As lajes alveolares são elementos eficientes do ponto de vista estrutural, pois os alvéolos permitem significativa redução de peso próprio sem comprometer a resistência e a rigidez. Além disso, é muito comum nesses elementos o uso de protensão, o que permite que estas lajes consigam vencer grandes vãos e se tornem uma solução competitiva. No entanto, para certas combinações de vãos, espessura da laje, ligações e propriedades dos materiais, esse sistema estrutural pode ser suscetível a vibrações excessivas. Há poucos estudos sobre a sensibilidade a vibrações destes elementos cuja aplicação é comum em situações de especial interesse como escritórios, nos quais as vibrações podem causar significativos incômodos aos usuários. Este trabalho visa contribuir para o melhor entendimento sobre a sensibilidade a vibrações de pavimentos com lajes sujeitas à ação dinâmica de atividades humanas. Além disso, pretende-se avaliar o comportamento dinâmico dos pavimentos com lajes alveolares em diferentes situações de interesse: painéis isolados, unidos por chaves de cisalhamento e após a concretagem da capa. Foi realizado um estudo experimental em um pavimento de um edifício comercial em estrutura de concreto pré-moldado nas três situações distintas da construção e foram obtidas as frequências naturais, modos de vibração e amortecimento para cada etapa, bem como uma análise do conforto ao usuário, a partir dos limites previstos em normas nacionais e internacionais. Foi também realizada uma análise numérica, na qual, além da determinação teórica de modos de vibração e frequências naturais, foram determinados os níveis de vibração gerados pelo caminhar de pessoas. As frequências naturais obtidas numericamente apresentaram diferença média de 11% com relação às experimentais. A diferença média dos picos de aceleração numéricos e experimentais foi de 9%. Tais resultados possibilitaram validar o modelo numérico proposto. A análise de conforto do pavimento indicou que a norma brasileira ANBT NBR 6118 (2014) não apresenta prescrições suficientes para se evitar vibrações excessivas em pavimentos com lajes alveolares protendidos. Os resultados permitiram concluir que as chaves de cisalhamento e a capa estrutural foram determinantes para garantir níveis aceitáveis de vibração no pavimento analisado. / Hollow core slabs are very efficient structural members, since their voids allow a significant reduction of self-weight, without jeopardizing the strength and stiffness. Moreover, prestressed concrete is commonly employed in this type of structure, allowing their use in large spans. Consequently, this is a very competitive solution. However, for certain combination of spans, slab thickness, connections and materials properties, this structural system can be susceptible to excessive vibrations. There is a lack of studies on vibration sensitivity of these elements, which are commonly applicable in situations of special interest, as offices, in which vibration can cause significant annoyance to users. This work aims to contribute to a better understanding about vibration sensitivity of hollow core slabs floors. Moreover, we intend to evaluate the dynamic behavior of hollow core slabs in different situations of interest: single panels, panels joined by shear keys and after completion of concrete topping. This analysis involves the determination of natural frequencies, mode shapes, damping ratios and vibrational levels generated by walking. An experimental study was carried out on a floor of a precast concrete structure of a commercial building in three different stages of construction. In this study, the natural frequencies, mode shapes and damping for each step were obtained, as well as an analysis of comfort, based on limits defined by national and international standards. A numerical analysis was also performed in which the vibration modes and natural frequencies were theoretically determined and the vibration levels generated by walking were estimated. The natural frequencies obtained numerically showed an average difference of 11% compared to experimental. The average difference between the numerical and experimental peak acceleration was 9%. These results allowed the validation of the numerical model proposed. The comfort analysis of the floor indicated that the Brazilian standard ANBT NBR 6118 (2014) does not provide sufficient provisions to avoid excessive vibrations in floors with prestressed hollow core slabs. The results showed that the shear keys and the structural topping were crucial to ensure acceptable levels of vibration.

