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This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Architectural Heritage on 2022, available online at: http://www.tandfonline.com/10.1080/15583058.2022.2096513 This paper presents the historical development of the vertical extensions of unreinforced masonry buildings in the Eixample district of Barcelona and their impact on the seismic behaviour. Existing masonry buildings of Eixample present significant seismic risk because, despite the low to moderate seismic hazard of Barcelona, they show a marked vulnerability given their average height of six storeys and the substantial slenderness of the walls. Between the end of the 19th century and the beginning of the 20th century, the vertical extensions, known as remuntes in Catalan, were a common solution to the increasing demographic demand of the city. In their majority, these vertical extensions add a structural irregularity that represents a potential vulnerability factor not yet investigated. The present study focuses on Eixample’s remuntes, including their historical development, the description of their structural features, and the identification of their most representative configurations in the existing building stock. A seismic analysis based on the Finite Element Method is presented on a reference model without extensions and three others with the most recurrent configurations of remuntes. The seismic response is investigated through pushover analysis. The results provide a better understanding of the negative impact of the vertical extensions on the seismic performance. This work was supported by the Ministry of Science, Innovation and Universities of the Spanish Government (MCIU) [RTI2018-099589-B-I00], the State Agency of Research (AEI) [RTI2018-099589-B-I00] and the European Regional Development Fund [RTI2018-099589-B-I00]; through the project SEVERUS (Multilevel evaluation of seismic vulnerability and risk mitigation of masonry buildings in resilient historical urban centres [RTI2018-099589-B-I00]; Agència de Gestió d'Ajuts Universitaris i de Recerca; MSc SAHC Consortium scholarship; Sapienza University of Rome.

This Master thesis was carried out within the research project PONT3 (Anticipating failure propagation of ageing bridges through a cost-effective interdisciplinary approach, reference PID2021-124236OB-C32) funded by the Spanish Ministry of Science and Innovation and the State Research Agency El projecte de recerca es centra en avaluar i caracteritzar ponts d'arc de maçoneria històrics de ferrocarril mitjançant mètodes de proves no destructives (NDT). L'objectiu és preservar i conservar aquestes estructures com a part del patrimoni històric. L'estudi es centra en un pont de maçoneria de principis del segle XX situat prop de Barcelona. El projecte comença amb una revisió del comportament estructural, les tècniques de construcció i els materials comúnment emprats en els ponts d'arc de maçoneria de ferrocarril. S'examinen diverses guies per avaluar els ponts d'arc de maçoneria per a l'avaluació del pont d'estudi. Una revisió bibliogràfica explora mètodes de proves no destructives i proves destructives menors per avaluar la condició general i les propietats mecàniques del pont. La investigació inclou un estudi detallat d'escriptori, investigant la informació històrica del pont, intervencions prèvies, construcció i geometria. A continuació, es realitza una investigació de camp i una campanya experimental que involucra la inspecció visual per identificar danys i avaluar la condició general del pont. Les dades recopilades permeten la creació d'un model geomètric 3D que mostra l'exterior i l'interior del pont. La campanya experimental utilitza proves no destructives com la velocitat de pols ultrasònica (UPV) i la termografia infraroja, així com proves destructives menors com el penetròmetre Windsor (PPT) i el martell de rebuig Schmidt (HRT). A més, es realitzen proves destructives al laboratori per determinar la resistència a compressió de la maçoneria. En general, el projecte té com a objectiu promoure l'ús de tècniques no destructives en la caracterització d'estructures de maçoneria històriques, contribuint a la base de dades experimentals i a la preservació d'aquests importants actius patrimonials. El proyecto de investigación se centra en evaluar y caracterizar puentes de arco de mampostería históricos de ferrocarril mediante métodos de pruebas no destructivas (NDT). El objetivo es preservar y conservar estas estructuras como parte del patrimonio histórico. El estudio se centra en un puente de mampostería de principios del siglo XX ubicado cerca de Barcelona. El proyecto comienza con una revisión del comportamiento estructural, las técnicas de construcción y los materiales comúnmente utilizados en puentes de arco de mampostería de ferrocarril. Se examinan varias guías para evaluar puentes de arco de mampostería para evaluar el puente de estudio. Una revisión bibliográfica explora métodos de pruebas no destructivas y pruebas destructivas menores para evaluar la condición general y las propiedades mecánicas del puente. La investigación incluye un estudio detallado de escritorio, investigando la información histórica del puente, intervenciones previas, construcción y geometría. A continuación, se llevó a cabo una investigación de campo y una campaña experimental que involucra la inspección visual para identificar daños y evaluar la condición general del puente. Los datos recopilados permitieron la creación de un modelo geométrico 3D indicando el exterior e interior del puente. La campaña experimental utiliza pruebas no destructivas como la velocidad de pulso ultrasónico (UPV) y la termografía infrarroja, así como pruebas destructivas menores como el penetrómetro Windsor (PPT) y el martillo de rebote Schmidt (HRT). Además, se realizan pruebas destructivas en el laboratorio para determinar la resistencia a compresión del ladrillo. En general, el proyecto tiene como objetivo promover el uso de técnicas no destructivas en la caracterización de estructuras de mampostería históricas, contribuyendo a la base de datos experimentales y a la preservación de estos importantes activos patrimoniales. The research project focuses on assessing and characterizing historical masonry railway arch bridges through non-destructive testing (NDT) methods. The objective is to preserve and conserve these structures as part of the historical heritage. The study centers around an early 20th-century masonry bridge located near Barcelona. The project begins with a review of the structural behavior, construction techniques, and materials commonly employed in railway masonry arch bridges. Various guidelines for assessing masonry arch bridges are examined to evaluate the case study bridge. A literature review explores non-destructive and minor destructive test methods for assessing the bridge's overall condition and mechanical properties. The research includes a thorough desk study, investigating the bridge's historical information, previous interventions, construction, and geometry. A site investigation and experimental campaign follow, involving visual inspection to identify damages and assess the overall condition. The gathered data enables the creation of a 3D geometrical model showcasing the bridge's exterior and interior. The experimental campaign employs non-destructive tests such as Ultrasonic Pulse Velocity (UPV) and Infrared Thermography, as well as minor destructive tests like the Windsor Pin Penetrometer (PPT) and Schmidt Hammer Rebound (HRT). Additionally, destructive tests are conducted in the laboratory to determine compressive strength. Overall, the project aims to promote the use of non-destructive techniques in characterizing historical masonry structures, contributing to the field's experimental database and the preservation of these important heritage assets.

