Masonry is a layered composite consisting of mortar and the masonry unit. Perfect bond between the masonry unit and the mortar is essential for the masonry to perform as one single entity in order to resist the stresses due to various loading conditions. Nature of stresses developed in the masonry unit and the mortar and the failure pattern of masonry subjected to compression greatly depends upon the relative stiffness of the masonry unit and the mortar. The thesis is focused on (a) some issues pertaining to masonry unit – mortar bond strength and its influence on masonry compressive strength, and (b) developing a finite element (FE) model to predict the compressive strength of masonry. Importance of masonry bond strength and masonry behaviour is highlighted in chapter 1. Characteristics of masonry units and mortars used in the investigations are presented in Chapter 2. Two types of soil-cement blocks with widely varying strength and elastic properties and cement-lime mortars of two different proportions were used in the investigations. Results of stress-strain relationships and other characteristics were determined for the blocks as well as for mortars. Block-mortar combinations were selected to have block modulus to mortar modulus ratio of <1.0, ~1.0 and >1.0. Different artificial methods of enhancing the shear bond strength of masonry couplets have been discussed in chapter 3. Shear bond strength of the masonry couplets was determined through a modified direct shear box test apparatus. Without altering the block and mortar properties, bond strength values for three block-mortar combinations were generated through experiments. Effect of pre-compression on shear bond strength has also been examined for certain block-mortar combinations. Considering five different bond strength values and three block-mortar combinations, compressive strength and stress-strain characteristics of masonry was obtained through the tests on masonry prisms. A detailed discussion on influence of shear bond strength on masonry compressive strength is presented. Major conclusions of the investigation are: (a) without altering the block and mortar characteristics shear bond strength can be enhanced considerably through the manipulation of surface texture and surface coatings, (b) masonry compressive strength increases linearly as the shear bond strength increases only for the combination of masonry unit modulus less than that of mortar modulus, (c) masonry compressive strength is not sensitive to bond strength variation when the modulus of masonry unit is larger than that of the mortar. Chapter 4 is dedicated to the development of a 3D FE model to predict the masonry compressive strength. Literature review of empirical methods/formulae and some failure theories developed to predict masonry strength are presented. Existing FE models for masonry dealing with both macro and micro modelling approaches are reviewed. The proposed FE model considers (a) 3D non-linear analysis combined with a failure theory, (b) uses multi-linear stress-strain relationships to model the non-linear stress-strain behaviour of masonry materials, (c) adopting Willam-Warnke’s five parameter failure theory developed for modelling the tri-axial behaviour of concrete, and (d) application of orthotropic constitutive equations based on smeared crack approach. The predicted values of masonry compressive strength are compared with experimental values as well as those predicted from other failure theories. The thesis ends with a summary of conclusions in chapter 5.

L'évaluation des risques naturels et du risque sismique en particulier a pris une importance croissante pour les autorités publiques ces dernières années, entraînant une adaptation importante des outils utilisés jusqu'à présent dans l'étude de la vulnérabilité du bâti. Il est nécessaire de mieux évaluer ces risques afin de mieux y faire face. De nouvelles approches doivent être proposées pour répondre à ces objectifs dont les approches numériques font partie. Parmi les méthodes numériques développées pour tenir compte de la spécificité du bâti maçonné figurent les approches par éléments discrets comme la méthode NSCD (« Non Smooth Contact Dynamics »). Les travaux présentés dans cette thèse visent à mieux appréhender le comportement mécanique et dynamique des ouvrages maçonnés en utilisant ce type de méthode implémenté dans le code calcul LMGC90, afin d'affiner la compréhension et la caractérisation de la vulnérabilité sismique des édifices en maçonnerie. La méthodologie que nous cherchons à mettre en place vise à traiter la vulnérabilité sismique de bâtiments spécifiques ou au contraire d'ensembles de bâtiments de même typologie. / The perception and the evaluation of natural risks and more particularly of the seismic hazard have never been so important and highlighted by the authorities. This phenomenon leads to a deep adjustment of tools used up to now in the assessment of the vulnerability of buildings. New approaches as numerical approaches have to be proposed so as to best estimate the risk. Among all the numeriacl methods developed to take into account specificities of masonry buildings, approaches by discrete elements methods as the NSCD method (“Non Smooth Contact Dynamics”) seem to be particularly well adapted. This PhD thesis aims to best understand the mechanical behaviour of masonry structures by using this discrete method implemented in the software LMGC90 so as to give an accurate estmation of the seismic vulnerability of buildings. The very purpose of this work is to develop a calculation tool able to deal with the vulnerabilityof both specific and common masonry buildings.

