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The significant number of seismic ground motion records to be considered when designing or assessing civil structures is a common restriction for employing advanced nonlinear dynamic methods. This is because the large computational time involved in the calculation of the nonlinear dynamic response of complex multi-degree-of-freedom systems. There are several strategies to overcome this limitation; however, the reliability estimation of the analyzed systems can be compromised. This research is focused on developing a methodology to achieve a probabilistic and reliable estimation of the seismic response of buildings by tackling the computational effort. To do so, a set of transfer functions extracted from the dynamic response of three building models have been obtained. Then, an optimal transfer function per building is identified as the one maximizing the prediction of engineering demand parameters (EDPs), when each structure is subjected to a large set of ground motions records. Results show that the response of a reduced number of records allows developing an enhanced strategy to obtain reliable results in terms of the main statistical moments of the EDPs. This increased capacity to analyze complex systems in an affordable time has important consequences in the identification of optimal designs in terms of the material-performance ratio, as well as in the estimation of expected seismic risk., We thank the companies "MUISCA Construcciones" and "Constructora Triple A", as well as the engineer Mario A. Silva and the architects Augusto Acuña and Carlos García, for having allowed the use of the monitoring results of the studied buildings. 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., Peer Reviewed, Postprint (published version)

Traumatic brain injuries (TBI) resulting from head impacts are a major public health concern, which prompted our research to investigate the complex relationship between the material properties of brain tissue and the severity of TBI. The goal of this research is to investigate how variations in brain and skull density influence the vulnerability of brain tissue to traumatic injury, thereby enhancing our understanding of injury mechanism. To achieve this goal, we employed a well-validated finite element head model (FEHM). The current investigation was divided into two phases: in the first one, three distinct brain viscoelastic materials that had been utilized in prior studies were analyzed. The review of the properties of these three materials has been meticulous, encompassing both the spectrum of mechanical properties and the behaviors that are relevant to the way in which brain tissue reacts to traumatic loading conditions. In the second phase, the material properties of both the brain and skull tissue, alongside the impact conditions, were held constant. After this step, the focus was directed towards the variation of density in the brain and skull, which was consistent with the results obtained from previous experimental investigations, in order to determine the precise impact of these variations in density. This approach allowed a more profound comprehension of the impacts that density had on the simulation results. In the first phase, Material No. 2 exhibited the highest maximum first principal strain value in the frontal region (emax=15.41% ), indicating lower stiffness to instantaneous deformation. This characteristic suggests that Material No. 2 may deform more extensively upon impact, potentially increasing the risk of injury due to its viscoelastic behavior. In contrast, Material No. 1, with a lower maximum first principal strain in the frontal region (emax=7.87%), displayed greater stiffness to instantaneous deformation, potentially reducing the risk of, Peer Reviewed, Postprint (published version)

Exploring the stochastic intricacies of bone microstructure is a promising way to make progress on the practical issue of bone fracture. This study investigates the fracture of human complete ribs subjected to bending and using acoustic emission (AE) for microfailure detection. As the strain increases, the number of AE signals per unit of time rises until, beyond a certain threshold, an avalanche of signals occurs, indicating the aggregation of numerous microfailures into a macroscopic fracture. Since microfailures appear randomly throughout the bending test, and given the lack of a deterministic law and the random nature of microfailures during the bending test, we opted to develop a stochastic model to account for their occurrence within the irregular and random microstructure of the cortical bone. Notable discoveries encompass the significant correlation between adjusted parameters of the stochastic model and the total number of microfailures with anthropometric variables such as age and body mass index (BMI). The progression of microfailures with strain is significantly more pronounced with age and BMI, as measured by the rate of bone deterioration. In addition, the rate of microfailures is significantly impacted by BMI alone. It is also observed that the average energy of the identified AE events adheres to a precisely defined Pareto distribution for every specimen, with the principal exponent exhibiting a significant correlation with anthropometric variables. From a mathematical standpoint, the model can be described as a double Cox stochastic and explosive (coxplosive process) model. This further provides insight into the reason why the ribs of older individuals are considerably less resilient than those of younger individuals, breaking under a considerably lower maximum strain., Peer Reviewed, Postprint (published version)

The paper presents an iterative procedure for the time domain deconvolution in nonlinear elastoplastic materials. The approach is intended for the generation of input motions for dynamic soil–structure interaction (DSSI) numerical analyses when the desired earthquake is specified at the surface of a nonlinear soil deposit. The main advantage is that the same constitutive model (or models) to be used in the DSSI simulation to characterise the soil deposit is also employed in the deconvolution procedure. Therefore, the desired surface motion is recovered from the free-field propagation of the resulting input motion at the base of the numerical model, accounting for the assumed constitutive behaviour of the ground. An application example is also presented, where the potential of the proposed approach is shown., Peer Reviewed, Postprint (published version)

In this paper, the correlation between different seismic intensity measures (IM) and engineering demand parameters (EDP) of reinforced concrete (RC) buildings was evaluated by means of nonlinear dynamic analyses (NLDA). The Costa Rican ground motion database and four RC buildings (4-, 6-, 8- and 10-stories) were considered in this research. Estimations of conventional IMs were derived directly from the ground motion records as well as from the response of a single degree of freedom (SDOF) linear oscillator, with a period equal to that of the fundamental period of the buildings. NLDAs were performed using unscaled and scaled records to account for different intensity levels, and the performance of the buildings was characterized in terms of three EDPs: the average inter-story drift ratio, the maximum inter-story drift ratio, and the Park & Ang damage index. Results demonstrate a significant improvement in the correlation between IMs and EDPs when the dynamic characteristics of the structure are accounted for through the response of the SDOF oscillator. On the other hand, the peak ground velocity turned out to be an effective IM, independent of the dynamic characteristics of the buildings. This is very useful when assessing potential seismic damage both for immediate decision-making and for the characterization of the seismic hazard of a region., Peer Reviewed, Postprint (published version)

At certain depths, the elastic properties of the ground are not affected by seismic waves. However, as they reach the surface, the soil density decreases and so does its elastic limit. This means that the expected ground motion acting at the foundation of a structure cannot be adequately described without considering the inelastic response of the soil near the surface. Therefore, one of the key elements in characterizing the seismic response of civil structures is the site effect. These depend mainly on the parameters of the soil beneath the structure and the features of the ground motion acting at the depth, where non-linear effects are negligible. Therefore, the main objective of this paper is to find an intensity measure that incorporates the information provided by the soil profile under the structure and the ground motion acting at the bedrock level. Due to the random nature of both elements, a probabilistic framework using Monte Carlo simulation has been developed to analyze this problem. For this purpose, random soil profiles have been generated to obtain a representative sample of likely scenarios of the study area. A large database of Colombian ground motion records has been used to model the seismic hazard. Finally, power functions capable of relating the input variables to the dynamic response of a large set of reinforced concrete structures have been derived by considering multi-regression analysis. It has been observed that, in several cases, intensity measures extracted from the displacement spectrum appear in the mathematical arrangements. These functions could be used to improve the efficiency of seismic risk prediction at the urban level., This research has been funded by the Spanish Research Agency (AEI) of the Spanish Ministry of Science and Innovation (MICIN) through the projects with references: PID2020-117374RB-I00/AEI/10.13039/501100011033 and TED 2021-132559B-I00—J-02970., Peer Reviewed, Postprint (published version)

