Thesis (PhD(Engineering)(Civil Engineering)) --University of Pretoria, 2007. / Includes bibliographical references.

O presente trabalho apresenta soluções e análises desenvolvidas em estruturas extravasoras em aproveitamentos a fio dágua, envolvendo análises nos critérios de operação de diversos tipos de descarregadores, tais como: soleira normal, labirinto, tulipa e comportas específicas. Para tanto se faz necessário o estudo e comparação de resultados a serem desenvolvidos em cada projeto com relação aos fatores hidráulicos, hidrológicos, geológicos, topográficos e dos riscos envolvendo prejuízos decorrentes de falhas nas estruturas hidráulicas. A avaliação de extravasores labirinto em aproveitamentos hidrelétricos de projetos aprovados pela Agência Nacional de Energia Elétrica ANEEL tem o objetivo de analisar a segurança em relação à construção e à operação, com foco no desenvolvimento de descarregadores adequados para cada estudo de caso presentes neste trabalho. Esta avaliação indica as condições geométricas, econômicas e hidráulicas do extravasor labirinto adequado para cada situação de aproveitamento hidrelétrico a fio dágua. / This paper studies solutions and analysis developed in spillways structures in hydroelectric development trickle, involving analysis of the operation criteria of several types of dischargers, such as threshold normal maze, morning glory and specific gates. For this purpose it is necessary to study and compare the results to be developed in each project about the factors hydraulic, hydrologic, geologic, topographic and risks involving losses due to failures in hydraulic structures. The evaluation of spillways maze in hydroelectric of projects approved by the National Agency of Electric Energy - ANEEL aims to analyze the safety for the construction and operation, focusing on the development of suitable dischargers for each case study in this work. This assessment indicates the geometric, economic and hydraulic conditions of the most suitable spillways maze for each situation of hydroelectric development trickle.

Orientador: José Gilberto Dalfré Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-25T09:00:41Z (GMT). No. of bitstreams: 1 Aguiar_DanielPrendadeOliveira_M.pdf: 5742459 bytes, checksum: 492e7af5746bf9c82efd2c0d6396f7ca (MD5) Previous issue date: 2014 / Resumo: O Brasil tem uma ampla base de sistemas de produção hidroenergética, com alguns deles atendendo a múltiplas finalidades. Dentre os usos múltiplos da água, a geração de energia elétrica se diferencia pela sua natureza fundamental à continuidade das atividades produtivas na sociedade moderna. A geração de energia hidroelétrica requer um conjunto de estruturas e equipamentos hidráulicos. No Brasil, muitas estruturas estão envelhecendo e levam às discussões acerca da sua segurança. A questão da segurança de barragens é premente. Alguns países já se preocupam com a utilização de longo prazo destas estruturas. Contudo, poucos são os países que possuem uma legislação referente à segurança de barragens, como Portugal, Grã-Bretanha, Espanha, Estados Unidos, Canadá, dentre outros. Em 2005, Zuffo desenvolveu e propôs o Índice de Segurança de Barragens ¿ ISB. O ISB visa reduzir a subjetividade na análise da segurança de barragens e é composto por vários critérios técnicos. A estes critérios, são atribuídos pesos por diversos profissionais da área e, através de um tratamento estatístico, compõem um índice global que indica o estado de segurança de uma barragem. Em 2010, foi sancionada a Lei Federal nº 12.334 que dispõe sobre a Política Nacional de Segurança de Barragens. Em 2012, a Resolução nº 143 do Conselho Nacional de Recursos Hídricos estabeleceu critérios gerais de classificação de barragens e as Resoluções nº 91/12 e nº 742/11 da Agência Nacional de Águas estabeleceu critérios para o Plano de Segurança da Barragem e das inspeções de segurança regulares. Neste contexto, este trabalho propõe alterações nos critérios que compõem o ISB, visando diminuir a subjetividade e aumentar a precisão e aplicação prática do método, incorporando itens exigidos pela legislação brasileira sobre segurança de barragens. O Índice de Segurança de Barragens ¿ ISB mostra ser uma importante ferramenta para o gestor da estrutura, órgãos governamentais, agências de fiscalização e uma proteção extra para a sociedade, pois considera os principais elementos e características técnicas do barramento, bem como dados de projeto, planos de operação e instalações existentes na área de influência da barragem / Abstract: Brazil has a broad base of hydropower production systems, with some of them serving multiple purposes. Among the multiple uses of water, electric power generation is distinguished by being crucial to the continuity of production activities in modern society. The hydropower generation requires a set of structures and hydraulic equipment. In Brazil, many structures are aging and lead to discussions about their safety. The issue of dam safety is urgent. Some countries have been concerned about the long-term use of these structures. However, there are few countries that have legislation concerning the safety of dams, such as Portugal, Britain, Spain, USA, Canada, among others. In 2005, Zuffo developed and proposed the Dam Safety Index ¿ DSI. The DSI aims to reduce subjectivity in the analysis of dam safety and consists of various technical criteria. To these criteria, weights are assigned by various professionals and, through a statistical treatment, make up a global index that indicates the security status of a dam. In 2010, was enacted Federal Law No. 12.334 which establishes the National Policy on Safety of Dams. In 2012, Resolution No. 143 of the National Water Resources Council established general criteria for the classification of dams and Resolution No. 91/12 and No. 742/11 of the National Water Agency has established criteria for the Dam Safety Plan and regular security inspections. In this context, this paper proposes changes to the criteria that make up the DSI in order to reduce subjectivity and increase the accuracy and practical application of the method, incorporating items required by the Brazilian legislation on dam safety. Dam Safety Index - DSI proved an important tool for managing the structure, government agencies, enforcement agencies and an extra protection for society, because it considers the main elements and technical characteristics of the bus, as well as design data, operation plans and existing facilities in the catchment area of the dam / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil

