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As abordagens sistêmica e do equilíbrio dinâmico na análise da fragilidade ambiental do litoral do Estado de São Paulo: contribuição à geomorfologia das planícies costeiras / Systemic approaches and the dynamic equilibrium in the analysis of environmental fragility of the coast of the state of S Paulo: contribution of geomorphology of coastal plainsFierz, Marisa de Souto Matos 10 December 2008 (has links)
A presente pesquisa tem como objetivo principal avaliar, por meio da abordagem sistêmica e do equilíbrio dinâmico, as diferenças de configurações geológicas e geomorfológicas e de fragilidade nos variados compartimentos geomorfológicos ao longo das planícies costeiras na enseada da Fortaleza, em Ubatuba, litoral norte de São Paulo e região de Peruíbe-Itanhaém, litoral centro-sul de São Paulo. Essas diferenças de configurações morfológicas são resultantes de processos pretéritos e do arcabouço geológico que sustentam as formas manifestadas na paisagem, moldadas pelos processos que atuam como agentes modeladores e de manutenção do equilíbrio dinâmico dessas formas. O equilíbrio dinâmico, nos moldes ecogeográficos de Tricart (1977), é mantido pela cobertura vegetal que pode manter constantes os processos de morfogênese e pedogênese ao longo da planície costeira que constituída de material friável, areias finas a muito finas que lhes conferem, a princípio, um caráter de fragilidade intrínseca. O equilíbrio dinâmico nos moldes geomorfológicos de Hack (1960, 1965) é mantido pela variação da resistência dos materiais que compõem o relevo, sustentando as formas. Essas duas abordagens auxiliaram na determinação da fragilidade ambiental, que é identificada e representada, sobretudo, pelas variações de resistência entre os diversos compartimentos ou subsistemas geomorfológicos mapeados ao longo da planície. Entretanto, em alguns trechos da planície costeira, sobretudo no litoral sul, onde o solo do tipo espodossolo apresenta horizonte B espódico também denominado, nesta tese, de fragipã (?), cuja principal característica é de caráter endurecido pela composição de ácidos húmicos e fúlvicos, retidos ali pelo processo de podzolização. Nestes trechos, os testes de resistência resultaram em poucos impactos de penetração ou nulos. O horizonte B espódico rígido, destarte a classificação da fragilidade ambiental obteve diversidades influenciadas pelas características desses trechos de espodossolos e por apresentarem interferências diretas nos processos de mudanças dos níveis topográficos. / The principal aim of this research, based on the Systems Approach and on the Dynamic Equilibrium, is to evaluate geological and geomorphologic different configurations and environmental fragility on the several geomorphologic topographic features in the coastal plains of Fortaleza bay in Ubatuba, located in the north coast of São Paulo and Peruíbe-Itanhaém area, located in center-southern coast of the São Paulo State.These morphological configurations differences are result of the geologic past processes and the geologic structure that sustain the stamped landscapes forms by active processes that behave as modeling agents and of maintenance of the dynamic equilibrium of this forms.The dynamic equilibrium by ecogeography principles of Tricart (1977) is maintained by the vegetal cover that prolong constant the process of morphogenesis and pedogenesis for all coastal plain that is mainly formed by material, thin to very thin sand particles that gives the region character of intensive fragility.The dynamic equilibrium on the geomorphologic models of Hack (1960, 1965) is maintained by the materials resistance variation that composes the reliefs forms. These both examples help in the determination of the environmental fragility that is identified and represented, mainly by the variations of the resistance among the various compartments geomorphologic or subsystems mapped throughout coastal plain. In some parts of the coastal plain, mainly in the south shore, where the kind of soil is Espodossoil presents level B espodic, also denominated as fragipã (?), which the principal characteristic is present by the character hardened by the composition of the humic and fulvic acids, retained there by the podzolization process. In these places the resistance tests resulted in few or null impacts penetration. The hardened level B espodic, regardless classification of the environmental fragility, showed direct interferences in the process of the changes on the topographic levels.