The use of the Material Extrusion technique with Thermoplastic Elastomers is currently growing because of the large number of benefits of this family of materials. They are processable materials with high flexibility, which makes them very useful, for example, in biomedical applications that require flexible objects with complex geometries. This study aims to characterize a specific polymer, namely polyether-block-amide-based polymer (PEBA), by analyzing its anisotropic behavior in printed samples and investigating the mechanical properties based on different printing orientations. Three orientations (X, Y, and Z) were used to relate the printing orientation to the type of bonds formed in the samples: intra-layer bonds, inter-layer bonds, and the deposited filament. Tensile tests following ASTM D638 were conducted to measure sample rigidity, while Acoustic Emission, an advanced Non-Destructive Technique, was employed to examine the trend of the failure process. The presence of voids was also observed to assess printing quality, which is influenced by the printing orientation and alters the quality of bonds. The results revealed that samples printed horizontally exhibited higher Young’s Modulus values and fewer voids in the inner parts. Vertically printed samples displayed inferior mechanical properties and a greater number of voids. Consequently, the intra-layer yielded better bond formation and minimized voids. Acoustic Emission analysis corroborated these findings by demonstrating distinct energy distribution patterns among the different printing orientations. Hits were concentrated at maximum stresses, primarily observed in the vertically printed samples, which experienced macroscopic failure. Furthermore, this particular specimen exhibited a vertical asymptote near the maximum stress level. The analysis of the energy of Acoustic Emission hits demonstrated a reasonably good fit with the Gutenberg-Richter (GBR) law based on the printing direction., The first author gratefully acknowledges the Universitat Politècnica de Catalunya for the financial support- of her predoctoral grant FPU-UPC, with the collaboration of Banco de Santander. The second author acknowledges the Ministerio de Universidades of Spain for her Margarita Salas Grant., Peer Reviewed, Postprint (published version)

The objective of this study was to quantitatively investigate the relationship between cerebral atrophy and the risk of injury in elderly individuals. To achieve this, a sophisticated computational biomechanics approach utilizing finite element analysis was employed to simulate the mechanical behavior of the brain and skull under various conditions. In addition, particular emphasis was placed on understanding the role of cerebral bridging veins (BVs) and their mechanical properties at different ages in the occurrence of head injuries. Head models representing healthy brains and five atrophy models were developed based on imaging data. After validation, the models underwent the identical impact loading conditions to enable the simulation of brain damage. The resulting outcomes of the models with brain atrophy were then compared to the results obtained from the healthy model, allowing for a comparative analysis. Simulations showed increased relative displacement with worsening brain atrophy, particularly in the frontal and occipital regions. Compared to the healthy brain model, relative displacement increased by 2.36 %–9.21 % in the atrophy models, indicating an elevated risk of injury. In severe brain atrophy (FEM 6), the strain reached 83.59 % in local model simulations, leading to damage and rupture of cerebral BVs in both young and elderly individuals. Mechanical tests on cerebral BVs demonstrated a negative correlation between age and ultimate force, stress, and strain, suggesting increased susceptibility to damage with age. An observed sharp decline of approximately 50 % in ultimate stress and 35 % in ultimate strain was noted as age increased. We implemented a 50 % reduction in the intensity of head impact forces; nevertheless, vascular damage continues to manifest in the elderly population. To establish a truly safe zone, it is imperative to further decrease the intensity of the impact. This investigation represents a significant step forward in our understand, Peer Reviewed, Postprint (author's final draft)

This research studies the dynamic behavior of human cortical bone specimens and investigates their mechanical properties using uniaxial tensile tests. The main experimental finding is that in the range of strain rate analyzed, there is a significant decrease in Young's modulus, which is not of viscoelastic origin. In fact, the observed behavior seems related to the findings of other researchers who observed that the microcraking damage depends on the strain rate in the same sense found in our work. This allows us to interpret the qualitative results as a consequence of the microcracking that takes place within the cortical bone, and not related to viscoelastic effects. A full and objective strain rate dependent model is proposed to explain the observed data. In addition, a general discussion of some families of viscoelastic models is given and the caution with which they should be used when dealing with complex materials such as bone., Postprint (author's final draft)

Numerous prior studies hypothesized a power-law relationship () between cortical bone Young's modulus (E) and density (¿) with an exponent , that has not been previously justified in the literature on a theoretical level. Moreover, despite the fact microstructure have been extensively studied, the material correlate of Fractal Dimension (FD) as a descriptor of bone microstructure was not clear in previous studies., Peer Reviewed, Postprint (author's final draft)

The aim of this article is to provide a scientific and statistical basis to identify the murder weapon in stabbing cases from the geometric characteristics of the stab-marks left on human ribs. For this purpose, a quantitative predictive model is developed, based on geometric measurements of the stab-mark and its location along the rib. A general method based on Bayesian inference and probabilities is used for the model development, rather than a deterministic model given its inability in certain occasions to identify the murder weapon. Following the process explained in this article to collect the stab-mark information required, the complete probabilistic model exposed attained a high accuracy in the identification of the murder weapon between two macroscopically identical blades with a microscopic alteration in one of them (more than 90% of correct identification is achieved)., Peer Reviewed, Postprint (author's final draft)

Soil site studies are crucial in the analysis of seismic hazard in populated areas. This study focusses on the use of the Ground Penetrating Radar as a non-destructive geophysical method to analysis the water content of a sedimentary basin of a local urban area in Cervantes Parks in Barcelona city. Main objective of this work is to understand further the local seismic soil site, and analysis the background clutter amplitude and frequency of the GPR signal applied on the seasonal changes of the underground water content. Changes produces in the GPR signal could be associated to the changes of the ground material due to the existence of water content and water flow, which influence the grain size distribution of the soil characterisation. Previously, several methodologies have been applied to determine the changes of the ground material due to the existence of water content and most importantly effect of the seasonal changes on the soil characterisation. GPR has been applied as a new technology and non-invasive to further analysis water content in shallow geology. Methodology applied on this study compromised in four different phases; Two seasonal data collection using 100 MHz centre frequency shielded antenna in both dry and wet season, radar images are proceeded with common post-processing approaches, following more innovative processing approach based on the Fast Fourier Transform (FFT) method in order to analysis background clutter amplitude and frequency spectrum to achieve an accurate interpretation of underground water content activities, in conclusion a comparative study of the results driven from radar images are elaborated considering historical knowledge. Results show that GPR is an efficient technique to analysis water content invasively considering low frequency antennas to achieve deeper penetration depth in sedimentary deposits, and predict shifting and increasing of the underground streams due to changes in weather conditions. Results could contribute, Peer Reviewed, Postprint (author's final draft)