Orientador: Ana Ines Borri Genovez / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil / Made available in DSpace on 2018-08-04T10:56:38Z (GMT). No. of bitstreams: 1 DalfreFilho_JoseGilberto_D.pdf: 10243119 bytes, checksum: 5829e5204ff010a8a6d3e3a1d85f4916 (MD5) Previous issue date: 2005 / Resumo: O equipamento tipo jato cavitante utiliza um bocal especialmente projetado para simular o fenômeno da cavitação desgastando uma amostra em um período de tempo curto. Isso ocorre, sobretudo, devido à magnitude da velocidade. Para maior eficiência do jato cavitante é necessária uma combinação da geometria do bocal, do diâmetro do orifício e da pressão disponível. No caso das estruturas hidráulicas se verifica o efeito simultâneo do fenômeno da cavitação e do impacto de um jato de alta velocidade. O objetivo deste trabalho foi desenvolver um equipamento tipo jato cavitante para avaliar o desgaste ocasionado pela cavitação em amostras de concreto. O estudo foi realizado no Laboratório de Hidráulica e Mecânica dos Fluidos da Faculdade de Engenharia Civil. A instalação permite variar os parâmetros de ensaio, de forma a obter a máxima eficiência do equipamento e definir o comportamento da amostra. O índice de cavitação de 0,14 é adequado aos ensaios em concretos de estruturas hidráulicas. Recomenda-se uma velocidade do jato em torno de 150 m/s, a adoção de 0,05 m de distância entre o bocal e a amostra e o uso de bocal cônico de 132°, com arestas vivas. A partir dos testes realizados, sugere-se um tempo de ensaio de quatro minutos para avaliação da resistência dos materiais face à ação da cavitação. Conclui-se que o equipamento tipo jato cavitante se mostrou adequado e eficiente para avaliação do desgaste provocado pela ação da cavitação, em um tempo curto de ensaio. As características do banco de ensaio permitem que ele seja instalado em laboratório ou em campo / Abstract: The cavitating jet apparatus uses an especially projected nozzle to produce cavitation and have the advantage of induce cavitational flow with short time test. That is due, mainly, to the magnitude of velocity. In order to obtain great efficiency of the cavitating jet apparatus one has to combine the nozzle geometry, the orifice diameter and the necessary pressure. In hydraulic structures it is verified the simultaneous effect of the cavitation phenomenon and the impact of a high velocity jet. The objective of this work was to develop a cavitating jet apparatus to evaluate the erosion caused by cavitation in concrete samples. The study was carried out in the Hydraulics and Fluid Mechanics Laboratory of the Civil Engineering, Architecture and Urbanism College. The installation allows varying the tests parameters, to get the maximum efficiency of the equipment and to obtain the sample damage. A cavitation index of 0,14 showed to be a value where damage in hydraulics structures was presented. It is suggested to perform tests with a jet velocity of approximately 150 m/s, the adoption of 0,05 m of distance between the nozzle and the sample and also the use of conical 132° nozzle with sharp edges, which showed to be adequate to the laboratory experiment with concretes ordinarily used in hydraulic structures. According to the tests, it can be normalize the adoption of four minutes test for evaluation of the cavitation samples resistance. It is concluded that the cavitating jet apparatus is adequate and efficient for evaluation of erosion through cavitation action in a short time tests. The characteristics of the experimental installation allow its use either in laboratory or in field tests / Doutorado / Recursos Hidricos / Doutor em Engenharia Civil