The most common form of dwellings in rural and semi-urban areas of India and other developing countries around the globe are one/two storey unreinforced masonry (URM) buildings. It is well known that such masonry buildings are most vulnerable during earthquakes. Out-of-plane flexural failures of walls are primarily responsible for collapse of URM buildings during an earthquake. The seismic performance of such buildings can be improved by reinforcing masonry walls in the horizontal and vertical directions with materials like steel, bamboo or fiber reinforced polymers (FRP). It is fairly easy to reinforce masonry in the horizontal direction by embedding the reinforcement in the bed joints of masonry construction. However, in the vertical direction, the reinforcement is generally provided in the cavities of hollow masonry units, which are grouted after placing the reinforcement. Even though the in-plane performance of masonry walls is enhanced with such a reinforcing technique, it still falls short in resisting out-of-plane lateral loads, as the vertical reinforcement is located close to neutral axis of bending. Hence, a novel technique of reinforcing masonry in the vertical direction on both the faces of the wall called containment reinforcement is proposed recently. Containment reinforcement improves ductility, energy dissipation and prevents overturning failure due to out-of-plane loading. The present study examines the role of containment reinforcement in improving out-of-plane / in-plane behavior of masonry. The research program consisted of characterizing the physical properties of the constituent materials of reinforced masonry, namely stabilized earth blocks, cement-soil-sand (1:1:6) mortar and steel and FRP reinforcement. The strength and elastic properties of masonry assemblages under compression, flexure and shear have been determined. The flexural behavior of three types of reinforced masonry assemblages namely; stretcher bond, English bond and rat-trap bond masonry beams under monotonic and reversed cyclic loading test protocols have been examined. The beams were reinforced with steel, Glass FRP (GFRP) and Carbon FRP (CFRP) materials. In the monotonic test protocol the moment-curvature relationships and ductility for each type of masonry beams were obtained. In the cyclic test protocols, the hysteretic behavior, energy dissipation and equivalent viscous damping characteristics were obtained. The shear behavior of unreinforced and reinforced masonry panels under diagonal tension (shear) was examined through monotonic and cyclic loading test protocols. A simple and cost effective device for producing horizontal to and fro motion to imitate earthquake ground motions, called shock table test facility, has been designed. The table platform is mounted on four wheels and moves on rails. The table is put into the motion through pendulum impacts. The table motion characteristics have been obtained using the parameters used to describe the earthquake ground motions like amplitude, frequency content, duration of the motion and mixed parameters. The parameters of the shock table motion have been compared with few of the recorded earthquake ground motions to evaluate the effectiveness of shock table testing protocol for examining the dynamic performance of scaled masonry building models. The performance of two half scaled containment reinforced masonry building models subjected to base motions provided through shock table and conventional shaking table was evaluated. The dynamic properties of masonry, responses and failure patterns were obtained. A non-linear finite element (FE) model was developed and calibrated using the experimental data generated in the flexural and shear testing of reinforced and unreinforced masonry beams and panels. The FE model was further used for analysis of half scale masonry building model tested on shock table and recalibrated by comparing responses of numerical model with experimentally measured responses. Furthermore, the finite element model was used to assess the performance of two storey unreinforced and containment reinforced symmetric/asymmetric masonry buildings subjected to a series of earthquake ground motions of increasing severity. The studies conducted conclude that the masonry with containment reinforcement was effective in mitigating seismic risks of masonry buildings in moderate to severe seismic regions. The provision of containment reinforcement significantly improved equivalent hysteretic damping at design displacement and offered excellent ductility to masonry elements. The existing construction practice can easily accommodate the provision of containment reinforcement with little modification to the construction sequence. The extra effort in construction does commensurate with the enhancement in the seismic performance of the masonry buildings.

