This thesis is concerned with both the static and dynamic analysis of parabolic arches. In the dynamic part, special attention is given to the free vibration of such arches. The following procedure is followed. The loading conditions are assumed and a infinitesimal segment of the arch is taken so as the differential equations relating deflections and slope changes on both ends of the segment are developed. These obtain a set of general equations for elastic parabolic arches. In dynamics, the equations of general curved structure are developed through considerations of dynamic equilibrium. A sudden removal of loading is assumed to cause the structure to vibrate freely. Then, a method of separating variables for partial differential equations is used to get the equations of deflection components. Each special characteristic function is derived for each special set of boundary conditions so as to get an unlimited number of modes of free vibrations. The Fourier series is employed to determine the coefficients of the dynamic equations, and to get a series-form solution for deflections. Finally, two numerical examples are given to represent the practical application. Two kinds of parabolic arches, one with two-hinged supports and the other with fixed-ends are considered in each procedure. / Master of Science

Since the Eighteenth century, a great amount of research has been done using the elastic analysis technique in the field of curved structures. Recently the question of behavior beyond the yielding range has become increasingly important. By applying the methods of plastic analysis, the collapse load of a structure can be determined, and also the stress distribution and the deflection, just before collapse, can be calculated. However the evolution of the stress distribution and the deflection at any section of the structure between the load causing first yielding and the collapse load is still an unsolved problem. Concerning the problem of evolution of the stress distribution in the inelastic range, most literature relies on the simple plastic theory in which the effect of the axial force on the formation of a plastic hinge is neglected. In fact this conception is in serious error in some cases, especially when the curved structure is a shallow arch, the stresses developed are apparently governed by the axial force. Literature considering the combined effects of bending moment and axial force is very rare. In this thesis, the author proposes a new method, incorporating effects of both axial force and bending moment, of determining the evolution of stress distributions and the deflections in the inelastic range. The thesis includes three parts. In the first to parts, the theory for the stress analysis and for the deflection of a rectangular section is presented. The third part contains three examples to illustrate the use of the new method in practical engineering problems. / Master of Science

I've titled my thesis, "Intrinsics" because my architectural design is an attempt to respond to what is inherent in the materials, in the way materials are joined, in the flow of forces through the structure, in the site and surroundings, and in the human nature of a person using the building type I'm designing. This is a tectonic approach, so my thesis is also "An Exploration of Tectonic Expression" with a Montessori school as a project vehicle. The site is next to the Roanoke Public Library in Elmwood Park in Roanoke, Virginia. The primary materials are glue-laminated wood beams and arches, metal connectors, and reinforced concrete walls. I explored what can happen if each layer of a glue-laminated member is allowed to act independently, separating from the girder in appropriate places to recombine into a new whole. The monolith transforms into a pattern of parts. / Master of Architecture

The neutral point of a truss-column joint can be determined very easily, using the thrust stiffnesses. Once the neutral point is determined the moment and thrust distribution about the neutral point may be performed quite rapidly, since the thrusts and moments converge more rapidly about the neutral point than about the joint. The actual process of distribution of moments and thrusts follows the pattern outlined by Professor D.H. Pletta in his <u>Notes on Statically Indeterminate Structures</u>⁷. / Master of Science

In this thesis, new design concepts for arch bridges using ultra high-performance fibre-reinforced concrete are developed for spans of 50 to 400 m. These concepts are light-weight and efficient, and thus have the potential to significantly reduce the cost of construction. Lightness is achieved by the thinning of structural components and the efficient use of precompression in the arch, rather than by the decrease of bending stiffness. Using the advanced properties of the material, the design concepts were shown to reduce the consumption of concrete in arch bridges by more than 50% relative to arches built using conventional concrete technology. In addition to span length, other design parameters including span-to-rise ratio and deck-stiffening were considered, resulting in a total of seventy-two design concepts. Other important contributions made in this thesis include: (1) the development of a simple analytical model that describes the transition of shallow arches between pure arch behaviour and pure beam behaviour, (2) a comprehensive comparative study of 58 existing concrete arch bridges that characterizes the current state-of-the-art and serves as a valuable reference design tool, and (3) the development and experimental validation of general and simplified methods for calculating the capacity of slender ultra high-performance fibre-reinforced concrete members under compression and bending. The research presented in this thesis provides a means for designers to take full advantage of the high compressive and tensile strengths of the concrete and hence to exploit the economic potential offered by the material.