M.Ing. (Mechanical Engineering) / The development of crashworthy seats for helicopters during the past three decades is discussed. The primary design criteria is mentioned and the disadvantages of crashworthy seats that are currently in use are highlighted. An hydraulic energy absorber which automatically compensates for the mass of the seat occupant was designed and a simulation model was developed. The concept for the control valve used was obtained from WARRICK [25]. Results of the simulations correlated well with those of WARRICK. A prototype of a mechanical/hydraulic accelerometer was designed, manufactured and tested. The results obtained from the experiments compared favourably with simulation values. The simulated and experimental results indicate that the concept of using an hydraulic energy absorber, in a crashworthy seat, is very satisfactory. Future crashworthy seat designs could be enhanced by incorporating this promising device.

The results of hydrodynamic analyses of two problems involving offshore structures are displayed graphically. This form of presentation of the results and the liberal use of colour have been found to significantly help the ease in which the results are interpreted. For the transformation of waves around an artificial island, a time history of the evolution of the regular, unidirectional wave field around an artificial island is obtained. Through the use of colour, regions in which wave breaking occurs have been clearly defined. The numerical technique used is based on the finite element method using eight noded isoparametric elements. The determination of the transformed wave field takes wave breaking, wave refraction, diffraction, reflection and shoaling into account. The graphical display is achieved by using a plotting program developed for the output of finite element analyses. The motions of a semi-submersible rig are computed from the RAO curves of the rig, used to obtain its' small response in a random sea. The numerical technique used in the analysis assumes that the vertical members are slender and may be analysed using the Morison equation whereas the hulls are treated as large members which are discretised and analysed using diffraction theory. The discretisation of the cylinders and hulls together with the time history of the rig's motions are displayed graphically. Once again, the graphical display is plotted using a program developed for the output of finite element analyses for four noded elements. In this case, a finite element technique has not been employed but the results were ordered to act as though this is the case. The slender members (cylinders) and large members (hulls) are clearly distinguishable by using different colours. The elements used in the analysis are also clearly shown. The VAX 11/730 system was used to obtain the results shown. A video tape, using the results of a time stepping procedure, was made by successively recording the hardcopies produced by the VAX printer. The time stepping could also be seen, in real time, on the IRIS. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

In the construction of buildings and infrastructures, high resistance materials are used due to current design requirements, concrete being one of the main materials used in the execution of these projects whose cement content is limited to obtaining an economic concrete and of minimum retraction. This limitation requires the use of new additions such as Nano Silica (NS), which due to its nanometric structure is used as a partial replacement for cement, producing an increase in strength in concrete. The present investigation studies the partial replacement of the NS in the cement to determine its behavior in compressive strength, diametric compressive strength, water permeability coefficient. The results indicate that with an addition of 0.225% of NS the compressive strength and splitting tensile strength are increased and the water permeability coefficient decreases, all of them compared to a conventional concrete.

