• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 96
  • 48
  • 29
  • 8
  • 7
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 224
  • 66
  • 39
  • 34
  • 27
  • 26
  • 24
  • 22
  • 20
  • 18
  • 17
  • 17
  • 16
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Aglomeração urbana descontínua: o exemplo de Araguari e Uberlândia/MG

Araújo, Flávia Aparecida Vieira de 15 June 2016 (has links)
A análise das aglomerações urbanas exige o entendimento acerca da diferenciação entre continuidade territorial urbana e continuidade espacial. Enquanto a continuidade espacial é compreendida pelas inter-relações e pelos fluxos estabelecidos, ou seja, pela integração espacial, a continuidade territorial está ligada ao tecido urbano. Portanto, a continuidade espacial pode se manifestar de forma simultânea e associada à descontinuidade territorial. Partindo dessa perspectiva, o objetivo central desta pesquisa consiste em identificar e dimensionar as interações espaciais que levam a um processo de aglomeração urbana entre os municípios de Araguari e Uberlândia/MG, apesar da não continuidade territorial da mancha urbana. A intensidade dessas interações foi identificada a partir dos deslocamentos realizados pelos moradores dos dois municípios em busca de trabalho, educação e saúde. Para o alcance dos objetivos propostos adotaram-se diversos procedimentos metodológicos, tais como a pesquisa bibliográfica e documental. A fim de identificar os fluxos de educação e trabalho analisaram-se os microdados do Censo Demográfico 2010. Para o setor de educação também foi levantado, em Araguari, o local de residência dos alunos matriculados no Instituto Master de Ensino Presidente Antônio Carlos (IMEPAC) e, em Uberlândia, o local de residência dos alunos matriculados na Universidade Federal de Uberlândia (UFU). A identificação dos fluxos de saúde foi feita com levantamento, em Uberlândia, da procedência dos pacientes que são internados no Hospital de Clínicas de Uberlândia da Universidade Federal de Uberlândia (HCU/UFU) e, em Araguari, da procedência dos pacientes atendidos no Pronto-Socorro Municipal. Também foram realizadas entrevistas semiestruturadas com diferentes atores sociais. Outra etapa importante foi a aplicação de questionários com usuários do transporte coletivo intermunicipal no embarque em Araguari e em Uberlândia. O trabalho foi organizado em cinco capítulos, sendo que, no primeiro, foi realizada uma discussão teórica sobre o conceito de aglomeração urbana, de forma a apresentar os critérios de identificação e classificação das aglomerações urbanas de caráter não metropolitano. O segundo capítulo analisa o processo de diferenciação entre Araguari e Uberlândia, o qual é resultante da distinta formação territorial dos municípios. O terceiro capítulo analisa a intensidade e o grau das interações espaciais entre os dois municípios, tendo como enfoques os fluxos estabelecidos no setor de trabalho. O quarto, por sua vez, enfoca os fluxos nos setores de educação e saúde, ao passo que o último capítulo realiza uma discussão de forma a investigar se os fluxos analisados nos capítulos anteriores possibilitam identificar se as interações espaciais estabelecidas entre Araguari e Uberlândia são marcadas por complementaridade ou por dependência. Como resultado identificou-se que, em função da expressividade dos fluxos estabelecidos entre os dois municípios frente aos demais do Triângulo Mineiro e Alto Paranaíba nos três setores selecionados, há a configuração de um processo de aglomeração urbana descontínua. Foi possível concluir ainda que, não obstante os fluxos no sentido Araguari-Uberlândia serem mais representativos do que no sentido contrário há coexistência de relações de dependência e de complementaridade entre os dois municípios. / The analysis of urban conurbations demands the understanding regarding the difference between urban territorial continuity and spatial continuity. While the spatial continuity is understood due to its interrelations and established fluxes, in other words, through the spatial integration, the territorial continuity is related to the urban tissue. Therefore, the spatial continuity can manifest in a simultaneous way or associated to the territorial discontinuity. From this perspective, the main objective of this research consists on identifying and dimensioning the spatial interactions that are driven to a urban conurbation process between the municipalities of Araguari and Uberlândia/MG, besides the not continuity of the territorial urban area. The intensity of these interactions was identified from the displacements by the dwellers from both municipalities in search of job occupations, education and health assistance. So it would be able to reach the proposed objectives we used several methodological procedures, such as a bibliographic and documental researches. In order to identify the education and work fluxes we analyzed the micro data from the Demographic Census 2010. For the educational sector it was also accomplished a research, in Araguari, the place of residence of students enrolled at Instituto Master de Ensino Presidente Antônio Carlos (IMEPAC) and, in Uberlândia, the place of residence of students enrolled at Universidade Federal de Uberlândia (UFU). The identification of health fluxes was done through a research, in Uberlândia, of the inpatients' origin at Hospital de Clínicas de Uberlândia of the Universidade Federal de Uberlândia (HCU/UFU) and, in Araguari, of the origin of patients that are attended at the Pronto-Socorro Municipal. Semi structured interviews were also accomplished with different social actors. Another important step was the use of questionnaires with the inter-municipal public transportation users at their boarding place in Araguari and Uberlândia. This paper was organized in five chapters, while in the first one we accomplished a theoretical discussion over the concept of urban conurbation, in order to presenting the identification and classification criteria and the urban conurbation of non metropolitan criteria. The second chapter analyses the differentiation process between Araguari and Uberlândia, which is a result of the distinct territorial formation of the municipalities. The third chapter analyses the intensity and degree of the spatial interactions between the two municipalities, having as a focus the established fluxes in the work sector. The fourth chapter, on the other hand, focuses on the education and health sectors, while the last chapter accomplishes a discussion to investigate if the analyzed fluxes in the previous chapters make it able to identify if the spatial interactions established between Araguari and Uberlândia are measured through complementarities or dependence. As a result it was possible to identify that, due to the expressiveness of the established fluxes between the two municipalities, beyond the further ones of Triângulo Mineiro and Alto Paranaíba in the three selected sectors, there is a configuration of a discontinuous urban conurbation process. It was also possible to conclude that, despite the fluxes between Araguari and Uberlândia being more representative than the other way around there's a coexistence dependence relationship and complementarity between the two municipalities. / Tese (Doutorado)
32

