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)

The effect of climate change on soil loss processes in mountainous areas represents a current and critical problem. In this work, this issue is addressed through the analysis of the stability of different types of slopes subjected to climatic actions by 1D thermo-hydraulic numerical modeling and the infinite slope approach. The study aims to establish an average value of the safety factor, its variance and the probability of failure for the conditioning factors. The atmospheric values incorporated in the stability calculations are from regional climate change predictive models. The correlation data considers the most appropriate climate change projection for our study area located in the Central Pyrenees (Spain). Current reports, when considering the Mediterranean area, predict a rise in temperature up to 4.8 ° C for the largest projections of greenhouse gas emissions, which influence thermal flux and heat transfer patterns and mass storage processes, hydraulic conductivity values, changes in saturation degrees and liquid pressures. While the rainfall in the winter season decreases, the intensity and duration remain through all stability analysis as one of the parameters with the greatest influence of all climatic factors, by directly intervening in the increase in pore fluid pressures. The application of an infinite slope model for the analysis of the safety factor allows a stability analysis when evaluating the responses of the numerical model Code Bright. Code Bright incorporates the problem of flow and balance of water, air and energy, and the reaction to atmospheric scenarios for different soil types and the thermal and hydraulic properties that influence the development of the slope failure. The evolution of the safety factors related to the atmospheric variables describes the components of the instability and the sensitivity of the constitutive parameters of the soil. Other factors such as heterogeneous resistances within the coupled model allow us to describ, We thank the entire team of the SMuCPhy project and its funding by the Spain Government (BIA 2015-67500-R) and AEI/FEDER, UE, and supported partially by the SENACYT Foundation – Panama., Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Postprint (published version)

La calidad de los modelos digitales de elevación (MDE) es fundamental en geomorfología, especialmente en los estudios multitemporales en los que se quiere reconocer los cambios de relieve mediante el cálculo del volumen erosionado o sedimentado. Generalmente, esto se consigue a partir de la comparación de MDE, obtenidos por interpolación de nubes de puntos, cuya exactitud depende de los datos y métodos de interpolación utilizados para construir el modelo. Utilizar diferentes métodos podría introducir un cambio significativo y no real en la comparación multitemporal. En este trabajo comprobaremos cómo el método de interpolación elegido (distancia inversa ponderada, kriging, vecino natural y red irregular triangulada), y otros parámetros influyen en la construcción del MDE en diferentes tipos de terreno. Los resultados revelan que el uso de un método u otro, en la generación de archivos ráster, para el cálculo de los cambios de volumen en el terreno, puede dar lugar a diferencias significativas en zonas de pequeña extensión en términos geomorfológicos. [ANGLÈS] The quality of characterization in digital elevation models (DEM) is fundamental in geomorphology, especially in multitemporal studies in which we want to recognize changes in relief by calculating eroded or sedimented volume. Generally, this is achieved from DEM whose accuracy depends on the data and interpolation methods used to construct the model. Different methods could introduce a significant not real change in multitemporal comparison. In this paper we will check how the interpolation method (inverse distance weighted, kriging, natural neighbor and triangulated irregular network), and other parameters, influence the construction of a DEM in different terrains. The results show that, in particular, the interpolation method can have an influence. Moreover, they reveal that the use of one method or another, in the generation of files for the calculation of volume changes in the terrain, can give rise to sig, Peer Reviewed, Postprint (published version)

Este documento se enmarca en el proyecto “POr una Cultura común del RIesgo SísmiCo” (POCRISC), de referencia EFA158/16/POCRISC, que es un proyecto Interreg-POCTEFA de la Unión Europea. POCRISC persigue proveer conocimiento, directrices y herramientas que permitan evaluar la vulnerabilidad sísmica global, preferentemente, pero no exclusivamente, de edificios esenciales, entendidos como, aquellos que son necesarios para la atención a la población y a los servicios, en caso de terremoto y, cuyo fallo, puede comprometer la gestión de la emergencia. Pero, su alcance va más allá y, la mayoría de los métodos, técnicas y elementos de esta guía, pueden ser aplicados a edificios resi denciales de importancia normal y a edificios de especial importancia, entre los que se incluyen, entre otros, aquellos que desempeñan una función especial, los que tienen un alto nivel de ocupación, y también, aquellos con un elevado valor económico o patrimonial. En este documento, se facilita el marco conceptual del riesgo sísmico, así como los antecedentes sobre las iniciativas para su evaluación, haciendo énfasis en el análisis de la vulnerabilidad y el daño físico directo. Para contextualizar la importancia de las normas sísmicas de diseño y los estudios de riesgo,se dedica un capítulo al análisis de la peligrosidad sísmica y a los niveles de daño asumibles en el diseño y construcción de edificios, en función del cometido o servicio que deben prestar, siempre primando, la protección de la vida y la prevención de colapso. Después de estos capítulos introductorios,se abordan los métodos que permiten evaluar la vulnerabilidad y el daño sísmico esperado. Estos métodos se clasifican como métodos de nivel I, LM-I, de nivel II, LM-II y métodos avanzados LMa. El método de primer nivel la vulnerabilidad del edificio se cuantifica mediante un índice y el sismo mediante la intensidad macrosísmica; funciones semi-empírcas permiten estimar el daño que un edificioexperimentará cuando sufra un sismo. El d, Preprint

