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The recent bridge collapses worldwide underscored the perilous state of the global bridge infrastructure. Structural health monitoring (SHM) methods, particularly vibration-based techniques, offer a non-destructive approach to evaluate bridge conditions. However, installing dedicated SHM systems on each of the millions of bridges worldwide is prohibitively expensive. Vehicle scanning methods (VSM) have emerged as a cost-effective alternative, leveraging vehicle-mounted sensors for bridge assessment. Previous VSM research has primarily focused on frequency and mode shape identification through accelerations derived from numerical models. A smaller subset has explored damage detection, either based on modal properties or direct analysis of vehicle accelerations. This study proposes a new damage index that distinguishes itself by establishing a physical connection between the accelerations recorded on the vehicle and the instantaneous curvature of the bridge. This analytical connection provides a straightforward and effective means for damage detection and localization in bridges using VSM, offering the advantage of efficiency and accuracy. As such, the proposed damage index avoids the use of modal properties for damage detection, which are known to be prone to several factors and are not necessarily accurate enough when used in VSM applications, and the over-fitting problems associated with data driven methods. Numerical investigations indicate that the proposed damage index is robust against the potentially adverse effects of several parameters including road roughness, measurement noise, bridge frequency, damage location, variations in boundary conditions, and vehicle speeds., Peer Reviewed, Postprint (published version)

Masonry arch bridges are essential elements of the road and railway networks of Europe, as they pertain to cultural heritage and play an important role in transportation. The integrity and safety of these centuries-old structures must be ensured. Therefore, there is great interest in understanding the behavior of masonry arch bridges and monitoring their health. Efficient methods for assessing the condition of structures, including inspections and monitoring, constitute a fundamental element of structural health monitoring (SHM) applications. Given the multitude of surveying techniques available, it becomes crucial to establish cost-effective sensor placement strategies capable of detecting structural failures. These strategies can involve identifying particularly sensitive areas, optimizing the number of sensors used, as well as refining the number and duration of monitoring setups, among other considerations. As part of the PONT3 project, which aims to develop a comprehensive and cost-effective approach to anticipate failure propagation in ageing bridges, this research focusses on developing interoperability-driven inspection and monitoring strategies to provide data that will allow anticipating the evolution of possible failure scenarios. In this regard, an extensive summary of the key characteristics of inspection and monitoring technologies, and typical system configurations in existing literature for masonry arch bridges are provided. Then, the measurable physical parameters of interest and applicable monitoring techniques for each of the physical parameters is discussed. Monitoring requirements in terms of measurement locations, accuracy, range, and temporal resolution and the aspects of developing cost functions are evaluated. The recommendations for interoperability-driven data collection to exchange and employ acquired information for the purpose of structural diagnosis concludes the framework. The study finally discusses a future outlook on the developmen, Peer Reviewed, Postprint (published version)

This paper presents a set of undertaken actions for characterizing masonry arch bridges using data structure suitable for proper embedment in Digital Twins and Heritage Building Information Modelling (HBM). Interfaces in bridge maintenance are relentlessly and increasingly sophisticated. For both new and existing bridges, these interfaces are tending towards their ability to deal with different sources of information. Comprehensive digital twins of heritage masonry arch bridges may include several sources of information gathered from the real asset. Measurements can be taken using many different techniques ranging from contact to contactless and from non-destructive to moderately destructive samples. In addition, these twins may base upon different numerical models aimed at predicting and anticipating the present and future behaviors of the asset, respectively. Masonry arch bridges are known for their complex material and structural characteristics. Digitizing these masonry properties is key for effective simulation and analysis, often involving homogenization of diverse material properties. The design of comprehensive information constructs able to store and federate multiple data layers within a single entity is still challenging. Layers must be connected using vast scoped solutions such as knowledge graphs, integrating measurements, simulations and other information sources. In this particular case study on a masonry arch bridge located in Catalonia, Spain, in-situ Non-Destructive Testing (NDT) data is conceptualized for proper infusion within HBIM schemas. This integration pursues a seamless information flow for analysis or predictive purposes., The financial support from the Ministry of Science and Innovation (Spain), the State Agency of Research, and the European Regional Development Fund (ERDF) through the project PONT3 (PID2021-124236OB-C32). Authors also acknowledge the #KPI50 initiative of Ashvin, an H2020 project under agreement 958161 for the complementary support to the development of twinning techniques in new sites. The fifth author acknowledges the financial support of the European Union – NextGeneration EU through the postdoctoral grant Margarita Salas., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

