Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH / by Neil Ray Klopfenstein. / M.C.P.

The gradual depletion of shallow water hydrocarbon deposits has forced the offshore oil and gas industry to develop reserves in deeper waters. Dynamically installed anchors have been proposed as a cost-effective anchoring solution for floating offshore structures in deep water environments. The rocket or torpedo shaped anchor is released from a designated drop height above the seafloor and allowed to penetrate the seabed via the kinetic energy gained during free-fall and the anchor’s self weight. Dynamic anchors can be deployed in any water depth and the relatively simple fabrication and installation procedures provide a significant cost saving over conventional deepwater anchoring systems. Despite use in a number of offshore applications, information regarding the geotechnical performance of dynamically installed anchors is scarce. Consequently, this research has focused on establishing an extensive test database through the modelling of the dynamic anchor installation process in the geotechnical centrifuge. The tests were aimed at assessing the embedment depth and subsequent dynamic anchor holding capacity under various loading conditions. Analytical design tools, verified against the experimental database, were developed for the prediction of the embedment depth and holding capacity.

Fiber reinforced polymers (FRPs) have gained popularity in upgrade projects for reinforced concrete structural elements within the last decade because of its ease of application and high strength-to-weight ratio. In the design of an effective retrofitting solution by means of an FRP system, the anchorage capacity has an important role. This study presents the results of an experimental program conducted to determine the strength of carbon fiber reinforced polymers (CFRPs) bonded to concrete prisms or hollow clay tiles that are finished with or without plaster. In the experimental program, different types of anchorage methods were tested in a double shear push-out test setup. A simple and effective strength model is proposed for strip type anchorages based on the existing analytical models and experimental observations from this study. This new model is suitable for determining the design capacity of CFRP-to-concrete and CFRP-to- hollow clay tile joints with or without plaster and accounts for the presence of embedment and concrete strength. Obtained results by using this model were found to closely match with the experimental observations.

Background and objectives: The control of anchorage is integral to successful orthodontic treatment. The objective of this research was to undertake three related projects to evaluate methods of increasing anchorage with the aim of adding to orthodontic knowledge and improve methods of treatment delivery. Methods: Two Cochrane systematic reviews were undertaken according to the methods published in the Cochrane Handbook for Systematic Reviews of Interventions, version 5.1.0. The influence of functional appliances on tooth position and the extraction decision was performed as a retrospective study using participants from a completed multicentre randomized trial. Results: 1- Statistically and clinically significant differences were found between the mean values of distal molar movement when surgical anchorage and conventional anchorage were compared. 2- Statistically significant differences were found between the mean values of distal molar movement and mesial upper incisor movement when intraoral distalising appliances and cervical headgear were compared.3- Fixed and removable functional appliances are equally effective in anchorage preparation. The type of functional appliance and time spent in Phase I treatment influenced the amount of lower incisor proclination. Conclusions: 1- Surgical anchorage is more effective than headgear without the inherent risks and compliance issues. However, intraoral appliances used in adolescence for distalisation of upper molars do not appear to have any advantages over cervical headgear. 2- Functional appliances reduce the anchorage requirements of a case primarily by reduction of the overjet, both fixed and removable functional appliances are equally effective in obtaining this. However, fixed functional appliances result in greater lower incisor proclination than removable functional appliances. 3- The type of functional appliance (removable or fixed) does not influence the extraction decision, however, this is influenced by overall space requirements.

My diploma theisis is focused on design and assessment of structural systém of industrial building in tended for livestock farming. The design is processed in two options. Both oft hem has the same dimensions but cross sections of the supporting elements are changed. Floor plan of the first part is a rectangular shape, dimension is 29,28 m x 24,8 m. Floor plan of the second part is a rectangular shape, dimension is 161,18 m x 46,8 m. Slope of saddle roof is 18°.