Una matriz tipológica de edificios (BTM, Building Typology Matrix) agrupa, en un conjunto de clases de edificios predefinidos, los edificios con sistemas estructurales y características de comportamiento similares, siendo un aspecto muy importante en los métodos de evaluación de la vulnerabilidad y el daño sísmico esperado. A partir de dicha matriz se pueden desarrollar modelos de predicción de daños y pérdidas para los tipos de edificios modelo que representan las características promedio de la población total de edificios dentro de cada clase. El objetivo de este trabajo es definir la BTM de la zona transfronteriza entre Francia, Andorra y España del proyecto “POr una Cultura común del RIesgo Sísmico” (EFA158/16/POCRISC). En base a la opinión de expertos y a las BTM de proyectos anteriores (Risk-UE, ISARD y SISPyr), se han definido 30 tipologías, proporcionando su descripción, código (según la nomenclatura Risk-UE), rango de alturas, rango de índices de vulnerabilidad y su correspondencia con: las tipologías definidas en Risk-UE y las clases de vulnerabilidad de las escalas EMS-98 y MSK. Esta información es de gran utilidad para la evaluación de la vulnerabilidad y predicción de daños en la zona POCRISC., Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Postprint (published version)

En esta comunicación se resume una guía para la evaluación de la vulnerabilidad sísmica de edificios esenciales, elaborada en el marco del proyecto EFA158/16/POCRISC. La guía incluye los antecedentes, los métodos de primer nivel (LM1), el método de segundo nivel (LM2), y el método de nivel avanzado (LMa), que se basa en el análisis dinámico. En el LM1, la acción se define por la intensidad macrosísmica y el edificio mediante índices de vulnerabilidad. En el LM2, la acción se define por el espectro de respuesta y el edificio por su espectro de capacidad y, en el LMa, la acción se define mediante acelerogramas y el edificio mediante modelos estructurales. Para un escenario específico los métodos permiten conocer las probabilidades de que se excedan determinados niveles o estados de daño en función de la severidad de la acción. La guía también aborda aspectos relacionados con la vulnerabilidad funcional y con la fragilidad social, cultural y económica., Postprint (published version)

Structural damage detection is an important issue in conservation. In this research, principal component analysis (PCA) has been applied to the temporal variation of modal frequencies obtained from a dynamic test of a scaled steel structure subjected to different damages and different temperatures. PCA has been applied in order to reduce, as much as possible, the number of variables involved in the problem of structural damage detection. The aim of the PCA study is to determine the minimum number of principal components necessary to explain all the modal frequency variation. Three estimators have been studied: T2 (the square of the vector norm of the projection in the principal component plan), Q (the square of the norm of the residual vector), and the variance explained. In the study, the results related to the undamaged structure needed one principal component to explain the modal frequency variation. However, the high damage configurations need five principal components to explain the modal frequency. The T2 and Q estimators have been arranged in order of increasing damage for all the performed experimental tests. The results indicate that these estimators could be useful to detect damage and to distinguish among a range of intensities of structural damage., 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., Peer Reviewed, 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)

Cultural heritage buildings are prone to failures when subjected to seismic events, and recent earthquakes worldwide resulted in many losses of these buildings. Therefore, there is a need for methodologies for assessing their seismic safety that should be based on enough knowledge of the building. Here, dynamic investigation by dynamic identification testing and dynamic monitoring increase significantly the level of knowledge about the assessed building. The dynamic identification tests give global information about the dynamic properties like natural frequencies that are useful in calibrating and updating a numerical model of the building that could be used in the seismic safety evaluation. Dynamic monitoring gives the dynamic properties’ evolution in time and may be used as an early warning tool able to send alarms when meaningful changes in dynamic properties are observed. This chapter gives some considerations on the different investigation activities of dynamic identification, dynamic monitoring, numerical model updating, and seismic safety assessment of cultural heritage buildings. As an application, the case study of the historic Mallorca cathedral is discussed., This study has been carried out within the context of the project “New Integrated Knowledge-based Approaches to the Protection of Cultural Heritage from Earthquake-Induced Risk-NIKER” sponsored by the European Commission (Grant Agreement No. 244123), which is gratefully acknowledged., Peer Reviewed, Postprint (published version)

A five-story reinforced concrete building severely damaged during the Mw 5.1, May 11th 2011, Lorca earthquake (Murcia, Spain), has been monitored with an interferometric radar and has been numerically modelled with the aim to study the evolution of the structural damage. An initial non-damaged and a final damaged configuration of the building after the earthquake have been modelled first. Radar measurements helped to calibrate the models. Four intermediate models, with damage configurations representing four steps of cumulative damage of the building facing the earthquake, have been built based on the information related to the building seismic damage included in a technical report. The objectives were to obtain calibrated numerical models, to perform a modal analysis, to calculate the capacity curve, and to study the evolution of the natural periods and the strength capacity of the building within each damage configuration representing the incremental damage process. Results show that a growth of 20% in the values of natural periods and reductions of 50% in the capacity lead the building over the severe damage state threshold. The interferometric radar is a suitable remote sensing technique to identify, in a rapid screening, the natural periods of mid and tall damaged buildings., 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). Esteban Cabrera, sponsored by the University of Azuay (UDA), obtained a scholarship from the Ministry of Higher Education, Science and Technology, SENESCYT, Government of Ecuador, for doctoral studies in the Earthquake Engineering program at UPC-Barcelona-Tech. Yeudy F. Vargas-Alzate has been granted an Individual Fellowship (IF) in the research grants program of the Marie Sklodowska-Curie Actions (MSCA) of the European Union/European (H2020-MSCA-IF-2017) No 799553., Postprint (published version)