Este trabalho apresenta um novo modelo numérico para simulação de juntas de argamassa em estruturas de alvenaria no plano via método dos elementos finitos. Neste modelo, blocos de alvenaria e juntas de argamassa são representados separadamente. Elementos finitos com alta razão de aspecto são utilizados para representar as juntas de argamassa e são inseridos na malha de elementos finitos através de uma técnica de fragmentação de malha. A principal vantagem desta técnica consiste na utilização de modelos constitutivos contínuos para representar regiões descontínuas, uma vez que seu campo de deformações quando a altura do elemento de interface tende a zero é semelhante ao apresentado pela abordagem de aproximação contínua de descontinuidades fortes. Um modelo constitutivo contínuo baseado na mecânica do dano foi desenvolvido para representar o comportamento dos elementos de interface. Este modelo consegue representar a abertura e fechamento de fraturas, bem como o efeito de atrito em função da tensão de confinamento nas interfaces. Como o objetivo deste trabalho consiste na simulação da formação e propagação de fraturas ao longo das juntas de argamassa, comportamento elástico linear foi atribuindo aos elementos triangulares de três nós utilizados na discretização dos blocos de alvenaria. Vários exemplos numéricos são apresentados. Inicialmente, testes básicos são realizados para demonstrar as principais características do modelo quando submetido a carregamentos de tração, compressão e cisalhamento. Posteriormente, estruturas de alvenaria submetidas a carregamentos estáticos são analisadas e os resultados comparados com as respostas experimentais a fim de validar o modelo proposto. A técnica proposta se mostrou bastante promissora para simulação da formação e propagação de fratura em juntas de argamassa de estruturas de alvenaria. / This work presents a novel numerical model to simulate the failure process in masonry structures subjected to static loads via finite element method. Brick and mortar joints are modeled separately with their own constitutive equations. Interface finite element with high aspect ratio are used to simulate the mortar interface and inserted by the mesh fragmentation technique. The main advantage of this strategy is supported by the fact that, as the aspect ratio of a standard low-order solid finite element increases, the element strains also increase, approaching the same kinematics as the Continuum Strong Discontinuity Approach. A constitutive model was developed, based on the continuum damage mechanics, in order to represent the behavior of the interface finite elements. This model is able to simulate the creation and propagation of cracks, as well as, the frictional effects in dependence on stress confinement on the interfaces. Furthermore, as the objective of this work aims to simulate the failure in the mortar joints, the brick elements are assumed as linear elastic material. Three node standard triangular finite element are used to represent the bricks. Several numerical models are carried out. Initially, basics tests are show in order to demonstrate the main characteristics of the proposed model subjected to tensile, compression and shear loads. Subsequently, masonry structures are subjected to static loads are analyzed and the results compared with the experimental responses in order to validate the proposed model. This technique proved to be very promising for the simulation of failure onset and propagation in mortar joints of masonry structures.

A construção de edifícios em alvenaria estrutural tem evoluído de maneira significativa no Brasil. Os edifícios têm se tornado cada vez mais altos, atingindo a marca de 20 pavimentos. Quanto mais altos os edifícios, maiores se tornam os níveis de compressão provenientes dos carregamentos verticais e a sua composição com as ações devidas ao vento e ao desaprumo, obrigando a um maior emprego da alvenaria estrutural armada. A aderência bloco/graute como fator limitante à capacidade do conjunto armadura/graute/bloco na absorção da compressão e tração simples ou da tração oriunda da flexão não é especificada nas normas tanto nacionais como internacionais. Este trabalho tem como objetivo principal estudar o comportamento da interface bloco/graute, tanto para blocos de concreto como cerâmicos e com a presença ou não de armadura, submetidos a solicitações que provocam tração e compressão. Recursos experimentais e numéricos foram realizados para o desenvolvimento da presente pesquisa. Foram feitos ensaios de caracterização dos materiais, dos componentes e da alvenaria, além de ensaios de \"push-out\" (empurramento) para determinar a resistência de aderência na interface graute/bloco e ensaios de \"pull-out\" (arrancamento) considerando-se a presença de barras de armadura para o estudo do comportamento do conjunto graute/bloco/armadura utilizados. Posteriormente foram realizadas modelagens computacionais no programa DIANA, que é baseado no método dos elementos finitos, para prever o comportamento estrutural dos modelos. A partir dos resultados experimentais e numéricos pôde-se concluir que existe uma boa aderência entre as paredes dos blocos de concreto e o graute, suficiente para evitar o escorregamento, sendo possível mobilizar toda a resistência de tração das barras de armadura de diâmetros usuais, desde que devidamente ancoradas. Já com os blocos cerâmicos observa-se uma menor aderência entre as paredes dos blocos e o graute, podendo ocorrer o escorregamento do material de enchimento, antes que a armadura alcance sua tensão de escoamento. O graute de maior resistência à compressão e menor fator água cimento (graute G30) apresentou maior resistência de aderência em relação ao graute mais fraco (graute G14) e de maior fator água/cimento. Quanto aos limites estabelecidos para a tensão de escoamento das armaduras, observa-se que, no caso de blocos de concreto, não deve haver restrição. Em contraposição, quanto aos blocos cerâmicos, o problema é mais complexo, cabendo a realização de mais ensaios para a confirmação de limites, com a variação de blocos e grautes. Os resultados do estudo paramétrico apontam limites que devem ser adotados no caso de diâmetro superior