Avec l'augmentation de la demande énergétique et la raréfaction des réserves prouvées de pétrole, l'exploration pétrolière se tourne vers des sites de plus en plus difficiles, notamment les bassins géologiquement complexes. Pour évaluer les paramètres clés de l'exploration-production, des logiciels de simulation sont utilisés pour reconstituer l'historique du bassin. La modélisation physique et la formulation numérique sur lesquelles ils s'appuient doivent alors être enrichies pour mieux appréhender (voire prédire) le développement des surpressions. Cette thèse comporte deux volets: l'amélioration de la modélisation du géomatériau grâce à la micromécanique et le développement d'un outil de simulation gérant les spécificités de notre problème. Une nouvelle modélisation micromécanique du géomatériau est proposée pour tenir compte du mécanisme de pression-dissolution (compaction chimique). L'intérêt de la micromécanique est d'obtenir une loi macroscopique calibrée avec des données microscopiques mesurables en laboratoire. Depuis les travaux d'Athy (1930), modéliser l'évolution de la porosité aux grandes échelles de temps reste une problématique majeure. Aujourd'hui elle est estimée à l'aide de courbes empiriques de porosité-profondeur, qui hélas présentent une grande variabilité. Notre approche consiste à calculer la porosité au cours de l'enfouissement à l'aide de la déformation du squelette et de la pression de pore, ces deux variables couplées étant issues de la résolution d'équations mécaniques fondamentales. Une formulation originale a été conçue selon cette approche pour traiter la sédimentation et le déséquilibre de compaction, tensoriellement, en grandes déformations, suivant un mécanisme de compaction mécanique, avec un comportement évoluant dans le temps. L'implémentation numérique est quasiment aboutie et a déjà été validée partiellement avec des résultats analytiques. Une fois finalisé, cet outil de simulation devrait permettre de traiter des situations non oedométriques (contrairement aux simulateurs actuels) et permettre l'étude des bassins à histoire tectonique complexe / With the rise of energetic demand and the growing scarcity of proved reserves of oil, the oil industry explores areas of extreme conditions and geologically complex basins. To estimate the key parameters for exploration-production, simulation softwares are used to reconstitute the history of the basin. The physical modelling and the numerical formulation on which they lean must be enriched to understand (even predict) overpressures. This thesis work contains two items: the improvement of the modelling of geomaterials using micromechanics and the development of a hydromechanical simulation tool handling the specificities of our problem. A new micromechanical modelling of geomaterials is designed to take into account the mechanism of pressure-dissolution (chemical compaction). The asset of micromechanics is to produce a macroscopic law calibrated with microscopic data which can be measured in laboratory. Since the work of Athy (1930), modelling the evolution of porosity over geological time-scale remains a major challenge. Today it is estimated by means of empirical curves of porosity-depth, which regrettably present a big variability. Our approach consists in evaluating the porosity during burial relatively to the strain of the skeleton and the pore pressure - these two coupled variables resulting from fundamental mechanical equations. An original formulation is designed according to this approach to treat the sedimentation and the desequilibrium compaction, tensorially, in large strains, following a mechanism of mechanical compaction, with a time-dependent behavior. Its numerical encoding is almost finished and has already been partially validated with analytical solution. Once finished, this simulation tool should allow to treat not only oedometrical situations but more general situations (contrary to current simulators) and study basins with complex tectonic history

Este trabalho enfoca a análise estrutural de um dos tipos de laje que vem ganhando espaço no mercado brasileiro, que é a laje formada por vigotas de concreto protendido. O objetivo principal do trabalho é contribuir na avaliação do comportamento desse tipo de laje com relação aos momentos fletores negativos no apoio, mediante análise teórica. Esta análise foi realizada a partir da relação momento x curvatura proposta pelo CEB-90 em conjunto com a técnica do carregamento incremental para a consideração da não-linearidade física do concreto. Esse método foi avaliado através da comparação com resultados experimentais de painéis alveolares encontrados na literatura, verificando que o modelo teórico representa satisfatoriamente o comportamento estrutural de lajes formadas por elementos pré-moldados protendidos. A partir disto, fez-se análises em situações representativas de projeto de lajes formadas por vigotas protendidas, chegando-se as seguintes conclusões: a) a utilização da continuidade favorece fortemente a redução dos deslocamentos; b) os deslocamentos praticamente independem da taxa de armadura de continuidade; c) a evolução do momento fletor negativo no apoio e momento fletor positivo máximo no vão apresentou um comportamento padrão para os casos analisados; d) esse comportamento foi independente da taxa de armadura de continuidade e e) a taxa de armadura de continuidade afetou praticamente o valor da carga última. / This work aims the