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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

Análisis comparativo entre muros de concreto armado y muros Krainer para estabilizar el talud del río Rímac en San Juan de Lurigancho / Comparative analysis between reinforced concrete walls and Krainer walls to stabilize the slope of the Rímac river in San Juan de Lurigancho

Ramírez Chávez, Harry Alexander, Reupo Padilla, Carlos Gustavo 21 July 2020 (has links)
El río Rímac en épocas de avenidas suele socavar la ribera del río ocasionando deslizamientos del terreno que ponen en contante peligro a la población local. Para ello, se analizará dos propuestas de solución en un tramo de 150 metros en el talud del río Rímac, en el distrito de San Juan de Lurigancho. Las propuestas son una convencional y otra que por el momento no es muy conocida en nuestro país. La primera alternativa es la construcción de muros de concreto armado, debido a su alta efectividad en este tipo de problemática. La segunda alternativa, es la construcción de Muros Krainer, estos son un tipo de muro innovador, considerados como un método de bioingeniería que tiene como objetivo simular un muro de tierra armada. Se realizará un análisis estático y pseudoestático para cada tipo de muro en estudio. A su vez, el objetivo de dichos análisis es obtener el factor de seguridad, así como verificar el desempeño de este con los valores requeridos para cada muro con la ayuda de hojas de cálculos y herramientas computacionales. Por otro lado, se efectuará un análisis de costo con la conformación de análisis de precios unitarios para cada partida que requiere la elaboración de ambos muros. El producto del análisis estático y pseudoestático para los muros estudiados satisfacen los valores requeridos para su estabilidad. Sin embargo, el resultado del costo directo para la realización del muro Krainer resulto menor a comparación del costo directo del muro de contención de concreto armado. / The Rímac river in times of avenues usually undermines the riverbank causing landslides that endanger the local population. For this, two solution proposals will be analyzed in a 150-meter section on the slope of the Rímac river, in the San Juan de Lurigancho district. The proposals are one conventional and another that at the moment is not well known in our country. The first alternative is the construction of reinforced concrete walls, due to its high effectiveness in this type of problem. The second alternative is the construction of Krainer Walls, these are an innovative type of wall, considered as a bioengineering method that aims to simulate a reinforced earth wall. A static and pseudostatic analysis will be carried out for each type of wall under study. In turn, the objective of said analyzes is to obtain the safety factor, as well as verify its performance with the values required for each wall with the help of spreadsheets and computational tools. On the other hand, a cost analysis will be carried out with the formation of unit price analyzes for each item that requires the preparation of both walls. The product of the static and pseudostatic analysis for the studied walls satisfy the values required for their stability. However, the result of the direct cost for the realization of the Krainer wall was lower compared to the direct cost of the reinforced concrete retaining wall. / Tesis
2

Behavior of reinforced concrete panels constructed of high strength materials

Robert, Stephen Douglas 01 May 2010 (has links)
Concrete structures designed to meet blast criteria often require substantial increases in structural system size, weight, and cost when using conventional materials, but using higher strength materials may offer a way to mitigate these increases while achieving desired performance levels. The primary objective of this research is to investigate the performance of a high-strength Portland cement concrete, high-strength low-alloy vanadium (HSLA-V) rebar material combination that meets or exceeds blast resistance criteria while allowing a more efficient structural design than can be achieved using conventional materials. Twelve panels consisting of both single and double mat conventional Grade 60 rebar or HSLA-V rebar in combination with 4 ksi or 15 ksi concrete were tested using the ERDC quasi-static water chamber. Permission to publish this thesis was granted by the Director of the Geotechnical and Structures Laboratory and the U.S. Army Research Laboratory.
3

Moisture Content and Mould Risk in Concrete Outer Walls / Fuktinnehåll och Mögelrisk i Ytterväggar av Betong