According to the Sendai Framework for Disaster Risk Reduction (2015–2030), disasters have demonstrated that the recovery, rehabilitation and reconstruction phase, which needs to be prepared ahead of a disaster, is a critical opportunity to “Build Back Better”, integrating disaster risk reduction into development measures. In this respect, a significant number of structures, that constitute several European urban nuclei, belong to old constructive typologies, which were designed and built without any consideration for the seismic hazard. One of the most used typologies exhibiting this shortcoming is unreinforced masonry (URM). Therefore, an important step towards increasing resilience of European cities is to deeply understand the seismic behavior of this frequent typology. In order to do so properly, detailed probabilistic nonlinear building models should be developed. However, including the uncertainties associated with this typology is challenging due to the heterogeneity of the different manufacturing techniques, executed under primitive industrial standards, and to the construction techniques, which are dependent on regional uses and criteria in a pre-code scenario. The object of this research is twofold. First, a detailed quantification of the uncertainties related to the mechanical properties of this construction material is conducted. Then, the influence of this variability on the seismic performance of a representative building model of the Eixample district in Barcelona, Spain, is analysed. This building typology represents 72% of the building stock in this district with an average age of 90 years, which means that the construction practice, at that time, was only regulated by early council guidelines that are considered pre-code rules. Specifically, the probabilistic approach is illustrated with a case study performed on an existing seven-story (high-rise) URM. A detailed numerical model of this structure has been developed and randomized taking into accou, Peer Reviewed, Postprint (published version)

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Architectural Heritage on 2020, available online at: http://www.tandfonline.com/10.1080/15583058.2020.1831101., Detection of structural damage is an important issue. Some techniques require knowledge of the undamaged state or in-depth knowledge of the construction materials used. The application of principal component analysis to the temporal variation in natural frequencies is a promising technique. With an undamaged structure a single principal component will suffice to explain the change in modal frequencies with weather variables, whereas more components are needed in the case of damaged structures. Like all other detection techniques, it has advantages and drawbacks. The main advantages are the ability to work without knowledge of the previous state of the structure, the relatively short monitoring time required (about 10 days), low cost, and low number of instrumentations. The main drawback is the need for more studies to correlate degree of damage with the number of principal components. This paper presents the results obtained for six structures: Mallorca Cathedral, four university buildings in Barcelona, and a reduced model structure in a laboratory. We also propose a semiautomatic algorithm to track modal frequencies over time and add a discussion of operational modal analysis in real buildings., This research was partially funded by the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government and by the European Regional Development Fund of the European Union through the project referenced as CGL2015-65913-P (MINECO/FEDER, UE). We also want to acknowledge the management and maintenance services of the UPC schools of Industrial Engineering (ETSEIB) and Architecture (ETSAB) for their readiness and help, and the Department of Quantum Physics and Astrophysics of the University of Barcelona for the meteorological data., Peer Reviewed, Postprint (author's final draft)

Moisture is one of the main causes of degradation of heritage buildings. Early detection of zones affected by moisture is crucial information for preservation and maintenance of those structures. Ground-penetrating radar (GPR) is an effective survey method to assess damage in civil engineering and structures. Several methodologies involving this technique have been applied to determine the extension of damping in concrete, stone, and brick structures. This article summarizes the different signal analysis techniques generally used to detect moisture from GPR data. Four different case studies are included, covering different types of buildings. The case studies include the description of the problem, the results, the methodology (data acquisition, survey parameters, and processing), and the limits and advantages. Comparing the different studies, the limitations and advantages are associated with each type of problem and a final discussion describes other non-destructive testing techniques, numerical simulations and methodologies that could provide more reliable understanding when combined with GPR data., Peer Reviewed, Postprint (published version)

The statistical relationship between parameters that represent the intensity of ground motions induced by earthquakes (Intensity Measures, IM) and the nonlinear response of buildings (Engineering Demand Parameters, EDP) has been analyzed In this paper. To do so, the time-history response of a set of probabilistic 3D models, which simulate the dynamic behavior of Reinforced Concrete buildings, has been calculated via Non-Linear Dynamic Analysis. In this way, clouds of IM-EDP points are obtained and used to quantify efficiency and sufficiency. It has been observed that spectral velocity- and energy-based IMs are excellent proxies for EDPs; at least for those related to the deformation field of the structure. Finally, according to the epicenter location and azimuthal orientation of the models, subsets of results have been classified and statistically analyzed. The objective has been to present new evidence on the dependency between seismic fragility and the incidence angle of the incoming waves., Yeudy F. Vargas-Alzate has been granted an Individual Fellowship in the research grant program of the Marie Sklodowska-Curie Actions, European Union/European (H2020-MSCA-IF-2017) No 799553. This author is deeply grateful to this institution. This research has also been partially funded by the European Regional development Fund (ERDF) and the Spanish Government (Ministry of Science and Innovation) through the research projects EFA158/16/POCRISC and PID2020117374RB-I00 /AEI/10.13039/501100011033., Postprint (published version)

The research conducted in this work focuses on the uncertainties related to the mechanical properties of the construction material of interest (i.e., unreinforced masonry -URM), and the influence of their variability on the seismic performance of a representative seven-story URM building of the Eixample district in Barcelona, Spain. The selected building typology represents 72 % of the building stock in this district, with a mean age of 90 years and the use of early council guidelines that are considered as pre-code rules. The results are presented in terms of correlations between damage parameters and material properties. A numerical model of the building was developed and, considering the variability of the material properties, a sample of 1000 numerical models has been used as a benchmark. The seismic response of each variant of the building’s numerical model is obtained through a simplified non-linear static procedure aiming to compare and categorize the influence of each of the selected mechanical properties on the seismic performance of the building. The analysis carried out shows that the variability in the material properties generates important uncertainties in the seismic response of these URM buildings, leading to over or underestimate the damage when performing the analysis for specific buildings and without a probabilistic approach., 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)

Several methodologies for assessing seismic risk extract information from the statistical relationship between the intensity of ground motions and the structural response. The first group is represented by intensity measures (IMs) whilst the latter by engineering demand parameters (EDPs). The higher the correlation between them, the lesser the uncertainty in estimating seismic damage in structures. In general, IMs are composed by either a single (scalar-based IMs) or a group of features of both the ground motion and the structure (vector-valued IMs); the latter category provides higher efficiency to explain EDPs when compared to the first one. This paper explores how to find new vector-valued IMs, which are highly correlated with EDPs, by means of multi-regression analysis. To do so, probabilistic nonlinear dynamic analyses have been performed by considering a seven-story reinforced concrete building as a testbed. At a first stage, 30 scalar-based IMs have been correlated with 4 EDPs (i.e., 120 groups of IM-EDP pairs have been studied). Afterwards, the structural responses have been classified as elastic, inelastic and a combination of both. It has been analyzed how efficiency behaves when making these classifications. Then, 435 vector-valued IMs have been created to enhance the predictability of the scalar EDPs (i.e., 1740 groups of IM-EDP pairs have been analyzed). Again, the most efficient IMs have been identified. Sufficiency, which is another statistical property desired in IMs, has also been examined. Results show that the efficiency and sufficiency to predict the structural response increase when considering vector-valued IMs. This sophistication has important consequences in terms of design or assessment of civil structures., This research has been partially funded by the European Regional Development Fund (ERDF) of the European Union (EU), through project with reference EFA158/16/POCRISC (INTERREG/POCTEFA. EU) and 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. The support of these institutions is highly recognized and acknowledged. Yeudy F. Vargas-Alzate has been granted an Individual Fellowship (IF) in the research grant program of the Marie Sklodowska-Curie Actions (MSCA), European Union/European (H2020-MSCA-IF-2017) No 799553. This author is deeply grateful to this institution., Peer Reviewed, Postprint (published version)