structural analysis in a type of slabs that is increasing its utilization in Brazil. These slabs are made by precast prestressed joists. The main objective of this work is the evaluation of the behavior of this type of slabs by theoretical analysis of the bending moments on the supports of continuous slabs. In the theoretical analysis was carried out the consideration of the non-linear of the concrete behavior through the moment x curvature relationship of Model Code CEB-90 add incremental load technique. This methodology was appraised with experimental results of panels of hollow core slabs and this methodology was able to represent satisfactorily the behavior of slabs made by precast prestressed elements. Analysis of representative cases of slabs with precast prestressed joists was carried out and the main conclusions were: a) the use of continuity aids highly to decrease the displacements; b) displacements were practically independent of reinforcement ratio on the support; c) the development profiles of the bending moments had a standard behavior to the analysed cases; d) this behavior was independent of reinforcement ratio on the support and e) the reinforcement ratio on the support affected practically the ultimate load value.

Este trabalho enfoca a análise estrutural de um dos tipos de laje que vem ganhando espaço no mercado brasileiro, que é a laje formada por vigotas de concreto protendido. O objetivo principal do trabalho é contribuir na avaliação do comportamento desse tipo de laje com relação aos momentos fletores negativos no apoio, mediante análise teórica. Esta análise foi realizada a partir da relação momento x curvatura proposta pelo CEB-90 em conjunto com a técnica do carregamento incremental para a consideração da não-linearidade física do concreto. Esse método foi avaliado através da comparação com resultados experimentais de painéis alveolares encontrados na literatura, verificando que o modelo teórico representa satisfatoriamente o comportamento estrutural de lajes formadas por elementos pré-moldados protendidos. A partir disto, fez-se análises em situações representativas de projeto de lajes formadas por vigotas protendidas, chegando-se as seguintes conclusões: a) a utilização da continuidade favorece fortemente a redução dos deslocamentos; b) os deslocamentos praticamente independem da taxa de armadura de continuidade; c) a evolução do momento fletor negativo no apoio e momento fletor positivo máximo no vão apresentou um comportamento padrão para os casos analisados; d) esse comportamento foi independente da taxa de armadura de continuidade e e) a taxa de armadura de continuidade afetou praticamente o valor da carga última. / This work aims the structural analysis in a type of slabs that is increasing its utilization in Brazil. These slabs are made by precast prestressed joists. The main objective of this work is the evaluation of the behavior of this type of slabs by theoretical analysis of the bending moments on the supports of continuous slabs. In the theoretical analysis was carried out the consideration of the non-linear of the concrete behavior through the moment x curvature relationship of Model Code CEB-90 add incremental load technique. This methodology was appraised with experimental results of panels of hollow core slabs and this methodology was able to represent satisfactorily the behavior of slabs made by precast prestressed elements. Analysis of representative cases of slabs with precast prestressed joists was carried out and the main conclusions were: a) the use of continuity aids highly to decrease the displacements; b) displacements were practically independent of reinforcement ratio on the support; c) the development profiles of the bending moments had a standard behavior to the analysed cases; d) this behavior was independent of reinforcement ratio on the support and e) the reinforcement ratio on the support affected practically the ultimate load value.

This thesis has discussed both properties and geometry of concrete slabs used in bridges. It gave understanding on behavior of concrete in both tension and compression zones and how crack propagates in specimens by presenting both theory of fracture and performing concrete tests like tension splitting, uniaxial compression and uniaxial tension tests. Furthermore, it supported experimental tests with finite elements modelling for each test, and illustrated both boundary conditions and loads. The thesis has used ARAMIS cameras to observe crack propagations in all experimental tests, and its first study at LNU that emphasized on Brazilian test, because of importance of this test to describe both crushing and cracking behavior of concrete under loading. It’s an excellent opportunity to understand how concrete and steel behave individually and in combination with each other, and to understand fracture process zone, and this has been discussed in theory chapter. The geometry change that could affect stresses distributions has also described in literature and modelled to give good idea on how to model slabs in different angles in the methodology chapter. Thus, thesis will use finite elements program (Abaqus) to model both experimental specimens and concrete slabs without reinforcement to emphasize on concrete behavior and skewness effect. This means studying both properties of concrete and geometry of concrete slabs. This thesis has expanded experimental tests and chose bridges as an application.

