Ce travail a pour but d'apporter des éléments de connaissance sur le comportement des enceintes de confinement des centrales nucléaires françaises. L'aptitude au confinement de ce type de structures est garantie par la faible perméabilité du béton. En cas d'accident, le béton est protégé de la fissuration par la compression biaxiale assurée par les câbles de précontrainte orthoradiaux et verticaux. Dès lors, il s'agit de vérifier deux points principaux : premièrement, le niveau de précontrainte doit rester suffisamment élevé pour équilibrer les contraintes de traction induites lors d'un accident, deuxièmement, la fissuration du matériau qui apparaît hors situation accidentelle doit être limitée. La réalisation de ces objectifs passe par la connaissance du comportement du béton depuis sa fabrication jusqu'à la fin de la durée d'exploitation du réacteur. L'étude du matériau est séparé en deux grandes périodes : la phase du jeune âge caractérisée par de forts couplages chemo-thermo-mécaniques et la phase du long terme où le matériau subit des sollicitations hydro-mécaniques. Une modélisation couplant l'hydratation, les transferts thermiques et hydriques et la mécanique est développée : elle est apte à décrire les principaux mécanismes en jeu. Ce modèle est implanté dans le logiciel CAST3M : le nombre limité de paramètres permet de faciliter le processus d'identification. En parallèle à ce travail de modélisation, plusieurs essais expérimentaux ont été réalisés : certains sont destinés à la détermination de paramètres spécifiques (par exemple, le coefficient de Poisson du fluage propre), d'autres ont pour but d'évaluer la pertinence des mécanismes physiques retenus dans la modélisation (notamment sur les couplages séchage-retrait-fluage). Par la diversité des phénomènes abordés, cette étude s'articule autour de plusieurs axes. La première partie traite des phénomènes thermo-chimiques du béton au jeune âge et du séchage des matériaux cimentaires : problèmes qui ont en commun leur nature diffuse. Une attention particulière est portée sur l'identification des principaux paramètres d'influence de ces deux phénomènes. La deuxième partie concerne l'étude des déformations différées du béton. Contrairement à la décomposition conventionnelle de ces déformations, fluage et retrait sont corrélés et induisent un endommagement du matériau. La modélisation proposée, qui se place dans le cadre de la mécanique des milieux poreux non saturés, permet de considérer une partie des interactions entre ces déformations. La dernière partie se concentre sur l'étude du comportement différé de structures. Les résultats mettent en lumière l'importance de certains verrous technologiques dans la prédiction du comportement à long terme d'une enceinte de confinement. / This work aims to study the behaviour of the containment buildings in a nuclear power plant. The gas-proofing of these structures is based on the low conductivity of concrete (the hydraulic conductivity is around 10-11 m/s for a standard concrete). However, if cracks appear, this material property increases and the containment may not be longer guaranteed. In accidental situations, the concrete is protected from cracking by the bi-axial prestressing of the internal safety enclosure. The ageing of the structure may have two main consequences : firstly, the prestress has to remain sufficiently high to counterbalance the tensile stress caused by an accident, secondly, cracking induced by non-accidental loads has to be limited. These aims cannot be satisfied if the behaviour of the concrete is not understood from its manufacturing to the end of the operating life of the nuclear reactor.\\ The lifespan of the structure is broken down into two distinguished periods : on one hand, strong chemo-thermo-mechanical couplings characterise the early age phase, on the other hand, the material is under hydro-mechanical stress during the long term phase. In the proposed modelling, hydration, thermal and hydric transfers are coupled with the mechanical behaviour of the concrete- the main mechanisms are considered. The model is implemented in the software \textit{CAST3M} : the limited number of parameters facilitate the identification process. In tandem with this work, several experimental tests are realised. Parameters are identified from their results, moreover, some of the experimental observations confirmed the physical mechanisms considered in the model. \\ Because of the complexity of the different phenomenon, this document is built around the following principles. The first part deals with the chemo-thermal couplings at early age and the drying process of concrete at long term : the nature of these two problems is diffusive. This part is focused on the identification of the main parameters of these two phenomenons. The second part is about the delayed strains in concrete. Unlike the conventional decomposition of these strains, creep and shrinkage are correlated and influence the damage evolution. Mechanics of unsaturated porous media is used to consider the couplings between these strains. The last part is focused on the delayed behaviour of structures. Results highlight the importance of some technological barriers in order to predict accurately the long-term behaviour of a containment building.