Esta pesquisa teve como principal objetivo analisar o comportamento de lajes alveolares protendidas de uso corrente no Brasil (pequenas espessuras e alta protensão) quanto ao cisalhamento em região fissurada por ação do momento fletor, para diferentes situações: sem e com capa e com preenchimento parcial de alvéolos. Foi desenvolvido um estudo teórico com o emprego de equacionamentos analíticos disponíveis na literatura técnica, envolvendo as recomendações da norma brasileira NBR 6118:2003 (Projeto de Estruturas de Concreto), do ACI-318:2008 (Building code requirements for structural concrete) e da EN 1992-1-1 (2004) (Eurocode 2- Projeto de estruturas de betão Parte 1-1: Regras gerais e regras para edifícios). Foram feitas comparações com resultados experimentais obtidos a partir de inúmeros ensaios de lajes alveolares protendidas. As unidades ensaiadas nesta pesquisa foram disponibilizadas por quatro empresas brasileiras de intensa atividade no mercado, sendo analisadas as capacidades resistentes de diferentes tipos. Assim, foram realizados 96 ensaios, 31 para a determinação da capacidade resistente à flexão e 65, ao cisalhamento, sendo selecionados modelos de lajes com grande emprego no mercado brasileiro. A partir desses ensaios, foi possível entender melhor o comportamento das lajes alveolares protendidas produzidas no Brasil. Com as diversas análises, considerando os ensaios experimentais e um vasto estudo teórico quanto ao dimensionamento dessas lajes, verificou-se a adequabilidade de equações de diferentes normas. Assim, foi possível identificar o equacionamento que melhor representa o comportamento das peças produzidas no Brasil, considerando inclusive peculiaridades de comportamento, que apresentam diferenças constratantes com relação a unidades produzidas em outros países. A partir desses estudos, produziu-se um amplo memorial de cálculo, considerando as diversas tipologias de lajes estudadas, com o objetivo de contribuir de modo didático com os engenheiros de estrururas. Logo, com esta pesquisa, foi possível não somente melhorar o entendimento do comportamento de tais lajes alveolares, como também fornecer subsídios para a avaliação desses elementos, considerando as características específicas das lajes produzidas no Brasil e, assim, contribuir para a padronização do dimensionamento junto à norma brasileira NBR 14861 (Laje pré-fabricada - Painel alveolar de concreto protendido). / This work had as major objective to analyze the behavior of Brazilian prestressed hollow core slabs - small thickness and high level of prestressing - considering shear in a cracked region due to bending moment, for different design situations: without concrete topping, with concrete topping and with filling the voids. A theoretical study was developed with the use of analytical equations available in the technical literature, involving the recommendations of the Brazilian code NBR 6118:2003 (Design of concrete structures), ACI-318: 2008 (Building code requirements for structural concrete) and EN 1992-1-1 (2004) (Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings), comparing experimental results from many prestressed hollow core slabs tests. The slabs tested in this study were provided by four different Brazilian companies with intense activity in the market, and the resistant capacity of different typologies was analyzed. Thus 96 tests were made, 31 to determine the bending capacity and 64 for the determination of shear strength, and were selected slab models from the Brazilian market that are highly employed. From these tests, it was possible a better understanding of the prestressed hollow core slabs behavior produced in Brazil. With several analysis considering the experimental tests and an ample theoretical study about the design of these slabs, the adequacy of different codes equations were verified. Thus, it was possible to identify the equations that best represent the behavior of elements produced in Brazil, also considering the behaviour peculiarities of these slabs that have contrasting differences, if compared with units produced in other countries. From these studies it was produced a large design manual, considering the various types of studied slabs, aiming to contribute in a didactic way to the structural engineers. So, with this research, it was possible not only to improve comprehension of the behavior of such prestressed hollow core slabs, as well as provide information for evaluation of these elements, considering the specific characteristics of the slabs fabricated in Brazil and thus to contribute with the standardization of the design in the Brazilian code NBR 14861 (Prefabricated slab - Prestressed concrete hollow core panel).