Är äldreomsorgen möjlig att påverka vid valurnan? : En studie om den politiska majoritetens effekt på kostnaden för och kvaliteten inom äldreomsorgen i svenska kommuner

Bäckström, Mattias, Helldin, Måns January 2021 (has links)
Ett sedan länge betraktat problem inom politisk ekonomi är om, och i så fall i vilken utsträckning, politiska partier påverkar ekonomiska policyutfall. Syftet med studien är att undersöka om det rådande politiska majoritetsförhållandet i kommunfullmäktige har en effekt på kostnaderna för och kvaliteten inom en verksamhet som kommit att hamna allt högre på den politiska dagordningen under coronapandemin – äldreomsorgen. Studien tar avstamp i teoretiska utgångspunkter i form av medianväljarteoremet och citizen candidate-modellen. I syfte att estimera effekten av den politiska majoriteten på äldreomsorgen tillämpas en skarp regression discontinuity (RD) design för två kostnadsmått och två kvalitetsmått; antalet fallskador bland personer 80 år och äldre per 1 000 invånare samt brukarbedömning avseende äldreomsorg i särskilt boende. Resultatet visar att en vänsterblocksmajoritet är associerad med drygt 23 procent högre kostnader för äldreomsorg i kronor per invånare samt drygt sex procentenheters lägre nivå i fråga om brukarbedömning än jämfört med andra partikonstellationer. Resultaten är dock inte stabila över olika ekonometriska specifikationer och ytterligare studier skulle därmed behövas för att säkrare kunna belägga ett eventuellt samband.
33

Regression discontinuity design with unknown cutoff: cutoff detection & effect estimation

Khan Tanu, Tanvir Ahmed 27 August 2020 (has links)
Regression discontinuity designs are increasingly popular quasi-experimental research designs among applied econometricians desiring to make causal inferences on the local effect of a treatment, intervention, or policy. They are also widely used in social, behavioral, and natural sciences. Much of the existing literature relies on the assumption that the discontinuity point or cutoff is known a-priori, which may not always hold. This thesis seeks to extend the applicability of regression discontinuity designs by proposing a new approach towards detection of an unknown discontinuity point using structural-break detection and machine learning methods. The approach is evaluated on both simulated and real data. Estimation and inference based on estimating the cutoff following this approach are compared to the counterfactual scenario where the cutoff is known. Monte Carlo simulations show that the empirical false-detection and true-detection probabilities of the proposed procedure are generally satisfactory. Finally, the approach is further illustrated with an empirical application. / Graduate
34