La vulnerabilidad sísmica es uno de los aspectos fundamentales para la determinación del riesgo sísmico de una región o zona en particular. Los estudios de vulnerabilidad sísmica son imprescindibles en la determinación del riesgo sísmico y en la elaboración de planes de mitigación de las catástrofes producidas por terremotos. En este informe se implementan métodos estadísticos para evaluar la vulnerabilidad sísmica de los municipios incluidos en la zona de estudio del proyecto POCRISC. Estas metodologías incluyen la asignación estadística de las clases de vulnerabilidad de la escala macrosísmica europea en base a la distribución de los edificios según su periodo de construcción, número de plantas y/o tipología estructural. Esta actividad se enmarca en la Acción 3 y es pieza esencial para el desarrollo de escenarios automáticos de daño a partir de las intensidades del ShakeMap para el Pirineo. La caracterización de la vulnerabilidad de la región transfronteriza se ha adaptado al grado de información disponible sobre el parque de edificios en cada una de las regiones. La parte española y francesa disponen de censos que proveen informaciones de diverso detalle, calidad, escala y periodicidad mientras que Andorra no dispone de censos oficiales y requirió de trabajo de campo para recopilar los datos necesarios. Los resultados de la vulnerabilidad se han organizado en una base de datos cuyo formato facilita su integración en el sistema para la generación de los escenarios de daño y para su representación geoespacial. El desarrollo de esta base de datos, que estará disponible bajo demanda, facilitará el desarrollo de escenarios de daño y otros estudios relacionados con los esfuerzos para la evaluación y mitigación de la vulnerabilidad y riesgo sísmico de la región transfronteriza del Pirineo., Preprint

Esta guía y la matriz tipológica de edificios propuesta en la misma, se han desarrollado en el contexto del proyecto “POr una Cultura común del RIesgo SísmiCo” POCRISC, de referencia EFA158/16/POCRISC 2 . El proyecto ha sido financiado por el Fondo Europeo de Desarrollo Regional (FEDER) y se enmarca en el progr ama Interreg V-A España Francia Andorra (POCTEFA 2014-2020) de la Unión Europea. El programa POCTEFA 2014-2020 tiene por objeto reforzar el desarrollo económico y social de la zona fronteriza franco-española- andorrana. Su acción se centra en el desarrollo de actividades económicas, sociales y medioambientales transfronterizas a trav és de estrategias comunes que promueven una ordenación territorial sostenible. El proyecto se ha desarrollado en el período 2018-2021. Este documento es un compendio de las tipologías constructivas de edificios que se consideran representativas de las diferentes regiones de estudio del proyecto POCRISC, y que abarcan la zona transfronteriza entre España, Andorra y Francia. El propósito de esta matriz de tipología de edificios (Building Typology Matrix, BTM), es agrupar en un conjunto de clases los edificios con sistemas estructurales y características de comportamiento similares. Se pretende así, facilitar el análisis de su vulnerabilidad, frente a demandas potenciales asociadas a movimientos sísmicos. Dichas tipologías se han definido mediante juicio de experto, tomando como referencia las tipologías identificadas en el marco del proyecto Risk-UE (Milutinovic y Trendafiloski, 2003; Faccioli 2006; Mouroux y Le Brun 2008; Barbat et al. 2010; Lantada et al. 2010). Por otra parte, la información contenida en este informe está directamente relacionada con la Base de Datos de Vulnerabilidad para la zona de estudio del proyecto POCRISC (Lantada et al. 2021) incluida en la acción 3, y en la Guía de evaluación de la vulnerabilidad (Pujades et al. 2021) y la Guía de reducción de la vulnerabilidad (Meza et al. 2021), ambas desarrolladas en, Preprint

El uso de técnicas geomáticas y modelos 3D del terreno en el estudio de riesgos naturales se ha incrementado notablemente en las últimas décadas. En este trabajo nos centramos en la caracterización de discontinuidades del macizo rocoso, con el objetivo de identificar el volumen de salida potencialmente inestable, necesario para evaluación de la peligrosidad de los desprendimientos rocosos. La zona de estudio es Pala de Morrano (PN Aigüestortes). A partir de vuelos fotogramétricos desde plataformas aéreas (RPAS y helicóptero) se generaron dos modelos 3D y un tercero desde cobertura terrestre. Se completaron los datos con un TLS (Terrestrial Laser Scanning), que se asumió como ground truth. La caracterización se realiza mediante el plugin Fast Marching de Cloud Compare, sobre estos modelos. Los modelos generados tienen una notable completitud, mayor al 95%, destacando la combinación de terrestre y helicóptero sin apenas oclusiones (98%). Se concluye que para el objetivo fijado de la obtención de las familias de discontinuidades todos los modelos fotogramétricos son válidos, destacando que el generado por fotogrametría terrestre es el que presenta mayor similitud con el obtenido con el TLS, siendo el óptimo en base a su coste-beneficio, seguido del generado por fotogrametría desde multicóptero, Peer Reviewed, Postprint (published version)

The effect of climate change on soil loss processes in mountainous areas represents a current and critical problem. In this work, this issue is addressed through the analysis of the stability of different types of slopes subjected to climatic actions by 1D thermo-hydraulic numerical modeling and the infinite slope approach. The study aims to establish an average value of the safety factor, its variance and the probability of failure for the conditioning factors. The atmospheric values incorporated in the stability calculations are from regional climate change predictive models. The correlation data considers the most appropriate climate change projection for our study area located in the Central Pyrenees (Spain). Current reports, when considering the Mediterranean area, predict a rise in temperature up to 4.8 ° C for the largest projections of greenhouse gas emissions, which influence thermal flux and heat transfer patterns and mass storage processes, hydraulic conductivity values, changes in saturation degrees and liquid pressures. While the rainfall in the winter season decreases, the intensity and duration remain through all stability analysis as one of the parameters with the greatest influence of all climatic factors, by directly intervening in the increase in pore fluid pressures. The application of an infinite slope model for the analysis of the safety factor allows a stability analysis when evaluating the responses of the numerical model Code Bright. Code Bright incorporates the problem of flow and balance of water, air and energy, and the reaction to atmospheric scenarios for different soil types and the thermal and hydraulic properties that influence the development of the slope failure. The evolution of the safety factors related to the atmospheric variables describes the components of the instability and the sensitivity of the constitutive parameters of the soil. Other factors such as heterogeneous resistances within the coupled model allow us to describ, We thank the entire team of the SMuCPhy project and its funding by the Spain Government (BIA 2015-67500-R) and AEI/FEDER, UE, and supported partially by the SENACYT Foundation – Panama., Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Postprint (published version)