Seismic behavior of masonry walls has been heavily investigated, especially by means of laboratory experiments employing cyclic tests to determine the mechanical parameters and seismic capacity. Nevertheless, the dynamic properties of the tested walls often remain unknown, even though the nature of the seismic response is dynamic and profoundly affected by the structure's dynamic properties. This paper presents an investigation on the dynamic properties of three different masonry wall panels in healthy and damaged states, and examines if damage quantification via tracking the changes in dynamic properties is feasible. Ambient vibration and impact measurements are used for the dynamic identification of wall panels, before and after they are tested in reversed-cyclic in-plane shear-compression tests. The natural frequencies, damping ratios, and mode shapes of the walls are determined and compared to each other. Moreover, the damage progression and its effect on the dynamic features of the URM wall panel is investigated using a discrete element model of the benchmark wall that is validated in terms of the force-displacement response and damage pattern of the wall. The results of the study indicate that changes in natural frequencies and mode shapes are traceable, although it is difficult to infer damage quantification relationships from these changes. The outcomes of this study also highlight that numerical models verified with the nonlinear quasi-static behavior do not necessarily match the wall's dynamic behavior, and that more research is required to update nonlinear numerical models. Overall, the results contribute to the knowledge regarding the dynamic characteristics of masonry walls in healthy and damaged conditions, and to quantify the damage in masonry walls as well as the changes in their dynamic properties., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món, 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, Preprint

Masonry arch bridges are a significant component of Europe's road and railway networks, contributing to cultural heritage and playing a crucial role in transportation. Ensuring the integrity and safety of these centuries-old structures is of paramount importance. Dynamic identification methods offer an effective approach to assess the performance of masonry arch bridges and update Finite Element (FE) models, thereby reducing uncertainties. However, practical limitations often restrict measurements to a few discrete locations, necessitating the identification of optimal sensor locations to capture crucial structural behaviour. This study focuses on the Joncadella Viaduct in Spain, a unique hybrid arch bridge comprising both masonry and concrete spans. As part of the PONT3 Project, which aims to develop a comprehensive and cost-effective approach to anticipate failure propagation in aging bridges, this research focuses on the masonry section of the bridge that comprises four of the thirteen spans. By creating 3D FE models of the masonry portion and the entire bridge, an Optimum Sensor Placement (OSP) study is conducted using the effective independence method (EFI) for varying numbers of sensors and dynamic identification test setups. The study also involves calibrating the boundary conditions of the partial FE model to match the dynamic properties of the full bridge model. The obtained results will guide field measurements to update the FE model of the partial arch bridge, thereby reducing uncertainties related to boundary conditions and material properties., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les persones, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.4 - Redoblar els esforços per a protegir i salvaguardar el patrimoni cultural i natural del món, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, 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, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Postprint (published version)

This article presents a numerical study that aims to explore the dynamic behavior of railway bridges under vibrations induced by heavy-haul traffic. For this purpose, a finite element code that can conduct moving load and moving mass analysis of single span bridges was developed. The software was validated by comparing the numerical response to the analytical solution for various speeds. The numerical analysis of the benchmark bridge under the benchmark train showed the interplay between the natural frequency of the bridge, the mass of the train and the loading frequency. A comprehensive parametric study to investigate the impact of different parameters on the dynamic behavior of railway bridges is also provided. The bridge span length, normalized train length, normalized mass of the train, bridge deck stiffness, and train speed are the variables considered in the parametric study. The results of the extensive numerical analyses improve the understanding of railway bridge behavior under heavy-haul trains, and highlight the impact of the inertial effect of the trains on bridges, especially for varying span length and deck stiffness. It is also demonstrated that, when the train-to-bridge mass ratio exceeds 40%, the inertial effects of the train mass needs to be included in the analysis in order to obtain a reliable estimate of the bridge behavior under different train speeds., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