Hollow-core flooring units are designed as simply supported members. However, frequently in construction, continuity is established between the units and supporting structure by the addition of insitu topping concrete and steel reinforcement. This change in structural form can result in negative bending moments and axial forces being induced in the floor by seismic and other structural actions. Significant negative moments are induced by load combinations that include the effects of seismic forces due to vertical ground motion. The focus of this research was two failure mechanisms possible under these loading conditions, a flexural failure and a shear failure. Both failure mechanisms were investigated analytically and experimentally. A brittle flexural failure was observed experimentally in a sub assembly test that contained starter bars and mesh reinforcement in the insitu topping concrete. The failure occurred at loads lower than those predicted using standard flexural theory. It appears that, due to the prestressing and low reinforcement ratio of the topping concrete, the assumption that plane sections remain plane is not appropriate for this situation. It is proposed that a strain concentration factor be introduced to account for the effects of tension stiffening. This factor improves the correlation between observed and predicted flexural strength. The second failure mode investigated was a flexure shear failure in a negative moment zone. Flexural cracks reduce the shear strength of a reinforced concrete member. Analytical predictions suggest that some hollow-core floor details could be prone to this type of brittle failure. A flexure shear failure was not observed experimentally; however, this does not eliminate the possibility of this failure mode. A summary of other failure mechanisms possible in hollow-core flooring is also presented. All failure modes should to be considered as part of establishing a hierarchy of failure in the design or retrofit of hollow-core floors.

xiv, 138 p. : ill. (some col.) / In this dissertation, we demonstrate the generation of optical Raman frequency combs by a single laser pump pulse traveling in hydrogen-filled hollow-core optical fibers. This comb generation process is a cascaded stimulated Raman scattering effect, where higher-order sidebands are produced by lower orders scattered from hydrogen molecules. We observe more than 4 vibrational and 20 rotational Raman sidebands in the comb. They span more than three octaves in optical wavelength, largely thanks to the broadband transmission property of the fiber. We found that there are phase correlations between the generated Raman comb sidebands (spectral lines), although their phases are fluctuating from one pump pulse to another due to the inherit spontaneous initiation of Raman scattering. In the experiment, we generated two Raman combs independently from two fibers and simultaneously observed the single-shot interferences between Stokes and anti-Stokes components from the two fibers. The experimental results clearly showed the strong phase anti-correlation between first-order side bands. We also developed a quantum theory to describe this Raman comb generation process, and it predicts and explains the phase correlations we observe. The phase correlation that we found in optical Raman combs may allow us to synthesize single-cycle optical pulse trains, creating attosecond pulses. However, the vacuum fluctuation in stimulated Raman scattering will result in the fluctuation of carrier envelope phase of the pulse trains. We propose that we can stabilize the comb by simultaneously injecting an auxiliary optical beam, mutually coherent with the main Raman pump laser pulse, which is resonant with the third anti-Stokes field. / Committee in Charge: Dr. Steven van Enk, Chair; Dr. Michael G. Raymer; Dr. Daniel A. Steck; Dr. David M. Strom; Dr. Andrew H. Marcus

As lajes alveolares são elementos eficientes do ponto de vista estrutural, pois os alvéolos permitem significativa redução de peso próprio sem comprometer a resistência e a rigidez. Além disso, é muito comum nesses elementos o uso de protensão, o que permite que estas lajes consigam vencer grandes vãos e se tornem uma solução competitiva. No entanto, para certas combinações de vãos, espessura da laje, ligações e propriedades dos materiais, esse sistema estrutural pode ser suscetível a vibrações excessivas. Há poucos estudos sobre a sensibilidade a vibrações destes elementos cuja aplicação é comum em situações de especial interesse como escritórios, nos quais as vibrações podem causar significativos incômodos aos usuários. Este trabalho visa contribuir para o melhor entendimento sobre a sensibilidade a vibrações de pavimentos com lajes sujeitas à ação dinâmica de atividades humanas. Além disso, pretende-se avaliar o comportamento dinâmico dos pavimentos com lajes alveolares em diferentes situações de interesse: painéis isolados, unidos por chaves de cisalhamento e após a concretagem da capa. Foi realizado um estudo experimental em um pavimento de um edifício comercial em estrutura de concreto pré-moldado nas três situações distintas da construção e foram obtidas as frequências naturais, modos de vibração e amortecimento para cada etapa, bem como uma análise do conforto ao usuário, a partir dos limites previstos em normas nacionais e internacionais. Foi também realizada uma análise numérica, na qual, além da determinação teórica de modos de vibração e frequências