The goal of my thesis is the design of a multipurpose sport hall in Litoměřice locality made in two separate variants. Objects ground plan dimensions are 38x38 meters and the height of the object is 16 meters. Used material is S235 steel and C20/25 concrete. The periphery and roof casing of the object is realized from sandwich panels. The carrying construction of the object is made from cross truss, oblong truss and from pillars. Thesis consists of assessing the carrying elements of the construction, selected details and drawing documentation.

The special condition in the Anchorage, Alaska draws my attention when I traveled to this place. The downtown area is in the far north of the city, it is an interesting point to develop the lifestyle and living condition for the people stay in the northern city. My thesis starts from the research on the surrounding areas and determines what function of the building suits the site the best. Besides, the shape of the building has some extensions and elevations in order to emphasize the connection between the building and the surrounding spaces. Whats more, the design of the square and the interior parking space are based on the research of the special weather condition in the Anchorage, Alaska. Throughout the various stages of the design, the final project has the steel structure for the primary structural system and metal perforated board for the elevation to balance the huge body of the building. The feature of the project's function and programmatic needs are based on the connections between the site and the surroundings. / Master of Architecture

Made available in DSpace on 2014-07-29T15:03:33Z (GMT). No. of bitstreams: 1 Dissertacao Emmele G Fontenelle.pdf: 3889725 bytes, checksum: 2db009d8581a8358994f13fbf37f6062 (MD5) Previous issue date: 2011-06-27 / Fastenings inserted in concrete are used in order to allow the introduction of these components in concrete structures, enabling the structural link between metal structures and concrete foundation and between prefabricated components and fixing reinforcement elements. This work will study specifically an anchoring system pre-installed (cast-in-place anchor), consisting of single head studs with square head and subjected to tensile force. Assays were performed in 30 headed studs, using self-compacting concrete with compressive strength in the C-30 class. The main variables are the presence and rate of reinforcement, the arrangement of reinforcement in the blocks, and the influence of both the flexural reinforcement (longitudinal and transverse) and the shear reinforcement (hairpins) on the load capacity of the anchorage. The experimental results were compared with five methods of design found in the literature and show that the flexural einforcement has no effect in increasing the load capacity of the anchorage. The use of a shear reinforcement together with the flexural reinforcement can increase the capacity of the anchor up to 64%. Increasing the distance of the hairpins in relation to the head stud reduces the ultimate load achieved by the anchoring system while the increase in diameter and / or in the number of layers of hairpins can increase the ultimate load. / Pinos de ancoragem inseridos em concreto são empregados com a finalidade de permitir a fixação de elementos para a introdução de solicitações nas estruturas de concreto, viabilizando as ligações estruturais entre estruturas metálicas e a fundação de concreto, entre componentes pré-fabricados e na fixação de elementos de reforço. Neste trabalho será abordado e estudado especificamente um sistema de ancoragem pré-instalado, composto por pino de ancoragem único com cabeça quadrada e submetido à força de tração. Foram realizados ensaios em 30 pinos, utilizando-se concreto auto-adensável com resistência à compressão na classe C-30, tendo como principais variáveis a presença e taxa de armadura, e disposição da armadura nos blocos, analisadas tanto na armadura de flexão (longitudinal e transversal) quanto na armadura de cisalhamento (grampos). Os resultados experimentais foram comparados com cinco métodos de cálculo da literatura e mostram que a armadura de flexão não influencia no aumento da capacidade de carga do pino de ancoragem. A utilização de uma armadura de cisalhamento juntamente com a armadura de flexão pode aumentar a capacidade de carga do pino em até 64%. O afastamento dos grampos em relação ao pino diminui a carga última atingida pelo pino de ancoragem, enquanto o aumento do diâmetro e/ou o aumento do número de camadas dos grampos pode aumentar a carga última.