An experimental development of systems for tests on stainless steel members and frames aimed at providing interoperability is presented. In the context of the project PINOX, tests on stainless steel members and frames have been conducted and provided with traditional measurement techniques. In addition, systems aimed at providing interoperable data to other platforms were added, namely: i) Measurement systems for developing low-cost sensor-to-cloud applications as well as Digital Image Correlation, ii) Displacement measurement for developing virtual and augmented reality applications and iii) terrestrial laser scan (TLS) measurements for developing IFC models for design and analysis across BIM platforms. In the first case, the interest is related to developing interoperable, low-cost, cloud-based, open-source tools in the context of structural engineering laboratories. In the second case, the interest is the use of virtual (VR) and augmented reality (AR) as alternative media when deploying tests on structural elements. The third case is explored for obtaining measurements and tracking initial imperfections on real structures, with great interest for in situ applications. Conclusions about educational, technological and practical potential of these applications are pointed out., This experimental programme was developed in the frame of the Project BIA2016-75678-R, AEI/FEDER, UE “Comportamiento estructural de pórticos de acero inoxidable. Seguridad estructural a acciones accidentales de sismo y fuego”, funded by MINECO (Spain). Special thanks to Josep Gili, Nieves Lantada and Albert Torrente members of the research group EGEO –UPC., Postprint (published version)

Fragmentation in rockfalls reduces the size of the blocks and increases the number of fragments. It affects the runout and the impact energies, having implications in the associated hazard and therefore in the subsequent risk. In some rockfall events, a young debris cover is formed during the first impacts, with a substantial reduction of the particle size. The large number of small particles generated in the debris cover suggests that beside the breakage of the particles, comminution by crushing and grinding may also occur during the impact. This contribution presents the results of the comminution tests carried out in the laboratory.A set of one, three and five stacked bricks of different colors were released. The tests aim at verifying and quantifying the following hypotheses for the brick located in the lower position of the stack: i) the fragments generated should be smaller, ii) the number of fragments generated should increase, and iii) both effects should intensify as the number of the stacked bricks increases. A total of 78 reduced scale tests were carried out using a set of stacked bricks that were dropped from a height of 4.26 m. The resulting fragments were separated by colors according to their initial position in the stacking and sieved obtaining the grain size distribution. A high-speed camera was used to record and interpret each test. A 3D photogrammetric reconstruction after each test was generated to register the final deposit. The obtained grain size distributions confirm the proposed hypothesis. Confinement reduces the maximum fragment size while increases substantially the total number of generated fragments and those effects increase with the number of stacked bricks., Postprint (published version)

The existing theory for shore-transverse rhythmic sand bars relies on morphodynamic instabilities involving the wave-driven longshore current and rip currents. Intriguingly, transverse finger bars are common on coasts with sediment excess, something not related to those currents. Here we show that, if the actual beach profile is above the equilibrium profile, cross-shore transport can induce an instability triggered by onshore transport together with wave refraction by the emerging bars. We use a numerical model that filters out the dynamics associated to longshore and rip currents but includes a simplified version of cross-shore transport and is able to reproduce the formation of shore-transverse bars. The alongshore spacing scales with the wavelength of the incident waves and the cross-shore extent is approximately equal to the distance from shore to the depth of closure. The modeled bars compare qualitatively well with observations at El Trabucador back-barrier beach (Ebro delta, Western Mediterranean Sea)., Postprint (published version)

Photogrammetry is one of the widest techniques used to monitor terrain changes which occur due to natural process and geological natural risk zones. In order to carry out terrain monitoring, it is necessary to eliminate all the non-ground elements. One of the most variable elements in this monitoring is the presence of vegetation, which obscures the ground and can significantly mislead any multitemporal analysis to detect terrain changes. Therefore, the focus of this paper is about how best to filter the vegetation to attain an accurate reading of the terrain. There are several methods to filter it based on colourising an excessive greenness vegetation index or non-visible channels as the IR in the well-known index NVDI. However, achieving this kind of information is not always possible because its high cost. Instead this channel we can add new information using the HSV colour space obtained from the RGB information. In this paper, we propose a double possibility, on one hand work wit h RGB+HSV for a supervised segmentation on images. On the other, to use excessive greenness vegetation indices and RGB+HSV for the segmentation of point clouds. The results shown that the use of additional channels HSV can significantly improve the segmentation in both studies, and therefore render a much more accurate assessment of the underlying terrain, Peer Reviewed, Postprint (published version)

The analysis of the impacts of future environmental changes on rainfall-induced landslides is of great importance. Recent studies have shown that these changes will affect the frequency and magnitude of shallow slides and debris flows. In this study, we focused on the effects of climate changes as well as land use and land cover (LULC) changes on rainfall-induced slope failures at regional scale. A newly developed physically-based susceptibility model was applied and the Val d’Aran area, located in the Central Pyrenees (Spain), was selected as study site. First, the catastrophic landslide episode, which affected the Val d’Aran area in June 2013, was used for a preliminary validation of the susceptibility model. Then, the future LULC changes until the end of the 21th century were simulated in the study area and incorporated in the regional landslide model. The results revealed an overall increase of stability in the future, because of the larger area of forest and the consequent higher cohesion due to augmented root strength. In the next step, the impacts of future climate changes were calculated including a higher rainfall intensity. We assumed an increase of 15%, which corresponds to the last findings obtained from the ensemble of regional climate models using RCP 4.5 and 8.5 scenarios. This increase in rainfall intensity produced a reduction of the overall slope stability in the study area. However, comparing the effects produced by LULC and rainfall changes revealed that the LULC changes have a greater influence than the changes related to the rainfall conditions. This means that the overall stability in the study area slightly improves in the future. Multiples assumptions and simplifications were introduced in these preliminary calculations of the future landslide susceptibility, and additional simulations are necessary to confirm the observed trends. Nevertheless, the results seem to be coherent with the outcomes of other recent studies and give some valuable i, The study was funded by the national research project called “Slope mass-wasting under climate change” (smucphy.upc.edu) granted by the Spain Government (project reference number BIA 2015-67500-R) and co-funded by AEI/FEDER, UE., Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Postprint (published version)