naturais, foram determinados os níveis de vibração gerados pelo caminhar de pessoas. As frequências naturais obtidas numericamente apresentaram diferença média de 11% com relação às experimentais. A diferença média dos picos de aceleração numéricos e experimentais foi de 9%. Tais resultados possibilitaram validar o modelo numérico proposto. A análise de conforto do pavimento indicou que a norma brasileira ANBT NBR 6118 (2014) não apresenta prescrições suficientes para se evitar vibrações excessivas em pavimentos com lajes alveolares protendidos. Os resultados permitiram concluir que as chaves de cisalhamento e a capa estrutural foram determinantes para garantir níveis aceitáveis de vibração no pavimento analisado. / Hollow core slabs are very efficient structural members, since their voids allow a significant reduction of self-weight, without jeopardizing the strength and stiffness. Moreover, prestressed concrete is commonly employed in this type of structure, allowing their use in large spans. Consequently, this is a very competitive solution. However, for certain combination of spans, slab thickness, connections and materials properties, this structural system can be susceptible to excessive vibrations. There is a lack of studies on vibration sensitivity of these elements, which are commonly applicable in situations of special interest, as offices, in which vibration can cause significant annoyance to users. This work aims to contribute to a better understanding about vibration sensitivity of hollow core slabs floors. Moreover, we intend to evaluate the dynamic behavior of hollow core slabs in different situations of interest: single panels, panels joined by shear keys and after completion of concrete topping. This analysis involves the determination of natural frequencies, mode shapes, damping ratios and vibrational levels generated by walking. An experimental study was carried out on a floor of a precast concrete structure of a commercial building in three different stages of construction. In this study, the natural frequencies, mode shapes and damping for each step were obtained, as well as an analysis of comfort, based on limits defined by national and international standards. A numerical analysis was also performed in which the vibration modes and natural frequencies were theoretically determined and the vibration levels generated by walking were estimated. The natural frequencies obtained numerically showed an average difference of 11% compared to experimental. The average difference between the numerical and experimental peak acceleration was 9%. These results allowed the validation of the numerical model proposed. The comfort analysis of the floor indicated that the Brazilian standard ANBT NBR 6118 (2014) does not provide sufficient provisions to avoid excessive vibrations in floors with prestressed hollow core slabs. The results showed that the shear keys and the structural topping were crucial to ensure acceptable levels of vibration.

Esta pesquisa teve como principal objetivo analisar o comportamento de lajes alveolares protendidas de uso corrente no Brasil (pequenas espessuras e alta protensão) quanto ao cisalhamento em região fissurada por ação do momento fletor, para diferentes situações: sem e com capa e com preenchimento parcial de alvéolos. Foi desenvolvido um estudo teórico com o emprego de equacionamentos analíticos disponíveis na literatura técnica, envolvendo as recomendações da norma brasileira NBR 6118:2003 (Projeto de Estruturas de Concreto), do ACI-318:2008 (Building code requirements for structural concrete) e da EN 1992-1-1 (2004) (Eurocode 2- Projeto de estruturas de betão Parte 1-1: Regras gerais e regras para edifícios). Foram feitas comparações com resultados experimentais obtidos a partir de inúmeros ensaios de lajes alveolares protendidas. As unidades ensaiadas nesta pesquisa foram disponibilizadas por quatro empresas brasileiras de intensa atividade no mercado, sendo analisadas as capacidades resistentes de diferentes tipos. Assim, foram realizados 96 ensaios, 31 para a determinação da capacidade resistente à flexão e 65, ao cisalhamento, sendo selecionados modelos de lajes com grande emprego no mercado brasileiro. A partir desses ensaios, foi possível entender melhor o comportamento das lajes alveolares protendidas produzidas no Brasil. Com as diversas análises, considerando os ensaios experimentais e um vasto estudo teórico quanto ao dimensionamento dessas lajes, verificou-se a adequabilidade de equações de diferentes normas. Assim, foi possível identificar o equacionamento que melhor representa o comportamento das peças produzidas no Brasil, considerando inclusive peculiaridades de comportamento, que apresentam diferenças constratantes com relação a unidades produzidas em outros países. A partir desses estudos, produziu-se um amplo memorial de cálculo, considerando as diversas tipologias de lajes estudadas, com o objetivo de contribuir de modo didático com os engenheiros de estrururas. Logo, com esta pesquisa, foi possível não somente melhorar o entendimento do comportamento de tais lajes alveolares, como também fornecer subsídios para a avaliação desses elementos, considerando as características específicas das lajes produzidas no Brasil e, assim, contribuir para a padronização do dimensionamento junto à norma brasileira NBR 14861 (Laje pré-fabricada - Painel alveolar de concreto protendido). / This work had as major objective to analyze the behavior of