In this thesis, new design concepts for arch bridges using ultra high-performance fibre-reinforced concrete are developed for spans of 50 to 400 m. These concepts are light-weight and efficient, and thus have the potential to significantly reduce the cost of construction. Lightness is achieved by the thinning of structural components and the efficient use of precompression in the arch, rather than by the decrease of bending stiffness. Using the advanced properties of the material, the design concepts were shown to reduce the consumption of concrete in arch bridges by more than 50% relative to arches built using conventional concrete technology. In addition to span length, other design parameters including span-to-rise ratio and deck-stiffening were considered, resulting in a total of seventy-two design concepts. Other important contributions made in this thesis include: (1) the development of a simple analytical model that describes the transition of shallow arches between pure arch behaviour and pure beam behaviour, (2) a comprehensive comparative study of 58 existing concrete arch bridges that characterizes the current state-of-the-art and serves as a valuable reference design tool, and (3) the development and experimental validation of general and simplified methods for calculating the capacity of slender ultra high-performance fibre-reinforced concrete members under compression and bending. The research presented in this thesis provides a means for designers to take full advantage of the high compressive and tensile strengths of the concrete and hence to exploit the economic potential offered by the material.

Call number: LD2668 .T4 1984 K66 / Master of Science

Neste estudo avaliou-se as características dos arcos dentais e das estruturas miofuncionais orais de 61 crianças na faixa etária de 36 a 60 meses que apresentavam hábito de sucção de chupeta ou não, e a relação entre o uso e tipo de chupeta com diversos aspectos comportamentais da mãe, grau de escolaridade materna e renda familiar. Estes últimos três aspectos foram avaliados por meio de questionário distribuído à s mães, e as características dos arco dentais e das estruturas miofuncionais orais por meio de exame clínico. As crianças foram dividas em três grupos conforme o uso e tipo de chupeta: 1. grupo que nunca sugou chupeta, 2. grupo que sugava somente a chupeta anatômica (ortodôntica) e, 3. grupo que sugava somente a chupeta convencional. Não foi encontrada associação estatisticamente significante entre o uso da chupeta e o sexo e número de irmãos da criança, renda familiar e grau de estudo formal da mãe. Verificou-se que o período de aleitamento materno menor e o fato de ter tido uma ou mais chupetas já no enxoval do bebê, favoreceram o uso da chupeta. Não foi encontrada relação estatisticamente significante entre o tipo de arco dental, relação terminal dos segundos molares decíduos, linha média e espaço primata entre os três grupos avaliados. Notou-se que a relação canina Classe II foi significantemente maior nas crianças que sugavam chupeta do que naquelas que não tinham este hábito. Constatou-se que tanto a chupeta anatômica como a convencional, favoreceram o desenvolvimento da mordida aberta anterior e cruzada posterior. Não houve diferença estatisticamente significante entre as médias de mordida aberta anterior nas crianças que usavam chupeta convencional ou anatômica (p=0,344). A prevalência da mordida cruzada posterior foi estatisticamente maior nas crianças que sugavam a chupeta convencional do que naquelas que sugavam a anatômica (ortodôntica) ou não tinham este hábito (p=0,010). As distâncias intercaninas do arco superior foram significantemente menores nas crianças que sugavam chupeta do que naquelas sem este hábito. Já nas distâncias intercaninas do arco inferior, não houve diferença entre os três grupos. A dimensão da sobressaliência foi maior em ambos os grupos de chupeta quando comparados ao grupo sem hábito de sucção (p=0,000). Em relação ao modo de sugar a chupeta, observou-se que a sobressaliência nas crianças que sugavam sempre a chupeta (p= 0,021), foi estatisticamente maior do que daquelas que sugavam às vezes . Das estruturas miofuncionais orais avaliadas, houve associação estatisticamente significante entre a mobilidade da bochecha (p=0,022) e formato do palato duro (p=0,042) com o uso e tipo de chupeta; sendo que as crianças que nunca sugaram chupeta, apresentaram uma prevalência maior de normalidade destas duas estruturas do que aquelas que sugavam chupeta. / This study evaluated through clinical examination the characteristics of the dental arches and myofunctional oral structures of 61 children aged 36- to-60-months, who either had pacifier-sucking habit or did not. Pacifier use and type was compared to family income and mother’s attitudes and educational level. This was assessed by a questionnaire distributed to the mothers. The children were divided into three groups: 1. those who never had pacifier sucking habit, 2. those who only used anatomic or orthodontic pacifier, and 3. those who only used conventional pacifier. No statistically significant relationship was found between pacifier use and the family income, mother´s educational level, and child´s sex and number of siblings. The children who were breastfed for a smaller period of time and had one or more pacifiers on his/her layette had higher prevalence of pacifier sucking habit. No statistical significant relationship was found between arch type (Type I or Type II according to Baume´s classification), terminal plane relationship of second primary molars, medline and primate spaces among the three groups studied. Class II primary canine relationship was significantly greater among pacifier users than among those without this sucking habits. It was observed that both, the anatomic (orthodontic) and conventional pacifiers lead to anterior open bite and posterior crossbite. No significant difference was found between the ones who used the anatomic (orthodontic) pacifier or the conventional one, in respect to the mean openbite (p=0,344). Compared to children without sucking habit, children with pacifier habit had a greater mean overjet (in milimeters) (p=0,000). Posterior crossbite was statistically different among the children who used the conventional pacifier when compared to the other two groups (p=0,010). The upper intercanine distance was significantly smaller among those who had pacifier sucking-habit when compared to those habit-free, but no significant difference was found among the three groups with respect to the lower intercanine distance. Among the myofunctional oral structures evaluated, the ones that demonstrated statistical difference among the three groups were the cheek mobility (p=0,022) and the hard palate shape (p=0,022); being that the group of children who never sucked a pacifier, showed a higher prevalence of normality of these two structures than the ones who had a pacifier sucking habit. In regards to how frequent the child sucked the pacifier throughout the day, it was seen that those who “always sucked" had a significantly greater overjet (p=0,021), than those who “suck sometimes" or “just held" the pacifier in the mouth.