a 10 mm. De maneira simplificada, como ponto para futuras verificações pode-se propor: 75% para Ø 12,5 mm, 50% para Ø 16 mm e 25% para Ø 20 mm. As análises numéricas realizadas nos modelos ensaiados a push-out e pull-out representaram adequadamente o comportamentos observado em laboratório, permitindo a realização da análise paramétrica. / The construction of structural masonry buildings has evolved significantly in Brazil. The buildings have become ever higher, reaching the level of 20 floors. Higher buildings lead to lager compression levels, coming from the vertical loads combined to the horizontal actions due to wind and lack of verticality, obliging a greater use of reinforced structural masonry. The block/grout adherence is not specified in both national and international standards. This work aims to study the behavior of the block/grout interface, for both concrete and clay blocks, with and without reinforcement, submitted to tensile and compressive forces. Experimental and numerical resources were used to development of this study. The experimental program studied the masonry behavior using push-out specimens to determine the bond strength between the grout and the concrete unit, and pull-out specimens to study the behavior of the interface of the grout/block/reinforcement. Computational modelling was carried out using the FEM software Diana, which has a library with constitutive models suitable for civil engineering application, to complete the study and understand the structural behavior of the block/grout interface. The experimental results showed that there is a good bond between the concrete blocks internal faces and the grout, enough to prevent infill-slippage, and that the whole tensile strength of the usual reinforcement rebars is achieved provided they are properly anchored. Nevertheless, for clay blocks there is a low bond between the clay blocks internal faces and the grout, allowing the infill-slippage before the reinforcement bars reach their yield stress. The higher strength grout with lower water/cement ratio (grout G30) presented higher bond strength compared to the lower strength grout and higher water/cement ratio (grout G14). In the case of concrete blocks there should be no restriction limits on the yield stress of reinforcement, in a practical sense and considering other prescribed limits. In contradiction, in the case of clay blocks, additional tests should be carried out for establishing limits, with varying blocks and grouts. The parametric analysis indicates limits that should be adopted for a diameter larger than 10 mm. The authors of this research suggest 75% for Ø 12.5 mm, 50% for Ø 16 mm and 25% for Ø 20 mm as a reference point for future investigations. The numerical analysis showed that the computer models of the push-out and pull-out specimens represented adequately the behavior of the physical models, and thus can be used in parametric analysis.

Le rôle crucial des interfaces solides dans les problèmes de structures dans de nombreux domaines de l'Ingénierie est désormais bien connue et c'est certainement un sujet de grand intérêt scientifique. Aujourd'hui, la modélisation analytique et numérique des interfaces structurelles représentent un défi du fait desphénomènes physiques très complexes qu'il faut prendre en compte (tels que adhésion, contact non-conforme,microfissuration, frottement, contact unilatéral) autant que le besoin d'avoir des méthodes numériques qui soient capables de traiter à la fois la faible épaisseur des zones d'interface et les sauts dans les champs physiques concernés. Cette thèse vise à développer un outil analytique cohérent et général qui soit capable de dépasser les limitations des stratégies existantes et concernant la modélisation des interfaces emph{soft} et emph{hard} caractérisées par une microfissuration évolutive. Une nouvelle approche, appelée emph{Imperfect Interface Approach} (IIA), est proposée. Elle couple de manière cohérente arguments de théorie asymptotique et techniques d'homogénéisation pour les milieux microfissurés dans le cadre de la emph{Non-Interacting Approximation} (NIA). Dans le cadre de l'élasticité linéaire, l'IIA est employée avec succès pour obtenir un ensemble de modèles d'interfaces imparfaites.En généralisant la méthode de développement asymptotique à la théorie élastique des déformations finies, un modèle d'interface soft non-linéaire a été dérivé. Comme une nouvelle application, l'IIA est appliquée afin de formuler un modèle de contact non-conforme à raideurs equivalents. Simulations numériques appliquées à la maçonnerie ont été effectuées. / The crucial role of solid interfaces in structural problems in several engineering fields is well-established and they represent certainly a scientific topic of great interest. Nowadays, analytical and numerical modeling of structural interfaces are challenging tasks, due to the complex physical phenomena to take into account (such as adhesion, non-conforming contact, microcracking, friction, unilateral contact), as well as to the need of numerical methods suitable for treating small thickness of the interface zones and jumps in the physically relevant fields.Present PhD thesis aims to develop a consistent and general analytical tool able to overcome some modeling shortcomings of available modeling strategies accounting for soft and hard interfaces, and characterized by evolving microcracking. A novel approach, referred to as emph{Imperfect Interface Approach} (IIA), is proposed. It consistently couples asymptotic arguments and homogenization techniques for microcracked media in the framework of the Non-Interacting Approximation (NIA). In the context of linear elasticity, the IIA is successfully employed to derive a set of imperfect interface. By generalizing the matched asymptotic expansion method to finite strains, a nonlinear soft interface model has been derived. As a new general application, the IIA is applied to formulate a spring-type model for non-conforming contact. Finally, numerical simulations applying the soft interface models obtained in both linear and nonlinear cases to masonry structures, are carried out, showing effectiveness and soundness of the proposed formulation.