This article presents a novel methodology to extract the bridge frequencies from the vibrations recorded on train-mounted sensors. Continuous wavelet transform is used to distinguish the bridge frequencies from the other peaks that are visible in the Fourier amplitude spectrum of the accelerations recorded on train bogies. The efficacy of the proposed method is demonstrated through numerical case studies. For this, a detailed three-dimensional finite element model that can capture the vibration characteristics of the bridge, track, and train is created, and each component of the model is separately validated. The train model used is a three-dimensional multi-degree-of-freedom system that can simulate the pitching and rolling behavior. The train was then virtually driven over the bridge at different speeds and under varying track irregularities to evaluate the robustness of the proposed method in extracting bridge frequencies from train-mounted sensors under different conditions. The proposed methodology is shown to be capable of identifying bridge modal frequencies even for aggressive track irregularity profiles and relatively high speeds of trains., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The out-of-plane flexural bending capacity of masonry is a fundamental property for understanding the behavior of masonry structures. This study investigates the behavior of unreinforced masonry wallettes subjected to combined compression-flexural loading using the discrete element method (DEM), and provides a novel framework to estimate the masonry strength. A simplified micro-modeling strategy is utilized to analyze a masonry wallette, including the variation of the mechanical properties in masonry units and joints. Stochastic DEM analyses are performed to simulate brickwork assemblages, assuming a strong unit-weak joint material model typical of most masonry buildings, including historical ones. Once the proposed computational approach is validated against the experimental findings, the effect of spatial and non-spatial variation of mechanical properties is explored. Two failure types are identified: joint failure and brick failure. For each failure mechanism, the variability of the response and the effects of the modeling parameters on the load-carrying capacity is quantified. Afterward, Lasso regression is employed to determine predictive equations in terms of the material properties and vertical pressure on the wallette. The results show that the most important parameters changing the response are the joint tensile strength and the amount of vertical stress for joint failure, whereas the unit tensile strength dominates the response for brick failure. Overall, this research proposes a novel framework adopting validated advanced computational models that feed on simple test results to generate data that is further utilized for training response prediction models for complex structures., Peer Reviewed, Postprint (published version)

This article investigates the damping behavior of masonry arch bridges under service loads extracted from experimental data and provides guidelines on how to emulate this behavior in numerical analysis, particularly in discrete element model applications. First, an experimental campaign is undertaken and vibrations on three masonry arch railway bridges under train loads were monitored. The modal damping ratios from several sensors on each bridge were extracted by isolating the modal component of free decay vibrations which commence immediately after the train leaves the bridge. The modal damping ratios identified under service loads were compared with their counterparts identified under ambient vibrations. The suitability of mass-proportional, stiffness-proportional and Rayleigh damping models in emulating damping in masonry arch bridges was evaluated. In the numerical phase of the study, a single-arch masonry bridge was modeled using mixed discrete continuum approach and a moving load analysis was conducted without applying any additional viscous damping. The results of the numerical analysis indicate that the inherent damping in discrete element models provided by their nonlinear nature can be sufficient to emulate the damping behavior of masonry arch bridges under service loads. The research provided in this article is unique in the sense that it combines an experimental study and a numerical study on damping of masonry arch bridges under service loads. Unlike its counterparts in literature, which use either ambient vibrations or seismic action, damping values are computed under appropriate levels of vibration amplitudes for service loads, which is critical to estimate the modal damping ratios accurately under these loads., Peer Reviewed, Postprint (published version)