L’interaction dynamique entre le sol et les structures (IDSS) a fait l’objet de nombreuses études sous l’hypothèse de l’élasticité linéaire, bien que les effets de l’IDSS puissent être différents entre un système élastique et un système inélastique. De fait, les méthodologies usuelles développées à partir des études élastiques peuvent ne pas être adaptées aux bâtiments conçus pour dissiper de l’énergie par de l’endommagement lors de séismes sévères. De plus, il est bien connu que la limite d’élasticité du sol est normalement atteinte même pour de séismes relativement faibles. En conséquence, si les effets inélastiques de l’IDSS sont négligés, les études d’endommagement sismique des bâtiments peuvent être très inexactes. L’objectif de ce travail est de développer une stratégie générale pour l’étude du problème de l’IDSS non-linéaire dans le contexte de l’analyse de la vulnérabilité sismique des bâtiments. Ainsi, des modèles d’éléments finis réalistes sont développées et appliquées à des problèmes d’IDSS non-linéaires. Les modèles couvrent une large gamme des conditions pour le sol et des typologies de bâtiments soumis à plusieurs bases de données sismiques. Une stratégie de modélisation a été développée et validée afin de réduire significativement le coût numérique. Pour cela, un modèle 2D équivalent a été développé, implanté dans GEFDyn et utilisé pour effectuer une importante étude paramétrique. De nombreux indicateurs de comportement non-linéaire de la structure et du sol ont été proposés pour synthétiser leur fonctionnement lors du chargement sismique. De surcroît, une stratégie d’évaluation de la vulnérabilité sismique basée sur l’information apportée par une base des données sismiques a été développée. De façon, générale, les résultats ont mis en évidence une réduction de la demande sismique lorsque les effets inélastiques de l’IDSS sont pris en compte. Cette réduction est liée fondamentalement à deux phénomènes : l’amortissement par radiation et l’amortissement hystérétique du sol. Ces deux effets ont lieu simultanément pendant le mouvement sismique. Il est alors très difficile d’isoler l’influence de ces deux phénomènes. En effet, le mouvement effectif transmis à la structure n’est pas le même que celui en champs libre du aux effets d’interaction, ainsi qu’à la modification locale du comportement du sol fortement lié aux poids du bâtiment. Une série de mesures de sévérité sismique et des mécanismes de dissipation d’énergie au niveau du sol et du bâtiment a été introduite dans le but d’analyser ces effets. Cependant, ces résultats sont en général très irréguliers et leur généralisation a été très difficile. Néanmoins, ces résultats mettent en évidence l’importance de la prise en compte des effets du comportement inélastique du sol. La plupart des cas étudiés ont montré un effet favorable de l’IDSS non-linéaire. Mais, en général, l’IDSS peut augmenter ou diminuer la demande sismique en fonction de la typologie de la structure, des caractéristiques du mouvement sismique et des propriétés du sol. Tout de même, il y a une justification économique pour étudier les effets du comportement non-linéaire du sol sur la réponse sismique. / The dynamic interaction of the soil with a superstructure (DSSI) has been the subject of numerous investigations assuming elasticity of both, superstructure and soil foundation behavior. Nevertheless, the effect of DSSI may differ between elastic and inelastic systems. Thus, the current interaction methodologies based on elastic response studies could not be directly applicable to structures expected to behave inelastically during severe earthquakes. Additionally, the soil is known to exhibit inelastic behavior even for relatively weak to moderate ground motions. Consequently, ignoring these characteristics in studying DSSI could lead to erroneous predictions of structural damage. The main purpose of this work is to develop a general strategy to address the full DSSI problem in the context of the seismic vulnerability analysis of structures. Thus, realistic Finite Elements models are constructed and applied in a practical way to deal with these issues. These models cover a large range of soil conditions and structural typologies under several earthquake databases. Some modelling strategies are introduced and validated in order to reduce the computational cost. Therefore, an equivalent 2D model is developed, implemented in GEFDyn and used in the large parametric study conducted. Several indicators for both structural and soil responses are developed in order to synthesize their behavior under seismic loading. Additionally, a vulnerability assessment strategy is presented in terms of measures of information provided by a ground motion selection. According to the investigation conducted in this work, there is in general a reduction of seismic demand or structural damage when non-linear DSSI phenomenon is included. This reduction can be associated fundamentally to two phenomena: radiative damping and hysteretic damping due to non-linear soil behavior. Both effects take place simultaneously during the dynamic load and it is extremely difficult to separate the contribution of each part in reducing seismic demand. Indeed, effective motion transmitted to the superstructure does not correspond to the free field motion because of the geometrical