<b>Understanding Online Media Reactions to Significant Price Increases for Eggs</b>

Sachina Kida (16898778) 25 April 2024 (has links)
<p dir="ltr">Retail prices for eggs surged during the period from early 2022 to mid-2023 in the U.S. Eggs are important to a wide range of people because of their nutritional benefits and cost relative to other protein sources. Thus, rapidly increasing egg prices can cause risks to numerous people. Using social media listening data, we analyzed the relationship between egg prices and online and social media attention and the relationship between egg prices and online and social media sentiment. Our findings suggest that egg prices are associated with the sentiment of the public as expressed in online media. However, the relationship between egg prices and online and social media attention is complex when studying the timing of increased concern with the timing of online news media coverage. Importantly, by leveraging a method of regression discontinuity in time, we show that online and social media conversations about eggs and egg prices tend to increase after the rapid rise in online news coverage. Similarly, online and social media conversations about eggs and egg prices tend to decrease after the rapid rise in online news coverage. This research also provided an example of how a total number of statements and sentiment score of social media listening data can be utilized to capture people’s attention levels, overall sentiment, and how they change over time.</p>
35

AN EXAMINATION OF THE ASSOCIATION BETWEEN MIDDLE SCHOOL STUDENTS' PERCEPTIONS OF TEACHER INTERACTIONS, HOME-SCHOOL DISSONANCE, AND SCHOOL ATTACHMENT

Stevens, Ruby Jewel 01 January 2009 (has links)
The purpose of this study was to investigate whether middle school students’ perceptions of teacher interactions and home-school dissonance are predictors of school attachment. The study sought to determine if there were differences in students’ perceptions of teacher interactions and home-school dissonance based on ethnicity, gender and/or grade level. This investigation is one of the first to explore the association between these variables. Data for this investigation was obtained from a larger study where surveys were administered to over 800 racially diverse students in grades 6 through 8 in Language Arts classrooms in two public middle schools with diverse student populations. Participants completed the Questionnaire of Teacher Interactions (QTI), the Cultural Discontinuity Between Home and School Scale (CDBHSS) and the School Attachment Questionnaire (SAQ). Based on the study sample, the QTI and SAQ were revalidated and produced new scale structures. Results of the multiple regressions, multivariate analysis of variance and post hoc tests revealed middle school students’ perceptions of teacher interactions and home-school dissonance significantly predict school attachment. Teacher interactions perceived as critical/passive, pleasant, or demanding were those making significant contributions. Student perceptions of pleasant teacher interactions were the greatest predictor of school attachment. Eighth graders perceived teachers to be more critical/passive than sixth graders. Sixth grade students perceived teachers to be more caring than seventh and eighth grades. Further, results indicated African American students perceived more critical/passive teacher interactions than their Caucasian and Asian American peers. While results indicate that home-school dissonance is a significant predictor of school attachment, results show that the impact of students’ perceptions of home-school dissonance is minimized when combined with teacher interactions. Implications for administrators, teachers, and university education departments are outlined. Recommendations for future research are also discussed.
36

La lecture du CP au CM2 avec le test de l'alouette : que peut-on dire du niveau des élèves à quarante ans de distance ? : comment se déroule cet apprentissage (continu/discontinu) ? / Literacy in students fron 2nd year to 6th year with the Alouette test : how is the level for forty years? : how chidren learn to read (continuously/discontinuously)?