Reliable estimation of seismic stability of structures built in seismically active regions is an objective that requires a complex investigation and different types of activities. For historical structures and monuments, this requirement is even more essential, because many of them represent unique heritage structures. In- situ testing of a monument for defining dynamic characteristics and seismic testing of scaled models represent the recommended activities to be considered as mandatory. Shake table testing of a scaled monument model provides valuable information about its seismic stability – weak parts and development of failure mechanism – as well as the crucial points of the structure that should be considered when designing the health monitoring system. This paper presents the results obtained by the shake table testing of scaled models of two historical masonry structures: the Old Bridge in Mostar and the ancient Protiron structure in Split. The monitored seismic response presented herein by the measured accelerations, relative and absolute displacements, and strains, as well as the damage identification during the shake table tests, provided essential information about their seismic stability, failure mechanism, and weak points. The obtained results have been used for verification of the analytical models for these two monuments, while the prospective of the conclusions derived from the tests has a possible implementation in planning their health monitoring system.

Zagreb Cathedral was severely damaged by the 5.4 magnitude earthquake on March 22, 2020. The Cathedral had already been hit by a hard earthquake of Richer magnitude 6.1 in 1880. It was restored in the neo-Gothic style (by H. Bolle) with ribbed vaults and arches supported by slender columns, but the spatial connection between the load-bearing elements is poorly executed and the structural system for horizontal loads has not been significantly improved. During the restoration, the two 108-meter towers erected next to the church caused a strong asymmetry of mass and stiffness. The distinct element method has shown good results in simulating large displacements or collapse of masonry structures. Therefore, the software 3DEC is used for the structural analysis of the Cathedral. Due to the complicated geometry, considerable effort was invested in the generation of the numerical model. Parametric modeling was used to partially automate the process. The brick- like arrangement of the blocks is used to model walls and vaults, and their nonlinear responses. Since the method is mesh-dependent, the size, shape, and connections of the blocks were adjusted so that their response curves match those from literature and experiments.