This study investigates the effect of spatially varying material properties on the in-plane seismic behaviour and capacity of an unreinforced pier-spandrel masonry system. The discontinuous nature of masonry is represented via a system of rigid blocks that can mechanically interact with each other along their boundaries. In the discontinuous modelling strategy, denoted as discrete rigid block analysis (D-RBA), deformations are lumped at the joints, and masonry units are replicated using two rigid blocks with a potential crack plane using the discrete element method (DEM). The obtained collapse mechanisms are automatically classified into two main categories via an algorithm processing the results of D-RBA. The adopted methodology offers a robust and time-efficient categorization of different collapse modes obtained from the computational model, which is required for better understanding the possible mechanisms developing in pier-spandrel structures and their occurrence rate. Accordingly, the most recurrent failure mechanisms are further investigated via upper- and lower-bound theorems of limit equilibrium analysis (LEA) by adopting an ad hoc coded optimization algorithm to ensure the solution's uniqueness. The results show that the DEM-based modelling approach provides a comprehensive understanding of the structural behaviour and capacity of pier-spandrel systems subjected to in-plane lateral loads. Further, the proposed probabilistic assessment workflow offers a broader perspective than deterministic analysis., Peer Reviewed, Postprint (author's final draft)

This study systematically assesses the efficacy of the vehicle scanning methods (VSM) in accurately estimating the mode shapes of bridges seated on elastic supports. Three state-of-the-art VSM methods are employed to obtain the mode shapes of bridges using the vehicle data during its travel. Two of the evaluated methods use a signal decomposition technique to extract the modal components of the bridge from the contact point of the response while the third one relies on the segmentation of the measured signals along the bridge deck and applying an operational modal analysis tool to each segmented signal to estimate the mode shapes. Numerical analyses are conducted on one single- and one two-span bridge, considering smooth and rough road profiles, different vehicle speeds, and presence of lead vehicle. The accuracy of the numerical models used in developing and assessing vehicle scanning models is tested, and the results of the study demonstrate the method using a half-car vehicle model and signal decomposition technique shows robustness against increasing vehicle speeds and road roughness while the method applying the segmentation of the measured signals provides relatively accurate mode shape estimates at the bridge edges at low speed, although the three methods have their limitations. It is also observed that simplified bridge and vehicle models can hide potential challenges that arise from the complexity of actual vehicle and bridge systems. Considering that a significant number of bridges worldwide are built on elastic supports, the practical success of vehicle scanning methods depends on their ability to handle elastic boundary conditions with reliability. Therefore, the article provides valuable insights into the capabilities and limitations of the current vehicle scanning methods, paving the way for further advancements and refinements in these techniques., Peer Reviewed, Postprint (published version)

Theoretical and experimental studies on loadbearing masonry walls have shown the significant influence of the axial load level (i.e., precompression) and wall aspect ratio on in-plane lateral resistance. Nonetheless, the impact of the precompression and spatial variability of the material properties needs to be further investigated at the scale of walls with openings. This study presents a stochastic analysis of unreinforced (URM) pier–spandrel systems subjected to both axial loads on piers and lateral loads, considering the spatial variation in material properties. A discontinuum-based computational model was utilized to assess the force–displacement behavior of a benchmark pier–spandrel structure under different vertical precompression levels on piers. A total of 750 simulations were carried out to propagate material uncertainties in lateral load analysis. The proposed modeling strategy, based on the discrete element method, explicitly represents joint openings, sliding, and crushing phenomena at the contact points defined between the adjacent discrete rigid blocks. According to the validated computational modeling strategy, meaningful inferences were made regarding the effect of the precompression level on the maximum displacement and ultimate lateral load-carrying capacity of the benchmark URM pier–spandrel system. The results showed that vertical pressure on piers had considerable influence on the displacement ductility of the system while yielding less variation in the displacement capacity. Furthermore, the appealing feature of the spatial probabilistic analysis is noted in the variation in the lateral load-carrying capacity of the structural system., Peer Reviewed, Postprint (published version)