Brazilian prestressed hollow core slabs - small thickness and high level of prestressing - considering shear in a cracked region due to bending moment, for different design situations: without concrete topping, with concrete topping and with filling the voids. A theoretical study was developed with the use of analytical equations available in the technical literature, involving the recommendations of the Brazilian code NBR 6118:2003 (Design of concrete structures), ACI-318: 2008 (Building code requirements for structural concrete) and EN 1992-1-1 (2004) (Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings), comparing experimental results from many prestressed hollow core slabs tests. The slabs tested in this study were provided by four different Brazilian companies with intense activity in the market, and the resistant capacity of different typologies was analyzed. Thus 96 tests were made, 31 to determine the bending capacity and 64 for the determination of shear strength, and were selected slab models from the Brazilian market that are highly employed. From these tests, it was possible a better understanding of the prestressed hollow core slabs behavior produced in Brazil. With several analysis considering the experimental tests and an ample theoretical study about the design of these slabs, the adequacy of different codes equations were verified. Thus, it was possible to identify the equations that best represent the behavior of elements produced in Brazil, also considering the behaviour peculiarities of these slabs that have contrasting differences, if compared with units produced in other countries. From these studies it was produced a large design manual, considering the various types of studied slabs, aiming to contribute in a didactic way to the structural engineers. So, with this research, it was possible not only to improve comprehension of the behavior of such prestressed hollow core slabs, as well as provide information for evaluation of these elements, considering the specific characteristics of the slabs fabricated in Brazil and thus to contribute with the standardization of the design in the Brazilian code NBR 14861 (Prefabricated slab - Prestressed concrete hollow core panel).

Ensaios não destrutivos são testes que não causam danos a estrutura ensaiada, o que os torna um excelente auxílio aos métodos de ensaios tradicionais quando estes apresentam alguma dificuldade de serem executados. Desta forma, este trabalho visa utilizar os ensaios de esclerometria e ultrassom, dando ênfase na transmissão indireta, para determinar a resistência à compressão nas primeiras idades do concreto e possibilitar um melhor controle tecnológico do material. Para se obter a relação entre os dados experimentais não destrutivos e a resistência à compressão, foram realizados ensaios em duas etapas. A primeira etapa foi desenvolvida em corpos de prova cilíndricos e prismáticos com três traços diferentes de concreto, onde foi variado o consumo de cimento. Na segunda etapa os ensaios foram realizados em uma laje alveolar produzida em laboratório. Com os dados coletados nos ensaios foi possível determinar a relação de crescimento da resistência, do índice esclerométrico e da velocidade do pulso ultrassônico ao longo do tempo, além das correlações velocidade x resistência, velocidade x índice esclerométrico; e a correlação múltipla entre os três fatores. Com base nisto, concluiu-se que é viável ter um bom controle tecnológico da resistência do concreto a partir dos ensaios não destrutivos. Este trabalho não obteve uma equação universal que correlacionasse os parâmetros para todos os tipos de traço de concreto, porém foram obtidas correlações satisfatórias para os traços ensaiados. Desta forma, é possível afirmar que o ensaio de ultrassom, especificamente posição indireta de 30 centímetros, e a esclerometria são ferramentas possíveis de serem aplicadas como auxílio à obtenção da resistência à compressão nas primeiras idades. / Non-destructive tests are tools that do not cause damage to the evaluated structure, which is an excellent support for traditional test methods. Therefore, this work used non-destructive tests such as rebound method and ultrasound, emphasizing the indirect transmission, to determine compression strength in the early age sand enable a better technological control of the material. Two-step tests were performed to see if there is a relationship between non-destructive test data and the compressive strength. The first one was performed in specimens with three different concrete compositions, where the cement ratio was varied, where as the second was carried out in a laboratory hollow core slab. With the experimental data was possible to determine the relationship of the compression strength, rebound number and ultrasonic pulse velocity over time; as the correlations strength x velocity, velocity x rebound number; and a multiple correlation between the three tests. Based on this, it was concluded that it is possible to have a good technological control of the concrete strength from non-destructive tests. A universal equation that correlates parameters for all types of concrete compositions was not found, but satisfactory correlations were obtained for the tested concretes. In this way, it is possible to affirm that the ultrasound test, specifically indirect position of 30 centimeters, and rebound method are possible tools to be applied as aid to obtain the compression strength in the early ages.