El presente trabajo busca mostrar la diferencia entre el caudal máximo diario anual y el caudal anual máximo instantáneo. Esto, porque el primero es el dato que se obtiene en la mayoría de estaciones de medición de caudal en todo el país y el segundo es el que se obtiene mediante estructuras hidráulicas que permiten medir el caudal en todo momento evitando el efecto de la socavación que genera el agua al escurrir por terrenos naturales proclives a esta. Se demostrará porque estos datos se deben considerar en la determinación de los caudales de diseño extremos de las estructuras hidráulicas. Se analizará y comparará ambos resultados y se explicará el por qué es importante trabajar con el caudal instantáneo en vez del máximo medio diario anual. Se justificará por qué a pesar de que el caudal anual máximo instantáneo es mucho más difícil de obtener, a largo plazo resulta más provechoso de utilizar. Se expondrá por qué el registro de caudal máximo diario anual el que tienen a disposición los ingenieros en la gran mayoría de ríos del litoral de nuestro país. Se demostrará que la diferencia entre ambos genera un error que representa un verdadero riesgo para el diseñador de infraestructura hídrica que basa sus cálculos en un registro que podría resultar peligroso pues puede estar subestimado. / This work seeks to show the difference between the annual maximum daily flow and the instantaneous maximum annual flow. This is because the first is the data obtained in most of the flow measurement stations throughout the country and the second is obtained by measurements of hydraulic structures that allow the flow to be measured at all times avoiding the effect of the undermining that generates water by draining through natural lands. It will be demonstrated why these data should be considered in determining the extreme design flow rates of hydraulic structures. Both results will be analyzed and compared and it will be explained why it is important to work with the instantaneous flow rate instead of the maximum annual average daily. It will be justified why although the maximum instantaneous annual flow is much more difficult to obtain, in the long term it is more profitable to use. It will be explained why the annual maximum daily flow record available to engineers in the vast majority of rivers along the coast of our country. It will be shown that the difference between the two generates an error that represents a real risk for the water infrastructure designer who bases his calculations on a record that could be dangerous and it may be underestimated. / Tesis

Inflatable dams are flexible membrane structures, pressurized with either air, water, or both, which have been used in recent years as a means of temporarily impounding water. A number of procedures have been developed to investigate the static behavior of the dams, but the dynamic behavior has been largely neglected. The few studies that have been done on dynamic behavior have used the simplifying assumption that the weight of the membrane was negligible. In this study, equations of equilibrium and equations of motion were derived for an air inflated dam impounding no water, but loaded with its own membrane weight. It was assumed that the effect of membrane extensibility is negligible in the analysis. Derivatives required in the equations of motion were approximated using finite difference equations. Computer programs were written to find solutions for the eigenvalues and eigenvectors of the equations of motion. The computer program plotted the mode shapes of vibration associated with the four lowest eigenvalues, as well as the static shape of the dam. The eigenvalues obtained were the square of the frequencies of the system, so the effects of a series of membrane weights on the frequencies of dams of various base lengths could be analyzed. / M.S.

The height of an overflow dam must be designed low enough to prevent the reservoir water level from exceeding a flood plain during flooding conditions. Because of this constraint, much of the available water storage area is wasted and the available pressure head for power generation will be less than maximum during normal conditions. Crest control gates alleviate this problem by providing a variable spillway height. The Flash Gate Board is a passive automatic crest control gate. Its purpose is to regulate flood water while providing increased water pressure for power generation or for additional water storage for a municipality. The governing equations for the Flash Gate Board system are derived and used to formulate models of the system. Computer simulations are used to examine the system response in a variety of operating conditions. The results of these simulations are presented and discussed. The results include an investigation which developed an optimum gate height to maximize the potential of the Flash Gate Board. An experimental model was developed to verify analytical results and to provide additional insight. Conclusions from the study, recommendations for future work, and modifications for a trouble-free design are discussed. / Master of Science