Björnsdóttir, Jóhanna Eir, Jóhannsson, Jóhann Björn January 2018 (has links)
Previous studies on the typical Icelandic external wall have shown thatcondensation occurs at the interior surface of the concrete and field inspectionshave supported this conclusion. The primary objective ofthis study is to analyse the hygrothermal behaviour of the typical Icelandicwall and evaluate the mould risk at the interior surface of theconcrete.A comparative study is performed to compare the hygrothermalperformance and mould growth risk of two concrete outer wall structureswith interior and exterior insulation, by performing a parametricstudy using the simulation program WUFI® Pro.Additional parametric studies are performed in order to analyse theeffect of various material properties of the Icelandic building materialson the hygrothermal behaviour of the wall. This part also utilizedWUFI® Pro.To investigate the thermal bridge of the Icelandic wall, simulationswere conducted with the COMSOL Multiphysics software to evaluatethe linear thermal bridge and the risk of condensation at the joint.Lastly, an experiment was set up at the Innovation Center Iceland tomodel the interior insulated wall-slab section. The experimental setupwas completed during this time but the results will be analysedfurther after the thesis work.The results from this study indicate that the typical Icelandic wall ismore sensitive to rain than to interior moisture load and that no condensationoccurs within the wall structure. As concrete is inorganic,the risk of mould growth in the wall structure is limited, however,with increased driving rain load the mould risk increases. The resultsalso revealed that the moisture content of the interior insulated wallwas a great deal higher compared to the exterior insulated wall. Furthermore,the humidity level at the interior surface of the concrete inthe interior insulated wall exceeded the recommended critical humiditylevel based on general suggestions. Finally, results indicated thatusing a more dense concrete resulted in higher relative humidity at theinterior surface but a lower total water content of the wall.
4

Utvärdering av skalväggar som byggnadsmetod / Evaluation of double walls as a construction method

Deumic, Emina, Hedin, Madelaine January 2010 (has links)
<p>Granskande av ritningar, tidsplaner och kalkyler för referensprojektet Hus N i Växjö har hjälpt oss kartlägga skalväggars för- och nackdelar. Från intervjuer har vi sedan kunnat se liknelser och skillnader om vad olika yrkesfolk i samma bransch tycker, sedan därifrån dragit slutsatser. Det är inte alltid enkelt att avgöra vilken byggnadsmetod som är att föredra för att projektet ska vara kostnadseffektivt, prefabricerat eller platsbyggd. Faktorer som byggnadens konstruktion, årstid, arbetsmiljö, resurser, tid och kostnad ska ta hänsyns till.</p><p>Genom att planera bättre, öka förtillverkningen, skapa en bättre samverkan mellan byggherrar, konsulter, entreprenörer, underentreprenörer och materialleverantörer, så anser man allmänt att man kan öka industrialiseringen av byggandet. Då man kan få kortare byggtider och lägre totalkostnader.</p><p><p><p> </p></p></p> / <p>Checking of blueprints, time plans and calculations for the reference project house-N in Växjö have helped us to map double walls' advantages and disadvantages. From interviews, we have seen similarities and difference what different people in same sector think, and how they make their conclusions. It is not always simple to decide the preferable building method in order to make the project cost-effective, prefabricated or suite-built. Factors such as the building's frame, season, work environment, resources, time and cost take considerations' to.</p><p>Through better planning, increase of prefabrication and achieving a better collaboration between developers, consultants, contractors, subcontractors and material suppliers, it is generally considered that it may increase the industrialization of the building. Then procurement of shorter construction times and lower overall costs can be achieved </p>
5

Examining the effects of openings at the base of slender reinforced concrete (tilt-up) wall panels subjected to varying wind pressures

Cook, Andrew January 1900 (has links)
Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer / This report examines the effects of openings located at the base of reinforced concrete slender wall panels (tilt-up panels) designed in accordance with the American Concrete Institute (ACI) Committee 318-11 Building Code Requirements for Structural Concrete Section 14.8 Alternative Design of Slender Walls. The parametric study calculates the reinforcement (longitudinal) required for specific panels in accordance with ACI 318-11 Section 14.8 and compares the designs to a finite element analysis conducted with SAP 2000 version 14 to determine the appropriateness of the assumptions made in Section 14.8. Furthermore, this report compares the design of a tilt-up panel designed by Section 14.8 Alternative Design of Slender Walls and designed by Section 10.10 Slenderness Effects in Compression Members.
6

Desempenho térmico de habitações do PMCMV em paredes de concreto : estudo de caso em São Carlos-SP e diretrizes de projeto para a Zona Bioclimática 4 / Thermal sensation in low-income brazilian houses built in concrete walls