and inertial interactions as well as the local modification of soil behavior, specially due to the supplementary confinement imposed by the superstructure’s weight. A series of strong-motion severity measures, structural damage measures and energy dissipation indicators have been introduced and studied for this purpose. Nevertheless, results are erratic and consequently, generalization was extremely difficult. Despite these difficulties, the results illustrate the importance of accounting for the inelastic soil behavior. The major part of the studied cases show beneficial effects such as the decrease of the maximum seismic structural demand. However, the non-linear DSSI could increase or decrease the expected structural damage depending on the type of the structure, the input motion, and the dynamic soil properties. Furthermore, there is an economic justification to take into account the modification effects due to inelastic soil behavior.

L'instabilité des blocs situés à la surface des excavations souterraines est un problème courant dans les milieux rocheux fracturés. Comme les méthodes exactes prenant en compte tous les blocs et leurs interactions sont très lourdes, l'approche des Blocs Isolés est souvent adoptée. Elle consiste à étudier chaque bloc en considérant qu'il est rigide et que le reste de la masse rocheuse est rigide et fixe. Néanmoins, aucune des méthodes existantes adoptant cette approche ne prend en compte de façon rigoureuse les contraintes initiales et le comportement des joints. Dans cette thèse, on développe une nouvelle méthode qui apporte des améliorations importantes aux méthodes conventionnelles de Blocs Isolés. Connaissant les contraintes initiales, on rend compte du processus d'excavation par le déchargement de la face libre du bloc. Les efforts sur les faces du bloc en contact avec la roche sont alors modifiés en respectant l'équilibre des forces et des moments, la loi de comportement des joints et le mouvement de corps solide du bloc. On aboutit ainsi à un système linéaire où les seules inconnues sont les vecteurs translation et rotation du bloc. Deux modèles sont proposés : le premier considère un comportement linéaire élastique des joints et, par conséquent, la stabilité est évaluée a posteriori. Le deuxième modèle, plus pertinent, considère un comportement hyperbolique des joints dans la direction normale et élastoplastique dans la direction tangentielle avec prise en compte de la dilatance. La méthode numérique adoptée pour la résolution du problème non linéaire est une intégration explicite dans le temps cinématique avec des pas de déchargement constants. La technique d'intégration surfacique utilisée permet d'étudier toute forme géométrique de bloc. La méthode proposée a été validée puis comparée aux méthodes conventionnelles. Des études paramétriques ont montré l'influence des contraintes initiales et des propriétés mécaniques des joints sur la stabilité. Le soutènement a été aussi intégré dans le code développé. Finalement, la nouvelle méthode a été appliquée pour l'étude d'un assemblage de blocs autour d'une excavation souterraine et comparée à un modèle prenant en compte tous les blocs via la méthode des Éléments Distincts. Elle a été aussi utilisée pour restituer un cas réel de chute de blocs. / Failure of rock blocks located at the surface of underground excavations is a common problem in discontinuous rock masses. Since exact methods that take into account all blocks and their interactions are computationally hard, the Isolated Blocks method is usually adopted. It consists in studying each block considering it to be rigid and the surrounding rock mass to be rigid and fixed. Nevertheless, none of the existing methods based on this approach takes into account initial stresses and joints behavior rigorously. In this thesis, a new method providing significant improvements to conventional Isolated Blocks methods is developed. Considering that initial stresses are known, the excavation process is modeled by unloading the block's free face. Stresses acting on the faces in contact with the rock mass are then resolved by taking into account force and moment balance equations, joints behavior and rigid body movement. This leads to a linear system where the block's translation and rotation vectors are the only unknowns.Two models are proposed: the first one assumes linear elastic joint behavior, thus the stability is evaluated a posteriori. The second, more realistic model, assumes joint behavior to be hyperbolic in the normal direction and elastoplastic in the tangential direction, while also accounting for dilatancy. This non-linear problem is solved numerically by explicit integration in the kinematic time with constant deconfining steps. Also, thanks to the surface integration technique used, any block geometry can be studied. The method proposed is validated and compared to other conventional methods. Parametric studies show the influence of initial stresses and the joints' mechanical properties on the stability. Rock support modeling is also integrated into the code. Finally, the new method is applied to study an assemblage of blocks around an underground excavation and is compared to a model that takes into account all the blocks with the Distinct Element Method. It is also used to reproduce an actual block failure case.