The most common prefabricated concrete slabs are hollow core slabs, which are usually pre-tensioned. How to design these parts is not compiled today in a manual where it is clear how this is done, this knowledge is generally classified as expert knowledge. The purpose was to bring forth how to design prefabricated pre-stressed hollow core slabs, HD/F, and then create a design aid that is compared by hand calculations with the PRE-Stress design program from StruSoft. Furthermore, to compare it with site-cast concrete slabs to see differences in the amount of material and the thickness of the structure under the same conditions.The design aid is not complete as some limitations had to be made. When it comes to results, the hand calculations in comparison with PRE-Stress have not resulted in identical answers but have proven to be on the safe side consistently through the design, which indicates that the design aid is fully functional. In the comparison with site-cast concrete slabs, it can be noted that prestressed hollow core slabs require less concrete volume, slimmer construction, and longer span widths but greater reinforcement volume. / Det vanligaste prefabricerade betongbjälklaget är håldäcksplattor som oftast är spännarmerade. Hur man dimensionerar dessa bärverksdelar finns idag inte samlat i en handbok där det står tydligt hur man gör, den kunskapen klassas generellt som expertiskunskap. Syftet var att ta fram hur man dimensionerar prefabricerade förspända håldäcksplattor, HD/F, och sedan skapa ett dimensioneringshjälpmedel som jämförs genom handberäkningar med PRE-Stress dimensioneringsprogram från StruSoft. Vidare genomfördes jämförande beräkningar för platsgjutet betongbjälklag för att se skillnader i materialmängd och konstruktionstjocklek under samma förutsättningar.Dimensioneringshjälpmedlet är inte komplett då vissa avgränsningar behövts göras. När det kommer till resultat har handberäkningar i jämförelse med PRE-Stress inte resulterat i identiska svar, men visat sig hamna på säkra sidan konsekvent genom dimensioneringen vilket tyder på att dimensioneringshjälpmedlet är fullt användbart. I jämförelsen med platsgjutet bjälklag kan man konstatera att förspända håldäcksplattor ger mindre betongvolym, slankare konstruktion och längre spännvidder men större armeringsmängd.

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Denna studie undersöker fenomenet stress och hur det figurerar i förskolan. Syftet med studien är att bidra med kunskap om förskollärares uppfattningar av stress i förskolan samt hur förskollärarna uppfattar att stress påverkar förskolans verksamhet. Studien utgår från en fenomenografisk ansats och jag har därmed valt att använda semistrukturerad intervju som metod för datainsamling, där respondenternas uppfattningar är centrala. Jag valde att intervjua fyra förskollärare från två olika förskolor. Resultatanalysen utgår från en fenomenografisk analysmodell och resultatet presenteras utifrån fenomenografins begrepp kategorier och utfallsrum. Resultatet visar att förskollärarna uppfattar att stress ofta orsakas av faktorer som inte går att påverka eller ibland ens förebygga. Vidare uppfattar de ändå att stressen går att hantera och lindra med hjälp av bland annat olika strategier, kollegialt stöd och struktur. Viktiga slutsatser är att det bör avsättas tid för relationsbyggande och återhämtning i förskolan samt att vardera arbetslag för diskussioner kring en, för dem, fungerande struktur samt gemensamt förhållningssätt. / This study examines the phenomenon of stress and how it figures in preschool. The purpose of the study is to contribute knowledge about preschool teachers' experience of stress in preschool and how preschool teachers perceive that stress affects the preschool's operations. The study is based on a phenomenographic approach and I have therefore chosen to use a semi-structured interview as a method for data collection, where the respondents' perceptions are central. I chose to interview four preschool teachers from two different preschools. The result analysis is based on a phenomenographic analysis model and the results are presented based on the phenomenographic concepts of categories and outcome spaces. The results show that the preschool teachers feel that stress is often caused by factors that cannot be influenced or sometimes even prevented. Furthermore, they still believe that the stress can be managed and alleviated using, among other things, different strategies, collegial support and structure. Important conclusions are that there should be time set aside for relationship-building and recovery in the preschool and that each work team has discussions about a structure that works for them and a joint approach.