Alvares, Simone Mesquita 13 June 2018 (has links)
O atual programa de contenção do déficit habitacional brasileiro, Minha Casa Minha Vida, criado em 2009, apesar de numericamente significativo, apresenta uma série de complicações e inadequações. Um importante exemplo é a inadequação das construções à Zona Bioclimática na qual o projeto é construído. Diante desse fato, o conforto térmico do usuário deixa a desejar pois os ambientes são desconfortáveis e nada sustentáveis do ponto de vista ambiental. Neste contexto, o trabalho teve como objetivo avaliar o desempenho térmico de habitações de interesse social do PMCMV na Zona Bioclimática 4 construídas com paredes de concreto armado moldadas no local, técnica de rápida execução que vem sendo utilizada em larga escala no país; complementarmente, foi analisada a percepção do usuário frente às condições de conforto térmico em um desses residenciais. A avaliação do desempenho térmico das habitações foi feita com base nos regulamentos nacionais NBR 15220 e NBR 15575 em seus procedimentos simplificados; para avaliar a ventilação, via método de visualização de escoamento (mesa dágua) e a insolação, via simulação computacional de horas de sombreamento com auxílio de cartas solares; para a avaliação da percepção do usuário frente ao conforto térmico, foram feitas pesquisas de campo em um dos empreendimentos de habitações sociais na zona em estudo tendo como base os questionários ASHRAE 55 juntamente com coleta de dados climáticos de temperatura e umidade relativa e com levantamento de modificações projetuais. A partir dos dados coletados, pôde-se confirmar objetivamente a inadequação aos limites mínimos estabelecidos pelas normas de desempenho térmico nos parâmetros de vedação vertical e cobertura. Em entrevista com os moradores, as casas foram consideradas desconfortáveis termicamente no inverno e verão. A partir do diagnóstico das alterações nos projetos, nota-se que a maior parte das casas sofrem alterações para maior adequação à vida dos moradores, essas que se tornam responsáveis pelo desconforto térmico. Fica evidente a necessidade do aumento da inércia térmica do sistema construtivo, para futuras casas construídas com o referido sistema além da necessidade de um plano de expansão da moradia que oriente o morador a fazer modificações que não prejudiquem o desempenho térmico do edifício e o conforto térmico dos habitantes. / The current Brazilian low-income housing program, named Minha Casa Minha Vida, was created in 2009 by the Brazilian government and despite being numerically significant, it has many significant issues that affect its quality. One important example is the used construction methods that do not take into account the climate or the bioclimatic zones where the houses are located resulting in energy efficiency, environmental and thermal confirm issues. This work is developed in this context and aims to evaluate the objective and subjective thermal performance of the houses built in the Zone 4 with reinforced concrete walls molded in place, which is a widespread construction technique within the studied program. Thermal performance of the dwellings was analyzed in the light of the Brazilian regulation norm NBR15220 and NBR 15575. Surveys based on ASHRAE 55 norm were conducted to evaluate the user\'s thermal comfort perception and in situ measurements were taken at the studied bioclimatic zone. From the data collected, we conclude that the houses do not meet the norm limits and that they are also subjectively uncomfortable, during summer and winter. As means to increase comfort, we note that all houses dwellers modified their houses making it clear that future houses should have more thermal inertia and that, as the program expands, dwellers should be instructed to not make construction changes that might affect their thermal comfort.
7

Utvärdering av skalväggar som byggnadsmetod / Evaluation of double walls as a construction method

Deumic, Emina, Hedin, Madelaine January 2010 (has links)
Granskande av ritningar, tidsplaner och kalkyler för referensprojektet Hus N i Växjö har hjälpt oss kartlägga skalväggars för- och nackdelar. Från intervjuer har vi sedan kunnat se liknelser och skillnader om vad olika yrkesfolk i samma bransch tycker, sedan därifrån dragit slutsatser. Det är inte alltid enkelt att avgöra vilken byggnadsmetod som är att föredra för att projektet ska vara kostnadseffektivt, prefabricerat eller platsbyggd. Faktorer som byggnadens konstruktion, årstid, arbetsmiljö, resurser, tid och kostnad ska ta hänsyns till. Genom att planera bättre, öka förtillverkningen, skapa en bättre samverkan mellan byggherrar, konsulter, entreprenörer, underentreprenörer och materialleverantörer, så anser man allmänt att man kan öka industrialiseringen av byggandet. Då man kan få kortare byggtider och lägre totalkostnader. / Checking of blueprints, time plans and calculations for the reference project house-N in Växjö have helped us to map double walls' advantages and disadvantages. From interviews, we have seen similarities and difference what different people in same sector think, and how they make their conclusions. It is not always simple to decide the preferable building method in order to make the project cost-effective, prefabricated or suite-built. Factors such as the building's frame, season, work environment, resources, time and cost take considerations' to. Through better planning, increase of prefabrication and achieving a better collaboration between developers, consultants, contractors, subcontractors and material suppliers, it is generally considered that it may increase the industrialization of the building. Then procurement of shorter construction times and lower overall costs can be achieved
8