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Estudo comparativo da variação de escala na fragilidade ambiental e vulnerabilidade natural do solo na bacia hidrográfica do rio jundiaí / Comparative study of scale variation in environmental fragility and natural soil vulnerability in the Jundiaí River basinFagundes, Mariana Guarnier 26 June 2013 (has links)
Este trabalho apresenta um estudo comparativo sobre a variação de escala (1:50.000 e 1:250.000) nas metodologias desenvolvidas por ROSS (1994) e por CREPANI (2001), na geração de cartas de fragilidade ambiental e de vulnerabilidade natural à perda do solo. Cada metodologia apresenta uma forma particular de calcular os graus de fragilidade ambiental e vulnerabilidade à perda do solo, mas ambas se baseiam no princípio da ecodinâmica de Tricart, no qual os processos de pedogênese (formadores de solo) e morfogênese (modificadores das formas de relevo) são os principais atores na classificação do meio ambiente. Nesta classificação ocorre a compartimentação do meio ambiente em áreas homólogas, o que permite o agrupamento e a síntese das informações referentes ao meio físico, como também relativas às intervenções antrópicas dentro dessas áreas. Este processo é realizado dentro de um SIG (Sistema de Informação Geográfica). O efeito da variação de escala no modelo de fragilidade ambiental possui maior representatividade para o tema geomorfologia. Os demais temas não sofrem alteração significativa, na medida em que ficam subjulgados ao índice de dissecação do relevo, sendo esta variável a determinante do grau de fragilidade de cada área. Na metodologia de Crepani a vulnerabilidade à perda do solo é decorrente da média aritmética da ponderação dos temas, de modo que, independentemente da escala, as duas cartas de vulnerabilidade à perda do solo apresentam os valores extremos (muita baixa e muito forte) atenuados, e o valor mediano preponderante. Tendo em vista que em função do menor grau de detalhamento das curvas de nível e densidade de drenagem na escala 1:250.000, quando comparadas a 1:50.000, as formas de relevo, declividade e os tipos de solos a elas associados possuem valores reduzidos de ponderação quanto à estabilidade, sendo mais brandos na escala 1:250.000 e mais marcantes na escala 1:50.000. Deste modo, as classes de fragilidade ambiental forte e muito forte são mais expressivas na escala 1:50.000, enquanto as classes fraca e muito fraca aparecem com maior frequência na escala 1:250.000. O mesmo acontece no valor da média calculada para a determinação do grau de vulnerabilidade à perda do solo, de modo que as classes alta e muito alta são mais expressivas na escala 1:50.000, enquanto as classes baixa e muito baixa aparecem com maior frequência na escala 1:250.000. / This paper presents a comparative study on the variation of scale (1:50,000 and 1:250,000) on methodologies developed by Ross (1994) and CREPANI (2001), the generation of letters of environmental fragility and vulnerability to natural soil loss . Each methodology presents a particular form of calculating the degrees of environmental fragility and susceptibility to loss of the soil, but both are based on the principle of ecodynamics Tricart, which processes pedogenesis (forming ground) and morphogenesis (modifiers landforms ) are the main actors in the classification of the environment. This classification is the partitioning of the environment in homologous areas, allowing grouping and summary information relating to the physical environment, but also related to human interventions within these areas. This process is accomplished with a GIS (Geographic Information System). The effect of variation in the scale model of environmental fragility has greater representation to the theme geomorphology. The other themes will not change significantly since become subdued by dissection index relief, and this variable determining the degree of fragility of each area. In methodology Crepani vulnerability to soil loss is due to the arithmetic average of the weighting of topics, so that, regardless of the scale, two letters of vulnerability to loss of soil present extreme values (very low and very strong) attenuated and median predominant. Considering that due to the lesser degree of detail the contours and drainage density at 1:250,000 scale, compared to 1:50,000, the landforms, slope and soil types associated with them have reduced values of weighting for stability, being more lenient on the scale 1:250,000 and 1:50,000 most striking. Thus, the classes of environmental fragility strong and very strong are more significant on the scale of 1:50,000, while the low and very low classes appear more frequently in the scale 1:250,000. The same happens on the average value calculated to determine the degree of vulnerability to loss of the soil, so that the high and very high classes are more significant 1:50,000, while classes low and very low appear most frequently in 1:250,000 scale.
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Potências da fragilidade: só um corpo vivo sobreviveGrinfeld, Tatiana 07 May 2014 (has links)
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Previous issue date: 2014-05-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Powers fragility: only a living body survives brings questions about what is a fragile body a body that is breakable and creator at the same time. The body may be very fragile and yet find connections in life, which move and which makes possible new possibilities and ways of life. The research seeks to reflect on the powers of a body that suffered with situations of disease or war situations. Questions about fragility, power, body, life, death, time, space and memory and the coexistence of what could be considered antagonistic.