La conservación del patrimonio cultural esta considerado como un principio fundamental en la vida cultural de las sociedades modernas. En los últimos años, se han realizado extensas investigaciones en torno a esta área, conduciendo a desarrollos en la inspección, ensayos no destructivos, monitorización y análisis estructural de monumentos.Por otra parte, el análisis de construcciones antiguas formula importantes desafíos dada la complejidad de su geometría, la variabilidad de las propiedades de los materiales tradicionales, las diferentes técnicas de construcción, la ausencia de conocimiento sobre los daños existentes, y de cómo afectan determinadas acciones a las construcciones a lo largo de su vida.Dichos desafíos suponen que las construcciones del patrimonio arquitectónico estén sometidas a una serie de dificultades de diagnóstico y restauración, que limitan la aplicación de las disposiciones normativas y las pautas vigentes en el ámbito general de la construcción. Y es por todo ello que la comprensión, el análisis y la reparación de construcciones históricas se establece como uno de los desafíos más importantes de los técnicos modernos.¿Sería razonable operar a un enfermo sin tener constancia objetiva del mal que adolece?, en ese caso ¿porqué intervenimos en nuestra herencia cultural sin tener conocimiento contrastado de las causas desencadenantes de sus procesos patológicos?Respondiendo a la cuestión formulada, las intervenciones en las construcciones antiguas, dada su fragilidad, requieren precisión, detalle y formación especial en el desarrollo de un estudio previo riguroso de diagnóstico que de soporte a las decisiones sobre las técnicas de intervención que deben adoptarse.En este proceso es fundamental la fase de reconocimiento - análisis, dado que es en esta etapa en la que se plantean hipótesis y se comprueban, de forma objetiva, a través de cálculos y ensayos. Dentro de la fase referida, debe prestarse especial atención al reconocimiento experimental, dado que dicha inspección además de contribuir a la obtención de parámetros de entrada de los modelos de análisis, tiene como misión el contribuir a calibrarlos mediante la comprobación experimental de los resultados obtenidos analíticamente en determinados puntos de control.Por su parte, es deseable que dicho reconocimiento experimental se realice de la forma menos intrusiva posible para con la construcción, sobremanera en el caso de bienes de carácter monumental.En línea con lo argumentado, la investigación que se presenta incide, dentro del proceso metodológico general de intervención en una construcción antigua, en la fase del reconocimiento experimental, in situ, ligeramente destructivo, y a su vez, dentro de éste, en las técnicas orientadas a obtener información útil desde un punto de vista de la caracterización mecánica de elementos estructurales de fábrica.En este sentido, se pretende contribuir a la puesta a punto, en España, de métodos para la evaluación in situ de la fiabilidad de los elementos estructurales existentes en construcciones históricas de obra de fábrica. Para ello, se van a focalizar los esfuerzos en el calibrado, en laboratorio, de las técnicas de gatos planos, hole drilling y mini-presurometría de fábricas, y posteriormente se aplicarán a casos reales in situ. / Cultural heritage conservation is considered as a fundamental principle of modern societies' cultural life. In recent years, extensive research has been done on this area, leading developments on inspection, non-destructive testing, monitoring and monument structural analysis.In other hand, old buildings analysis implies significant challenges due to the complexity of its geometry, variability of traditional materials properties, different construction techniques, lack of knowledge about existing damage, and how certain actions affect throughout their life to buildings.These challenges mean that architectural heritage buildings are subject to diagnosis and refurbishment difficulties, which limit the application of standards and construction guidelines. That is why the understanding, the analysis and the historic buildings' repair, are considered as one of the most important challenges of modern technicians.Would it be reasonable to operate a patient without objective evidence of the illness that suffers? In that case, why do we intervene in our cultural heritage without knowing the causes that have initiated its pathological processes?Answering to this question, interventions in old buildings, because of its fragility, require accuracy, detail and a special education in the development of a previous diagnostic study, in order to give support to decisions to be adopted on intervention techniques.In this process, it is essential the phase survey - analysis, because it is at this stage where the hypothesis are set out and verified with calculations and tests. Within this phase, it should pay special attention to experimental survey, since such inspection contributes to both obtaining input parameters of the model analysis, and contributes to calibrate it using the experimental verification of the results obtained analytically at certain checkpoints.Moreover, it is desirable that such experimental survey is performed of the least intrusive way as possible for the construction, greatly in the case of monumental constructions.Within the general process of intervention on old constructions, the research presented insists on the on-site experimental survey stage, slightly destructive, and within it, on the techniques aimed to obtain useful information for the mechanical characterization of masonry structural elements.In this sense, it aims to contribute to the development in Spain of methods for on-site evaluation of the structural elements' reliability in masonry historical buildings. For this, efforts will focus on the calibration, in laboratory, of the techniques of flat jacks, hole drilling and masonry mini-pressurometer, and then its application to real on-site cases.