Desempenho térmico de habitações do PMCMV em paredes de concreto : estudo de caso em São Carlos-SP e diretrizes de projeto para a Zona Bioclimática 4 / Thermal sensation in low-income brazilian houses built in concrete walls

Simone Mesquita Alvares 13 June 2018 (has links)
O atual programa de contenção do déficit habitacional brasileiro, Minha Casa Minha Vida, criado em 2009, apesar de numericamente significativo, apresenta uma série de complicações e inadequações. Um importante exemplo é a inadequação das construções à Zona Bioclimática na qual o projeto é construído. Diante desse fato, o conforto térmico do usuário deixa a desejar pois os ambientes são desconfortáveis e nada sustentáveis do ponto de vista ambiental. Neste contexto, o trabalho teve como objetivo avaliar o desempenho térmico de habitações de interesse social do PMCMV na Zona Bioclimática 4 construídas com paredes de concreto armado moldadas no local, técnica de rápida execução que vem sendo utilizada em larga escala no país; complementarmente, foi analisada a percepção do usuário frente às condições de conforto térmico em um desses residenciais. A avaliação do desempenho térmico das habitações foi feita com base nos regulamentos nacionais NBR 15220 e NBR 15575 em seus procedimentos simplificados; para avaliar a ventilação, via método de visualização de escoamento (mesa dágua) e a insolação, via simulação computacional de horas de sombreamento com auxílio de cartas solares; para a avaliação da percepção do usuário frente ao conforto térmico, foram feitas pesquisas de campo em um dos empreendimentos de habitações sociais na zona em estudo tendo como base os questionários ASHRAE 55 juntamente com coleta de dados climáticos de temperatura e umidade relativa e com levantamento de modificações projetuais. A partir dos dados coletados, pôde-se confirmar objetivamente a inadequação aos limites mínimos estabelecidos pelas normas de desempenho térmico nos parâmetros de vedação vertical e cobertura. Em entrevista com os moradores, as casas foram consideradas desconfortáveis termicamente no inverno e verão. A partir do diagnóstico das alterações nos projetos, nota-se que a maior parte das casas sofrem alterações para maior adequação à vida dos moradores, essas que se tornam responsáveis pelo desconforto térmico. Fica evidente a necessidade do aumento da inércia térmica do sistema construtivo, para futuras casas construídas com o referido sistema além da necessidade de um plano de expansão da moradia que oriente o morador a fazer modificações que não prejudiquem o desempenho térmico do edifício e o conforto térmico dos habitantes. / The current Brazilian low-income housing program, named Minha Casa Minha Vida, was created in 2009 by the Brazilian government and despite being numerically significant, it has many significant issues that affect its quality. One important example is the used construction methods that do not take into account the climate or the bioclimatic zones where the houses are located resulting in energy efficiency, environmental and thermal confirm issues. This work is developed in this context and aims to evaluate the objective and subjective thermal performance of the houses built in the Zone 4 with reinforced concrete walls molded in place, which is a widespread construction technique within the studied program. Thermal performance of the dwellings was analyzed in the light of the Brazilian regulation norm NBR15220 and NBR 15575. Surveys based on ASHRAE 55 norm were conducted to evaluate the user\'s thermal comfort perception and in situ measurements were taken at the studied bioclimatic zone. From the data collected, we conclude that the houses do not meet the norm limits and that they are also subjectively uncomfortable, during summer and winter. As means to increase comfort, we note that all houses dwellers modified their houses making it clear that future houses should have more thermal inertia and that, as the program expands, dwellers should be instructed to not make construction changes that might affect their thermal comfort.
9

Nosná železobetonová konstrukce vícepodlažního obytného objektu / Load-bearing reinforced concrete structure of a multi-storey residential building