International audience; The non-smooth contact dynamics method was selected to investigate the damage occurred to typical masonry churches (namely Apennine churches) belonging to Central Italy areas affected by the seismic activity started in 2016. The investigated buildings show discontin-uous dynamics since the optioned method gave the chance to properly model the temples as multi rigid body systems using the Signorini's impenetrability condition and the dry-friction Coulomb's law, achieving a thoughtful response to ground seismic solicitations. The results provided by the assessment grant an overview of the most common damages and failure mechanisms, giving the guidelines to restoration projects that fully respond to structural needs.

This paper investigates the mechanical behaviour of heritage structures subjected to seasonal temperature variations. To this end, the constitutive equation of masonry-like materials, which has been embedded in the finite element code NOSA-ITACA (www.nosaitaca.it), is used to model the static and dynamic behaviour of simple arched masonry structures subjected to thermal loads.

Most of the computational approaches based on Heyman's theory rely on the safe theorem and can only tackle kinematical problems (KPs) with non-homogeneous boundary displacements for simple geometries. So far, no computational tools have been developed to directly address the KP for generic 2D structures taking into account different mechanical scenarios and foundation settlements simultaneously. With this aim, compas_prd, a new computational Python-based tool has been developed. It is based on the piecewise rigid displacement (PRD) method, which couples the KP with the equilibrium problem (EP), allowing the search for a mechanism and its corresponding internal stress state even in large displacements. Both KP and EP are framed as linear programming problems, allowing fast computational solving. Looking at an approximate cross-section of a multi-span masonry bridge, different mechanical scenarios are addressed to illustrate the abilities of compas_prd, also taking into account an initial deformed configuration., International Journal of Masonry Research and Innovation, 6 (4), ISSN:2056-9459, ISSN:2056-9467

This paper focuses on the generation of complex geometrical models with solid elements in historical masonry buildings, suitable for structural simulations. The complexity of the system is addressed by dividing it into parts following the typical observed hierarchy, e.g. (a) pier, (b) walls, (c) nodal zones, (d) vaults, etc. Automatic procedures are developed to model the most complex parts of the structural system such as the masonry vaults or the nodal zones. The result is to generate the solid geometry of the structure using a parametric model, with the advantage of significant reduction of the modelling time and better meshing for numerical simulation purpose. The developed models according to the proposed automatic reconstruction procedure can be used for the creation of the geometric model as well as the structural model.

Developing suitable tools to assess the actual structural performance and designing and executing interventions to improve that performance is a key issue in the field of conservation and enhanceme...

Textile Reinforced Mortars (TRMs) have found extensive attention for externally bonded reinforcement of masonry and historical structures. However, only few information is available regarding their mechanical properties and effectiveness in improving the seismic performance of strengthened structures. This paper presents an extensive numerical investigation on the effect of TRM composites on the nonlinear response and failure modes of masonry walls. The effect of boundary conditions and the TRM type on the performance of strengthened walls are critically discussed and presented. It is shown that the performance and failure mode of the walls can significantly change after strengthening, an important issue that should be considered at the design stage. Finally, the effect of TRM application on the nonlinear response of a large historical masonry facade in Macau is investigated and presented., The first author is grateful to the SAHC Master Programme for the grant awarded. The second author acknowledges the financial support of the Ministerio da Ciencia, Tecnologia e Ensino Superior, FCT, Portugal, under the grant SFRH/BPD/92614/2013 as well as the financial support of the European Union's Marie Curie Individual Fellowship program under REA grant agreement No. 701531., info:eu-repo/semantics/publishedVersion

This research is focused on the experimental characterisation of the compressive behaviour of masonry in existing buildings. The proposed technique is based on in situ core drilling of masonry members. Two walls were built making use of terracotta handmade bricks and lime mortar, without cement, to reproduce a low-strength historical masonry. Core samples were extracted from the walls and then regularized to perform a non-standard compression test in the laboratory. Stack-bonded prisms were also tested under compression. A direct comparison is made between the results from the proposed non-standard tests on core samples and the tests suggested by the available standards on prismatic samples. The proposed minor destructive technique shows to be effective for the mechanical characterisation of existing masonry structures, including historical ones.