Izard, Amélie 02 October 2013 (has links)
Dans un contexte idéologique où la question de la baisse du niveau revient de façon récurrente dans l’espace public, nous nous sommes servie du test de L’alouette (Lefavrais, 1967) pour mener une étude comparative du niveau en lecture des élèves du CP au CM2. Les résultats indiquent qu’à quarante ans d’écart, le niveau en lecture a diminué de six mois. Au-delà de cette baisse relative, apparaît un fait tout aussi intéressant : celui d’un accroissement des écarts. On constate alors un décrochage des élèves les plus en difficulté et un décollage des élèves les plus performants. Le test de L’alouette étant basé sur une conception traditionnelle de la lecture, nous y avons vu là, l’occasion de mettre à l’épreuve les modèles dominants en lecture : les modèles développementaux. De cette façon, nous nous sommes demandée dans quelle mesure le test de L’alouette nous informe quant à l’apprentissage de la lecture et plus particulièrement en ce qui concerne le caractère discontinu ou continu de la lecture. Les résultats obtenus semblent aller dans le sens d’une discontinuité certes, mais qui ne serait pas absolue. Ainsi, dès le début de l’apprentissage les élèves utiliseraient une procédure lexicale en plus de la procédure par médiation phonologique. L’une ou l’autre étant dominante à certains moments de l’apprentissage. / The fall of the level of ability in literacy has often been brought to public attention, so we used the Alouette test (Lefavrais, 1967) to make a comparative study on the levels of literacy in students aged from 2nd year to 6th year. The study indicates that in forty years the level of literacy in students has reduced by six months. In addition to this decline, there also appeared to be widening gaps between the two extremes of ability. Those who experience the most difficulty become disengaged whereas those with the highest level of ability take off. As the Alouette test is based on the traditional concept of literacy, this allowed us to test the other dominant developmental theories. In this way we were able to question whether the Alouette test could tell us about the process in which children learn how to read whether continuously or discontinuously. The results seem to show that the tendency is for the discontinuity, but not entirely. Hence, as soon as children learn to read they would use a lexical process in addition to using phonological mediation, both being dominant at different times during their education.
37

Vliv strukturálních fondů Evropské unie na regionální rozvoj / The effect of EU Structural Funds on regional performance

Žďárská, Barbora January 2019 (has links)
The regional policy of the European Union is financed through a system of structural and investment funds, which allocates substantial amounts during each programming period to boost the regional growth. Currently, the regional policy uses almost a half of the European Union's budget. According to such an extensive investment plan it is believed that the structural funding has a positive impact on the regional performance. This thesis provides an analysis of the Objective 1 (Convergence strategy) treatment effect on the regional GDP and employment growth during two last programming periods 2000-2006 and 2007-2013 using mostly nonparametric estimation method of the regression dis- continuity design. The thesis contributes to existing literature since the current research studies do not provide conclusive results. Based on the estimation re- sults we did not find statistically significant effect of the Objective 1 treatment on the GDP per capita growth nor employment growth. These findings are robust to various model specifications and estimation methods. JEL Classification R11, R58, C21, C31 Keywords the European Union, regional policy, the Objec- tive 1, regression discontinuity design Title The effect of EU Structural Funds on regional performance Author's e-mail zdarskabarbora@seznam.cz...
38

[en] BLOCK-FLEXURE TOPPLING MECHANISM: CASE NW SLOPE TINTAYA´S MINE / [pt] MECANISMOS DE RUPTURA BLOCO - FLEXURAL EM MACIÇOS ROCHOSOS: CASO DO TALUDE NORTE DA MINA DE TINTAYA (PERU)

JORGE DUENAS RAMIREZ 06 March 2007 (has links)
[pt] Esta tese apresenta o fenômeno de ruptura por tombamento bloco-flexural, que acontece na zona NW da mina Tintaya. O objetivo do presente estudo é contribuir o conhecimento de este tipo de fenômeno de ruptura, quantificando as características do maciço rochoso com as técnicas da mecânica das rochas. O trabalho inicia-se por uma caracterização geral da zona de estudo, com especial relevo das propriedades geomecánicas das descontinuidades presentes, pelo que foram desenvolvidos mapeamentos das caras de bancada e a amostragem da rocha intacta, esta data permitiu estabelecer correlações dos parâmetros geomecânicos e fazer a análise cinemática da zona de estudo. Após de fazer a caracterização e avaliação das características das descontinuidades, foi definido o tombamento bloco-flexural, pelo jeito das descontinuidades presentes no maciço, já que este tipo de ruptura é mais complexo do que os outros tipos de tombamento, porque é uma combinação de tombamento e deslizamento dos blocos. Em vez da ruptura flexural de colunas contínuas, neste caso o tombamento é resultado de deslocamentos acumulados das juntas transversais. Com o objetivo de fazer uma análise numérica, obtou-se por um modelo contínuo- equivalente que inclui os efeitos de orientação e espaçamento das juntas é o modelo de plasticidade de Cosserat. O contínuo de Cosserat, conhecido também como contínuo micropolar acrescenta os graus de liberdade de rotação ao contínuo convencional. Pelo que foi analisado este tipo de ruptura através de uma modelagem computacional com um programa de elementos finitos feito na PUC-Rio, assim, tornar possível a modelagem computacional com a teoria do continuo de Cosserat. / [en] This thesis presents the block - flexural toppling failure phenomenon, which happens at NW zone of the Tintaya´s mine. The objective of the present study is to contribute the knowledge of this type of phenomenon of failure, quantifying the characteristics of rock mass with the techniques of the rock mechanics. The work begins for a general characterization of the zone, with special relief of the geomechanical properties of the discontinuities, which were developed the window sampling (bench face mapping) and sampling of the intact rock, this information allowed to establish correlations of the geomechanical parameters and make feasible kinematics analysis from the zone of study. After doing the rock mass characterization and evaluation of the characteristics of the discontinuities, the block - flexural toppling failure was defined, on those long column rocks crossed by numerous huge subhorizontal joints. The block-flexural type failure is a complex phenomenon compared with other types of toppling failure, because it is a combination of pure toppling and sliding. With the intention of numerical analysis, I have been proposed analyzing this rupture for a continuum - equivalent model of Cosserat, that includes the orientation and the discontinuity´s spacing. This model is known also as continuum micropolar, which adds the degrees of freedom of rotation to a conventional continuum. It was analyzed this type of failure through a computational modeling with a program of finite elements made in the PUC-Rio, so, the computational modeling possible with the theory of continuum of Cosserat.
39

