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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

Možnosti odstranění zelených řas z betonových konstrukcí / The possibilities of green algae removal from concrete structures

Cochlárová, Milena January 2014 (has links)
This master´s thesis deals with the suppression of algal growth on concrete structures. The subject of the work is to design and coatings their own structural concretes containing protective element in order to inhibit the growth of algae. As the coating are tested commercially avaiable and newly created systems. Testing systems are based on the portland cement and chelates of metal (Cu, Ni, Co, Mn, Zn, Al).
2

Análise dos efeitos de segunda ordem em pilares solicitados a flexão oblíqua composta. / Analysis of second order in the pillars requested by oblique bending composite.

Ceccon, Jorge Luiz 04 August 2008 (has links)
Na verificação do estado limite último das estruturas reticuladas em concreto armado se tem sempre os pilares solicitados à flexão oblíqua composta, seja devido a momentos fletores transmitidos pelas vigas ou lajes ou devido a imperfeições construtivas ou por ações normais ao eixo da peça comprimida, atuantes entre seus pontos de vinculação. Neste trabalho se está comparando os resultados que se obtém por dois processos de cálculo, quais sejam, a) Integração numérica com desacoplamentos das flexões nas duas direções principais de inércia com o uso da rigidez secante obtida de diagrama momento-curvatura, ou seja, os esforços de segunda ordem são calculados em cada direção como se não houvesse a solicitação de flexão na direção ortogonal e ao final se verifica a segurança da peça no Estado Limite Último considerando a flexão oblíqua composta; b) integração numérica considerando a flexão oblíqua composta com a curvatura obtida de diagrama momento-curvatura ponto a ponto já no cálculo dos efeitos de segunda ordem. Foram processados 215.740 pilares cuja análise conduz à conclusão de que se pode usar o procedimento citado no item (a) acima, com segurança e sem prejuízo da economia. / At check reticulated reinforced concrete structures in the ultimate limit state one always have the columns requested by a compression with biaxial bending , be due bending moments transmitted bay beams or slabs or due constructions imperfections or actions normal to the axis of the compressed piece acting between its points of attachment. This work is to compare the results that are obtained by two methods of calculation, which are: a) Numerical integration in each main direction of inertia with the use of secant stiffness obtained from bending-curvature diagram, it is, the second order efforts are calculated in each direction as if there was not request bending in the orthogonal direction and the end check the safety at ultimate limit state of the column by considering the biaxial bending; b) Numerical integration in each main direction of inertia with curvatures obtained point to point of moment-curvature diagrams, that consider the biaxial bending, to calculate the second order effects. Were processed 215.740 columns whose analysis leads to the conclusion that we can use the procedure mentioned in tem a) above, safely and without prejudice to the economy.
3

Análise da biorreceptividade de estruturas de concreto ao ataque microbiológico (algas)

Rota Rizzardo, Alice Medeiros 11 November 2016 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2017-02-08T14:24:17Z No. of bitstreams: 1 Alice Medeiros Rota Rizzardo_.pdf: 15860447 bytes, checksum: d47251ec7d258066e526c8a2911c9564 (MD5) / Made available in DSpace on 2017-02-08T14:24:17Z (GMT). No. of bitstreams: 1 Alice Medeiros Rota Rizzardo_.pdf: 15860447 bytes, checksum: d47251ec7d258066e526c8a2911c9564 (MD5) Previous issue date: 2016-11-11 / itt Performance - Instituto Tecnológico em Desempenho da Construção Civil / A durabilidade de estruturas de concreto é assunto de interesse no contexto de sustentabilidade, pois a sustentabilidade das obras concluídas pode ser verificada por meio da análise da durabilidade dos seus materiais constituintes. A previsão de vida útil de um material poderá ser verificada estudando os seus mecanismos de degradação. Dentre os fatores de degradação do concreto, encontra-se a biodeterioração. Contudo, o ataque microbiológico ainda é um assunto pouco estudado na área de construção civil. A proposta deste trabalho foi verificar a biorreceptividade de concretos com diferentes relações água/cimento e diferentes acabamentos de superfícies ao desenvolvimento de algas a partir do desenvolvimento de um método de análise da biorreceptividade do concreto específico para este trabalho. O método consistiu em ensaio acelerado de biodeterioração em câmaras de ensaio com temperatura e iluminação controladas, alto teor de umidade e inoculação de alga coletada in loco. A análise permitiu verificar um decréscimo da mancha biológica nos corpos de prova de todas as variáveis. A diferença da velocidade do decréscimo da mancha biológica nas diferentes variáveis evidenciou a biorreceptividade dos materiais. Foi possível identificar uma tendência em que quanto maior a relação água/cimento, maior a biorreceptividade e quanto menor a rugosidade, menor a biorreceptividade. Assim, estes parâmetros poderão auxiliar na obtenção de concretos mais duráveis frente ao crescimento de algas. / The durability of concrete structures is subject of interest in the context of sustainability, since the sustainability of the edifications can be verified by analyzing the durability of their constituent materials. Among the factors degradating the concrete there is the biodeterioration. Nevertheless the microbiological attack is still a subject little studied in the construction area. The purpose of this was verify the bioreceptivity of concrete with different water / cement ratio and different surface finishing facing the development of algae from the development of a method of analysis of the concrete bioreceptivity specific to this work. The method consisted of accelerated test of biodeterioration in test chambers with temperature and lighting controlled, high humidity and inoculation of Heterochlorellas luteoviridis, algae collected in loco and identified in the laboratory. The analysis has shown a decrease of biological stains in the specimens of all variables. The difference of decrease rate of biological stain on different variables showed the materials bioreceptivity. It was possible the verification that the higher the water / cement ratio, the greater the biorreceptividade and in the same way the lower the roughness, the lower the biorreceptividade. Thus, these parameters could help in getting more durable concrete facing the growth of algae.
4