The uncertainties in the numerical models used for the optimal sensor placement (OSP) studies of civil infrastructures, specifically bridges, considerably affect the results. These effects can be more prominent if the modeling uncertainties are of a kind that significantly alters the mode shapes of the structure, such as the boundary conditions of the model. Yet, these effects on the results of OSP analysis remain unexplored, and there are no available methodologies to address all types of model uncertainties in OSP for civil infrastructures. This research presents a new framework to determine the optimal sensor locations to identify the modal properties of bridges under severe modeling uncertainties and its application on a railway bridge. The framework includes finite element model generation and a sensitivity study to select the most influential parameters that change the dynamic response of the bridge. The selected parameters are used in Monte Carlo simulations, and the results enable quantifying the relative amount of information presented at the candidate sensor locations. This information is combined with the spatial position of the candidate sensor locations, and a hierarchical clustering algorithm is used to obtain the optimal sensor locations and the number of sensors. In addition, the OSP analysis is carried out using the Effective Independence method to contribute to the state-of-the-art literature that investigates the uncertainties in OSP for civil infrastructures and uses this method., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les persones, Postprint (author's final draft)

The final authenticated version is available online at https://doi.org/10.1007/s10518-023-01744-5., Predicting the seismic behavior of unreinforced masonry (URM) structural systems is a complex task, given various inherent sources of uncertainty associated with material properties, geometry, and boundary conditions. As the selection of computational strategies is a trade-off between prediction accuracy and computational cost, it is often challenging to find a consensus. To this end, this study presents three computational modeling strategies that can be used in the seismic analysis of URM structures. The first two approaches utilize the discrete element method (DEM) and are based on pre-defined macro-block mechanisms, whereas the third approach makes use of the computational thrust line analysis (CTLA). Such methods provide accurate predictions on the in-plane lateral load-carrying capacity of URM pier-spandrel structures with a reasonable computational cost and fewer input parameters, making them efficient compared to detailed numerical models. The results are found to be in good agreement with the experimental data on two full-scale pier-spandrel systems with either timber lintel or shallow arch above a central opening. This study also provides a detailed comparison of the applied methods and suggests multi-level use of proposed modeling strategies for better informed decision-making, starting from the most simplified method (CTLA) towards the advanced solutions as more information is collected., Peer Reviewed, Postprint (author's final draft)