The stability and erosion of natural and man-made slopes is influenced by soil-vegetation-atmosphere interactions and the thermo-hydro-mechanical slope conditions. Understanding such interactions at the source of slope mass-wasting is important to develop land-use planning strategy and to promote environmentally adapted mitigation strategies, such as the use of vegetation to stabilize slopes and control erosion. Monitoring is essential for calibrating and validating models and for better comprehending the physical mechanisms of soil-vegetation-atmosphere interactions. We approached this complex problem by means of an experimental work in a full-scale monitored embankment, which is divided into four instrumented partitions. These partitions are North or South-faced and present a bare and vegetation cover at each orientation. Our main findings show that vegetation enhances rainfall infiltration and decreases runoff, which reduces slope stability and surficial erosion, while plant transpiration induces higher suctions and hence slope stability. Concerning thermal aspects, vegetation reduces the incidence of net solar radiation and consequently heat flux. Thus, daily temperature fluctuations and evaporation decreases. However, the effect of vegetation in the development of dryer soil conditions is more significant than the orientation effect, presenting higher drying rates and states at the North-vegetated slope compared to the South-bare slope., This research was funded by the national researchs projects called “Slope mass-wasting under climate change (SMuCPhy, project reference number BIA 2015-67500-R)” and “Multiscale analysis of soil erosion in steep slopes (EROSLOP, project reference number PID2019-104266RB-I00) granted by the Ministry of Economy and Competitiveness of Spain and co-funded by AEI/FEDER, UE., Peer Reviewed, Postprint (published version)

El objetivo de este documento es proveer recomendaciones para la instrumentación de edificios esenciales, si bien éstas también pueden ser útiles para otros tipos de edificios y estructuras civiles. Para contextualizar estas recomendaciones se aportan elementos sobre la instrumentación en zonas donde el peligro sísmico es alto y donde la instrumentación de determinados edificios se prescribe en los correspondientes códigos sísmicos. Las recomendaciones específicas se refieren al análisis modal operacional, incluyendo el análisis modal computacional, que debe ser un compañero de viaje del operacional. Se resumen las diferentes etapas de un proyecto de estudio de vibraciones ambientales, se describen brevemente las lecciones aprendidas en las instrumentaciones realizadas en POCRISC y, en base a éstas, se dan unas recomendaciones específicas, en referencia a la instrumentación propiamente dicha y al análisis y tratamiento de la señal, en los dominios del tiempo y de la frecuencia. Se concluye resaltando cómo, a pesar de las limitaciones y dificultades de las aplicaciones a detección y cuantificación de daño, la monitorización modal de edificios tiene un importante potencial futuro en la monitorización de la salud estructural, que va más allá del daño estrictamente sísmico., Preprint

Hazard scenarios are defined by a representative event of a certain magnitude, which corresponds to a frequency of occurrence or annual probability. In rockfall, scenario magnitude is identified by the total volume detached. Therefore, in diffuse hazard assessment it is crucial to fit this relationship magnitude/frequency, called McF, where cumulated frequency is quoted in spatial & temporal terms. Inventories are the classical source of data to deal with this objective. Last decade, TLS or digital photogrammetry monitoring came to offer a complementary approach. The samples obtained by the two methods have a specific coverage and each has its own lack of information that can be compensated together., Peer Reviewed, Postprint (published version)

Purpose: the importance of sustainability in architecture currently necessitates the integration of innovative teaching strategies on the subject into architecture programs. This study aims to introduce and examine peer learning pedagogy by peer tutoring to educate architecture students in sustainable design. Design/methodology/approach: based on class assignments proposed in two different architecture sustainability-focused courses in the second and fourth years of the Bachelor of Science in architecture program, a total of 103 students assessed the proposed peer learning experience and its impact on their sustainability mindsets and education. Subjective surveys for evaluating the peer learning experience were designed and delivered at different stages of the course sequences. A total of 502 survey responses were obtained in the study. Findings: the qualitative and quantitative data analysis confirms that the proposed peer learning by peer tutoring increased students’ knowledge, motivation and commitment to sustainable design. In addition, participants became more confident in applying sustainable design skills and their academic grades improved more than 25% compared to previous courses using traditional teaching methods. Originality/value: Traditional architecture education has long been criticized for their pedagogical methodologies based primarily on passive learning. Recently, these programs have begun to prepare students to become active learners and communicators in collaborative and multidisciplinary environments. A mixed-method approach of combining pre-/post-experience surveys and analysis of final grades was used to determine the level of success and the quantifiable behavior change delivered by students involved in this peer learning experience., Peer Reviewed, Postprint (published version)

Persistent scatterer interferometry (PSI) is a group of advanced interferometric synthetic aperture radar (SAR) techniques used to measure and monitor terrain deformation. Sentinel-1 has improved the data acquisition throughout and, compared to previous sensors, increased considerably the differential interferometric SAR (DInSAR) and PSI deformation monitoring potential. The low density of persistent scatterer (PS) in non-urban areas is a critical issue in DInSAR and has inspired the development of alternative approaches and refinement of the PS chains. This paper proposes two different and complementary data-driven procedures to obtain terrain deformation maps. These approaches aim to exploit Sentinel-1 highly coherent interferograms and their short revisit time. The first approach, called direct integration (DI), aims at providing a very fast and straightforward approach to screen-wide areas and easily detects active areas. This approach fully exploits the coherent interferograms from consecutive images provided by Sentinel-1, resulting in a very high sampling density. However, it lacks robustness and its usability lays on the operator experience. The second method, called persistent scatterer interferometry geomatics (PSIG) short temporal baseline, provides a constrained application of the PSIG chain, the CTTC approach to the PSI. It uses short temporal baseline interferograms and does not assume any deformation model for point selection. It is also quite a straightforward approach, which improves the performances of the standard PSIG approach, increasing the PS density and providing robust measurements. The effectiveness of the approaches is illustrated through analyses performed on different test sites., This work has been partially funded by AGAUR, Generalitat de Catalunya, through a grant for the recruitment of early-stage research staff (Ref: FI_B 00741) and through the Consolidated Research Group RSE, “Remote Sensing” (Ref: 2017-SGR-00729). It has been also partially funded by the Spanish Ministry of Economy and Competitiveness through the DEMOS project “Deformation monitoring using Sentinel-1 data” (Ref: CGL2017-83704-P) and by AGAUR., Peer Reviewed, Postprint (published version)