Relationships with contemporary artists are made and there are some images of works of these artists along the dissertation.
The reflections here meet partnership at the thought of some contemporary philosophers / Potências da fragilidade: só um corpo vivo sobrevive traz questões sobre o que é um corpo frágil. O corpo pode estar muito fragilizado e, mesmo assim, encontrar conexões que o fortaleça, que o movimente e que torne possível que novas possibilidades do viver sejam criadas.
A pesquisa busca refletir sobre as potências de um corpo que sofreu abalos e passou por situações traumáticas, sejam estas situações de doenças ou situações de guerra. São colocadas questões sobre fragilidade, potência, corpo, vida, morte, tempo, espaço e memória e sobre a coexistência do que poderia ser considerado antagônico.
São feitas relações com artistas contemporâneos e, ao longo da dissertação foram inseridas algumas imagens de trabalhos destes artistas.
As reflexões aqui propostas encontram parceria no pensamento de alguns filósofos da contemporaneidade
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Photothermal studies on cryoprotectant media / Études photothermiques de milieux cryoprotecteursMathew, Allen 11 July 2018 (has links)
La mise en place, l'étalonnage et l'utilisation d'un nouveau banc expérimental basses températures basé sur une technique photothermique appelée photo pyroélectricité (PPE) sont décrits dans ce manuscrit. Les échantillons que nous avons étudiés en utilisant ce nouvel instrument sont le glycérol, le 1,2 propanediol et leurs mélanges binaires avec l'eau. Ce sont des cryoprotecteurs bien connus (CPAs) utilisés dans la cryoconservation, qui est une technique de préservation des cellules et tissus vivants en les refroidissant à des très basses températures. Le but ultime de la cryoconservation est d'éviter ou de maîtriser la formation de glace et d'atteindre un état vitreux ou amorphe. La vitesse de refroidissement, de chauffage et la concentration des CPAs utilisés sont les paramètres clés qui déterminent la formation de la glace. Par conséquent, l'étude des propriétés thermiques, en particulier près de la transition vitreuse (Tg) des solutions binaires des CPAs avec de l'eau est très importante pour comprendre leur comportement lors du refroidissement. La PPE a été utilisée pour étudier l'effusivité et le temps de relaxation ∝ caractéristique de la transition vitreuse. Le Tg et la fragilité (m) ont été déterminés à partir des données de la PPE en utilisant le modèle d'Havriliak Negami. L'état vitreux présente une très grande viscosité, de l'ordre de 10¹² Pa.s au voisinage du Tg. Le Tg et m peuvent être calculés à partir de l'évolution de la viscosité en fonction de la température ou par calorimétrie différentielle à balayage (DSC). Ainsi, des études à l'aide de ces deux techniques ont été menées et les résultats ont été comparés avec les données de la PPE. / The construction, calibration and application of a new low temperature instrument based on a photothermal technique called photo pyroelectricity (PPE) is described in this manuscript. The samples we studied using the new PPE instrument were glycerol, 1,2 propanediol and their binary mixtures with water. These liquids are well known cryoprotectants (CPAs) used in cryopreservation, which is a technique to preserve the living cells and tissues from biological degradation by cooling to sub zero temperatures. The ultimate goal in cryopreservation is to avoid or control the ice formation and attain a glassy or amorphous state.The rate of cooling and heating and the concentration of the CPAs used are the key parameters that determine the ice formation. Therefore, studying the temperature dependent thermal properties especially near their glass transition temperature (Tg) of the binary solutions of CPAs with water at different concentrations are highly important to understand their behavior while cooling. The PPE technique was used to study the effusity and the ∝ relaxation time near the glass transition phenomenon. The Tg and fragility (m) were determined from the PPE data using the Havriliak Negami model. The glassy state has a characteristic property of very high viscosity, of the order of 10¹² Pa.s at Tg. The Tg and m can be calculated from the temperature evolution of viscosity or from Differential Scanning Calorimetry (DSC) measurements. Therefore, viscosity and DSC studies were conducted on the samples and were compared with PPE data.