Because of the incomplete knowledge we have of the mechanical characteristics and of the history of loading of historical structures, these are often advantageously analyzed by means of graphic statics, e.g. using thrust lines as possible load paths within masonry arches to demonstrate their stability. In this context, theory of plasticity provides a powerful theoretical framework for the limit state analysis of structures, in particular for those in masonry on condition of several key assumptions: infinite strength in compression but zero in traction; no sliding failure. Starting with the analysis of a simple trussed framework and to basic bended structures, this paper emphasizes that limit analyses implying graphic statics can lead to similar conclusions about the collapse load factor that the ones obtained using the Principle of Virtual Works. Then it states a way to adapt this methodology to ancient masonry structures and presents results obtained for a simple arch analysis.

This study presents some numerical results related to the analysis of the structural damage of a historic masonry building, Palazzo Gulinelli, in Ferrara, Italy. A detailed analysis of the inhomogeneities of the facade, historic documentation, and recent restoration interventions carried out in an adjacent building, suggest that the Palace underwent various modifications both on the structural configuration and on the borne loads. Such modifications might be the main cause of some differential settlements and of the consequent significant crack pattern on the load-bearing walls. Therefore, in the present paper the occurrence of a crack pattern on the facade is simulated by carrying out standard linear and non-linear finite element (FE) homogenized models; differential settlements are applied in order to reproduce the structural changes occurred over time. Previous experiences of the authors (for example, Acito and Milani in 2012 and Mallardo et al. in 2008), the current crack pattern of the building (of i...

This paper reports on a structural safety assessment and performance evaluation of the upper choir of the Santa Maria de Belém Church in the Jerónimos monastery, Lisbon, one of the most important cultural heritage buildings in Portugal. The possibility of adding a new 20 t organ to the upper choir and its effects on the church structure's response are presented. A refined and a simplified finite-element model is developed to investigate the structure's performance under self-weight and seismic actions. A sensitivity analysis is performed to investigate the effect of masonry mechanical properties and rib cross-sections on the structural response, given the difficulty in accurately obtaining this information. The results show that the safety level of the structure is acceptable, even in the case of adding a heavy new organ.

In the last years significant developments occurred with respect to the possibilities of experimental and numerical analysis of ancient cultural heritage buildings. Such advances result from the societal growing concern about the preservation of this heritage, together with the evident cultural and economic importance of this activity. Recommendations for interventions in architectural heritage structures recently issued by ICOMOS are briefly reviewed here, with a discussion about the proposed methodology. Then, a case study is fully detailed, including the aspects of survey, advanced numerical analysis, diagnosis, justification of remedial measures and detailing of the adopted strengthening. The paper also advocates that significant information can be obtained from numerical analysis, namely with respect to the understanding of existing damage and to the minimum and adequate design of strengthening. A clear understanding of the structural behaviour, based on sophisticated tools of analysis, can therefore reduce the extent of the remedial measures in the restoration of ancient structures. In this case, a masonry chimney with severe damage is strengthened keeping the old fabric, as a significant example that ancient timber and masonry structural elements can often survive if appropriate methodologies for diagnosis and repair measures are adopted.

Masonry structures are complex systems that require a thorough and detailed knowledge and information regarding their behavior under seismic loading. Appropriate modeling of a masonry structure is a prerequisite for a reliable earthquake resistant design or assessment. However, modeling a real structure to a robust quantitative (mathematical) representation is a very difficult, complex and computationally demanding task. This paper presents a methodology for earthquake resistant design or assessment of masonry structural systems. The entire process is illustrated using case studies from historical masonry structures in the European area. In particular, the applicability of the proposed method is checked via analyses of existing masonry buildings in three countries, namely Greece, Portugal and Cyprus, with different seismicity levels, influencing the risk impacting the masonry structures. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structures, through the comparison of the results obtained.

Seismic damage and vulnerability of five historical masonry structures surveyed after the 1999 Kocaeli and Duzce, Turkey earthquakes are discussed in this paper. The structures are located in two neighboring cities that have been struck by five very large (M-s >= 7.0) earthquakes during the 20th century alone. Older masonry mosques with arches and domes and their masonry minarets (slender towers) were among the most affected structures in this highly seismic region. While some of the religious and historical structures had virtually no damage, most structures suffered significant damage or collapsed. In the city of Bolu, for example, approximately 600-year-old Imaret, 500-year-old Kadi, 250-year-old Sarachane, and 100-year-old Yildirim Bayezid mosques suffered substantial structural damage after the 1999 earthquakes. Another historical mosque surveyed in Duzce partially collapsed. Most common factors contributing to deterioration of historical structures are also presented. Furthermore, a brief overview of issues associated with analysis and modeling of historical masonry structures is provided.