Last decade, real time kinematics (RTK) GPS methods have been developed with high productivity and good theoretical precision, enabling the coverage of wide areas. The main objective of this contribution is to ascertain the performance of this method in the study of thest areas "A" (about 12 km2) within the Doñana National Park wetlands. One of the aims of the research Project was the detection and monitoring of sub-decimiter level terrain changes due to water erosion or sand sedimentation. The technique used is GPS navigation and profiling along N-S paths 50 m apart during the dry season. The firts survey has been carried out in summer 1998, including repeatability tests. About 20000 terrain points have been obtained. The survey has been reapted in July 2000. After filtering and editing, conclusions about precision have been derived from the repeatability test and compring both surveys. Other practical remarks are related with the total number of GPS available during the fieldwork, the inicialization process using RTK at increasing distances, and the GPS positioning during high geomagnetic activity days., Peer Reviewed, Postprint (published version)

Works carried out to monitor the displacements of the Vallcebre landslide (Pyrenees range, NE of Spain) since 1987 are presented. The landslide, which extends over an area of about 0.8 km2 and affects more than 20 × 106 m3, has experienced displacements of up to one meter per year in some points and periods. It has been periodically monitored since 1987, using a wide range of surface and in-hole techniques: triangulation with theodolite, Terrestrial Photogrammetry, Electronic Distance Measurement, GNSS-GPS, inclinometers, wire extensometers, piezometers, DInSAR (satellite) and GBSAR (terrestrial). The results obtained using new techniques are compared with those obtained with GNSS-GPS and a wire extensometer, and checked against fixed stable points. From this comparison, we conclude that even though wire extensometers and inclinometers may have the highest precision, in practice, all systems play potentially valuable roles in providing meaningful data for monitoring at different study stages. In the near future, we envisage the installation of a Distributed Fiber Optic array to monitor the risk with a certain space and time continuity. After the evaluation of the precision and advantages of the different methods, the complementary use of some of them is strongly recommended., The three decades work summarized here has been funded mainly by EC and Spanish Research Projects. In chronological order: TESLEC (Temporal stability and activity of landslides in Europe with respect to climatic change; EC; contract EV5V-CT94.0454); NEWTECH (New technologies for landslide hazard assessment and management in Europe; EC contract ENV4-CT96-0248 and Spanish CICYT contract AMB96-2480-CE); CICYT project (Cartografía de la susceptibilidad a los deslizamientos del terreno en el área del Alto Llobregat … Vallcebre mediante los SIG; Spanish CICYT contract AMB97-1091-C06); MODEVALL (Modelación hidrológico-mecánica del deslizamiento de Vallcebre; Spanish Science and Education Ministry, MEC, contract CGL2005-05282); SAFELAND (Living with landslide risk in Europe: Assessment, effects of global change, and risk management strategies; EC, 7thFP, grant agreement 226479); PYRMOVE (Research network funded by AGAUR, Government of Catalonia; grant number 2014CTP00051); PYRMOVE (Prevention and cross-border management of risk associated with landslides; funded by Interreg V-A, POCTEFA, and by the European Regional Development Fund, ERDF; project EFA364/19). The last project is still active., Peer Reviewed, Postprint (published version)

Terrestrial Laser Scanners (TLS) provide manifold possibilities in construction sites. In buildings assembled with steel frames, the “as-built” configuration of the structure can be virtualized by means of TLS measurements in the form of digital 3D point cloud data. This paper presents an integration of procedures related to the reproduction of realistic wire representations of steel frames. This integration encompasses the use of terrestrial laser scanning (TLS) measurements and the development of BIM-friendly wire models based on these measurements. These models are intended to be used in subsequent geometrically nonlinear analysis of the frames using similar BIM environments. All measurements are taken on laboratory tests of sway and non-sway stainless steel subjected to vertical and lateral loading. The “as-built” geometrical initial conditions can be used for the development of models embedded within BIM platforms for their subsequent usage in structural verification., This experimental programme was developed in the frame of the Project BIA2016-75678-R, AEI/FEDER, UE “Comportamiento estructural de pórticos de acero inoxidable. Seguridad frente a acciones accidentales de sismo y fuego”, funded from the MINECO (Spain) and to which financial support is acknowledged. Special thanks to Josep Gili, Nieves Lantada and Albert Torrente members of the research group EGEO –UPC., Peer Reviewed, Postprint (published version)

The use of massive data capture techniques in architectural heritage has enhanced the development of new methodologies that have an important impact on their conservation and understanding. The research proposes the study of formal anomalies in the cloister of the Cathedral of Tarragona (c. 12th century). It is a relevant Gothic construction in Catalonia, with the special singularity that part of its structure is raised over an important pre-existing Roman wall. The investigation is based on a point cloud obtained with a terrestrial laser scanner (TLS) and the systematization of the 3D analysis methodology of the point cloud through different reference shapes. In general terms, the construction is in good condition, so the discrepancies between real construction and the shapes of reference are small, with some exceptions. Nevertheless, the different approximations used allowed us to identify some relevant features, such as the variability of the form of rib vaults, and the influence of the criteria used in the definition and location of reference forms., Peer Reviewed, Postprint (published version)