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Análise comparativa da fragilidade ambiental da sub-bacia hidrográfica dos Arroios Juá e Caracol : bacia hidrográfica do Rio Caí / RSDamasceno, Maycon Pereira January 2011 (has links)
A Geografia desde a sua concepção como ciência tem no espaço geográfico, o seu principal objeto de estudo, o que nos permite analisar a dinâmica existente entre as relações que se estabelecem entre os diferentes grupos sociais, ao longo do tempo, e a sua materialização no espaço. Através de sua evolução histórica, a ciência geográfica contribuiu de forma significativa para a compreensão das consequências das ações que o homem como agente atuante e modificador do espaço pode acarretar sobre o ambiente natural, buscando analisar e orientar o seu planejamento. Sobre essa perspectiva, esta pesquisa toma como unidade de análise as Bacias Hidrográficas dos Arroios Juá e Caracol. A área de estudo está localizada na região nordeste do estado do Rio Grande do Sul, a Sub-Bacia do Arroio Juá possui uma área de 12487,27 ha, com altitudes que variam entre 200 e 980 metros, abrange os municípios de Caxias do Sul e São Francisco de Paula. O arroio Juá é afluente direito do Rio Caí. O Arroio Caracol, com uma área total de 6631,89 ha, também integra a Bacia hidrográfica do Caí tem sua sub-bacia estendida pelos municípios de Canela e Gramado. Área de estudo desse projeto insere-se na região do Alto Caí sob influência dos remanescentes do Bioma Mata Atlântica no nordeste do estado Rio Grande do Sul. Objetivo principal deste estudo é avaliar e comparar, através da análise de fragilidade ambiental, o nível de intervenção antrópica e a situação ambiental das sub-bacias do Arroio Juá e Caracol, afluentes do Rio Caí, RS. Dessa forma a pesquisa busca fornecer, através de técnicas cartográficas, uma caracterização detalhada das fragilidades de cada sub-bacia. Fez-se uso dos procedimentos operacionais descritos por Ross (1994), quanto ao estudo das fragilidades potencial e emergente. O mapa de fragilidade ambiental gerado é resultado da interpolação dos mapas de uso da terra, declividade e tipo de solo. Por meio desse produto cartográfico pretende-se fornecer subsídios para identificação das áreas com fragilidade potencial e emergente e dessa forma, colaborar com um melhor planejamento do uso dor recursos naturais. / Geography since its conception as science has in geographic space, its main object of study, allowing us to analyze the dynamics between the relationships established between different social groups, over time, and its materialisation in space. Through their historical, geographical science has contributed significantly to the understanding of the consequences of actions the man acting as an agent and modifier of space can have on the natural environment, seeking to analyze and guide your planning. About this perspective, this research takes as its unit of analysis of the Basin Streams Juá and Caracol, a systemic and integrated approach of the various elements, processes and interactions. The study area is located in the northeastern state of Rio Grande do Sul, the Sub-Basin Brook Juá covers the cities of Caxias do Sul and São Francisco de Paula. It has an area of 12487.27 ago, with altitudes ranging between 200 and 980 meters. Juá The stream is a tributary of the River Fall. Arroyo Caracol which also includes the Fall River Basin sub-basin has its extended by the municipalities of Gramado and Canela, with a total area of 6631.89 for. Study area is part of this project in the Upper Fall under the influence of the remnants of Atlantic Forest biome in northeastern Rio Grande do Sul state goal of this study is to evaluate and compare, through analysis of environmental fragility, the level of intervention anthropogenic and environmental situation of the sub-basins and Juá Arroyo Caracol, Fall River tributaries, RS. Thus the research seeks to provide mapping techniques through a detailed characterization of the weaknesses of each sub-basin. Was use of the operating procedures described by Ross (1994), and the study of emerging and potential weaknesses. The map of environmental vulnerability is the result of interpolation generated maps of land use, slope and soil type. Through this cartographic product is intended to provide a basis for identifying areas with potential and emerging weakness and therefore, collaborate with a better plan to use pain natural resources.