A maioria dos edifícios de concreto pré-moldado, construídos no Brasil e no exterior, é constituída por lajes alveolares. Este trabalho considera o estudo da continuidade dessas lajes. No cálculo desses elementos, a prática comum é considerá-los como simplesmente apoiados. Para melhorar o desempenho, é possível promover a continuidade nos apoios intermediários. Isso pode ser feito colocando armadura na região tracionada da ligação, no interior da capa, ou através de barras concretadas dentro dos alvéolos. O objetivo deste trabalho é investigar o comportamento de pavimentos formados por lajes alveolares com continuidade, com armadura na capa. Para isso, foi realizado um estudo envolvendo análise teórica e experimental em três modelos. Esses modelos, em escala real, foram submetidos a um carregamento transversal, distribuído de forma linear. Os estudos teóricos consideraram uma simulação numérica com elementos de viga e a fórmula de Branson para descrever o comportamento não linear físico do material. Além disso, foram avaliadas as expressões dos principais códigos nacionais e internacionais, no que diz respeito à ruptura por cisalhamento da seção transversal e da interface laje-capa. Os resultados da análise experimental indicaram que o modelo 1 rompeu por cisalhamento da seção transversal, com o mecanismo de tração diagonal do concreto. O modelo 2 apresentou ruptura por cisalhamento da interface. No modelo 3, a ruptura foi por flexão. O comportamento dos modelos ensaiados foi governado pela fissuração da capa na região de momento negativo. A análise teórica com elementos de barra representou de forma satisfatória o comportamento dos modelos ensaiados. As únicas formulações que apresentaram resultados coerentes com os três ensaios foram: EUROCODE 2:2004, para o cálculo da resistência ao cisalhamento da interface, e FIB MODEL CODE 2010, para o cálculo da resistência ao cisalhamento da seção transversal. Conclui-se que a continuidade melhora o desempenho das lajes alveolares, uma vez que reduz os deslocamentos no meio do vão e aumenta a capacidade de carga. / Most buildings of precast concrete built in Brazil and abroad consist of hollow core slabs. This paper considers the study of the continuity of these slabs. In design of these elements the common practice is to consider them as simply supported. To improve the performance it is possible to promote the continuity in the intermediate supports. This can be done by placing reinforcement in the tensioned region of the connection, inside the topping, or by bars concreted inside the voids. The aim of this work is to investigate the behavior of hollow core floors with continuity, with reinforcement in the topping. For this, a study involving theoretical and experimental analysis was conducted in three models. The full-scale models were subjected to a transverse loading distributed linearly. The theoretical studies have considered a numerical simulation with beam elements and the Branson formula to describe the physical nonlinear behavior of the material. Furthermore, the specifications of the major Brazilian and international codes were evaluated, with respect to failure by shear of the cross section and the slab-topping interface. The results of the experimental analysis indicated that the model 1 failed by shear of the cross section with the mechanism of diagonal tension of the concrete. Model 2 presented shear failure of the interface. In model 3, the failure was by flexure. The behavior of the tested models was ruled by cracking of the topping in region of negative bending moment. Theoretical analysis with beam elements represented satisfactorily the behavior of the tested models. The only formulations that presented consistent results with the three tests were: EUROCODE 2:2004, to calculate the shear strength of the interface, and FIB MODEL CODE 2010, for calculating of the shear strength of the cross section. It is concluded that the continuity improves the performance of the hollow core slabs, as it reduces the displacements at mid-span and increases the bearing capacity.