Los puentes de arco de fábrica (MAB) desempeñan un papel crucial en las redes de carreteras y ferrocarriles de todo el mundo, especialmente en Europa. A pesar del papel fundamental que desempeñan estas infraestructuras, son algunas de las partes más vulnerables de las redes de transporte existentes. Por ello, es vital poder contar con un sistema que ayude a la monitorización, detección y alerta temprana de problemas para su seguridad estructural. Esta tesis, titulada "Ubicación óptima de los sensores para medir las vibraciones de un puente de arco de fábrica” se centra en el desarrollo y análisis de una investigación de Optimal Sensor Placement (OSP) para el Viaducto de la Joncadella. El trabajo realizado en esta tesis tiene como objetivo llenar el vacío existente en la literatura actual con respecto a la colocación óptima de sensores en puentes arco de fábrica, con la esperanza de mejorar la aplicación de sistemas de Monitorización de la Salud Estructural (SHM). El desarrollo de un modelo numérico 3D se lleva a cabo a través de una investigación histórica del puente. Se realiza un análisis modal de estos modelos para identificar los modos dominantes y evaluar las frecuencias y formas modales. Para lograr configuraciones óptimas de colocación de sensores, se codifica en MATLAB un algoritmo sencillo que utiliza el método de la independencia efectiva (EFI). A través de esta investigación, se implementan diferentes tipos de sensores, como sensores uniaxiales y triaxiales, y tres enfoques de análisis diferentes para analizar las entradas de desplazamiento modal. La reconstrucción de la forma modal se lleva a cabo para evaluar la calidad de los datos obtenidos a partir de las colocaciones de los sensores seleccionados. Se concluye que una configuración óptima de 14 sensores triaxiales captura adecuadamente el comportamiento global de la estructura, ya que reconstruye con precisión las formas modales, ofreciendo así información sobre el comportamiento del puente. Ade, Masonry arch bridges (MAB) play a crucial role in road and railway networks worldwide, especially in Europe. Despite the critical role these pieces of infrastructure play, they are some of the most vulnerable parts of the existing transportation networks. As such, it is vital to be able to have a system in place which aids in the monitoring, detection and early warning of problems to their structural safety. This thesis, titled “Optimal sensor placement for vibration measurements of a masonry arch bridge” focuses on the development and analysis of an Optimal Sensor Placement (OSP) investigation for the Joncadella Viaduct. The work done in this thesis aims to fill the gap in current literature regarding the Optimal Sensor Placement on masonry arch bridges, in hopes to improve the implementation of Structural Health Monitoring (SHM) systems. The development of a 3D numerical model is accomplished through a historical research of the bridge. Modal analysis is performed on these models to identify dominant modes and evaluate modal frequencies and shapes. To achieve optimal sensor placement configurations, a simple algorithm using the Effective Independence (EFI) method is coded in MATLAB. Through this investigation, different sensor types, such as uniaxial and triaxial sensors, and three different analysis approaches are implemented to analyze the inputs of modal displacement. Modal shape reconstruction is conducted to assess the quality of data obtained from the selected sensor placements. It is concluded that an optimal sensor configuration of 14 triaxial sensors adequately captures the global behavior of the structure, as it accurately reconstructs the modal shapes thus offering insights into the bridge’s behavior. In addition, this thesis concludes with recommendations for a temporary configuration of rotating sensor placement, demonstrating the ability to capture multiple points along the bridge, allowing for global monitoring of the bridge.

This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/JENMDT.EMENG-6930., Perforated unreinforced masonry (URM) walls are used in most existing masonry buildings as structural and nonstructural elements. Depending on the size and position, openings may detrimentally affect the stiffness and seismic capacity of URM walls. This research investigates the structural behavior of perforated URM walls with different opening sizes and proportions subjected to lateral loading using the discrete element method (DEM). In the applied modeling strategy, masonry walls are composed of rigid blocks, where their mechanical interactions are simulated via point-contact hypotheses. Once the numerical approach is validated, parametric analyses are performed to better understand the effect of different opening sizes and their aspect ratios on the failure mechanism and shear capacity of perforated URM walls. The results quantify the lateral load–carrying capacity and demonstrate its inverse relationship with the opening size. Furthermore, a slight influence of contact stiffness (varied from 10 to ) on the ultimate lateral load in DEM-based simulations is noted. Finally, the obtained shear force capacities are compared against the strength prediction equations provided in current US standards. In most cases, the predictions of the US standard provide conservative values relative to the DEM results., Peer Reviewed, Postprint (author's final draft)

The final authenticated version is available online at https://doi.org/10.1007/s40571-022-00493-7, This research explores the mechanical behavior of dry-joint masonry subjected to combined shear–torsion–bending loading via the discrete element method (DEM), which has not been thoroughly investigated in the literature. It also aims to shed light on the accuracy and effectiveness of DEM simulations when the unit–mortar-interfaces are exposed to complex loading scenarios. Throughout this study, the masonry walls are represented as a system of rigid blocks that can mechanically interact with each other via contact points. The proposed modeling strategy is validated against recent experimental findings, and parametric analyses are performed considering the number of contact points and the stiffness. The results reveal that discrete element models can provide accurate predictions when sufficient numbers of contact points are defined on the contact plane. Thus, the required number of contact points to be utilized in the DEM-based simulations is suggested. Furthermore, the dependency of the results on the contact stiffness values, which are associated with vertical pressure, is demonstrated. Tailoring the models based on the suggested discretization ensures capturing the sophisticated stress distributions developing at the joints in masonry structures accurately., Peer Reviewed, Postprint (author's final draft)