Γίνεται μια γενική ανφορά στο πρόβλημα της ενίσχυσης φέρουσας τοιχοποιίας με σύνθετα υλικά και παρουσιάζονται οι μέχρι τώρα τεχνικές και τρόποι εφαρμογής της μεθόδου. Στη συνέχεια αναπτύσεται λογισμικό το οποίο συνδιάζει την χρήση των πεπερασμένων στοιχείων και των προσομοιωμάτων θλιπτήρων-ελκυστήρων για την σύνθεση του τασικού πεδίου μεμονομένων δομικών στοιχείων Φ.Τ. Αντικειμενικός σκοπός είναι η σύνθεση ενός δικτυώματος από την επίλυση του οποίου να προκύπτει η τοπολογία των οπλισμών και η εκτίμηση του απαιτούμενου εμβαδού σύνθετου υλικού. Παρουσιάζονται τα πειραματικά αποτελέσματα που έχουν προκύψει απο δοκίμια περισφιγμένα διαφόρους τύπους σύνθετου υλικού, για διαφορετικά γεωμετρικέ χαρακτηριστικά και ποσότητες οπλισμού, καθώς και υλικό εμποτισμού. Βαθμονομείται ένα αναλτυικό προσομοίωμα για την περισφιγμένη τοιχοποιία με σύνθετα υλικά. Καταστρώνονται οι εξισώσεις σχεδιασμού Φ.Τ. ενισχυμένης με σύνθετα υλικά για τις κλασσικές περιπτώσεις καταπόνησης και συντίθεται λογισμικό που χρησιμοποιεί τις εξισώσεις αυτές. / Strengthening of masonry structures with FRPs. A general overview of the method and presentation of all the related topics that are known until today. Evaluation of a software that combines the finite element method with the strut-and -tie models in the composition of the stress field of a given load bearing masonry element. The purpose of the method is to compose a truss, from the given stress field, in order to identify the topology of the reinforcment (FRP strips), as well as the amount of the strips needed to be placed in the positions of the struts. Experimental investigation of the confined masonry with FRPs. Presentation of the experimental data using specimens with various b/h ratios confined with different type of fibers, layers of reinforcement, smoothening radious of the corners and with different type of impregnation materials. Synthesis of the equations governing the most important cases of strengthening masonry structures with FRPs and composition of a software for the design of such cases.