Robustness of composite framed structures in fire

Beshir, Moustafa January 2016 (has links)
This thesis presents the results of a research study to investigate the behaviour of axially restrained composite beams at ambient and elevated temperatures, and how composite beams and their connections contribute to the robustness of composite framed structures in fire. The commercial finite element analysis package (ABAQUS, 2010) was used to develop the numerical simulation models. This research includes the following four main parts: (1) validation of the simulation model; (2) behaviour of axially restrained composite beams with partial shear interaction at ambient and elevated temperatures; (3) behaviour of composite beams with realistic connections at elevated temperatures and methods of increasing composite beam survival temperatures; and (4) response and robustness of composite frame structures with different extents of damage at elevated temperatures. Based on the results of composite beams, it was found that the survival of axially restrained beams is dominated by the development of catenary action. By utilising catenary action, it is possible for composite beams to develop load carrying capacity significantly above that based on bending resistance. During the development of catenary action, the compression force in the concrete flange of the composite beam decreases, thus reducing the forces in the shear connectors. As a result, the behaviour of shear connector failures ceases to be an issue during the catenary action stage. The results further show that, the load carrying capacities/survival temperatures of composite beams increase by increasing the level of axial restraint up to a certain limit and then decrease at higher levels. Typical realistic composite structures can provide composite beams with sufficient axial restraint to develop catenary action. For detailed composite beams with composite connections, three different beam sizes were investigated using flushed and extended end plate connections with different amounts of slab reinforcement, different load ratios and different bolt sizes. It has been found that the most important method to increase the survival time of composite beams is to use extended end plate connections with sufficient top and bottom reinforcement meshes in the concrete slab, i.e. increasing the amount of slab reinforcement is more beneficial than increasing the bolt size or the number of bolts. Based on the results of modelling a four bay (9 m each, two storey, 4 m high) composite frame with different extents of fire damage to different members, it was found that whenever any of the columns failed, progressive collapse of the frame would occur. Therefore, damages to columns should be prevented or the columns should be designed and constructed to allow for possible damage. If the beams are damaged, it is still possible for the damaged frame to achieve the reference fire resistance time of the undamaged structure (which is used as the criterion to accept that the damaged frame has sufficient robustness) by developing catenary action in the damaged beam. For this to happen, the columns should be designed to resist the catenary tensile force (tying force) in the beams, in addition to the compressive force.
5

Análise dos efeitos de segunda ordem em pilares solicitados a flexão oblíqua composta. / Analysis of second order in the pillars requested by oblique bending composite.

Jorge Luiz Ceccon 04 August 2008 (has links)
Na verificação do estado limite último das estruturas reticuladas em concreto armado se tem sempre os pilares solicitados à flexão oblíqua composta, seja devido a momentos fletores transmitidos pelas vigas ou lajes ou devido a imperfeições construtivas ou por ações normais ao eixo da peça comprimida, atuantes entre seus pontos de vinculação. Neste trabalho se está comparando os resultados que se obtém por dois processos de cálculo, quais sejam, a) Integração numérica com desacoplamentos das flexões nas duas direções principais de inércia com o uso da rigidez secante obtida de diagrama momento-curvatura, ou seja, os esforços de segunda ordem são calculados em cada direção como se não houvesse a solicitação de flexão na direção ortogonal e ao final se verifica a segurança da peça no Estado Limite Último considerando a flexão oblíqua composta; b) integração numérica considerando a flexão oblíqua composta com a curvatura obtida de diagrama momento-curvatura ponto a ponto já no cálculo dos efeitos de segunda ordem. Foram processados 215.740 pilares cuja análise conduz à conclusão de que se pode usar o procedimento citado no item (a) acima, com segurança e sem prejuízo da economia. / At check reticulated reinforced concrete structures in the ultimate limit state one always have the columns requested by a compression with biaxial bending , be due bending moments transmitted bay beams or slabs or due constructions imperfections or actions normal to the axis of the compressed piece acting between its points of attachment. This work is to compare the results that are obtained by two methods of calculation, which are: a) Numerical integration in each main direction of inertia with the use of secant stiffness obtained from bending-curvature diagram, it is, the second order efforts are calculated in each direction as if there was not request bending in the orthogonal direction and the end check the safety at ultimate limit state of the column by considering the biaxial bending; b) Numerical integration in each main direction of inertia with curvatures obtained point to point of moment-curvature diagrams, that consider the biaxial bending, to calculate the second order effects. Were processed 215.740 columns whose analysis leads to the conclusion that we can use the procedure mentioned in tem a) above, safely and without prejudice to the economy.
6