Damage detection algorithms employing the conventional acceleration measurements and the associated modal features may underperform due to the limited number of sensors used in the monitoring and the smoothing effect of spline functions used to increase the spatial resolution. The effectiveness of such algorithms could be increased if a more accurate estimate of mode shapes were provided. This study presents a hybrid structural health monitoring method for vibration-based damage detection of bridge-type structures. The proposed method is based on the fusion of data from conventional accelerometers and computer vision-based measurements. The most commonly used mode shape-based damage measures, namely, the mode shape curvature method, the modal strain energy method, and the modal flexibility method, are used for damage detection. The accuracy of these parameters used together with the conventional sparse sensor setups and the proposed hybrid approach is investigated in numerical case studies, with damage scenarios simulated on a simply-supported bridge. The simulations involve measuring the acceleration response of the bridge to ambient vibrations and train crossings and then processing the data to determine the modal frequencies and mode shapes. The efficiency and accuracy of the proposed hybrid health monitoring methodology are demonstrated in case studies involving scenarios in which conventional acceleration measurements fail to detect and locate damage. The robustness of the proposed method against various levels of noise is shown as well. In the studies considered, damage as small as 10% decrease in flexural stiffness of the bridge and localized in less than 1% of the span-length of the bridge is reliably detected even with very high levels of measurement noise. Finally, a modified modal flexibility damage parameter is derived and used to alleviate the shortcomings of the modal flexibility damage parameter., Peer Reviewed, Postprint (published version)

This study investigates the influence of the uncertainty in material properties on the in-plane lateral behavior and capacity of stone masonry walls via a stochastic discontinuum analysis framework. The framework is demonstrated via the 3D numerical assessment of an unreinforced masonry (URM) wall using a stochastic analysis in the form of Monte Carlo simulations. The random parameters considered in this study are the prism compressive strength of masonry, the tensile strength of the masonry units and joints, and the friction angle for joints and units. Novel research is conducted using a fast and accurate DEM model to determine whether the spatial variability of the material properties should be taken into account. In addition, the effects of joint-to-joint correlation of modeling parameters are examined to identify if such a correlation exists. A total of 1200 stochastic discontinuum analyses for 12 different cases are carried out. The results call attention to considering the spatial variability of the modeling parameters in the stochastic analysis, as they significantly reduce the variation in the wall’s strength and displacement capacity. Results also demonstrate the influence of the correlation between bedjoint parameters on the strength and failure mode of the walls. Ultimately, propagation of the uncertainty in the joint friction angle into the strength and displacement capacity of the walls is quantified., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

© 2022 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0, This study aims to improve our current understanding of the seismic assessment of load-bearing unreinforced masonry (URM) systems by proposing a probabilistic computational modeling framework using the discrete element method (DEM). The main objective is to predict the structural behavior and capacity of URM walls with openings subjected to lateral loading, considering uncertainties in material properties. The proposed modeling strategy represents masonry as an assembly of rigid blocks interacting along their boundaries by adopting the point-contact hypothesis. Fracture energy-based softening contact models are implemented into a commercial discrete element code (3DEC) to better simulate both the pre- and post-peak behavior of masonry. The results highlight the influence of material properties on the force capacity, displacement capacity (drift limits), and collapse mechanisms of walls with openings. Based on the applied non-spatial probabilistic analyses, the most commonly observed failure mechanisms are further assessed using a simplified macro-block formulation. As a result, practical, yet necessary, inferences are made, providing valuable contributions. Furthermore, the validated discontinuum analysis framework is demonstrated as an accurate structural analysis strategy and a useful approach to simulating the potential collapse mechanism of load-bearing URM structures., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (author's final draft)