Cette thèse décrit la conception et la réalisation d'une plateforme expérimentale pour le refroidissement par laser et le guidage d’atomes de Rb dans les fibres à cristal photonique à cœur creux (HC-PCF). Cette plateforme a pour but de fournir un système polyvalent pour explorer le refroidissement par laser à l’intérieur des fibres avec l'objectif à plus long terme de réaliser une fibre optique constituée d’un cœur rempli d’atomes froids (micro-cellule photonique). La plateforme a été conçue pour héberger plusieurs expériences sur le guidage d'atomes froids et thermiques ainsi que la spectroscopie dans les HC-PCFs pour répondre à plusieurs questions ouvertes liées par exemple à l'effet de la surface interne des HC-PCFs sur la structure énergétique des atomes ainsi que le piégeage et le refroidissement des atomes. La plateforme comprend une chambre spécifique à vide ultra-élevée (UHV) et un ensemble de lasers pour le refroidissement et le guidage des atomes à l'intérieur du HC-PCF hautement adapté. La chambre UHV a été conçue pour accueillir plusieurs HC-PCFs et deux pièges magnéto-optiques (MOT). Les HC-PCFs ont été conçus et fabriqués avec différents diamètres de cœur, contenu modal et post-traités avec des matériaux différents pour la surface interne du cœur. Par exemple, les diamètres du cœur varient de ~ 30 μm à ~ 80 μm traités avec une couche d'aluminosilicate ou une couche de PDMS afin de fournir un grand espace de paramètres pour évaluer l'effet de la surface sur les atomes confinés dans les fibres. Ainsi, le système a été construit et caractérisé. Le laser de refroidissement/repompage a été stabilisé en fréquence, avec une variance d'Allan de σ(τ)=3,8×10^(-11)/√τ. Avec ce système nous avons généré un MOT avec les deux isotopes du Rb, avec une température de refroidissement faible de l’ordre de 7 μK. La plateforme est maintenant opérationnelle pour entreprendre le premier guidage atomique et explorer la faisabilité du refroidissement des atomes à l'intérieur des HC-PCFs. / This thesis reports on the design and fabrication of an experimental platform for in-fibre laser cooling of Rb and atom optics. By in-fibre laser cooling, we mean the long term aim of laser cooling thermal Rb atoms of a Photonic MicroCell (PMC), and subsequently developing what would be cold-atom photonic crystal fibre (PCF). The platform was designed to harbor several experiments on cold and thermal atom guidance and in-fibre spectroscopy so to address several open questions related for example to the effect of the core inner-wall surface on the atom energy structure and on selective fibre mode excitation for atom trapping and cooling. The completed platform comprises a specific and large ultra-high vacuum (UHV) chamber and a set of lasers for both atom cooling and atom guiding inside highly tailored hollow-core PCF (HC-PCF). The UHV chamber was designed to accommodate several HC-PCFs and two magneto-optical traps (MOT). The HC-PCF were designed, fabricated and post-processed to exhibit different core diameter, modal content and core inner surface material. For example, the mode field diameters range from ~30 µm to ~80 µm for the fundamental Gaussian-like core mode, and the surface materials include pure silica, a layer of Aluminosilicate or a layer of PDMS so to provide a large parameter space in assessing the effect of surface on the fibre-confined atoms. The system has been constructed and characterized. The cooling/repumping laser was frequency-stabilized, with measured Allan variance deviation of σ(τ)=3.8×10^(-11)/√τ. With the system we generated MOT with both isotopes of the Rb atom, with a cooling temperature as low as 7 µK. The platform is now operational to undertake the first atom guidance and explore the feasibility of atom cooling inside a HC-PCF.

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.