Badány, Kristián January 2022 (has links)
The objective of the diploma thesis is a design and check of load-bearing concrete structure of multi-storey residential building. The building is located in Brno. The total ground plan’s dimensions are 39,32 x 22,58 metres, total height of the building in the highest point is 10,29 metres. The object is three-storey building with rectangular plan with partial basement designed as cast-in-place concrete frame and two above-ground floor designed as reinforced concrete walls and masonry walls. Load-bearing floor structures are designed as reinforced concrete slabs. Drawing documentation is included.
10

The impact of stage casting on shrinkage restraint in concrete walls / Gjutetappindelningens påverkan på krymptvång i betongväggar

Amjadi, Cindy, Melek, Justyna January 2020 (has links)
The most used widely material in the construction and industrial industry is concrete. Concrete is a material that has been used for a long time and will remain to do so. Therefore, it is especially important to obtain knowledge of the material’s properties and how it is affected by various conditions. A major problem with concrete is cracking that occurs when its shrinkage is prevented. When a concrete wall is cast against ground, shrinkage occurs. The cracks that develop due to this can cause leaks and reinforcement corrosion that not only reduces the lifespan of the concrete, but are also making it aesthetically ugly. One solution to reduce the restraint is to divide the casting into stages. This study contains investigation whether a thoughtful stage casting is a method that can theoretically and practically affect the shrinkage restraint and thereby the cracking in concrete walls. This report observes the tensile stresses in a 15 meter long concrete wall with strength class C30/37. The wall is exposed for two different relative humidity circumstances, indoor environment which gives 50% and outdoor environment which gives 80%. The analysis comprises four different casting methods for a wall; casting in one piece and three casting methods according to thoughtful stage casting. The contemplated time range between the casting stages is normal production time, 30 days, and extended production time, 60 days. At first the calculations for shrinkage and creep of the concrete had to be done according to Eurocode 2. The results from the calculations are thereafter used in the finite element program FEM-Design from the company Strusoft. The results in the report demonstrates the tensile stresses that arise in a 15 meter long wall without the stages and when the casting is done with thoughtful stages. A variation of the foundation depth consisting of non-cohesive soil is also presented for one of the casting methods. The conclusion of the results is that stage casting is a solution to reduce restraint and thereby stresses in concrete walls. The results reveal that the tensile stresses are reduced with the highest value of approximately 80%. The efficiency of casting into stages is possible and practicable within a normal production time. / Det mest använda materialet i anläggnings- och industribranschen är betong. Betong är ett material som har använts länge och kommer fortsätta att användas. Därför är det främst viktigt att ha kunskap om materialets egenskaper och hur det påverkas av olika förhållanden. Ett stort problem med betong är sprickbildning när dess krympning förhindras. När en betongvägg gjuts mot ett underlag förekommer krymptvång. Sprickorna som uppstår på grund av detta kan orsaka läckage och armeringskorrosion som minskar betongens livslängd och är dessutom estetiskt fula. Ett sätt att minska tvånget är att dela in gjutningen i etapper. I detta arbete undersöks om en genomtänkt gjutetappsindelning är en metod som teoretiskt och praktiskt kan påverka krymptvånget och därmed sprickbildningen i betongväggar. Denna rapport betraktar dragspänningarna i en 15 meter lång betongvägg med hållfasthetsklassen C30/37. Väggen utsätts för två olika relativa luftfuktighetsförhållanden, inomhusmiljö samt utomhusmiljö vilket ger ett värde på 50% och 80%. Analyserna omfattar fyra olika gjutningsmetoder för väggen; gjutning utan etappindelning samt gjutning utförd enligt tre genomtänkta etappindelningar. Tiden som betraktas mellan gjutetappsindelningarna begränsas till normal produktionstid, 30 dagar, och en förlängd produktionstid, 60 dagar. Först utförs handberäkningar enligt Eurokod 2 på betongens krympning och krypning för att sedan sätta in resultaten i finita element programmet FEM-Design från Strusoft. Resultaten i rapporten redovisar de maximala dragspänningarna som uppstår i en 15 meter lång vägg utan etappindelning och då gjutning genomförs av genomtänkt etappindelning. Även en variation av friktionsjordens djup analyseras för en utav etappindelningarna. Slutsatsen av resultaten är att gjutetappindelning är en lösning till reduktion av tvång och därmed minskad spänning i betongväggar, då de maximala dragspänningarna reducerades med som högst ca 80%. Effektiviteten av gjutetappindelning är möjlig inom en normal utförandetid.

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