key words: Czech English, foreign accent, word stress, word accent, stressed syllable, duration, f0, acoustic cues. This study investigates the acoustic properties of word stress in Czech English. The notion of foreign accent is introduced and its drawbacks are presented. Further on the various influences on the perceived degree, or strength, of foreign accent are discussed. Faulty realization of word stress is identified as one of the factors that contribute to unintelligibility of non-native speech (Benrabah, 1997; Hahn, 2004; Cutler, 1984). In Chapter 2 we compare the results of studies that used speakers of a variety of languages and form a basic theory on the acquisition of acoustic cues to word stress. We are mostly interested in f0 and duration. This theory, based on the feature hypothesis (McAllister et al., 2002 in Lee, Guion & Harada, 2006), states that languages that have a similar stress system to that of English (Dutch, Arabic) use their native cues to signal word stress, while non-contrastive languages (Vietnamese, Czech) prefer cue/s that are phonologically active on segmental level in their native language. Speakers of Vietnamese, a tone language, were found to prefer f0 over duration (Nguyen, 2003), so for Czech, a language that uses phonological vowel duration, it is expected that...

Esta dissertação objetiva estudar a fala de sergipanos migrantes residentes em São Paulo e em sua região metropolitana, com o intuito de verificar suas taxas de acomodação (TRUDGILL, 1986) à fala paulistana, no que concerne ao grau de abertura das vogais médias pretônicas (como em negócio e coragem), tratado como uma variável numérica (a partir dos valores de F1). Para tanto, os pressupostos teóricos variacionistas (LABOV, 2008 [1972]), o conceito de redes sociais (MILROY, 1987; MILROY & LLAMAS, 2013 [2002]) e algumas definições caras à terceira onda (ECKERT, 2012), como o de identidade (KIESLING, 2013), são tomados como norteadores. O corpus da pesquisa é formado por 27 entrevistas sociolinguísticas realizadas com sergipanos migrantes pertencentes a duas redes sociais distintas. A rede 1 é mais fechada (com uma mobilidade geográfica mais limitada e com um contato menos frequente com paulistanos) e é composta por 16 informantes residentes em Taboão da Serra e Cotia, cidades metropolitanas de São Paulo. A rede 2, por sua vez, é mais aberta (tem mais contato com paulistanos) e é formada por 11 sujeitos, moradores de Osasco, Carapicuíba e São Paulo. Partindo da premissa de que os indivíduos estão se acomodando às pessoas com quem estão conversando rotineiramente, a hipótese central do estudo é que as taxas de acomodação dos migrantes estejam correlacionadas à configuração de suas redes. Dessa maneira, como os sujeitos da rede 2 conversam, com mais frequência, paulistanos, eles tendem a estar mais acomodados à fala paulistana. Além disso, a pesquisa lida com o conceito de identidade com o intuito de testar a hipótese de que o migrante que se identifica mais com Sergipe, do que com São Paulo, tende a estar menos acomodado à nova realidade linguística. Tal teste é realizado com um índice chamado índice de vínculo com Sergipe, criado a partir de um questionário respondido pelos próprios informantes depois da entrevista sociolinguística. O principal resultado das análises é que a hipótese sobre a configuração das redes não se confirma, ou seja, não faz diferença, para as taxas de acomodação, se o informante pertence à rede mais fechada ou à mais