Alternativní řešení montovaného železobetonového skeletu výrobní haly / Alternative design of the precast reinforced concrete frame of the production hall

Konečný, Michal January 2019 (has links)
The aim of the thesis is to design a load-bearing precast concrete structure of production facility. Part of the diploma thesis is to design alternative roofing construction including economic comparison. Internal forces analysis was processed by Dlubal RFEM 5.16 software. In order to find out the expected results, were created simple bar models and the spatial model of the structure was processed later. Structural design report was created for selected elements of the concrete structure including drawings.
7

Návrh předpjaté mostní konstrukce / Design of prestressed bridge structure

Anděl, Martin January 2014 (has links)
The aim of this thesis was to suggest two alternatives of a prestressed concrete bridge structure over the river Jihlava in Ivančice and to design the chosen one. The structure was designed as a one-span frame bridge with the span range of 46,0 m. Both design and relevant drawing documentation of the slab, abutment and strip foundation was made.
8

Železobetonová nosná konstrukce / Reinforced concrete load-bearing construction

Eliášová, Kristýna January 2015 (has links)
My diploma thesis presents structural design of an apartment block in Praha Smíchov. It is a reinforced concrete column structure with six floors. Plane dimensions of the building are 19x36 m. The project includes design of main structural system elements - columns, ceiling plate, foundation and staircase structure.
9

Hi-Performance Sport Centre

Steyn, Pieter W.A. 26 November 2003 (has links)
The city of Centurion houses various sporting facilities such as SuperSport Park and Centurion Gymnastics Club as well as other training facilities. The proposed site for this thesis is on the edge of the Hennops River and forms part of the Lyttelton Agricultural holdings. It borders SuperSport Park as well as the Centurion Rugby club. The proposed site is located North of South Street in Centurion. Currently there is only one Hi-Performance Sport Centre in South Africa. It is located on the Sports grounds of the University of Pretoria. This centre, although only one year old, is already fully booked well into the year 2004. The overwhelming response to this sports facility is a clear indication that centres like these are in great demand in South Africa. One of the main reasons for its popularity is our appealing weather that attracts many foreign athletes. Another reason is the diversity of sport in one complex and the highly equipped training facilities. The athletes can be monitored throughout training with the proper nutrition and medical support. It is the only facility of its kind, combining a training facility with accommodation. This thesis proposes to provide the Centurion area with a similar centre and including improvements to the existing centre. According to the Centurion Integrated Development Framework the site and its surroundings should be used for sport development and recreational facilities. The surrounding sports grounds are another reason for the choice of site. The site is visible from the main road between Pretoria and Johannesburg (N1 Highway) which increases visibility. According to the Centurion Integrated Development Framework all the developments adjacent to the N1 highway should convey a hi-tech image. This thesis evolved as a comprehensive reaction to the immediate site and the physical, social, cultural and technological conditions. It is the amalgamation of these concepts and ideas that serves as metaphor for the architectural response and process. Since the thesis deals with the professional sport industry and high technological precision research and training, so too does this project focus on presenting this idea of "precision" throughout the architectural-, space-, and tangible experience. In totality, the proposed design is the synthesis of various interrelated influences. The product is site specific, individualistic and realistic. / Dissertation (MArch (Prof))--University of Pretoria, 2003. / Architecture / unrestricted
10

Jeddah Auto Mall

Altahlawi, Naif 05 November 2008 (has links)
This Project demonstrates a constructive approach in Jeddah, Saudi Arabia where the building would be a symbol of luxury. The auto mall gives a common platform to different car makers to display their cars and address their competition under one roof which would be convenient for customers to compare cars. The building has twelve show room units. Each unit has a display area, offices, and a service area. The roof structure system facilitates a large open span beneath it. A series of concrete arches is the most significant element of design in the building since it not only holds the roof structure but also brings its individuality and defines the character of the building. With a free column plan beneath it, customers will have a better view of cars presented in show rooms. The structural system in lower floors is separated from the roof to facilitate a different structure system. This project is designed to attract tourists as well as local residents to address the growth and the new social life of the Middle East's wealthiest city. / Master of Architecture

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