O objetivo deste trabalho foi avaliar a influencia da proximidade entre miniimplantes autoperfurantes e as raizes dentarias sobre a estabilidade destes dispositivos de ancoragem. A amostra consistiu de 40 mini-implantes inseridos entre as raizes do primeiro molar e segundo pre-molar superiores de 21 pacientes, como recurso de ancoragem para retracao anterior. A largura do septo no local de insercao (LSI) e a menor distancia da cabeca do mini-implante a raiz dentaria (MDR) foram mensuradas nas 40 radiografias pos-cirurgicas. Sob este aspecto, os miniimplantes foram divididos em duas categorias de grupos: de acordo com a largura do septo no local de insercao, grupos G1L (LSI3mm) e G2L (LSI>3mm), e de acordo com a proximidade do mini-implante a raiz adjacente, grupos G1P (MDR0mm) e G2P (MDR>0mm). A estabilidade dos mini-implantes foi avaliada mensalmente pela quantificacao do grau de mobilidade, e a partir desta variavel foi calculada a proporcao de sucesso. Tambem foi avaliada a influencia das seguintes variaveis sobre o grau de estabilidade: caracteristica do tecido mole no local de insercao, o grau de sensibilidade, a quantidade de placa, a altura de insercao e o periodo de observacao. As duas categorias de grupos foram comparadas quanto ao grau de mobilidade e proporcao de sucesso por meio do teste de Mann-Whitney e do teste Exato de Fisher, respectivamente. Adicionalmente, avaliou-se a influencia das demais variaveis sobre a estabilidade deste sistema de ancoragem atraves do teste t e do teste do Qui-quadrado. Os resultados obtidos demonstraram que não houve diferenca estatisticamente significante para o grau de mobilidade e proporção de sucesso entre os mini-implantes inseridos em septos do grupo G1L e G2L. A proximidade entre os mini-implantes avaliados e as raizes dentarias adjacentes (grupos G1P e G2P) tambem nao influenciou na estabilidade e proporcao de sucesso deste sistema de ancoragem. A proporcao de sucesso total encontrada foi de 90% e nenhuma variavel demonstrou estar relacionada ao insucesso dos miniimplantes. No entanto, observou-se maior sensibilidade nos pacientes cujos miniimplantes apresentavam mobilidade, e que a falha destes dispositivos de ancoragem ocorria logo apos sua insercao. / The purpose of this study was to evaluate the influence of the proximity between self-drilling miniscrews and dental roots on the stability degree. The sample consisted of 40 miniscrews inserted in the interradicular septum between maxillary second premolars and first molars to provide skeletal anchorage for anterior retraction. The forty post-surgical radiographs were used to measure the septum width in the insertion site (SWI) and the smallest distance between miniscrew head and dental root (SDR). In this regard, the miniscrews were divided in two categories of groups: according to the septum width in the insertion site, groups G1W (SWI 3mm) and G2W (SWI>3 mm), and according to the miniscrew dental root proximity, groups G1P (SDR0mm) and G2P (SDR>0mm). The mobility degree (MD) was monthly quantified to determine miniscrew stability, and the success rate of these devices was calculated. This study also evaluated the influence of following variables on the stability degree: soft tissue characteristics in the insertion site (attached gingiva, mucogingival junction and alveolar mucosa), sensitivity degree during miniscrew load, plaque amount around miniscrew, insertion height, and total evaluation period. All the groups were compared regarding mobility degree and success rate using t test and Fisher exact test, respectively. The results showed no significant difference in mobility degree and success rate between groups G1W and G2W. The miniscrew dental root proximity did not influence the stability and success rate of this anchorage system when G1P and G2P were compared. The total success rate found was 90% and no variable was associated with the miniscrew failure. Nevertheless, the results showed that greater patient sensitivity degree was associated to the miniscrews mobility and the failure of these anchorage devices happened in a short time after their insertion.