Les structures en maçonnerie représentent une proportion importante des maisons individuelles et sont plus vulnérables notamment lorsqu'elles sont soumises à des mouvements de terrain. Pour faire face aux conséquences de ce problème, une plate-forme d'essais a été développée pour simuler des mouvements de terrain et leur effet sur des modèles de structure en surface. Ce travail de thèse s'appuie sur un modèle physique réduit et développe des méthodes d'évaluation des dommages des structures maçonnées à l'aide de l'expérimentation physique. Dans un premier temps, un modèle physique à échelle réduite sous gravité terrestre (1g) a été conçu pour reproduire ce phénomène. Ce modèle d'interaction sol-fondation-maçonnerie est à l'échelle de 1/40. Le sol analogique est constitué d'un sable de Fontainebleau. La fondation de la structure est fabriquée à partir de silicone liquide, et les murs en maçonnerie sont constitués de petits blocs en bois. Pour mesurer les champs de déplacement du sol et de la structure, une technique de corrélation d'images numériques (DIC) est utilisée. Des discussions à propos de l'usage de cette technique lors de la réalisation d'un essai, notamment la prise en compte des erreurs de mesures, ont été également abordées. Dans un deuxième temps, on évalue les dommages par les méthodes conventionnelles basées sur des indicateurs de dommages et des abaques. Ensuite, des nouveaux outils basés sur la technique DIC sont proposés pour réaliser une évaluation de dommages plus efficace, et plus aisée. Le premier outil se basant sur le modèle d'interaction sol-structure de Winkler permet d'identifier les modes de rupture dans la structure. Pour cela, le problème inverse de l'interaction sol-structure a été résolu et les modes de rupture du mur, basés sur les efforts internes, ont été identifiés. Ensuite, un modèle DIC-M est proposé pour reproduire les fissures dans la maçonnerie. Le point clé de ce modèle concerne les mouvements des blocs qui sont simulés par un système d'éléments distincts. Par ce moyen, la reproduction des fissures, puis l'identification et la quantification des fissures deviennent aisées. Plus précisément, un nouvel indicateur de dommages lié à la longueur des fissures permet de mieux quantifier les dommages et de cartographier les fissures. L'incertitude de mesure est déterminée par une simulation de Monte-Carlo des erreurs de déplacements. Dans un troisième temps, la performance des outils développés est évaluée au travers d'un exemple d'évaluation des dommages potentiels. Une maison individuelle en maçonnerie soumise aux mouvements de terrain a été étudiée à l'aide de l'expérimentation physique. Une campagne d'essais considérant les positions les plus sensibles par rapport à la cuvette d'affaissement est réalisée. L'évaluation du niveau de dommage a été réalisée à l'aide des mesures de déformations et des caractéristiques de fissures observées. La comparaison entre les méthodes conventionnelles et la méthode développée montre la pertinence de l'indicateur longueur des fissures, et cet indicateur peut être considéré comme un nouvel outil lors d'évaluation des dommages dans la pratique. Pour conclure, des recommandations opérationnelles ont été suggérées afin d'obtenir une meilleure estimation du niveau de dommages de la structure. / Masonry structures present a significant proportion of individual houses and are especially more vulnerable when subjected to ground movements. To deal with consequences of this problem, a test-platform has been developed in order to simulate ground movements and their effect on structure models on the surface. This thesis is based on a reduced physical model and develops damage assessment methods for masonry structures using physical modelling. Firstly, a small-scaled physical model under Earth's gravity (1g) has been developed to reproduce this phenomenon. This model of soil-foundation-masonry interaction has a scale factor of 1/40. The analogue soil consists of the Fontainebleau sand. The foundation part of the structure is made of liquid silicon and masonry walls are made from small wooden blocks. To measure displacements fields of the soil and the structure, a digital image correlation (DIC) technique is used. Discussions about the use of this technique when performing a test, especially the consideration of measurement errors, are also addressed. Secondly, we first assess the damage through conventional methods based on damage indicators and graphs. Then, new easy to use tools based on the DIC technique are proposed to carry out a more effective damage assessment. The first tool helps identify failure modes in the structure, based on the Winkler soil-structure interaction model. To do this, the inverse problem of soil-structure interaction is resolved, and the failure modes, based on internal forces, are identified. Then, a DIC-M model is proposed to reproduce the crack propagation in the masonry wall. The key point of this model consists in the simulation of the block movements in a discrete element system (DES). Consequently, cracks can appear easily, and then the crack identification and quantification become easier. More precisely, a new damage indicator related to the cumulated length of cracks allows to better quantify the damage and the cartography the cracks. The measurement uncertainty is determined by Monte-Carlo simulation. Thirdly, the performance of proposed tools is discussed through an example of assessing potential damages. An individual house in masonry subjected to ground movements was studied using physical experimentation. A test campaign related to the most sensitive positions of the structure with respect to the subsidence centre is performed. Damage assessment is conducted using deformation measurement and crack characteristics. The comparison between conventional and developed methods shows the relevance of the damage indicator related to the cumulated length of cracks, and this indicator can be considered as a new tool for damage assessment in practice. Finally, operational recommendations are suggested in order to obtain a better estimation of the damage level of the structure.