O objetivo desta pesquisa foi avaliar as áreas de tensões produzidas por arcos ortodônticos expandidos associados a diferentes tipos de bráquetes durante a fase de alinhamento e nivelamento ortodôntico. A partir de modelos de gesso adquiridos durante a fase de nivelamento ortodôntico do arco dentário inferior de um mesmo paciente, obteve-se 3 modelos fotoelásticos que receberam 3 diferentes tipos de bráquetes: convencional (Ovation®, GAC International, New York, EUA), autoligável ativo (In-Ovation®, GAC International, New York, EUA) e autoligável passivo (Damom 3MX®, Ormco, Califórnia, EUA), associados a arcos de liga de níquel-titânio 0.014\" e 0.014\" x 0.025\" e de liga de aço 0.019\" x 0.025\". Os modelos fotoelásticos com os respectivos arcos e bráquetes ortodônticos foram observados em polariscópio circular, e as imagens fotográficas das regiões dos incisivos, pré-molares e molares foram analisadas qualitativa e quantitativamente. A análise qualitativa foi realizada pela identificação da ordem e coloração das franjas nos locais onde ocorreram, e a quantitativa foi realizada utilizando o software Matlab® para a identificação dos padrões de cores RGB nas áreas dos terços médio-apicais dos dentes de cada região. Os dados obtidos das diferentes associações arcos/bráquetes ortodônticos foram comparados estatisticamente pelo teste de Wilcoxon. Pode-se concluir que, na região dos incisivos, as maiores tensões ocorreram quando os arcos ortodônticos foram associados aos bráquetes autoligados passivos. Na região dos pré-molares, as maiores tensões ocorreram quando o arco 0.014\" foi associado ao bráquete convencional, em movimentos de segunda ordem (extrusão) e de angulação, e quando os arcos retangulares foram associados aos bráquetes autoligados passivos. Na região dos molares, as maiores tensões ocorreram quando os arcos retangulares foram associados aos tubos ortodônticos com maior prescrição de inclinação (Ovation® e In-Ovation®). / The aim of this research was to evaluate the areas of tension produced by expanded orthodontic arches associated with different types of brackets during the orthodontic leveling phase. From plaster models of a single patient lower dental arch obtained during the orthodontic alignment and leveling phase, three photoelastic models were developed that received three different types of brackets: convencional (Ovation®, GAC International, New York, EUA); active self ligation bracktes (In-Ovation®, GAC International, New York, EUA) e passive self ligation bracktes (Damom 3MX®, Ormco, Califórnia, EUA), associated with 0.014\" and 0.014\" ? 0.025\" titanium-nickel alloy arches and 0.019\" ? 0.025\" alloy steel arches. These models were analyzed in a circular polariscope; photographic images of the incisor, premolar, and molar regions were qualitatively and quantitatively analyzed. The first analysis was obtained by identifying the photoelastic fringe order at sites where they occurred, and the second one was obtained using Matlab® software to identify RGB color patterns in middle apical tooth areas of each region. Data from the different orthodontic arches and brackets were compared using the Wilcoxon test. Our results showed that in the incisors region the greatest tensions occurred when the orthodontic arches were associated to the self-ligating passive brackets; in the premolars region, by the association of the 0.014\" arch and conventional bracket in second order (extrusion) and angulation movements and when the rectangular arches were associated with the passive self-ligating brackets. The greatest tensions in the molar regions occurred by association of rectangular arches and inclination high prescriptions orthodontics tubes (Ovation® and In-Ovation®).

