragmentación. El funcionamiento de RockGIS ha sido verificado y validado mediante ensayos a escala real y en diversos desprendimientos rocosos naturales. En esta contribución presentamos la evolución de RockGIS en los últimos años y su aplicación a diversos casos de estudio., Este estudio ha sido desarrollado en el marco del Proyecto de Investigación “Caracterización y modelado de desprendimientos de rocas” con el acrónimo RockModels, financiado por el Ministerio de Economía y Competitividad de España, y cofinanciado por la Agencia Estatal de Investigación (AEI) y el Fondo Europeo de Desarrollo Regional (FEDER) sobre el marco del Plan Estatal de Investigación Científico-Técnica e Innovación con código de referencia BIA2016-75668-P (AEI/FEDER,UE) y el proyecto de investigación “Avances en el análisis cuantitativo del riesgo de caída de rocas (QRA) incorporando desarrollos en geomática (GeoRisk)” con referencia PID2019-103974RB-I00, financiado por MCIN/AEI/10.13039/501100 011033, Ministerio de Ciencia e Innovación (MCIN) y la Agencia Estatal de Investigación (AEI)., Postprint (published version)

La evaluación del riesgo y el diseño de medidas de protección frente a desprendimientos de rocas requieren la predicción de las posibles trayectorias de los bloques susceptibles de desprenderse, así como la velocidad y la energía de llegada a las zonas que se deban proteger. Considerar la fragmentación introduce desafíos adicionales al modelado, tales como la energía disipada durante la fragmentación y la distribución de la energía restante entre los nuevos fragmentos. Para aclarar algunos de estos puntos se realizó un experimento a escala real, en el que se observaron las trayectorias de 16 bloques y de los fragmentos generados tras el impacto, empleando tres cámaras de video de alta velocidad. Para determinar la posición espacial de los bloques, hemos desarrollado un programa que permite calcular las velocidades, los momentos lineales, las energías en el instante anterior y posterior al impacto y, finalmente, los coeficientes de restitución asociados al impacto, Peer Reviewed, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.1 - Enfortir la resiliència i la capacitat d’adaptació als riscos relacionats amb el clima i els desastres naturals a tots els països, Postprint (published version)

Fragmentation is a common feature of rockfall that exerts a strong control on the trajectories of the generated blocks, the impact energies, and the runout. In this paper, we present a set of four real-scale rockfall tests aimed at studying the fragmentation of the rocky blocks, from the global design of the field procedure to the data analysis and the main results. A total of 124 limestone, dacite, or granite blocks ranging between 0.2 and 5 m3 were dropped from different heights (8.5 to 23.6 m) onto four slopes with different shapes (single or double bench) and slope angles (42º to 71º). The characteristics of the blocks, in particular the size, surface texture and joint condition, were measured before the drops. The trajectories of the blocks and both the initial and the impact velocities were tracked and recorded by means of three high-speed video cameras. A total of 200 block-to-ground impacts have been studied. On average, 40% of the blocks broke upon impact on the slope or on the ground, making it necessary to measure the fragments. The initial and final sizes of the blocks/fragments were measured by hand with tape, though photogrammetric techniques (UAV and terrestrial) were also used for comparison purposes. The information gathered during the field tests provides a deep insight into the fragmentation processes. On the one hand, the high-resolution slow-motion videos help to describe when and how the block breakage takes place and the spatial distribution of the pieces. On the other hand, it is possible to compute the block trajectories, the velocities, and the energy losses using videogrammetry. The results include, for instance, a block average fragmentation of 54% and 14% for the limestone and granitoids, respectively; the systematic inventory of the size fragments, which may be used for fitting the power law distributions; and after each breakage, the total angle of aperture occupied by the fragments has been measured, with values in the range 25º–145º., The authors acknowledge the support of the Spanish Ministry of Economy and Competitiveness for the research projects RockRisk (BIA2013-42582-P), RockModels (BIA2016-75668-P, AEI, ERDF/FEDER, UE) and GeoRisk (PID2019-103974RB-I00/AEI/10.13039/501100011033). GeoRisk is funded by the Agencia Estatal de Investigación (AEI) on the framework of the Plan for Scientific-Technical Research and Innovation. The support of the Spanish Ministry of Education (grants to the second and third authors, codes FPU13/04252 and BES-2014-069795, respectively) and the BBVA Foundation (thirteenth author’s contract) is also appreciated. The collaboration of Canteras Hermanos Foj and Canteras Ponderosa S.A., Marc Janeras, and S. Moreno is greatly acknowledged. Finally, we thank two anonymous reviewers and the Editor who helped to improve the structure and content of the final version. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature., Peer Reviewed, Postprint (published version)

The final publication is available at Springer via http://dx.doi.org/10.1007/s10346-021-01775-6, It is widely accepted that future environmental changes will affect rainfall-induced shallow slides in high-mountain areas. In this study, the Val d’Aran region located in the Central Pyrenees was selected to analyze and quantify the impacts of land use and land cover (LULC) and climate changes on regional landslides susceptibility. We analyzed 26 climate models of the EURO-CORDEX database focussing on the future rainfall conditions. The IDRISI TerrSet software suite was used to create the future LULC maps. These two inputs were analyzed individually and in a combined way defining 20 different scenarios. All these scenarios were incorporated in a physically based stability model to compute landslides susceptibility maps. The results showed that both environmental conditions will considerably change in the future. The daily rainfall will increase between 14 and 26% assuming a return period of 100 years. This intensification of precipitation will produce an overall decrease of the stability condition in the study area. Regarding the LULC prediction, the forest area will significantly increase, while in particular grassland, but also shrubs decrease. As a consequence, the overall stability condition improves, because the root strength is higher in forest than in grassland and shrubs. When we analyzed the combined impacts, the results showed that the positive effect of LULC changes is larger than the negative influence of rainfall changes. Hence, when combining the two aspects in the future scenarios, the stability condition in the study area will improve., This study was funded by the national research project EROSLOP (PID2019-104266RBI00/AEI/10.13039/501100011033) of the Spain Government. Zizheng Guo acknowledges the financial support of China Scholarship Council for his research at UPC BarcelonaTECH, and Fundamental Research Funds for National Universities, China University of Geosciences (Wuhan)., Peer Reviewed, Postprint (author's final draft)

Fatal landslides are a widespread geohazard that have affected millions of people and have claimed the lives of thousands around the globe. A change in climate has significantly increased the frequency and magnitude of rainfall, which affect the susceptibility of slopes to shallow landslides. This paper presents a methodological framework to assess the future changes in extreme and seasonal rainfall magnitudes with climate model projections. This framework was applied to project summer rainfall over Wanzhou County, China, using an ensemble of four regional climate models (RCMs) from the East Asian domain of the Coordinated Downscaling Experiment (CORDEX) under the Phase 5 Coupled Intercomparison Modeling Project (CMIP5). The results find that extreme daily rainfall was projected to decrease in the mid-21st century, with an uncertainty measured by a coefficient of variation between 5% and 25%. The mean seasonal rainfall is projected to increase in the mid-21st century up to a factor of 1.4, and up to a factor of 1.8 in the late-21st century. The variation in the mid21st century ranged from 10% to 35%, and from 30% to 50% in the late-21st century. This case study delivered a proof-of-concept for a methodological framework to derive shallow landslide-triggering rainfall scenarios under climate change conditions. The resulting spatially distributed climate change factors (CCFs) can be used to incorporate future rainfall scenarios in slope susceptibility models and climate impact assessments., Peer Reviewed, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Postprint (updated version)