aberta. Verificou-se, nesse sentido, que existe uma grande variação entre os indivíduos de uma mesma rede. Ademais, não foi constatada correlação entre o índice de vínculo com Sergipe do migrante e seu grau de acomodação. A análise mais minuciosa de dois migrantes da rede 2 revela que existe uma concentração de vogal /o/ mais baixa quando os falantes estão avaliando as diferentes pronúncias brasileiras e estão discursando sobre sua origem, sobretudo quando usam a palavra nordeste (e suas derivações). Tal descoberta mostra que, em pesquisas sobre acomodação dialetal, é importante voltar-se para a análise do indivíduo e para suas posturas (stance). / This masters thesis presents a study of pre-stressed mid-vowels /e/ (negócio business) and /o/ (coragem courage) in the speech of 27 speakers who migrated from Sergipe to São Paulo. In their original dialect, speakers born and raised in Sergipe (as in other areas of Northeastern Brazil Cardoso, 1999; Callou et al, 2009) tend to open these vowels, relative to their pronunciation by speakers born and raised in São Paulo. Under the assumption that speakers tend to accommodate their speech (TRUDGILL, 1986) to the variety spoken by those with whom they routinely speak, the central hypothesis is that migrants may have different rates of accomodation in the pronunciation of those vowels, depending on the configuration of their networks. That way, migrants whose networks include more Paulistanos would tend to pronounce these vowels more similarly to these speakers, as opposed to migrants whose networks include more Sergipanos and speakers from other Northeastern areas of Brazil. The data were extracted from sociolinguistic interviews, recorded with these migrants according to their participation in two social networks. Network 1 is more closed (limited geographical mobility and less frequent contact with Paulistanos) and comprises 16 migrants living in Taboão da Serra and Cotia, metropolitan cities of São Paulo. Network 2 is more open (more contact with Paulistanos) and comprises 11 subjects, residents of Osasco, Carapicuíba and São Paulo. Data collection and analyses were carried out in accordance with Sociolinguistics (LABOV, 2008 [1972]), the concept of social networks (MILROY, 1987; MILROY & LLAMAS, 2013 [2002]) and third-wave conceptualizations (ECKERT, 2012), such as stance and identity (KIESLING, 2013). Vowel openess was treated as a numeric variable (measured in Praat Boersma & Weenink, 2014 through formant F1, in Hertz). Results do not confirm the network hypothesis, as the degrees of migrants accommodation did not significantly differ according to their network. Rather, there is great variability amongst speakers, including those who are members of the same network. Additionally, there is no correlation between the variable and whether the migrants identify themselves more to the new city or to their Northeastern origins (through an index based on answers to an identity questionnaire performed at the end of the sociolinguistic interviews). Moreover, there is also great variability throughout their interviews. By analyzing more closely the speech of two migrants from Network 2, it is noteworthy that there is a concentration of higher-F1 tokens of /o/ in the word nordeste (Nordeste Northeast), when the speakers are talking about their views on their origins and their original dialect. These findings call for further analysis of individual speech, when it comes to research on dialect accommodation.