Real-scale fragmentation tests provide high quality data in order to study the fragmentation pattern of rock blocks. In the tests carried out, the initial rock mass, in terms of both volume and shape, was reconstructed by means of 3D photogrammetry. The fragments size distribution of the bocks tested was measured by hand using a tape. The drop tests were performed in four different sites, releasing a total of 124 blocks and measuring 2907 fragments. The obtained fragment size distributions may be well fitted using power laws. The survival rate (Sr), which is the proportion of remaining block shows a wide range of values. Observing the fragment distribution, two parameters are needed to characterize the fragmentation: the number of fragments produced and Sr. The intensity of the fragmentation is expressed by the exponent of the fitted power laws. Although the results are highly variable and show a stochastic behavior of the fragmentation, we have identified different patterns that reflect some local test conditions, This research was funded by the Spanish Ministry of Economy and Competitiveness and co-funded by the Agencia Estatal de Investigación (AEI) and The European Regional Development Fund (ERDF/FEDER, UE), grant number BIA2016-75668-P (AEI/FEDER, UE)., Peer Reviewed, Postprint (published version)

Cardona area presents surface rising and subsidence active movements. In 1999 a series of sinkholes appeared due to the infiltration of Cardener River water into the mine tunnels, damaging surface infrastructures. Since then, high precision GNSS/GPS was used annually to position a network of 40 points spread over the area. GNSS/GPS work is carried out with the Fast-Static (FS) method. Additionally the surface movements have been monitored with satellite Differential Interferometry Synthetic Aperture Radar (DInSAR). Results indicate that the movement has a complex spatial distribution although consistent along time. Some areas show surface rising during the last two decades, while other areas show subsidence. The use of the two techniques allowed to determine the most plausible causes of these movements generated by a set of interwoven natural and human-induced complex processes., Peer Reviewed, Postprint (published version)

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 scen, This research was funded by the research grant program Marie Sklodowska-Curie Actions (MSCA), European Union/European (H2020-MSCA-IF-2017) No 799553. This research was also partially funded by the Spanish Government’s Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Funds (ERDF) of the European Union (EU) through projects with references CGL2015-65913 -P (MINECO/ERDF, EU) and EFA158/16/POCRISC (INTERREG/POCTEFA. EU). The support of these institutions is highly recognized and acknowledged., Peer Reviewed, Postprint (published version)

Basemaps are the main resource used in urban planning, building and infrastructure asset management. Therefore, they must be accurate and up to date to better serve citizens, contractors, property owners and town planning departments. Traditionally, they have been updated by aerial photogrammetry, but this is not always possible and alternatives need to be sought. In such cases, a useful option for large scales is the mobile mapping system (MMS). However, automatic extraction from MMS point clouds is limited by the complexity of the urban environment. Therefore, the influence of the urban pattern is analysed in three zones with varied urban characteristics: areas with high buildings, open areas, and areas with a low level of urbanization. In these areas, the capture and automatic extraction of 3D urban elements is performed using commercial software, which is useful for some elements but not for manholes. The objective of this study is to establish a methodology for extracting manholes automatically and completing hidden buildings' corners, in order to update urban basemaps. Shape and intensity are the main detection parameters for manholes, whereas additional information from satellite image Quickbird is used to complete the buildings. The worst rate of detection for all the extracted urban elements was found in areas of high buildings. Finally, the article analyses the computing cost for manhole extraction, and the economic cost and time consume of the entire process, including the proposed methodolgy using an MMS point cloud and the traditional survey in this case., Peer Reviewed, Postprint (updated version)

Risk management due to natural hazards is a multidimensional and complex problem since it requires the knowledge and experience of several disciplines. The effectiveness of risk management can be analyzed, inviting to the action through weakness identification of the urban area. This article proposes a methodology based on the morphological analysis to support the decision-making on disaster risk management, taking as a starting point the results of a holistic evaluation of the seismic risk. The results of the holistic evaluation of risk are achieved aggravating the physical risk using the contextual conditions, such as the socio-economic fragility and the lack of resilience. In consequence, the risk mitigation can be performed through the reduction of the potential damage and consequences involved; and the improvement of social conditions. The proposed methodology allows prioritizing the risk reduction strategies according to i) performance level of component indicators involved into the Disaster Risk Management index, DRMi; ii) physical risk factors dependent from the potential damages, and iii) aggravating factors involved in the aggravating coefficient. Moreover, it involves 35 strategies to reduce the physical risk and the aggravating social conditions of the urban area. The proposed methodology has been applied to the city of Mérida (Venezuela), located within an area of high seismic activity. The performance level of the indicators involved in the DRMi was evaluated by a survey to local experts. As a result, eleven strategies have been identified to reduce the potential damage and to improve the social conditions of this city., Peer Reviewed, Postprint (author's final draft)

Document intern presentat al European Convention for Constructional Steelwork. Technical Committee TC8. Stability., This document presents an integration of measurement-to-design procedures related to structural analysis of tubular frames. TLS-based data-gathering and the automated transformation of the corresponding point clouds to as-built realistic BIM representations of the steel structures were performed. The measurement corresponds to an experimental program on four stainless steel frames. Point-cloud data was gathered during several test stages, including the unloaded case. Subsequently, a set of mathematical processing of the results is performed for the sake of generating realistic wire models. The automatic generation of these structures is developed within algorithmic modelling environments. The imperfection patterns are identified, processed and analyzed using comparison benchmarks., This experimental programme was developed in the frame of the Project BIA2016-75678-R, AEI/FEDER, UE “Comportamiento estructural de pórticos de acero inoxidable. Seguridad frente a acciones accidentales de sismo y fuego”, funded from the MINECO (Spain)., Preprint