A long and complete series of monthly rainfall amounts corresponding to Barcelona city (Catalonia, NE Spain), exceeding two centuries (years 1786–2019), is analysed in detail. The obtained results of periodicity (annual scale), time trends (monthly, seasonal and annual scales), statistical distribution (seasonal and annual scale) and fractal/multifractal structures and self-similarity at monthly scale depict the complex structure of this pluviometric regime, which is characterized by moderate increasing and decreasing trends on rain amounts, varying from +0.08¿mm·year-1 (February) to -0.07¿mm·year-1 (September) and quite evident changes on the pluviometric trends at annual and seasonal scales when the rainfall data are analysed for segments of 50¿years from 1800 up to 2019. A good example could be the relevant change on the annual scale time trend, from +0.77¿mm·year-1 (years 1800–1850) to -0.17¿mm·year-1 (years 1950–2019). Clear evidences of decreasing pluviometry for spring, summer and autumn for the last segment (1950–2019) in comparison with the other three segments, including years 1800–1950, are also detected. Additionally, increasing rainfall patterns complexity, expected difficulties on monthly rainfall forecasting and the increasing irregularity of monthly amounts is also detected by interpreting fractal and multifractal results. Irregularity increases on the monthly rainfall series and on the rainfall regime complexity derived from multifractal parameters, could be associated with the very notable increase of CO2 emissions into the atmosphere, globally varying from 51.1¿×¿106 metric tonnes (year 1820) to 36.6¿×¿109 metric tonnes (year 2019) and the tropospheric concentration increasing from 280.8 ppm (year 1850) to 397.5 ppm (year 2014), being the probable relationship between tropospheric concentrations and changes on rainfall patterns the objective of future researches., 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

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

Advantages offered by a pluviometric network in Catalonia (NE Spain) have permitted a detailed analysis of the two primary results derived from the autoregressive ARIMA process applied to monthly rainfall amounts. The first was the spatial distribution of the necessary number of previous monthly amounts needed to predict the next amount. The second was the spatial distribution of discrepancies between the real recorded amount and those derived from the autoregressive process. The heterogeneous spatial distribution of both parameters of the ARIMA process is in accordance with the complex spatial distribution of the monthly rainfall regime in Catalonia and fractal/multifractal analyses of several monthly rainfall time series. The statistical distribution of monthly discrepancies also permits a prediction of the probable evolution at monthly scale of drought episodes in terms of length and accumulated rainfall deficit. The results of the ARIMA algorithm are characterised by a few cases of raingauges with remarkable differences (10-20¿mm/month) between real and autoregressive amounts, a predominant number of emplacements lowering 10¿mm/month and a not negligible number of cases with discrepancies lower than 5¿mm/month. In terms of percentages with respect to average monthly amounts, most of discrepancies do not exceed 15%, and only in a very few cases they are within the 20-40% range. It is also worth mentioning that the discrepancies between real and predicted drought lengths use to be no longer than one month. Results corresponding to monthly series recorded at two Earth Sciences observatories are described with more detail to illustrate the advantages offered by the ARIMA autoregressive process in the prediction of beginning, continuity and end of drought episodes., Postprint (author's final draft)

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Earthquake Engineering on 2019, available online at: http://www.tandfonline.com/10.1080/13632469.2019.1597783, Recent research have proven the importance of considering the directionality effect on the expected seismic damage of structures. However, it demands a high computational effort if the nonlinear dynamic analysis (NLDA) is used to estimate the seismic response. This paper presents a simplified approach to obtain peak response parameters for a building subjected to bi-directional ground motions considering the directionality effect. To do so, the maximum and median response spectra, considering all the non-redundant response spectra, of several ground motion pairs are calculated. Afterwards, a spectral matching technique is applied to these spectra and new acceleration components are obtained. A series of NLDA are performed with these new components and the roof displacement and base shear values are calculated. These results are compared with the maximum and median values, calculated by performing a series of NLDA, after rotating the earthquakes records by considering increments of 1° in the interval 0°–180°. The results agree with both approaches validating the efficiency of the simplified proposed approach., This research was partially funded by the Spanish Government’s Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Fund (ERDF) of the European Union (EU) through the project referenced as CGL2015-65913-P (MINECO/ERDF, EU). The first author is supported by a Ph.D. scholarship grant from the Institute for the Training and Development of Human Resources (IFARHU) and the Government of Panama’s National Secretariat of Science, Technology, and Innovation (SENACYT)., Peer Reviewed, Postprint (author's final draft)

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

The estimation of the Earth's surface temperature (LST) from the infrared thermal radiation (TIR) emitted by the Earth detected by means of remote sensing has allowed a giant leap in climate analysis. The specialized literature has highlighted the singular importance of the LST in the generation of the Urban Heat Island (UHI), especially at night. It is during the night that the effects of UHI become more apparent, due to the low cooling capacity of urban construction materials and is during night-time that temperatures can cause higher health risks, leading to the aggravation of negative impacts on people’s health and comfort in extreme events such as heat waves becoming more and more frequent and lasting longer. However, the study of nocturnal UHIs is still poorly developed, due to the structural problems. On the one hand, the scarcity of meteorological stations that allow obtaining the air temperature (Ta) with an adequate degree of spatial resolution. And, on the other, due to the limited temporal availability of medium / high resolution nocturnal satellite images that make it possible to know the LST at night. Traditional methods for obtaining nocturnal UHI have been directed either to extrapolation of data from weather stations, or obtaining Ta through urban transects. In the first case, the lack of weather stations in urban landscapes makes it extremely difficult to obtain data to extrapolate and propose models at a detailed resolution scale. In the second case, there is a manifest difficulty in obtaining data simultaneously and significantly representative of urban and rural zones. Remote sensing images are another methodology used to measure night-time UHI, but the greatest limitation of this method is the scarcity of high-resolution images that allow rigorous night-time LST to be obtained. Only MODIS, or Sentinel 3, offer free mid-resolution night-time thermal imaging for LST and UHI analysis. Furthermore, the integration of LST (obtained from remote sensi, Peer Reviewed, Postprint (author's final draft)