Compulsory voting and TV news consumption: evidence from Brazil / Voto obrigatório e consumo de informação no Brasil

Raphael Guinâncio Bruce 03 December 2015 (has links)
Do people acquire more information when they are obligated to participate in elections? This dissertation presents empirical evidence on the effects of compulsory voting laws on the consumption of TV news. In Brazil, the law determines that every literate citizen over the age of eighteen and under seventy at the day of the election is subject to a number of penalties if they don\'t attend the ballots. This provides a natural experiment which allows us to identify the causal effect of being under a compulsory voting regime on information acquisition. Using national survey data on the consumption of media we find that, for those who have been exposed to the law for the first time, compulsory voting has a significant and substantial positive impact on the probability of an individual to watch Brazil\'s main newscast, Rede Globo\'s Jornal Nacional. No impact is found, though, for citizens who transition from the voluntary to the compulsory voting regime when they reach the age of seventy. / Pessoas que são obrigadas a votar procuram fazer isso de maneira informada? Essa dissertação procura saber se a lei de voto obrigatório brasileira induz eleitores a consumirem mais informação via noticiários televisivos. Mais especificamente, procuramos saber se o consumo de informações via o noticiário Jornal Nacional, transmitido pela Rede Globo, aumenta em decorrência da exposição à lei. No Brasil, todo cidadão alfabetizado com idade maior que dezoito e menor que setenta anos está sujeito a uma série de punições caso se abstenha sem justificativa nas eleições. Isso gera um experimento natural que nos permite utilizar a técnica de regressão descontínua para recuperar o efeito causal dessa lei sobre o consumo de informação por parte dos eleitores. Encontramos um aumento de 10,4% na probabilidade do eleitor jovem assistir o programa Jornal Nacional que pode ser atribuído especificamente ao fato desse cidadão ser obrigado a votar. Nenhum efeito é encontrado para cidadãos que deixam de ser obrigados aos setenta anos de idade
40

Localized failure for coupled thermo-mechanics problems : applications to steel, concrete and reinforced concrete / La rupture localisée pour les problèmes couplés thermomécaniques : applications en béton, acier et béton armé