O objetivo deste estudo foi avaliar a influência do padrão de crescimento craniofacial na espessura da cortical óssea alveolar e correlacioná-lo com a estabilidade dos mini-implantes ortodônticos. A amostra constituiu de 30 pacientes com 56 mini-implantes inseridos na região posterior vestibular da maxila como recurso de ancoragem na retração anterior. Inicialmente, os pacientes foram divididos de acordo com a média do ângulo FMA, em padrão de crescimento horizontal (grupo GH) e vertical (grupo GV). As espessuras das corticais ósseas foram mensuradas nos cortes axiais das imagens de tomografia computadorizada de feixe cônico. As médias econtradas em cada grupo foram comparadas pelo teste t. A correlação de Pearson foi realizada entre os valores do ângulo FMA e as espessuras das corticais ósseas. Posteriormente, para avaliar a influência do padrão de crescimento sobre a estabilidade dos mini-implantes, estes foram divididos em dois grupos também de acordo com o padrão de crescimento: GMI(H) horizontal e GMI(V) vertical. Os grupos foram comparados quanto ao grau de mobilidade e a proporção de sucesso dos mini-implantes pelos testes de Mann-Whitney e o teste Exato de Fisher. Através desses testes e do teste Qui-quadrado foi avaliada a influência das seguintes variáveis sobre o grau de estabilidade: características do tecido mole na região de inserção, sensibilidade, a quantidade de placa, o período de observação e a técnica utilizada para cada dispositivo. Os resultados obtidos demonstraram que a espessura da cortical óssea alveolar anterior (superior e inferior) e posterior (inferior) vestibulares foram maiores no grupo GH do que o grupo GV. Houve correlação negativa significante entre o FMA e as espessuras nas regiões anteriores inferiores (vestibular e lingual) e superior (vestibular). Não houve diferença significante nos resultados para o grau de mobilidade e proporção de sucesso dos mini-implantes nos grupos GMI(H) e GMI(V). O tempo médio de observação foi de 8,77 meses. A proporção de sucesso total foi de 89,29% e nenhuma variável mostrou estar relacionada com o sucesso dos mini-implantes. No entanto, observou-se maior sensibilidade nos pacientes cujo mini-implante apresentava mobilidade e a falha desses dispositivos de ancoragem ocorria logo após sua inserção. / This study aimed the assessment of the craniofacial growth pattern influence on the alveolar bone cortical thickness as well as the evaluation of the stability of orthodontic mini-implants. The sample comprised 56 mini-implants inserted on the posterior buccal region of the maxilla of 30 patients with the purpose of orthodontic anchorage for the anterior retraction. Initially, patients were divided by FMA mean according to the growth pattern as: horizontal group (GH group) and vertical group (GV group). The alveolar cortical bone thicknesses were measured in the axial sections of the images of cone-beam computed tomography. The means found for each group were compared with the t test. Pearson´s correlation was performed for the values of growth pattern (FMA) and for the thicknesses of cortical bone. In order to evaluate the influence of growth pattern on the stability of mini-implants, these devices were divided in two other groups, according to the growth pattern as: GMI(H), horizontal and GMI(V), vertical. The mobility degree and success rate of mini-implants shown by these two groups were compared using Mann-Whitney tests and Fisher Exact test. Through these tests and the Chi-square test the influence of the following variables on the degree of stability were evaluated: soft tissue characteristics of the insertion site, sensibility degree, plaque retention around miniimplant, observation period and technique used. The results demonstrated that the thickness of the anterior buccal cortical bone (upper and lower) and the posterior cortical bone (lower) were greater for the GH group than for the GV group. There was a significant negative correlation between the FMA and the thicknesses of the lower anterior regions (buccal and lingual) and upper regions (buccal). No significant difference was found regarding the mobility degree and the success rate of miniimplants between the groups GMI(H) and GMI(V). Total success rate found was 89.29% and no variable showed to be related to the success of mini-implants. Nevertheless, a greater sensibility was observed in patients whose mini-implants presented mobility and the failure of these anchorage devices occurred in a short time after insertion.