The pluviometric regime in the Western Mediterranean and concretely in Catalonia (NE Spain) is characterised by irregular amounts at monthly and annual scales, sometimes with copious short episodes causing foods and, conversely, sometimes with long dry spells exceeding 1 month length, depending on the chosen threshold level to defne the dry episode. Taking advantage of a dense network of rain gauges, most of them with records length of 50–60 years and some others exceeding 85 years, the evolution of these monthly and annual amounts is quantifed by means of their time trends, statistical signif- cance and several irregularity parameters. In agreement with the evolution of the CO2 emissions into the atmosphere and the increasing concentration, in parts per million (ppm), of this greenhouse gas, diferent time trends at annual scale have been detected up to approximately years 1960–1970 in comparison with the interval 1960–1970 to nowadays. Consequently, besides the greenhouse efects on the temperature regime, the infuence on the pluviometric regime could not be negligible., Rainfall data have been supplied by Servei Mete‑ orològic de Catalunya (Generalitat de Catalunya), Fabra Observatory (RACA, Barcelona) and Ebro Observatory (Ramón Llull University and CSIC, Spanish Government). This research was supported by the Spanish Ministry of Science, Innovation and Universities: grant 460 number PID2019-105976RB-I00] and grant number AGL201787658-R. The authors also thank the editor and the anonymous reviewers for their valuable comments and suggestions to improve the manuscript, Peer Reviewed, Postprint (published version)

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Architectural Heritage on 2019, available online at: http://www.tandfonline.com/10.1080/15583058.2019.1643947, The study of structural safety when it is covered by important paintings requires a careful analysis without affecting the paintings. Therefore, non-destructive surveys are the only feasible method to obtain data about its state. In Cueva Pintada case, the problem requires a detailed but noninvasive analysis because this cave was dug in volcanic tuff. The tuff presents poor consolidation. This geological material is very sensitive to vibration. Furthermore, the proximity to the city downtown increases vibrations due to traffic. Recently, a small rockfall produces damage and alerted of the cave state of conservation. The painting walls constraint many of the NDT surveys. Two methodologies have been applied: ground-penetrating radar (GPR) and passive seismic. GPR analysis allowed determining the inner structure of the tuff cave, and results were used to determine the zones that required a wider and dense vibration study. Radar images show important anomalies at depths of about 0.2 m to 0.8 m and from 1.5 m to the top of the roof, almost horizontal. Amplification factor measured by passive seismic survey ranges from 0.03 to 93, with near half of the ceil with amplifications higher than 5 and about 10% with amplifications over 50 times., This research was 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 the project referenced as CGL2015-65913-P (MINECO/ FEDER, UE)., Peer Reviewed, Postprint (author's final draft)

This paper summarizes a study whose primary objectives were to develop a model for nonlinear static analysis of unreinforced masonry (URM) buildings, considering the flexibility of the floor system and analyzing the influence of stiffening the floor system on the overall seismic response of such buildings. With this aim, a six-story building typical of the Eixample-Barcelona district was used as a case study. All the macro-elements, those that constitute the walls and the floor system, were developed with one-dimensional spring elements. The influence of stiffening the floor system was analyzed by applying conventional stiffening interventions to the two-floor systems common in the Eixample-Barcelona district. The overall seismic response was evaluated in terms of modal parameters, the characteristics of the pushover curves and the deformed shape of the floors. The outcomes are discussed in relation to recent studies and explained in the context of previous studies. Finally, in the two unstiffened cases of the prototype building, the stiffening of the floor system slightly increases in fundamental periods, slightly to moderately increases in base shear capacities, and significantly decreases in displacement capacities., Peer Reviewed, Postprint (author's final draft)

Estimations of seismic risk in urban areas should include quantifications of the expected damage to civil structures subjected to earthquakes. In buildings, this quantification depends on the maximum inter-story drift (MIDR), among other aspects. In this study, the correlation between several intensity measures (IMs) and the maximum inter-story drift of steel structures was investigated. Three steel frame buildings of 3, 7 and 13 stories were used as a testbed. These buildings were modelled as 2D framed structures. For the seismic hazard, forty strong ground motion pairs were selected (80 individual horizontal components) from the Italian database. These records were scaled to a specific peak ground acceleration (PGA) and matched to a design spectrum from Eurocode 8. Nonlinear dynamic analysis was used to estimate the seismic response of the structures. Thus, 720 nonlinear dynamic analyses (NLDA) were performed [3 structures × (80 as recorded accelerograms + 80 scaled records + 80 matched records)]. Preliminary results indicate that PGA and MIDR show the worst correlation. A higher correlation was observed for peak ground velocity, root-mean-square velocity and specific energy density intensity-based measures. Finally, a new IM, which is highly correlated with MIDR, is proposed. This IM is called IΔ-PGV and considers both the PGV and the significant duration., Peer Reviewed, Postprint (author's final draft)

Distances between consecutive aftershocks are analysed by means of mono- and multifractal theory with the aim of quantifying the complexity of the physical mechanism governing them, as well as their predictability and predictive instability. Hausdorff, Ha, and Hurst, H, exponents are determined by semivariograms and rescaled analysis, respectively. The exponent ß of the power law describing power spectral contents is also quantified. These three parameters permit a generation of fractional Gaussian noise, fGn, simulating distances. The complexity and predictive instability of physical mechanism generating the series of distances is quantified by means of the correlation dimension, µ*, the Kolmogorov entropy, ¿, and the Lyapunov exponents, ¿i, which are based on the reconstruction theorem formulation. Additionally, the multifractal detrended fluctuation analysis, MF-DFA, contributes with a different point of view to quantify the complexity of the series, in terms of fractal spectral width, W, spectral asymmetry, B, and the critical Hölder exponent, a0. By one hand, the MF-DFA is applied to the complete set of distances characterising the whole aftershock process. By the other hand, the MF-DFA is applied to segments of the series of distances with the aim of determining the evolution of the complexity since the mainshock up to the end of the stress relaxation process. Finally, an ARIMA multilinear regression process is applied to obtain some improvements, in comparison with fGn simulations, on the prediction of distances. The database for this analysis is obtained from the Southern California Seismic Network (SCSN) catalogue. Three series of aftershocks equalling to or exceeding magnitudes of 2.0, assuring seismic catalogue completeness, and associated with Landers (06/28/1992), Northridge (01/17/1994) and Hector Mine (10/16/1999) mainshocks are obtained. It is worth mentioning that common mono-multifractal behaviour for the three aftershocks series is not detected, w, Postprint (author's final draft)