Este trabalho aborda um dos tipos construtivos mais empregados em lajes de edificações no Brasil, que são as lajes com nervuras pré-moldadas com armação treliçada. O objetivo principal do trabalho é contribuir na avaliação da continuidade estrutural relativa aos momentos fletores negativos nos apoios destas lajes. Para a realização deste trabalho, as lajes em concreto pré-moldado formadas por vigota com armação treliçada foram analisadas segundo modelos teóricos e experimentais. Na análise teórica, a consideração da não-linearidade física do concreto é realizada a partir do uso da relação momento x curvatura proposta pelo código modelo CEB-90 em conjunto com a técnica do carregamento incremental. Os resultados do modelo teórico são confrontados com os resultados obtidos em ensaios experimentais de faixas de lajes contínuas dimensionadas com diferentes graus de redistribuição dos momentos fletores negativos. Nas análises realizadas observa-se que: a) o modelo teórico apresenta bons resultados comparados aos resultados experimentais, b) as lajes apresentam boa capacidade de rotação plástica, c) com alta taxa de armadura negativa não ocorre redistribuição de esforços, d) as flechas praticamente independem da taxa de armadura negativa e e) a força última é praticamente independente do grau de redistribuição adotado no dimensionamento. / This work deal with an usual type of slab in Brazil: slabs made by precast joist with lattice reinforcement. The goal of this work is the structural analysis of bending moments in the supports of slabs made by this kind of precast element. Theoretical and experimental models analyze this type of slab. In the theoretical analysis, the non-linear concrete behavior is done by moment x curvature relationship of Model Code CEB-90 add incremental load technique. The theoretical model is compared with experimental results of continuous strip slabs designed with different degrees of bending moment redistribution. In these analysis had been noted: a) the theoretical model presents good results compared with the experimental results, b) the slabs present good plastic rotation capacity, c) with high negative reinforcement ratio in the support does not happen moment redistribution, d) the displacement is practically independent of negative reinforcement ratio and e) the ultimate load is practically independent of redistribution degree idealized in the design.

Neste trabalho é enfocada a análise estrutural de lajes pré-moldadas formadas por vigotas treliçadas. Esta análise foi realizada mediante o modelo de grelha, considerando a não-linearidade do concreto armado utilizando-se a relação momento x curvatura e carregamento incremental. O modelo da não-linearidade do concreto armado foi avaliado com resultados experimentais de vigas bi-apoiadas e painéis de laje contínua. O trabalho inclui uma análise teórico-experimental de uma laje pré-moldada bidirecional isolada e simulações numéricas de casos representativos de arranjos estruturais das lajes treliçadas. As principais conclusões do trabalho foram: a) o modelo de grelha é bastante adequado para a análise de lajes nervuradas pré-moldadas; b) os resultados da análise teórico-experimental da laje pré-moldada indicam que os deslocamentos foram fortemente influenciados pela rigidez à torção e c) a redistribuição de momentos fletores nas lajes contínuas é relativamente pequena. / This work aims the structural analysis in precast slabs made by lattice joist. The scheme was carried out by using the grillage model considering the non-linear of the reinforced concrete through the relationship moment x curvature and incremental loads. The non-linear model of the reinforced concrete was appraised with experimental of simply supported beams and panels of continuos slabs. The work includes a theoretical-experimental analysis of a isolated bidirectional precast slabs and numeric simulations of representative cases of structural arrangements of the slabs witch lattice joist. The main conclusions of the work were: a) the grillage model is quite appropriate for precast ribbed slabs; b) the results of theoretical-experimental analysis of the precast slabs point out the relevance the torsional in the deflections and c) the bending moments redistribution in the continuous slabs are quite small.