Neste estudo avaliou-se as características dos arcos dentais e das estruturas miofuncionais orais de 61 crianças na faixa etária de 36 a 60 meses que apresentavam hábito de sucção de chupeta ou não, e a relação entre o uso e tipo de chupeta com diversos aspectos comportamentais da mãe, grau de escolaridade materna e renda familiar. Estes últimos três aspectos foram avaliados por meio de questionário distribuído à s mães, e as características dos arco dentais e das estruturas miofuncionais orais por meio de exame clínico. As crianças foram dividas em três grupos conforme o uso e tipo de chupeta: 1. grupo que nunca sugou chupeta, 2. grupo que sugava somente a chupeta anatômica (ortodôntica) e, 3. grupo que sugava somente a chupeta convencional. Não foi encontrada associação estatisticamente significante entre o uso da chupeta e o sexo e número de irmãos da criança, renda familiar e grau de estudo formal da mãe. Verificou-se que o período de aleitamento materno menor e o fato de ter tido uma ou mais chupetas já no enxoval do bebê, favoreceram o uso da chupeta. Não foi encontrada relação estatisticamente significante entre o tipo de arco dental, relação terminal dos segundos molares decíduos, linha média e espaço primata entre os três grupos avaliados. Notou-se que a relação canina Classe II foi significantemente maior nas crianças que sugavam chupeta do que naquelas que não tinham este hábito. Constatou-se que tanto a chupeta anatômica como a convencional, favoreceram o desenvolvimento da mordida aberta anterior e cruzada posterior. Não houve diferença estatisticamente significante entre as médias de mordida aberta anterior nas crianças que usavam chupeta convencional ou anatômica (p=0,344). A prevalência da mordida cruzada posterior foi estatisticamente maior nas crianças que sugavam a chupeta convencional do que naquelas que sugavam a anatômica (ortodôntica) ou não tinham este hábito (p=0,010). As distâncias intercaninas do arco superior foram significantemente menores nas crianças que sugavam chupeta do que naquelas sem este hábito. Já nas distâncias intercaninas do arco inferior, não houve diferença entre os três grupos. A dimensão da sobressaliência foi maior em ambos os grupos de chupeta quando comparados ao grupo sem hábito de sucção (p=0,000). Em relação ao modo de sugar a chupeta, observou-se que a sobressaliência nas crianças que sugavam sempre a chupeta (p= 0,021), foi estatisticamente maior do que daquelas que sugavam às vezes . Das estruturas miofuncionais orais avaliadas, houve associação estatisticamente significante entre a mobilidade da bochecha (p=0,022) e formato do palato duro (p=0,042) com o uso e tipo de chupeta; sendo que as crianças que nunca sugaram chupeta, apresentaram uma prevalência maior de normalidade destas duas estruturas do que aquelas que sugavam chupeta. / This study evaluated through clinical examination the characteristics of the dental arches and myofunctional oral structures of 61 children aged 36- to-60-months, who either had pacifier-sucking habit or did not. Pacifier use and type was compared to family income and mother’s attitudes and educational level. This was assessed by a questionnaire distributed to the mothers. The children were divided into three groups: 1. those who never had pacifier sucking habit, 2. those who only used anatomic or orthodontic pacifier, and 3. those who only used conventional pacifier. No statistically significant relationship was found between pacifier use and the family income, mother´s educational level, and child´s sex and number of siblings. The children who were breastfed for a smaller period of time and had one or more pacifiers on his/her layette had higher prevalence of pacifier sucking habit. No statistical significant relationship was found between arch type (Type I or Type II according to Baume´s classification), terminal plane relationship of second primary molars, medline and primate spaces among the three groups studied. Class II primary canine relationship was significantly greater among pacifier users than among those without this sucking habits. It was observed that both, the anatomic (orthodontic) and conventional pacifiers lead to anterior open bite and posterior crossbite. No significant difference was found between the ones who used the anatomic (orthodontic) pacifier or the conventional one, in respect to the mean openbite (p=0,344). Compared to children without sucking habit, children with pacifier habit had a greater mean overjet (in milimeters) (p=0,000). Posterior crossbite was statistically different among the children who used the conventional pacifier when compared to the other two groups (p=0,010). The upper intercanine distance was significantly smaller among those who had pacifier sucking-habit when compared to those habit-free, but no significant difference was found among the three groups with respect to the lower intercanine distance. Among the myofunctional oral structures evaluated, the ones that demonstrated statistical difference among the three groups were the cheek mobility (p=0,022) and the hard palate shape (p=0,022); being that the group of children who never sucked a pacifier, showed a higher prevalence of normality of these two structures than the ones who had a pacifier sucking habit. In regards to how frequent the child sucked the pacifier throughout the day, it was seen that those who “always sucked” had a significantly greater overjet (p=0,021), than those who “suck sometimes” or “just held” the pacifier in the mouth.