Standardized heavy rainfall profiles may contribute to a best knowledge concerning flash floods, ground erosion and runoff. Taking advantage of the rain rate gauges network of Barcelona city and applying a short integration time of 5 min, the heavy rainfall records with amounts above 25 mm and longer than 60 min have been selected along 15 years, being detected 499 records corresponding to 67 episodes. The amount distribution of these records are analysed at time deciles. By grouping these standardized rainfall profiles according to their similarity by means of the average linkage clustering algorithm, 10 clusters are derived, each one of them characterized by different time evolution of rainfall. The representative standardized rainfall profiles for every one of the clusters, together with maximum 5-min rain amounts and rainfall amounts characterizing them, permit to distinguish rainfall patterns. In addition, the extreme heavy rainfalls which may lead to flash floods are identified, as also their respective synoptic situations. In short, this analysis offers a description of heavy rainfall patterns in Barcelona city, complementing previous papers on the normalized intensity curves and 5-min intensity return periods. These heavy rainfall analyses would be very useful when designing drainage and sewerage systems in urban areas as Barcelona, where flash floods may be expected due to episodes of notable rainfall amount and intensity. The imperviousness density of the soil and an appropriate sewerage structure should be adapted to mitigate the effects of these copious and intense episodes., Peer Reviewed, Postprint (author's final draft)

Ground Penetrating Radar (GPR) is a prospecting method frequently used in monitoring asphalt pavements, especially as an optimal complement to the defection test that is commonly used for determining the structural condition of the pavements. Its application is supported by studies that demonstrate the existence of a relationship between the parameters determined in GPR data (usually travel time and wave amplitude) and the preservation conditions of the structure. However, the analysis of frequencies is rarely applied in pavement assessment. Nevertheless, spectral analysis is widespread in other fields such as medicine or dynamic analysis, being one the most common analytical methods in wave processing through use of the Fourier transform. Nevertheless, spectral analysis has not been thoroughly applied and evaluated in GPR surveys, specifically in the field of pavement structures. This work is focused on analyzing the behavior of the GPR data spectra as a consequence of different problems affecting the pavement. The study focuses on the determination of areas with failures in bituminous pavement structures. Results epitomize the sensitivity of frequencies to the materials and, in some cases, to the damage., This research has been partially funded by the Spanish 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). The study is also a contribution to the EU Action COST TU1208 “Civil Engineering Applications of Ground Penetrating Radar” financed by the European Union., Peer Reviewed, Postprint (published version)

The multifractal detrended fluctuation algorithm is applied to a series of distances and elapsed times between consecutive earthquakes recorded along the years 2000–2018 in the Canterbury region (New Zealand). The time evolution of several multifractal parameters (Hurst exponent, Hölder central and maximum exponents, spectral amplitude, asymmetry, and complexity index) is analyzed. Peaks of multifractal parameters, with statistical significance exceeding 95%, are associated with three earthquakes of notable magnitude (equaling or exceeding Mw = 5.7). Additionally, some other peaks are also associated with the swarm of earthquakes of moderate magnitude. Possible shortcomings created by this assignment to mainshocks or swarms can be removed by comparing the results corresponding to elapsed times and interevent distances between consecutive events. Additionally, the Buishand test, which is used to verify the statistical significance of the detected peaks, also discriminates between mainshocks of notable seismic magnitude and swarms of earthquakes with moderate magnitude. The obtained results, based on the multifractal structure of the seismic activity, could also represent some advances in predicting, with sufficient time, forthcoming mainshocks of high magnitude and mitigate their destructive effects., The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program, under Grant Agreement No. 823844, the ChEESE CoE Project., 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)

The paper investigates directionality effects of ground motions in the context of dynamic soil-structure interaction (DSSI) analyses. The problem addressed corresponds to a nonlinear soil deposit, overlaying firm ground, where the input motion was derived from an acceleration time history recorded at a rock outcrop. A simplified procedure is proposed to incorporate directionality effects. The main objective is to identify in advance the incidence angle producing the maximum response of a structure for a given earthquake. Results from the simplified procedure were evaluated by comparison with what is called here the complete rotational approach, where the behaviour of the structure, as a function of the incidence angle of the input motion, is derived through a large number of nonlinear dynamic soil-structure interaction analyses. The obtained results show the importance of considering directionality effects in DSSI analyses. The maximum response of the system was reasonably captured with the simplified approach., Peer Reviewed, Postprint (author's final draft)

The metropolitan region of Barcelona (BMR) is one of the most densely populated areas in the Mediterranean countries. The estimation of air temperature at a short scale from satellite measurements would contribute to a better understanding of the varied and complex spatial distribution of temperatures in BMR. This estimation would be a first step to study several patterns of the thermometric regime affecting population life quality and health. Taking advantage of MODIS data, air temperature measurements at 48 thermometric stations along the year 2015, together with their geographic and topographic data, multiple regression analyses have permitted to obtain fine spatial distributions (pixels of 1 km2) of minimum, mean and maximum daily air temperatures. Previous to the multiple regression, Pearson coefficients and principal component analysis offer a first overview of the relevance of the variables on the empiric temperatures. The most relevant variables on the multiple regression process at annual and seasonal scale are land surface temperatures, latitude, longitude and calendar day. At a monthly scale, altitude (maximum temperature) and continentality (cold months for minimum and hot months for maximum temperatures) are also relevant. The best fits between empiric temperatures and those derived from the multiple regression processes have square regression coefficients within the range (0.92–0.96) for the annual case, (0.70–0.92) at seasonal scale and (0.52–0.87) at monthly scale. The root mean square error varies from 1.5 to 2.0 °C (annual case), from 1.3 to 2.0 °C (seasonal scale) and from 1.2 to 2.1 °C (monthly scale). In agreement with these regression coefficients and mean square errors, the obtained spatial distribution of temperatures is of notable quality. As an outstanding application, the detection of several urban heat islands on different conurbations within BMR along the Mediterranean coast becomes possible., Postprint (author's final draft)

In this paper, remote and in situ techniques to estimate the dynamic response of a building to ambient vibration are reported: data acquired through a real-aperture radar (RAR) interferometer and conventional accelerometers are analyzed. A five-story reinforced concrete housing building, which was damaged during the May 11th 2011 Lorca (Spain) earthquake, is used as a case study. The building was monitored using both types of instruments. The dynamic properties of the building are estimated first taking acceleration measurements using a set of 10 high-precision accelerometers installed on the roof of the building. Further, the displacement–time histories, recorded with the RAR device pointing to a corner of the building, are analyzed. Then, the ability and shortcomings of RAR measurements to deal with the fundamental frequencies of vibration of the structure are investigated. The advantages and limitations of from-inside (accelerometric) and from-outside (RAR) measurements are highlighted and discussed. A relevant conclusion is that, after strong earthquakes, RAR may be an interesting and useful tool, as it allows surveying the structural response of mid-rise buildings remotely, without the need to enter the structures, which may be dangerous for inspectors or technicians in cases of severely damaged buildings. Given that the instrumented building suffered significant damage, the ability of these kinds of measurements to detect damage is also discussed., 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 (ERDF) of the European Union (EU) through projects with references CGL2015-65913-P (MINECO/ERDF, EU) and EFA158/16/POCRISC (INTERREG/POCTEFA. EU). R.E.A. holds a PhD fellowship from the Consejo Nacional de Ciencia y Tecnología (CONACyT) in México. L.A.P. is supported by a Ph.D. scholarship grant from the Institute for the Training and Development of Human Resources (IFARHU) and the Government of Panama’s National Secretariat of Science, Technology, and Innovation (SENACYT)., Peer Reviewed, Postprint (published version)