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Análise de fragilidade de sistemas de transmissão de energia elétrica através do cálculo de centralidadesReis, Eduardo Nunes dos 18 January 2016 (has links)
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Previous issue date: 2016-01-18 / Nenhuma / Análise de Contingências em sistemas elétricos de transmissão são de fundamental importância tanto para o planejamento quanto para a operação do sistema. Conhecimento do nível de importância e o impacto de interrupções em condições de operação da rede, em cada linha e em todas as barras de carga é crucial para a análise de segurança da rede. Este trabalho tem como objetivo avaliar a fragilidade dos sistemas elétricos de transmissão através de cálculo e análise das centralidades das redes, identificando seus nós mais importantes. Desta forma, pode-se obter informações sobre a rede com um menor custo computacional que as ferramentas disponíveis no momento. Os testes foram aplicados em redes IEEE padrão e em redes reais de grande escala, como o Sistema Interligado Nacional brasileiro (SIN). Os resultados foram comparados com os obtidos no software ANAREDE, software este que possui maior penetração entre as empresas de transmissão, e é baseado em cálculo de fluxo de potência. Com essa comparação é possível avaliar o grau de confiabilidade do método proposto.Os dados analisados mostram que o método pode ser utilizado como uma ferramenta auxiliar de baixo custo computacional para a avaliação de contingências fornecendo subsídios para análises mais aprofundadas dos nós indicados como críticos. Através da utilização do coeficiente de Correlação de Spearman verifica-se que os resultados do cálculo de centralidades possuem boa proximidade aos resultados do ANAREDE, com menor custo computacional e possibilidade de rodarredes de grande densidade de forma completa. / Contingency analysis of an electricity transmission system is of fundamental importance for both planning and system operation. Knowledge of the level of importance and the impact of outage in operating conditions of the network, were each one of the lines and on every load baseline is crucial for the analysis of network security. This work aims to evaluate the fragility of the electricity transmission system through centrality analysis of networks, identifying the most important nodes in the network. On this way, important information of the network can be achieved with lower computation cost than current available tools.Tests were performed on standard IEEE and in actual large scale networks, as the Brazilian National Interconnected Power System (NIPS). The results were compared with optimal results obtained from ANAREDE software, which is based on power flow calculation to check if the centrality-based method is reliable.The data analyzed show that the method can be used as an auxiliary tool with low computational cost for the evaluation of contingencies, providing support for further analysis of the nodes listed as critical.Spearman’s rank correlation coefficient was obtained for each centrality calculation and shows a close relation with results from ANAREDE software, with less computational cost and possibility to run high density networks at once.
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Fragilité financière par l'analyse des réseaux et l'approche comportementale / Financial fragility by network analysis and behavioral approachTran, Hieu 20 December 2018 (has links)
L'objectif de cette thèse est d'étudier la fragilité financière, c.à.d. la sensibilité du système financier par rapport aux perturbations. La difficulté principale concernant la fragilité financière dans le contexte actuel est la complexité croissante du système financier. piur remédier à ce problème, cette thèse s'inspire des deux courants relativement récents de la recherche économique : l'analyse des réseaux et l'économie comportementale. Les principaux concepts mobilisés sont les mécanismes de diffusion, de cascade et la rationalité limitée. Chapitre 1 étudie les effets des structures locales ds liens, spécifiquement la longueur des cycles transitifs sur la magnitude de la contagion financière. Chapitre 2 propose un modèle dynamique des paniques bancaires, dans lequel les paniques émergent par un mécanisme de cascade des retraits. Le but est de mieux comprendre comment les paniques se forment. Chapitre 3 étudie les paniques bancaires dans un contexte à la fois dynamique et comportemental, avec la présence du mimétisme et l'hétérogénéité des déposants. / This thesis studies financial fragility, i.e. the sensitivity of the financial system with respect to shocks. the main issue of financial fragility in the current context is the increased financial complexity. To address this problem, this study draws inspiration from two relatively recent streams of literature : econopmics of networks and behavioral economics. The main concepts in use are diffusion, cascade and bounded rationality. Chapter 1 studies how petterns of links, specifically, the length of transitive cycles affect the extent of financial contagion. Chapter 2 proposes a dynamic model in which bank runs arise as cascades of withdrawals. The aim is to better understand how bank runs occur. Chapter 3 studies bank runs in a dynamic and behavioral setting, with herding and heterogeneity of depositors.