Ngo, Van Minh 06 December 2013 (has links)
Ces dernières années, l'étude de la rupture localisée des structures massives sous chargement thermomécanique est devenue un enjeu important en Génie Civil du fait de l'augmentation du nombre de constructions endommagées ou totalement effondrées après un feu. Deux questions centrales ont émergé : la modélisation mathématique des phénomènes mis en jeu lors d'un feu d'une part et la simulation numérique de ces problèmes d'autre part. Concernant la modélisation mathématique, la principale difficulté est la mise en place de modèles thermomécaniques capables de modéliser le couplage existant entre les effets thermiques et mécaniques , en particulier dans une zone de rupture localisée. Comment le chargement mécanique affecte la distribution de température dans le matériau et inversement, comment le chargement thermique influence la réponse mécanique ? Sont des questions qui doivent être abordées. Ces questions sont d'autant plus difficiles à aborder que l'on considère une zone de rupture où la mécanique des milieux continus classiques ne peut pas être appliquée du fait de la présence de discontinuités du champ de déplacement et, comme cela est démontré dans ce travail, du flux thermique. Pour ce qui concerne la simulation numérique, la complexité du problème multi-physique posé en termes de système d'équations aux dérivées partielles impose le développement de méthodes de résolution approchées adaptées, efficaces et robustes, la solution analytique n'étant en général pas disponible. Cette thèse contribue sur les deux aspects précédents. En particulier, des modèles thermomécaniques pour le béton et l'acier (les deux principaux matériaux utilisés en Génie Civil) capables de contrôler simultanément les phases d'écrouissage accompagnées de plasticité et/ou d'endommagement diffus ainsi que la phase adoucissante due au développement de macro-fissures sont proposés. Le problème thermomécanique est ensuite résolu par une méthode dite «adiabatic operator split» qui consiste à séparer le problème multiphysique en une partie mécanique et une partie thermique. Chaque partie est résolue séparément en utilisant une fois de plus une méthode «d'operator split» dans le cadre des méthodes à discontinuités fortes. Dans ces dernières, une discontinuité du champ de déplacement ou du flux thermique est introduite et gérée au niveau élémentaire du code de calcul Éléments Finis. Une procédure de condensation statique élémentaire permet de prendre en compte ces discontinuités sans modification de l'architecture globale du code de calcul Éléments Finis fournissant les champs de déplacement et de température. Dans cette thèse est également abordée la question de l'évaluation de la réponse jusqu'à rupture de structures en béton armé de type poteaux/poutres soumises à un feu. L'originalité de la formulation proposée est de tenir compte de la dégradation des propriétés mécaniques du matériau due au chargement thermique pour la détermination de la résistance limite et résiduelle des structures mais également de prendre en compte deux types de rupture caractéristiques des structures poteaux/poutres à savoir les ruptures en flexion et les ruptures en cisaillement. Les travaux présentés dans cette thèse pourront être étendus pour décrire la rupture de structures en béton armé dans des cas bi ou tridimensionnels en tenant compte en particulier du comportement de l'interface acier/béton et/ou d'autres types de rupture comme la rupture par fatigue ou le flambage. Une extension possible est également la prise en compte des effets dynamiques mis en jeu lorsque la structure est sollicitée mécaniquement par un tremblement de terre ou un impact en plus de la sollicitation thermique. / During the last decades, the localized failure of massive structures under thermo-mechanical loads becomes the main interest in civil engineering due to a number of construction damaged and collapsed due to fire accident. Two central questions were carried out concerning the theoretical aspect and the solution aspect of the problem. In the theoretical aspect, the central problem is to introduce a thermo-mechanical model capable of modeling the interaction between these two physical effects, especially in localized failure. Particularly, we have to find the answer to the question: how mechanical loading affect the temperature of the material and inversely, how thermal loading result in the mechanical response of the structure. This question becomes more difficult when considering the localized failure zone, where the classical continuum mechanics theory can not be applied due to the discontinuity in the displacement field and, as will be proved in this thesis, in the heat flow. In terms of solution aspect, as this multi-physical problem is mathematical represented by a differential system, it can not be solved by an ‘exact’ analytical solution and therefore, numerical approximation solution should be carried out. This thesis contributes in both two aspects. Particularly, thermomechanical models for both steel and concrete (the two most important materials in civil engineering), which capable of controling the hardening behavior due to plasticity and/or damage and also the softening behavior due to the localized failure, are carried out and discussed. Then, the thermomechanical problems are solved by ‘adiabatic’ operator split procedure, which ‘separates’ the multi-physical process into the ‘mechanical’ part and the ‘thermal’ part. Each part is solved individually by another operator split procedure in the frame-work of embbed-discontinuity finite element method. In which, the ‘local’ discontinuities of the displacement field and the heat flow is solved in the element level, for each element where localized failure is detected. Then, these discontinuities are brought into the ‘static condensation’ form of the overall equilibrium equation, which is used to solved the displacement field and the temperature field of the structure at the global level. The thesis also contributes to determine the ultimate response of a reinforced concrete frame submitted to fire loading. In which, we take into account not only the degradation of material properties due to temperature but also the thermal effect in identifying the total response of the structure. Moreover, in the proposed method, the shear failure is also considered along with the bending failure in forming the overal failure of the reinforced structure. The thesis can also be extended and completed to solve the behavior of reinforced concrete in 2D or 3D case considering the behavior bond interface or to take into account other type of failures in material such as fatigue or buckling. The proposed models can also be improved to determine the dynamic response of the structure when subjected to earthquake and/or impact.

Page generated in 0.0548 seconds