The complex non-linear regime of the monthly rainfall in Catalonia (NE Spain) is analyzed by means of the reconstruction fractal theorem and the multifractal detrended fluctuation analysis algorithm. Areas with a notable degree of complex physical mechanisms are detected by using the concepts of persistence (Hurst exponent), complexity (embedding dimension), predictive uncertainty (Lyapunov exponents), loss of memory of the mechanism (Kolmogorov exponent), and the set of multifractal parameters (Hölder exponents, spectral asymmetry, spectral width, and complexity index). Besides these analyses permitting a detailed description of monthly rainfall pattern characteristics, the obtained results should also be relevant for new research studies concerning monthly amounts forecasting at a monthly scale. On one hand, the number of necessary monthly data for autoregressive processes could change with the complexity of the multifractal structure of the monthly rainfall regime. On the other hand, the discrepancies between real monthly amounts and those generated by some autoregressive algorithms could be related to some parameters of the reconstruction fractal theorem, such as the Lyapunov and Kolmogorov exponents. The monthly rainfall regime in Catalonia, NE Spain, is analyzed by means of the fractal theory with the aim of improving the knowledge about its complex physical mechanism., Peer Reviewed, Postprint (author's final draft)

En este artículo se presenta, en primer lugar, un marco teórico sobre el tema de los espectros de capacidad y su utilización en el estudio de la vulnerabilidad sísmica de los edificios. A continuación, se referencian los trabajos de algunos investigadores que han avanzado en la dirección de parametrizar tales curvas y se destacan sus más importantes conclusiones. Posteriormente, se introducen los modelos que se han usado en esta investigación y que se consideran representativos de las principales subclases de edificios de acero y se presentan sus espectros de capacidad. Finalmente, se procede a aplicar técnicas de parametrización de dichas curvas y se presentan los resultados obtenidos y las principales conclusiones., Peer Reviewed, Postprint (published version)

In this study, previous microzonation studies in Barcelona (Spain) were revisited, and available data on the predominant periods of soils in the city were compiled to develop an updated microzonation map of the city. In addition, the building database was updated and used to create a map of building fundamental periods. The crossing of soil predominant period and building fundamental period maps led to the detection of areas in which resonance phenomena and, indeed, increased amplification of the structural response are expected. Thus, zones of Barcelona were identified in which the seismic hazard is probably greater due to resonance effects. The improved microzonation maps and the detection of soil-building resonance areas contribute significantly to enhanced precision and awareness of seismic hazard and risk in Barcelona., We thank Lucille Banham for her assistance in the preparation of the English manuscript. This research was partially funded by the Spanish Government’s Ministry of Economy and Competitiveness (MINECO) and by the European Regional Development Fund (ERDF) of the European Union (EU) through the project referenced as CGL2015-65913-P (MINECO/ ERDF, EU). The first author is supported by a Ph.D. scholarship grant from the Government of Panama’s Institute for the Training and Development of Human Resources (IFARHU) and the National Secretariat of Science, Technology, and Innovation (SENACYT)., Peer Reviewed, Postprint (author's final draft)

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

Corrosion is a significant damage in many reinforced concrete structures, mainly in coastal areas. The oxidation of embedded iron or steel elements degrades rebar, producing a porous layer not adhered to the metallic surface. This process could completely destroy rebar. In addition, the concrete around the metallic targets is also damaged, and a dense grid of fissures appears around the oxidized elements. The evaluation of corrosion is difficult in early stages, because damage is usually hidden. Non-destructive testing measurements, based on non-destructive testing (NDT) electric and magnetic surveys, could detect damage as consequence of corrosion. The work presented in this paper is based in several laboratory tests, which are centered in defining the effect of different corrosion stage on ground penetrating radar (GPR) signals. The analysis focuses on the evaluation of the reflected wave amplitude and its behavior. The results indicated that an accurate analysis of amplitude decay and intensity could most likely reveal an approach to the state of degradation of the embedded metallic targets because GPR images exhibit characteristics that depend on the effects of the oxidized rebar and the damaged concrete. These characteristics could be detected and measured in some cases. One important feature is referred to as the reflected wave amplitude. In the case of corroded targets, this amplitude is lower than in the case of reflection on non-oxidized surfaces. Additionally, in some cases, a blurred image appears related to high corrosion. The results of the tests highlight the higher amplitude decay of the cases of specimens with corroded elements., Peer Reviewed, Postprint (published version)

Combined non-destructive techniques are applied in the study of a historical building in Barcelona. Santa Maria del Mar is a magnificent Mediterranean gothic church built between 1329 and 1383. Two of the most important characteristics of this building are the slender columns and the almost flat rooftop. This structure, used to create a visual impression of a unique space, transmits high loads to the tall columns. Previous to restoration, vaults, roofs, and columns were extensively assessed with non-destructive tests, in order to improve the knowledge of those structures. This information will be used in further simulations to analyse load distributions at each part of the structure. Ground and floor were also studied. The analysis of the columns was based on ground- penetrating radar (GPR) surveys and on seismic tomography. Finally, the dynamic behaviour of the structure was determined by seismic monitoring of the main nave and the bell tower. Results obtained at the radar survey highlight the existence of unexpected anomalies in homogeneous materials, supporting the hypothesis of an inner structure between arches and roof composed by hollow elements. Seismic tomography defined the inner geometry of the columns and detected some damage or lower quality stone in various zones. Seismic monitoring established the perfect junction between the bell tower and the main nave. GPR survey on the floor allowed detecting a large number of graves, and some images suggest the existence of large underground walls and some of the foundations of the main façade., Peer Reviewed, Postprint (published version)

The paper discusses the seismic assessment of Mallorca cathedral in Spain. This cathedral is an audacious Gothic structure built on the island of Mallorca during 14th-16th centuries, characterized by its large dimensions and slender structural members. For that purpose, different analysis methods were used. A 3D Finite Element (FE) model of the cathedral was created and then updated based on in-situ dynamic identification tests. Nonlinear static (pushover) analysis was firstly carried out applying the seismic loads in the longitudinal and transversal directions of the cathedral considering both positive and negative signs. The pushover results were compared with the results of the kinematic limit analysis as a way to cross check the seismic safety assessment. Although for such a large historical structure, the nonlinear time-history (dynamic) analysis requires a very high computer effort, an attempt to perform this type of advanced analysis was carried out., Peer Reviewed, Postprint (published version)