Este trabalho aborda um dos tipos construtivos mais empregados em lajes de edificações no Brasil, que são as lajes com nervuras pré-moldadas com armação treliçada. O objetivo principal do trabalho é contribuir na avaliação da continuidade estrutural relativa aos momentos fletores negativos nos apoios destas lajes. Para a realização deste trabalho, as lajes em concreto pré-moldado formadas por vigota com armação treliçada foram analisadas segundo modelos teóricos e experimentais. Na análise teórica, a consideração da não-linearidade física do concreto é realizada a partir do uso da relação momento x curvatura proposta pelo código modelo CEB-90 em conjunto com a técnica do carregamento incremental. Os resultados do modelo teórico são confrontados com os resultados obtidos em ensaios experimentais de faixas de lajes contínuas dimensionadas com diferentes graus de redistribuição dos momentos fletores negativos. Nas análises realizadas observa-se que: a) o modelo teórico apresenta bons resultados comparados aos resultados experimentais, b) as lajes apresentam boa capacidade de rotação plástica, c) com alta taxa de armadura negativa não ocorre redistribuição de esforços, d) as flechas praticamente independem da taxa de armadura negativa e e) a força última é praticamente independente do grau de redistribuição adotado no dimensionamento. / This work deal with an usual type of slab in Brazil: slabs made by precast joist with lattice reinforcement. The goal of this work is the structural analysis of bending moments in the supports of slabs made by this kind of precast element. Theoretical and experimental models analyze this type of slab. In the theoretical analysis, the non-linear concrete behavior is done by moment x curvature relationship of Model Code CEB-90 add incremental load technique. The theoretical model is compared with experimental results of continuous strip slabs designed with different degrees of bending moment redistribution. In these analysis had been noted: a) the theoretical model presents good results compared with the experimental results, b) the slabs present good plastic rotation capacity, c) with high negative reinforcement ratio in the support does not happen moment redistribution, d) the displacement is practically independent of negative reinforcement ratio and e) the ultimate load is practically independent of redistribution degree idealized in the design.

Neste trabalho é enfocada a análise estrutural de lajes pré-moldadas formadas por vigotas treliçadas. Esta análise foi realizada mediante o modelo de grelha, considerando a não-linearidade do concreto armado utilizando-se a relação momento x curvatura e carregamento incremental. O modelo da não-linearidade do concreto armado foi avaliado com resultados experimentais de vigas bi-apoiadas e painéis de laje contínua. O trabalho inclui uma análise teórico-experimental de uma laje pré-moldada bidirecional isolada e simulações numéricas de casos representativos de arranjos estruturais das lajes treliçadas. As principais conclusões do trabalho foram: a) o modelo de grelha é bastante adequado para a análise de lajes nervuradas pré-moldadas; b) os resultados da análise teórico-experimental da laje pré-moldada indicam que os deslocamentos foram fortemente influenciados pela rigidez à torção e c) a redistribuição de momentos fletores nas lajes contínuas é relativamente pequena. / This work aims the structural analysis in precast slabs made by lattice joist. The scheme was carried out by using the grillage model considering the non-linear of the reinforced concrete through the relationship moment x curvature and incremental loads. The non-linear model of the reinforced concrete was appraised with experimental of simply supported beams and panels of continuos slabs. The work includes a theoretical-experimental analysis of a isolated bidirectional precast slabs and numeric simulations of representative cases of structural arrangements of the slabs witch lattice joist. The main conclusions of the work were: a) the grillage model is quite appropriate for precast ribbed slabs; b) the results of theoretical-experimental analysis of the precast slabs point out the relevance the torsional in the deflections and c) the bending moments redistribution in the continuous slabs are quite small.