Esta dissertação objetiva estudar a fala de sergipanos migrantes residentes em São Paulo e em sua região metropolitana, com o intuito de verificar suas taxas de acomodação (TRUDGILL, 1986) à fala paulistana, no que concerne ao grau de abertura das vogais médias pretônicas (como em negócio e coragem), tratado como uma variável numérica (a partir dos valores de F1). Para tanto, os pressupostos teóricos variacionistas (LABOV, 2008 [1972]), o conceito de redes sociais (MILROY, 1987; MILROY & LLAMAS, 2013 [2002]) e algumas definições caras à terceira onda (ECKERT, 2012), como o de identidade (KIESLING, 2013), são tomados como norteadores. O corpus da pesquisa é formado por 27 entrevistas sociolinguísticas realizadas com sergipanos migrantes pertencentes a duas redes sociais distintas. A rede 1 é mais fechada (com uma mobilidade geográfica mais limitada e com um contato menos frequente com paulistanos) e é composta por 16 informantes residentes em Taboão da Serra e Cotia, cidades metropolitanas de São Paulo. A rede 2, por sua vez, é mais aberta (tem mais contato com paulistanos) e é formada por 11 sujeitos, moradores de Osasco, Carapicuíba e São Paulo. Partindo da premissa de que os indivíduos estão se acomodando às pessoas com quem estão conversando rotineiramente, a hipótese central do estudo é que as taxas de acomodação dos migrantes estejam correlacionadas à configuração de suas redes. Dessa maneira, como os sujeitos da rede 2 conversam, com mais frequência, paulistanos, eles tendem a estar mais acomodados à fala paulistana. Além disso, a pesquisa lida com o conceito de identidade com o intuito de testar a hipótese de que o migrante que se identifica mais com Sergipe, do que com São Paulo, tende a estar menos acomodado à nova realidade linguística. Tal teste é realizado com um índice chamado índice de vínculo com Sergipe, criado a partir de um questionário respondido pelos próprios informantes depois da entrevista sociolinguística. O principal resultado das análises é que a hipótese sobre a configuração das redes não se confirma, ou seja, não faz diferença, para as taxas de acomodação, se o informante pertence à rede mais fechada ou à mais aberta. Verificou-se, nesse sentido, que existe uma grande variação entre os indivíduos de uma mesma rede. Ademais, não foi constatada correlação entre o índice de vínculo com Sergipe do migrante e seu grau de acomodação. A análise mais minuciosa de dois migrantes da rede 2 revela que existe uma concentração de vogal /o/ mais baixa quando os falantes estão avaliando as diferentes pronúncias brasileiras e estão discursando sobre sua origem, sobretudo quando usam a palavra nordeste (e suas derivações). Tal descoberta mostra que, em pesquisas sobre acomodação dialetal, é importante voltar-se para a análise do indivíduo e para suas posturas (stance). / This masters thesis presents a study of pre-stressed mid-vowels /e/ (negócio business) and /o/ (coragem courage) in the speech of 27 speakers who migrated from Sergipe to São Paulo. In their original dialect, speakers born and raised in Sergipe (as in other areas of Northeastern Brazil Cardoso, 1999; Callou et al, 2009) tend to open these vowels, relative to their pronunciation by speakers born and raised in São Paulo. Under the assumption that speakers tend to accommodate their speech (TRUDGILL, 1986) to the variety spoken by those with whom they routinely speak, the central hypothesis is that migrants may have different rates of accomodation in the pronunciation of those vowels, depending on the configuration of their networks. That way, migrants whose networks include more Paulistanos would tend to pronounce these vowels more similarly to these speakers, as opposed to migrants whose networks include more Sergipanos and speakers from other Northeastern areas of Brazil. The data were extracted from sociolinguistic interviews, recorded with these migrants according to their participation in two social networks. Network 1 is more closed (limited geographical mobility and less frequent contact with Paulistanos) and comprises 16 migrants living in Taboão da Serra and Cotia, metropolitan cities of São Paulo. Network 2 is more open (more contact with Paulistanos) and comprises 11 subjects, residents of Osasco, Carapicuíba and São Paulo. Data collection and analyses were carried out in accordance with Sociolinguistics (LABOV, 2008 [1972]), the concept of social networks (MILROY, 1987; MILROY & LLAMAS, 2013 [2002]) and third-wave conceptualizations (ECKERT, 2012), such as stance and identity (KIESLING, 2013). Vowel openess was treated as a numeric variable (measured in Praat Boersma & Weenink, 2014 through formant F1, in Hertz). Results do not confirm the network hypothesis, as the degrees of migrants accommodation did not significantly differ according to their network. Rather, there is great variability amongst speakers, including those who are members of the same network. Additionally, there is no correlation between the variable and whether the migrants identify themselves more to the new city or to their Northeastern origins (through an index based on answers to an identity questionnaire performed at the end of the sociolinguistic interviews). Moreover, there is also great variability throughout their interviews. By analyzing more closely the speech of two migrants from Network 2, it is noteworthy that there is a concentration of higher-F1 tokens of /o/ in the word nordeste (Nordeste Northeast), when the speakers are talking about their views on their origins and their original dialect. These findings call for further analysis of individual speech, when it comes to research on dialect accommodation.

