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  • 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.
1

Um procedimento de retroanálise para pavimentos flexíveis baseado na teoria do ponto inerte e em modelagem matemática / A backcalculation procedure for flexible pavements based on inertial point theory and in mathematical modeling

Pereira, José Miguel Belucio 07 May 2007 (has links)
Apresenta-se um processo de retroanálise de pavimentos flexíveis baseado na teoria do ponto inerte para a retroanálise do subleito, readaptado para bacias de deflexões teóricas obtidas com o carregamento para o ensaio com a viga Benkelman. Além da retroanálise do subleito, foi desenvolvido um modelo matemático fatorial para a obtenção do módulo resiliente equivalente das camadas presentes sobre o subleito, consideradas como uma única, denominada camada equivalente. Para a readaptação da teoria do ponto inerte e elaboração do modelo fatorial foram utilizados bancos de dados de bacias deflectométricas teóricas geradas pelo programa ELSYM5. Avaliou-se o erro na retroanálise do subleito e da camada equivalente para o processo proposto mediante comparações com outras metodologias semelhantes de retroanálise. A teoria do ponto inerte proporciona o desenvolvimento de um algoritmo simples, convergente e de resposta única para retroanálise de subleito de pavimentos flexíveis, minimizando a influência da experiência do engenheiro na resposta do problema. O procedimento de retroanálise elaborado nesta pesquisa caracteriza-se por simplicidade, sendo de uso adequado, entre outros, para avaliações em nível de rede. / A backcalculation procedure for flexible pavements is introduced based on inertial point theory for subgrade backcalculation readapted to theoretical deflection basins obtained with the load to Benkelman beam test. Beside subgrade backcalculation, it was developed a factorial mathematical model to obtain equivalent resilient modulus from the layers presents upon subgrade, considered as unique and denominated equivalent layer. To the readaptation of inertial point theory and preparing of factorial model were used theoretical deflection bowls data base generated by ELSYM5 program. The subgrade and equivalent layer modulus backcalculation were evaluated to the proposed process through others similar backcalculation methodologies. The inertial point theory provides the development of simple algorithms, convergent and with unique solution for flexible pavements subgrade backcalculation minimizing the influence of engineer experience in the problem answer. The backcalculation procedure developed in this research is characterized by simplicity being of suitable use at network evaluation level among others.
2

Um procedimento de retroanálise para pavimentos flexíveis baseado na teoria do ponto inerte e em modelagem matemática / A backcalculation procedure for flexible pavements based on inertial point theory and in mathematical modeling

José Miguel Belucio Pereira 07 May 2007 (has links)
Apresenta-se um processo de retroanálise de pavimentos flexíveis baseado na teoria do ponto inerte para a retroanálise do subleito, readaptado para bacias de deflexões teóricas obtidas com o carregamento para o ensaio com a viga Benkelman. Além da retroanálise do subleito, foi desenvolvido um modelo matemático fatorial para a obtenção do módulo resiliente equivalente das camadas presentes sobre o subleito, consideradas como uma única, denominada camada equivalente. Para a readaptação da teoria do ponto inerte e elaboração do modelo fatorial foram utilizados bancos de dados de bacias deflectométricas teóricas geradas pelo programa ELSYM5. Avaliou-se o erro na retroanálise do subleito e da camada equivalente para o processo proposto mediante comparações com outras metodologias semelhantes de retroanálise. A teoria do ponto inerte proporciona o desenvolvimento de um algoritmo simples, convergente e de resposta única para retroanálise de subleito de pavimentos flexíveis, minimizando a influência da experiência do engenheiro na resposta do problema. O procedimento de retroanálise elaborado nesta pesquisa caracteriza-se por simplicidade, sendo de uso adequado, entre outros, para avaliações em nível de rede. / A backcalculation procedure for flexible pavements is introduced based on inertial point theory for subgrade backcalculation readapted to theoretical deflection basins obtained with the load to Benkelman beam test. Beside subgrade backcalculation, it was developed a factorial mathematical model to obtain equivalent resilient modulus from the layers presents upon subgrade, considered as unique and denominated equivalent layer. To the readaptation of inertial point theory and preparing of factorial model were used theoretical deflection bowls data base generated by ELSYM5 program. The subgrade and equivalent layer modulus backcalculation were evaluated to the proposed process through others similar backcalculation methodologies. The inertial point theory provides the development of simple algorithms, convergent and with unique solution for flexible pavements subgrade backcalculation minimizing the influence of engineer experience in the problem answer. The backcalculation procedure developed in this research is characterized by simplicity being of suitable use at network evaluation level among others.
3

Nouvelles utilisations des mesures de bassins de déflexion pour caractériser l’état structurel des chaussées / New uses of deflection bowls measurements to characterize the structural conditions of pavements

Le Boursicaud, Vinciane 08 November 2018 (has links)
L’évaluation des caractéristiques structurelles des chaussées permet l’optimisation de leur maintenance. La mesure de déflexion est une mesure de base de cette évaluation. Aujourd’hui,seuls la déflexion maximale et le rayon de courbures ont analysés. Pourtant, le curviamètre et le déflectographe relèvent le bassin de déflexion complet dont l’analyse permettrait d’extraire des paramètres plus sensibles à l’endommagement des chaussées. Actuellement, l’interprétation des mesures est seulement qualitative et aucun calcul inverse de l’état de dommage de la structure n’est réalisé. La thèse vise à améliorer l’interprétation des mesures de déflexion. Le fonctionnement des appareils a montré que leurs hypothèses de mesure conduisent à des biais de mesure. Pour pallier ce problème, une procédure de correction des mesures a été mise en place. La comparaison avec des bassins théoriques a montré que la méthode de correction était satisfaisante. Ensuite, une étude numérique visant à déterminer la sensibilité du bassin de déflexion à la présence de différents défauts a été conduite. Celle ci a montré que les indicateurs classiques de la mesure de déflexion étaient peu sensibles à un endommagement dans la chaussée. Une méthodologie a donc été développée pour la création d’indicateurs optimisés à un type de défauts spécifiques. L’étude sur cas théoriques a conduit à l’obtention de résultats concluants. L’ensemble de ces travaux a ensuite été validé sur sites expérimentaux pour des mesures de répétabilité, mais également sur site avec la présence avérée de défauts. Finalement, la thèse a envisagé l’utilisation des travaux précédents sur des mesures réelles recueillies sur itinéraire. / The evaluation of the structural characteristics of pavements is involved in their maintenance. The measurement of deflection is a key indicator of this evaluation. Currently, only the maximum deflection and the radius of curvature are analyzed. However, the curviameter and the deflectograph are able to record the whole deflection bowl and the parameters deduced from thismeasurement could help to better characterized damages on pavements. The interpretation of the measurements is only qualitative and back calculation of pavement layer moduli gives unsatisfactory results. The thesis aims to improve the interpretation of deflection measurements. The working principle of these apparatus and the measurement assumptions introduce several measurement biases.To overcome these issues, a correction process has been developed. The comparison with theoretical basins has given satisfactory results on bituminous or flexible pavements. Then, a numerical study has been conducted to determine the influence of pavements damages on the deflection measurement. By this study, it has been showed that the usual indicators of the deflection measurement are notable to detect all damages. So, a methodology hasbeen developed in order to create an optimized indicator specified to a special defect. A study on numerical results has been conducted to validate the implementation of these indicators. Then, the correction method and these new indicators have been tested on experimental sites with and without damages. At last, the research works have been studied at network level.

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