In this paper, we present the upgraded version of RockGIS, a stochastic program for the numerical simulation of rockfalls and their fragmentation, based on a fractal model. The code has been improved to account for a range of fragmentation scenarios, depending on the impact conditions. In the simulation, the parameters of the fractal fragmentation model that define the sizes of the generated fragments were computed at each impact according to the kinematic conditions. The performance of the upgraded code was verified and validated by real-scale rockfall tests performed in a quarry. The tests consisted of the release of 21 limestone blocks. For each release, the size and spatial distribution of the fragments generated by the impacts were measured by hand and from orthophotos taken via drone flights. The trajectories of the blocks and the resulting fragments were simulated with the code and calibrated with both the volume distribution and the runout distances of the fragments. Finally, as all the relevant rockfall parameters involved were affected by strong uncertainty and spatial variability, a parametric analysis was carried out and is discussed., This work has been carried out with the support of the Spanish Ministry of Economy and Competitiveness thanks to a fellowship to the first author (BES-2014-069795) and in the framework of the research project RockModels (Ref. BIA2016-75668-P, AEI/FEDER, UE). The collaboration of Canteras Hermanos Foj (Barcelona metropolitan area, Spain) is gratefully acknowledged., Peer Reviewed, Postprint (published version)

Rockfalls are slope instabilities very frequent and harmful in mountainous areas. They cause damage in infrastructures (roads and railways), buildings, vehicles and people.Several testswerecarried out to understand better these events. The field activities comprised real scale tests and the characterization of natural events in the N-E of Spain, mainly in the Pyrenees range. Moreover, in order to understand the behaviourof the blocks during the fall real scale tests were carried out. We dropped a total of 124 rock blocs under controlled conditions. Prior to the block release and during their propagation downslope, several geomatic techniques wereused to monitor the volumes, shapes and trajectories ofthe original blocks and their fragments (due to breakage); it is worth to highlight the videogrammetry to determinethe trajectoriesof the blocks. In order to survey the natural rock walls,source of the rockfalls, the so-called massive data capture by photogrammetry (both terrestrial and UAV-drone with image and video) and Terrestrial Laser Scanning(TLS) have been used, in this way the different techniques can be compared. Finally, for the monitoring of some rock cliffs, with recurrent rockfalls, the TLS was used, trying to catch some precursory displacements that may help in the risk management of the areas at the bottom. In our contribution, the aforementioned geomatic techniques (videogrammetry, photogrammetry –terrestrial or aerial --, and TLS) are combined and compared, highlighting the pros and cons of the different methods and their applications according to environmental conditions., Peer Reviewed, Postprint (published version)

The final publication is available at Springer via http://dx.doi.org/10.1007/s10518-018-0516-4, Risk assessment and management is an important step towards resilient and sustainable cities. Among many other perils, both natural and manmade, seismic risk is a major threat for resilience and sustainability. In recent decades, several methods for seismic risk assessment have been proposed, including the well-known Vulnerability Index Method (VIM). In this study, a probabilistic version of the VIM, which we call the Vulnerability Index Method-Probabilistic (VIM_P), is proposed. The VIM_P requires essential information on the seismic hazard and on the vulnerability of the building stock. Seismic hazard is determined using the exceedance rates of macroseismic intensities, as defined in the European Macroseismic Scale (EMS). Seismic vulnerability is defined by means of vulnerability probability density functions (pdf) that describe the probability distribution of the corresponding vulnerability index. Beta-like functions are used for these pdfs. VIM_P quantifies seismic vulnerability by means of three vulnerability curves, Lower, Best and Upper, according to the quantity and quality of available information, thus allowing three estimates of seismic vulnerability and risk. Then, seismic risk is computed via the convolution of seismic hazard and seismic vulnerability, considering semi-empirical damage functions. Seismic risk is given through the exceedance frequencies of the damage grades. To highlight the capabilities of the VIM_P, the seismic risk of about 70,000 residential buildings in Barcelona was assessed. According to the results, the exceedance frequency of the collapse damage state for more than the 50% of the buildings in the Eixample district would be greater than 1 × 10-5. This confirms the relatively high seismic risk in the city, mainly due to the high vulnerability of the built environment. Specific software, USERISK20015, has been developed for routine applications of VIM_P. It is hoped that VIM_P and this new tool for seismic risk assessment will be u, Peer Reviewed, Postprint (author's final draft)

The monitoring of morphologic changes in high-mountain environments is an important, but complex task. Terrestrial as well as airborne laser scanning (TLS and ALS) and digital photogrammetry (DP) using Unnamed Aerial Vehicle (UAV) can determine recent variations. In contrast, changes that occurred 20 or more years ago, need generally the application of DP and historic aerial photograph. We compared these four geomatic techniques and the resulting digital elevation models (DEM) that ranged over a 70-year time span (1946–2016). The accuracy of the different models and also the effect of different cell size were analysed. The accuracy analysis of the resulting DEMs shows important drawbacks, when historic aerial photographs are used. In these DEMs, the error in elevation can be important and a detailed analysis of morphologic changes is limited. Nowadays, the combination of DP and UAV is the technique with best cost-benefit ratio, although TLS could reveal similar precision. However, the application of TLS is restrained by the complex morphology and the presence of vegetation, which produce many shadows. Finally, the erosion rate was determined in our catchment. The resulting values range between 0.06 and 0.16¿m3/m2/y, which coincides rather well with data observed in other studies., Peer Reviewed, Postprint (published version)

This book brings together a series of theory and practice essays on risk management and adaptation in urban contexts within a resilient and multidimensional perspective. The book proposes a transversal approach with regard to the role of spatial planning in promoting and fostering risk management as well as institutions’ challenges for governing risk, particularly in relation to new forms of multi-level governance that may include stakeholders and citizen engagement. The different contributions focus on approaches, policies, and practices able to contrast risks in urban systems generating social inclusion, equity and participation through bottom-up governance forms and co-evolution principles. Case studies focus on lessons learned, as well as the potential and means for their replication and upscaling, also through capacity building and knowledge transfer. Among many other topics, the book explores difficulties encountered in, and creative solutions found, community and local experiences and capacities, organizational processes and integrative institutional, technical approaches to risk issue in cities., Thanks to University of Veracruz, Barcelona Supercomputing Center, CONACYT and PRODEP. This research has been partially funded by the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government and by the European Regional Development Fund (FEDER) of the European Union (UE) through projects referenced as: CGL2011-23621 and CGL2015-65913 -P (MINECO /FEDER, UE)., Peer Reviewed, Postprint (author's final draft)