Alkali Silica Reaction in concrete is a chemical deterioration process occurring between alkalis in cement paste and reactive aggregates. ASR increases expansion and cracking as well as other durability problems such as freezing and thawing. It is most probable that concrete structure will collapse unless mechanical, mineral, or chemical preventive measures are taken against ASR or this problem is realized and solved in the design stage of the concrete structure or later on. Rather than ordinary preventive measures in which mineral admixtures are used, mechanical ones were investigated in this study. In the experiment done by using the accelerated mortar bar method, reinforced concrete specimens on which pre-stressing force was applied were examined. The effects of reinforcement ratio and pre-stressing force on ASR based expansion and cracking were studied. Expansion and cracking developments in time were followed, and the connection between these phenomena and the energy produced by ASR was made. By applying the same mechanical preventive measures on the specimens prepared by using different reactive aggregates, the effectiveness of these methods with respect to the degree of v ASR was investigated. Also, the methods in question were compared with traditional preventive measures (fly ash). The investigation results show that reinforcement and pre-stressing force play a significant role in diminishing the effects of ASR.Keywords:Alkali-Silica Reaction, Reinforced Concrete Specimen, Pre-stressed Concrete, Mechanical Preventive Measures, Energy of ASR

Condition assessment and safety verification of existing bridges and decisions as to whether bridge posting is required are addressed through analysis, load testing, or a combination of methods. Bridge rating through structural analysis is by far the most common procedure for rating existing bridges. The American Association of State Highway and Transportation Officials (AASHTO) Manual for Bridge Evaluation (MBE), First Edition permits bridge capacity ratings to be determined through allowable stress rating (ASR), load factor rating (LFR) or load and resistance factor rating (LRFR); the latter method is keyed to the AASHTO LRFD Bridge Design Specifications, which is reliability-based and has been required for the design of new bridges built with federal findings since October, 2007. A survey of current bridge rating practices in the United States has revealed that these three methods may lead to different ratings and posting limits for the same bridge, a situation that carries serious implications with regard to the safety of the public and the economic well-being of communities that may be affected by bridge postings or closures. To address this issue, a research program has been conducted with the overall objective of providing recommendations for improving the process by which the condition of existing bridge structures is assessed. This research required a coordinated program of load testing and finite element analysis of selected bridges in the State of Georgia to gain perspectives on the behavior of older bridges under various load conditions. Structural system reliability assessments of these bridges were conducted and bridge fragilities were developed for purposes of comparison with component reliability benchmarks for new bridges. A reliability-based bridge rating framework was developed, along with a series of recommended improvements to the current bridge rating methods, which facilitate the incorporation of various in situ conditions of existing bridges into the bridge rating process at both component and system levels. This framework permits bridge ratings to be conducted at three levels of increasing complexity to achieve the performance objectives, expressed in the terms of reliability, that are embedded in the LRFR option of the AASHTO Manual of Bridge Evaluation. This research was sponsored by the Georgia Department of Transportation, and has led to a set of Recommended Guidelines for Condition Assessment and Evaluation of Existing Bridges in Georgia.