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Les enjeux contemporains de la protection de l'environnement au Niger / Contemporary issues of environmental protection in NigerSani, Abdoulkarim 19 December 2014 (has links)
La dégradation de l’environnement au Niger, prend une ampleur de plus en pluspréoccupante. L’enjeu pour les politiques publiques est de changer la relation entre l’homme et sonmilieu afin de renverser la tendance. A cet effet, dans un contexte interne caractérisé par l’instaurationde la démocratie et de l’Etat de droit et un contexte international caractérisé par la mondialisation dudroit de l’environnement suite à la conférence de Rio notamment, le droit s’est naturellement imposécomme l’outil essentiel de ces transformations. L’objectif de cette thèse est d’identifier et analyser lesactions de transformation de la relation entre l’homme et son milieu de vie dans l’objectif de lapérennité des ressources naturelles et la viabilité du cadre de vie en tant qu’enjeux de la protection del’environnement dans un Etat en situation fragilité. Le Niger s’est engagé dans un processus deproduction normative, avec l’ambition de produire un droit alliant standards internationaux et normeset pratiques locales que ça soit dans les procédés de prise de décision ou de méthodes de protection del’environnement. Avec un approche quasi-empirique, l’analyse des enjeux contemporains de laprotection de l’environnement au Niger, nous permettra de révéler la nature de la relation de l’hommeavec son milieu telle qu’établie par le droit dans un contexte démocratique et de mondialisation dudroit de l’environnement, mais aussi de révéler comment la situation de fragilité générale de l’Etat etde la société commande la mise en oeuvre de ce droit. / The environmental degradation in Niger, takes a scale of increasing concern. Thechallenge for public policy is to change the relationship between man and his environment inorder to reverse the trend. To this end, in an internal context characterized by theestablishment of democracy and the rule of law and an international context characterized bythe globalization of environmental law following the Rio Conference (1992) in particular, therule of law has naturally emerged as the key tool for these transformations. The objective ofthis thesis is to identify and analyze the actions of transformation in the relationship betweenman and his environment with the goal of sustainability of natural resources and sustainableliving environment as issues the environmental situation in a state fragility. Niger hasembarked on a normative production process, with the aim of producing a law combininginternational standards and local norms and practices that it is in the processes of decisionmaking and environmental protection methods. With an interdisciplinary approach, analysisof contemporary issues of environmental protection in Niger, allow us to reveal the nature ofman's relationship with his environment as established by law in a democratic context andglobalization of environmental law, but also reveal how the situation in general fragility of thestate and society control the implementation of this rule of law.
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Approche probabiliste dans la détermination des courbes de vulnérabilité des structures en génie civil / Probabilistic approach in determining the vulnerability curves of civil engineering structuresMekki, Mohammed 07 April 2015 (has links)
Dans le contexte du calcul sismique basé sur la notion de performance, lesingénieurs se trouvent confrontés à une tâche difficile pour estimer la performance etévaluer les risques des systèmes sol-structure en interaction. Afin d’accomplir cette tâcheavec succès, toutes les sources d'incertitudes aléatoires et épistémiques doivent être prisesen compte au cours du processus de conception. Ainsi, des méthodes appropriées sontnécessaires pour l'étude de la propagation de l'incertitude des paramètres du systèmedécrivant la structure, le sol, et les charges appliquées aux réponses structurelles endéfinissant des états limites de performance. L’objectif de cette thèse est de contribuer àl’étude du comportement sismique des structures en interaction avec le sol et d’offrir denouveaux outils pour le traitement de problèmes pertinents, orientés vers la nouvellephilosophie de conception parasismique des structures : la conception basée sur laperformance (performance-based design). Cet axe de recherche structure ce travail dedoctorat. La problématique s’inscrit dans le cadre de proposition de modèles simplifiés afind’aborder un problème compliqué tel que l’interaction sol-structure (ISS). Lecomportement non linéaire de la structure est déterminé par une approche capacitive baséesur la performance sismique telle que la méthode N2 proposée par P. Fajfar. Dans saversion originale, cette méthode considère que la structure est encastrée à sa base,négligeant ainsi l’ISS. Il s'agit d'une extension de la méthode N2 et que nous appelleronsN2-ISS. A notre connaissance, il n'existe pas d'études qui ont intégré l'ISS dans ce type deformalisme. Pour examiner la validité et la fiabilité du modèle présenté, une analysecomparative a été faite entre l'approche que nous proposons et trois autres méthodes: 1) laméthode introduite dans le code BSSC 1997, 2) la méthode proposée par Avilès & Perez–Rocha (2003) ainsi que 3) la méthode dynamique temporelle non linéaire. Les résultatsobtenus ont montré que la réponse en déplacement de la structure était assez proche dansles quatre méthodes.Les courbes de fragilité sont établies en tenant compte des effets de l’ISS et desincertitudes associées au chargement (mouvement du sol), aux propriétés de la structure,du sol, et de la fondation (impédances, ...). L’incertitude épistémique est égalementconsidérée de manière indirecte suite à la comparaison entre deux procédures d'évaluationdes états d’endommagements (Méthode de Park & Ang et Méthode de RISK-UE). L'étudea abouti aussi à une caractérisation