The final publication is available at Springer via http://dx.doi.org/10.1007/s10346-018-1087-9, Rockfalls are ubiquitous diffuse hazard in mountain regions, cliffs, and cutslopes, with the potential of causing victims and severely damaging buildings and infrastructures. A vast majority of detached rock masses break up when impacting the ground, generating multiple trajectories of rock fragments. In this paper, we present the quantitative risk analysis (QRA) of fragmental rockfalls. Fragmentation in rockfalls requires the redefinition of the probability of reach and the evaluation of the effect of multiple rock blocks trajectories on the exposure. An example of QRA was carried out at the Monasterio de Piedra, Spain, using RockGIS, a rockfall propagation model that takes fragmentation into account (Matas et al. Landslides 14:1565–1578, 2017). The results show that fragmentation has a significant but contrasting effect in the calculation of risk. The risk is reduced if the slope where blocks propagate is sufficiently long and gentle. The reason for this is that, compared to the unfragmented rock masses, the new fragments generated travel shorter distances with lesser kinetic energy. The effect disappears in case of large rockfalls. Conversely, the risk increases if the rock fragments propagate over steep slopes. The reason is that few blocks stop along the way while the generation of a cone of fragments increases the exposure. Our simulations also show that assuming a continuous flow of visitors or segregating the flow in groups of different number of people has only a minor influence on the results. Finally, we observed that the capability of the protection barriers to stop rockfalls of up to a few tens of cubic meters increases with fragmentation., Peer Reviewed, Postprint (author's final draft)

The analysis of seismic signals obtained from near-source triaxial accelerometer recordings of two sets of single-block rockfall experiments is presented. The tests were carried out under controlled conditions in two quarries in northeastern Spain; in the first test (Foj limestone quarry, Barcelona), 30 blocks were released with masses ranging between 475 and 11,480 kg. The second test (Ponderosa andesite quarry, Tarragona) consisted of the release of 44 blocks with masses from 466 to 13,581 kg. An accelerometer and three high-speed video cameras were deployed, so that the trajectories, velocities, and block fragmentation could be tracked precisely. These data were used to explore the relationship between seismic energy and rockfall kinetics (the latter obtained from video analysis). We determined absolute and relative values of seismic energy and used them to estimate rockfall volumes. Finally, the seismic signature of block fragmentation was assessed in both the frequency and time domains. The ratios of seismic energy after impact to kinetic energy before impact ranged between 10-7 and 10-4. These variables were weakly correlated. The use of seismic energy relative to impacting kinetic energy was preferred for the estimation of volumes. Block fragmentation impacts were dominated by higher acceleration spectrum centroid frequencies than those of nonfragmentation impacts: 56.62 ± 2.88 and 48.46 ± 4.39 Hz at Foj and 52.84 ± 12.73 and 38.14 ± 4.73 Hz at Ponderosa., Peer Reviewed, Postprint (published version)

Landslides are one of the most common and dangerous threats in the world that generate considerable damage and economic losses. An efficient landslide monitoring tool is the Differential Synthetic Aperture Radar Interferometry (DInSAR) or Persistent Scatter Interferometry (PSI). However, landslides are usually located in mountainous areas and the area of interest can be partially or even heavily vegetated. The inherent temporal decorrelation that dramatically reduces the number of Persistent Scatters (PSs) of the scene limits in practice the application of this technique. Thus, it is crucial to be able to detect as much PSs as possible that can be usually embedded in decorrelated areas. High resolution imagery combined with efficient pixel selection methods can make possible the application of DInSAR techniques in landslide monitoring. In this paper, different strategies to identify PS Candidates (PSCs) have been employed together with 32 super high-spatial resolution (SHR) TerraSAR-X (TSX) images, staring-spotlight mode, to monitor the Canillo landslide (Andorra). The results show that advanced PSI strategies (i.e., the temporal sub-look coherence (TSC) and temporal phase coherence (TPC) methods) are able to obtain much more valid PSs than the classical amplitude dispersion (DA) method. In addition, the TPC method presents the best performance among all three full-resolution strategies employed. The SHR TSX data allows for obtaining much higher densities of PSs compared with a lower-spatial resolution SAR data set (Sentinel-1A in this study). Thanks to the huge amount of valid PSs obtained by the TPC method with SHR TSX images, the complexity of the structure of the Canillo landslide has been highlighted and three different slide units have been identified. The results of this study indicate that the TPC approach together with SHR SAR images can be a powerful tool to characterize displacement rates and extension of complex landslides in challenging areas, Peer Reviewed, Postprint (published version)

This article presents a holistic and comprehensive approach for seismic risk assessment which involves the evaluation of the social fragility and the lack of resilience of the study area. That means, involves the characteristics of the social context that can exacerbated the situation when a hazardous event occurs. The proposed methodology allows a standardized assessment of the social fragility and lack of resilience, by means of an aggravation coefficient of which summarizes the characteristics of the social context using fuzzy sets and analytic hierarchy process. The selection of 20 social indicators is based on the indicators used by urban observatories of United Nations and other social researchers. These indicators are classified in six categories according to social item they describe: i) Dwelling, ii) Social development and poverty eradication, iii) Urban Planning, iv) Governance, v) Lack of resilience and vi) Demography. Applying the determination level analysis, thirteen prevailing social indicators are selected. The proposed methodology was applied to the city of Mérida (Venezuela). The average value of seismic physical risk was low and high for intensities VIII and IX respectively. However, parishes present results with important differences among them. The average value of the aggravation coefficient is medium. The average total seismic risk is moderate and very high for intensity VIII and IX respectively. According to the obtained results, the social context substantially aggravates the seismic physical risk in 5 of the 11 city parishes. Seven of them have a very high level of total seismic risk., Postprint (published version)