The knowledge of the structural behaviour of existing masonry requires a multilevel approach, with proper application of different diagnostic and assessment methodologies. The paper presents successful application of the results of in-situ tests on modelling the behaviour of historical structures. In order to obtain reliable material parameters for the application of different numerical models, different test methodologies a combination of Destructive Tests (DT), Minor Destructive Tests (MDT) and Non-Destructive Tests (NDT) were performed. Following this, two different models were applied for the assessment of seismic resistance of Pišece Castle – structural element model (SEM) for non-linear seismic analysis and 3D finite element model (FEM) for linear analysis by means of modal response spectrum analysis. The results of numerical analysis provided valuable information of the loadbearing capacity of structures, their seismic resistance as well as possible causes for the observed crack patterns.

Conservation and restoration of historical structures are still a challenge to modern practitioners even if considerable research advances have occurred in the last decades, namely with respect to non-destructive testing, mechanical characterization, tools for advanced numerical analysis, knowledge on traditional materials and techniques, and innovative materials and techniques. In the paper, the ICOMOS Recommendations for the Analysis, Conservation and Structural Restoration of Architectural Heritage are briefly reviewed, together with recent developments in structural analysis. The proposed methodology is applied to Monastery of Jerónimos, in Lisbon, Portugal, including the following steps: seismic action characterization, from the identification of earthquake source areas to the artificial generation of acceleration time histories, using specific theoretical models and including superficial site-effects; simple numerical modeling for a preliminary knowledge of the structural behavior; experimental mechanical characterization of materials and structural elements; installation of static and dynamic monitoring systems aiming at a better understanding of the static and dynamic behavior; development of advanced numerical models including calibration against relevant experimental data; non-linear dynamic analysis of the structure for different earthquake levels.

The analysis of historical structures in need of preservation and restoration interventions is a very complex task due to the large uncertainties in the characterization of structural properties and detailing in view of the structural response. Moreover, the predictive performance of numerical analyses and simulations depend on the availability of information about the constructional properties of the architectural complex, crack patterns and active degradation phenomena. In particular, local changes in material properties or damage due to past events (such as earthquakes) can affect individual structural elements. They can be hardly detected as a result of the maintenance interventions carried out over the centuries and the possibility to carry out limited or even no destructive investigations due to the historical relevance of the structure. Thus, non-destructive investigations play a fundamental role in the assessment of historical structures minimizing, at the same time, the invasiveness of interventions. The present paper deals with an explanatory case study concerning the structural investigations carried out in view of the seismic assessment of an Italian historical monument, the Carthusian monastery of Trisulti in Collepardo, erected in 1204 under Pope Innocenzo HI. The relevance of the case study is due to the application, in combination, of different NDT methods, such as sonic tests, and active and passive infrared thermography, in order to characterize relevant masonry elements. Moreover, an advanced system for the in-situ nondestructive vibration-based estimation of the tensile loads in ancient tie-rods is described and the main results obtained from its application for the characterization of the tie-rods of the cloister are presented.

Historical structures are particularly difficult to analyze due to the lack of mechanical data. Here, a case study is fully detailed, including the aspects of historical, damage and geometric investigations, of advanced numerical analysis, of justification of remedial measures and of detailing the adopted strengthening. The paper also advocates that significant information can be obtained from numerical analysis, namely with respect to the understanding of existing damage and to the minimum and adequate design of strengthening. A clear understanding of the structural behavior and reliable strengthening, based on sophisticated tools of structural analysis, can therefore reduce the extent of the remedial measures in the restoration of ancient structures.

The final publication is available at Springer via http://dx.doi.org/10.1617/s11527-015-0654-y An experimental campaign involving the compressive testing of a brick masonry pillar extracted from a historical building is presented in this paper. The test procedure and the instrumentation are designed in order to determine, in addition to the compressive strength and global Young's modulus of the structure, the behavior in different parts of the pillar. Material samples, representative of the external leaf and the infill, are extracted from the pillar and tested in compression. Differences in strength and elasticity of the two components are critically presented and their influence on the maximum load and failure mode of the pillar are discussed. Finally, a simple analytical model is employed in order to quantify the effect of the mismatch of Young's modulus of the two components of the pillar. Analogies between the studied pillar and three-leaf wall masonry are drawn.