préliminaire du risque sismique dans une partie de laville d'Oran dont les caractéristiques géologiques et géotechniques étaient disponibles.Cette étude a permis la cartographie du dommage et d'étudier la la vulnérabilité sismiquedes bâtiments. / In the context of performance-based earthquake engineering (PBEE), a challengingtask for structural engineers is to provide performance and risk assessment for structures orsoil-structure interaction (SSI) systems. In order to fulfill this task successfully, all relevantsources of aleatory and epistemic uncertainties must be accounted for during the designprocess. Thus, proper methods are required for the study of uncertainty propagation frommodel parameters describing the structure, the soil, and the applied loads to structuralresponses by defining some performance limit states. The objective of this thesis is tocontribute to the study of the seismic behavior of structures interacting with soil andprovide new tools for the treatment of relevant issues facing the new philosophy of seismicdesign of structures: performance-based design. The objective of this thesis is to contributeto the study of the seismic behavior of structures interacting with soil and provide newtools for the treatment of relevant issues facing the new philosophy of seismic design ofstructures: (performance-based design). This research structure this doctoral work. Theissue is part of proposed simplified models to address a complicated problem such as soilstructureinteraction (SSI). The nonlinear behavior of the structure is determined by acapacitive approach based on the seismic performance as N2 method proposed by P.Fajfar. In its original version, this method considers that the structure is fixed at its base,thus neglecting the ISS. The new proposed method called N2-SSI is an extension of the N2method. To our knowledge, there are no studies that have joined the SSI ISS in this type offormalism. The proposed approach is validated and compared with time history analysis,Building Seismic Safety Council (BSSC) method (NEHRP, 2003), and a method proposedby Aviles and Perez-Rocha (2003). The results obtained showed that the responsedisplacement of the structure was fairly close in the four methods.The fragility curves are established taking into account the effects of the ISS anddifferent uncertainty sources: the load (input ground motion), the soil, the structure and theSSI (impedances, ...). Epistemic uncertainty was investigated through comparison betweentwo different approaches in assessing damage states (Park and Ang and Risk-UE). Thestudy also resulted in a preliminary characterization of the seismic risk in a part of the Orancity, where geological and geotechnical characteristics were available. This study allowedthe mapping of the damage and the study of the seismic vulnerability of buildings.
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Application of bridge specific fragility analysis in the seismic design process of bridges in californiaDukes, Jazalyn Denise 08 April 2013 (has links)
The California Department of Transportation (Caltrans) seismic bridge design process for an Ordinary Bridge described in the Seismic Design Criteria (SDC) directs the design engineer to meet minimum requirements resulting in the design of a bridge that should remain standing in the event of a Design Seismic Hazard. A bridge can be designed to sustain significant damage; however it should avoid the collapse limit state, where the bridge is unable to resist loads due to self-weight. Seismic hazards, in the form of a design spectrum or ground motion time histories, are used to determine the demands of the bridge components and bridge system. These demands are compared to the capacity of the components to ensure that the bridge meets key performance criteria. The SDC also specifies design detailing of various components, including abutments, foundations, hinge seats and bent caps. The expectation of following the guidelines set forth by the SDC during the design process is that the resulting bridge design will avoid collapse under anticipated seismic loads. While the code provisions provide different analyses to follow and component detailing to adhere to in order to ensure a proper bridge design, the SDC does not provide a way to quantitatively determine whether the bridge design has met the requirement of no-collapse.
The objectives of this research are to introduce probabilistic fragility analysis into the Caltrans design process and address the gap of information in the current design process, namely the determination of whether the bridge design meets the performance criteria of no-collapse at the design hazard level. The motivation for this project is to improve the designer's understanding of the probabilistic performance of their bridge design as a function of important design details. To accomplish these goals, a new bridge fragility method is presented as well as a design support tool that provides design engineers with instant access to fragility information during the design process. These products were developed for one specific bridge type that is common in California, the two-span concrete box girder bridge. The end product, the design support tool, is a bridge-specific fragility generator that provides probabilistic performance information on the bridge design. With this tool, a designer can check the bridge design, after going through the SDC design process, to determine the performance of the bridge and its components at any hazard level. The design support tool can provide the user with the probability of failure or collapse for the specific bridge design, which will give insight to the user about whether the bridge design has achieved the performance objective set out in the SDC. The designer would also be able to determine the effect of a change in various design details on the performance and therefore make more informed design decisions.
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