Les structures en maçonnerie représentent une proportion importante des maisons individuelles et sont plus vulnérables notamment lorsqu'elles sont soumises à des mouvements de terrain. Pour faire face aux conséquences de ce problème, une plate-forme d'essais a été développée pour simuler des mouvements de terrain et leur effet sur des modèles de structure en surface. Ce travail de thèse s'appuie sur un modèle physique réduit et développe des méthodes d'évaluation des dommages des structures maçonnées à l'aide de l'expérimentation physique. Dans un premier temps, un modèle physique à échelle réduite sous gravité terrestre (1g) a été conçu pour reproduire ce phénomène. Ce modèle d'interaction sol-fondation-maçonnerie est à l'échelle de 1/40. Le sol analogique est constitué d'un sable de Fontainebleau. La fondation de la structure est fabriquée à partir de silicone liquide, et les murs en maçonnerie sont constitués de petits blocs en bois. Pour mesurer les champs de déplacement du sol et de la structure, une technique de corrélation d'images numériques (DIC) est utilisée. Des discussions à propos de l'usage de cette technique lors de la réalisation d'un essai, notamment la prise en compte des erreurs de mesures, ont été également abordées. Dans un deuxième temps, on évalue les dommages par les méthodes conventionnelles basées sur des indicateurs de dommages et des abaques. Ensuite, des nouveaux outils basés sur la technique DIC sont proposés pour réaliser une évaluation de dommages plus efficace, et plus aisée. Le premier outil se basant sur le modèle d'interaction sol-structure de Winkler permet d'identifier les modes de rupture dans la structure. Pour cela, le problème inverse de l'interaction sol-structure a été résolu et les modes de rupture du mur, basés sur les efforts internes, ont été identifiés. Ensuite, un modèle DIC-M est proposé pour reproduire les fissures dans la maçonnerie. Le point clé de ce modèle concerne les mouvements des blocs qui sont simulés par un système d'éléments distincts. Par ce moyen, la reproduction des fissures, puis l'identification et la quantification des fissures deviennent aisées. Plus précisément, un nouvel indicateur de dommages lié à la longueur des fissures permet de mieux quantifier les dommages et de cartographier les fissures. L'incertitude de mesure est déterminée par une simulation de Monte-Carlo des erreurs de déplacements. Dans un troisième temps, la performance des outils développés est évaluée au travers d'un exemple d'évaluation des dommages potentiels. Une maison individuelle en maçonnerie soumise aux mouvements de terrain a été étudiée à l'aide de l'expérimentation physique. Une campagne d'essais considérant les positions les plus sensibles par rapport à la cuvette d'affaissement est réalisée. L'évaluation du niveau de dommage a été réalisée à l'aide des mesures de déformations et des caractéristiques de fissures observées. La comparaison entre les méthodes conventionnelles et la méthode développée montre la pertinence de l'indicateur longueur des fissures, et cet indicateur peut être considéré comme un nouvel outil lors d'évaluation des dommages dans la pratique. Pour conclure, des recommandations opérationnelles ont été suggérées afin d'obtenir une meilleure estimation du niveau de dommages de la structure. / Masonry structures present a significant proportion of individual houses and are especially more vulnerable when subjected to ground movements. To deal with consequences of this problem, a test-platform has been developed in order to simulate ground movements and their effect on structure models on the surface. This thesis is based on a reduced physical model and develops damage assessment methods for masonry structures using physical modelling. Firstly, a small-scaled physical model under Earth's gravity (1g) has been developed to reproduce this phenomenon. This model of soil-foundation-masonry interaction has a scale factor of 1/40. The analogue soil consists of the Fontainebleau sand. The foundation part of the structure is made of liquid silicon and masonry walls are made from small wooden blocks. To measure displacements fields of the soil and the structure, a digital image correlation (DIC) technique is used. Discussions about the use of this technique when performing a test, especially the consideration of measurement errors, are also addressed. Secondly, we first assess the damage through conventional methods based on damage indicators and graphs. Then, new easy to use tools based on the DIC technique are proposed to carry out a more effective damage assessment. The first tool helps identify failure modes in the structure, based on the Winkler soil-structure interaction model. To do this, the inverse problem of soil-structure interaction is resolved, and the failure modes, based on internal forces, are identified. Then, a DIC-M model is proposed to reproduce the crack propagation in the masonry wall. The key point of this model consists in the simulation of the block movements in a discrete element system (DES). Consequently, cracks can appear easily, and then the crack identification and quantification become easier. More precisely, a new damage indicator related to the cumulated length of cracks allows to better quantify the damage and the cartography the cracks. The measurement uncertainty is determined by Monte-Carlo simulation. Thirdly, the performance of proposed tools is discussed through an example of assessing potential damages. An individual house in masonry subjected to ground movements was studied using physical experimentation. A test campaign related to the most sensitive positions of the structure with respect to the subsidence centre is performed. Damage assessment is conducted using deformation measurement and crack characteristics. The comparison between conventional and developed methods shows the relevance of the damage indicator related to the cumulated length of cracks, and this indicator can be considered as a new tool for damage assessment in practice. Finally, operational recommendations are suggested in order to obtain a better estimation of the damage level of the structure.