This article presents a numerical study that aims to explore the impacts of the stiffness of elastomeric bearings on the dynamic behavior of railway bridges under train-induced vibrations. For this purpose, a finite element code that considers vehicle–bridge interaction using a coupled approach was developed. The software was validated by comparing the numerical response to the analytical solution. The numerical analysis of single- and multi-span bridges with varying bearing stiffness values under passenger trains showed the interplay between bearing stiffness, its impact on the natural frequency of the bridge and the loading frequency. It is demonstrated that the amplitude of the maximum acceleration on the bridge depends heavily on the stiffness of the bearings. Furthermore, the bearing stiffness significantly impacts the location of the maximum acceleration on the bridge. The results of the extensive numerical analyses improve the understanding of the impact of the bearing stiffness on the dynamic behavior of bridges and highlight the importance of quantifying the boundary conditions correctly for reliable estimation of dynamic response of railway bridges under train-induced vibrations., Peer Reviewed, Postprint (published version)

Loose paint, which occurs in Munch’s paintings after exhibitions caused by mechanical loads during transport, handling and storing in deposit or exhibitions, is a recurring challenge and a major concern. An essential feature of many of the Munch paintings in the MUNCH collection is the porous and brittle paint layers with weak cohesive and adhesive properties. In this paper, we present some initial measurements of the accelerations that cause mechanical loads that act upon such paint layers during handling in-house on trolleys. This study is a part of a larger project that aims to investigate the effect of vibrations on fragile paintings during in-house transport, storing on screens and the impact of sound in exhibitions. The main objective is to determine acceptable vibration levels, and develop methods to reduce the damaging vibration and shock loading. In doing so we will manage to optimize ROS-analyses and develop more reliable preventive strategies., The authors are grateful to the art technicians Andreas Hans Mikael Öhman, Enrique Eduardo Roura Perez, Andrea Galiazzo and Tomas Siqveland Einarsson for transferring the trolleys during the measurements and making these measurements possible. We also acknowledge the collaboration with Barbara Ida de Haan and Kine Lillestrøm, former project leaders at MUNCH for the project Moving MUNCH to a new Museum, Ingvild Vestvik, former registrar at the same project. We also want to thank Mohammadreza Salehi at OsloMet who contributed to the measurements on the trolleys, and Mie Mustad, paintings conservator at MUNCH, for input and collaboration. A huge thanks to Clare Brignall for spelling and grammar check., Peer Reviewed, Postprint (published version)

Masonry arch bridges form a noteworthy portion of road and railway networks in Europe and Turkey. Structural assessment of such bridges is often required because of their vulnerability to seismic actions. However, there are no standardized or widely accepted procedures, and the available assessment methods comprise significant uncertainties. This paper presents a seismic assessment of a stone masonry arch bridge using different methodologies by investigating the seismic behavior of masonry arch bridges and the uncertainties in the assessment methods presented. The Finite Element (FE) macro-modeling approach is used in modeling the behavior of the structure under investigation, after undertaking ambient vibration testing and dynamic identification study to determine the dynamic parameters of the structure. These experimental parameters were used to update the FE model before performing the seismic assessment using Nonlinear Static Analysis (NSA), Nonlinear Dynamic Analysis (NDA) and Incremental Dynamic Analysis (IDA). The IDA helped to depict the complete picture of the seismic behavior, whereas the comparison of the results highlighted the limitations of the NSA and enabled presenting recommendations for future work. In addition, the effects of the interaction of horizontal and vertical components of earthquake records in NDA underlined the necessity for their consideration in similar studies., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.b - Per a 2020, augmentar substancialment el nombre de ciutats i assentaments humans que adopten i posen en marxa polítiques i plans integrats per promoure la inclusió, l’ús eficient dels recursos, la mitigació del canvi climàtic i l’adaptació a aquest, així com la resiliència davant dels desastres, i desenvolupar i posar en pràctica una gestió integral dels riscos de desastre a tots els nivells, d’acord amb el Marc de Sendai per a la reducció del risc de desastres 2015.2030, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Postprint (author's final draft)