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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

Utilização de capitéis para aumento de resistência à punção em Lajes de concreto armado

OLIVEIRA, Túlio Pessoa Souto Maior 31 August 2015 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-12T13:31:38Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação final Tulio.pdf: 2889761 bytes, checksum: 052b78ab493e64aa19addbe0117d79a0 (MD5) / Made available in DSpace on 2016-08-12T13:31:38Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação final Tulio.pdf: 2889761 bytes, checksum: 052b78ab493e64aa19addbe0117d79a0 (MD5) Previous issue date: 2015-08-31 / CNPq / Em lajes de concreto armado sem vigas, apoiadas em pilares, a resistência à punção torna-se um ponto crítico para seu dimensionamento. Até recentemente, os modelos mecânicos para se calcular a resistência à punção das lajes de concreto armado, eram muito complexos, sem praticidade para se aplicar em projetos. O dimensionameto à punção na maioria das normas são baseados em resultados experimentais sem uma modelação física. Uma das formas de se aumentar a resistência à punção é a utilização de capitéis. Para esse trabalho foi definido a utilização de capitéis curtos. As poucas informações sobre a utilização de capitéis curtos deixam os engenheiros receosos quanto a sua utilização. O objetivo desse trabalho é elucidar mais um pouco sobre esse tipo de solução para combate à punção. É apresentado como a litetura aborda a utilização dos capitéis curtos e como a sua utilização e suas dimensões são orientadas. Também é apresentado como os métodos normativos, ACI- 318/2014, NBR 6118/2014 e FIB MODEL CODE 2010 abordam a sua utilização e dimensionamento. É selecionado um caso de uma laje submetida à punção e feito o seu dimensionamento segundo os três métodos já mencionados. Também é feita uma comparação com os resultados experimentais obtidos na literatura, os quais são poucos, com os três métodos já citados. / In flat plates without beams, supported directly on columns, punching shear strength becomes critical in design. Until recently mechanically based models for punching shear computation in reinforced concrete slabs were too complex for routine design work. Punching shear strength checks are basically empirical for most design codes, without a mechanical model basis. A possible alternative to enhance punching shear capacity is to locally increase slab thickness through shear caps or drop panels. In this work, the shear cap option is studied in detail. Due to lack of information, designers are generally wary of the usage of shear caps. This work aims at gaining a better understanding of this type of solution for punching shear strengthening. A literature review is presented on shear cap usage as well as guidance with respect to its geometry. Also presented are design check procedures according to ACI-318/2014, NBR 6118/2014 and FIB MODEL CODE 2010. A case study of a slab subjected to punching shear is selected and its design reviewed according to the three abovementioned codes. Punching shear capacity of shear caps of the very few experimental results are compared with the presented verification procedures.
2

Punção em lajes de concreto armado com furo e transferência de momento: comparação de normas. / Punching shear in reinforced concrete stabs with hole and moment transfer: comparison of standards.

Silva, Carolina Ribeiro da 06 December 2017 (has links)
O crescente uso de lajes sem vigas (lisa com ou sem capitel) como solução estrutural de edificações, justificado por questões econômicas e construtivas, têm destacado a importância do estudo desses elementos estruturais. Já as desvantagens desse sistema estrutural estão associadas às altas tensões geradas na região próxima dos pilares, originando o fenômeno de punção. As normas atuais especificam uma seção íntegra resistente para dimensionamento à punção, entretanto, devido principalmente à passagem de instalações hidráulicas e elétricas através dos pavimentos, é necessária a execução de furações, em alguns casos muito próximas ao contorno dos pilares, o que implica diretamente na redução dessa seção e da resistência das lajes. Portanto, são necessários modelos de cálculo específicos para isso. A NBR 6118 tem critérios para esse problema, mas são antigos e precisam ser modernizados. Assim, comparando os dados experimentais de algumas pesquisas com as cargas últimas estimadas para normas vigentes (fib MC2010:2013, EC2:2004, ACI-318:2014 e NBR 6118:2014), este trabalho teve como objetivo identificar limitações das normas estudadas e verificar a eventual possibilidade de melhorias. Com base nos resultados observados foi proposta uma alteração para a NBR 6118: 2014 no cálculo da punção para lajes lisas com furo(s) na região do pilar, de modo que seja considerado no dimensionamento o momento gerado pela excentricidade do perímetro crítico devido à presença de furo(s) na laje. / The increasing use of flat slabs (slabs without beams with or without drop panel) as a structural solution of buildings, justified by economic and constructive issues, has highlighted the importance of the study of these structural elements. The disadvantages of this structural system are associated with high stresses generated in the region near of the columns, causing the punching shear phenomenon. The current standards specify a resistant section for punching shear design, however, due mainly to the passage of hydraulic and electric installations through the floors, it is necessary to execute holes, in some cases very close to the boundaries of the columns, which reduces this section and the slab strength. Therefore, it is necessary to specify calculation models for that. The NBR 6118 has criteria for this problem, nonetheless it is old and needs to be modernized. Comparing experimental data from some researches, with the estimated ultimate loads for current standards (fib MC2010: 2013, EC2: 2004, ACI-318: 2014 and NBR 6118: 2014), this work had as objective to identify limitations of the standards studied and verify possible improvements. Based on the observed results, it was proposed a modification for NBR 6118: 2014 in the design of the punching shear of flat slabs with hole(s) near of the column, considering the moment caused by the eccentricity of the critical perimeter due to the presence of hole(s) in the slab.
3

Análise da confiabilidade da ligação laje-pilar interno sob punção de acordo com a NBR-6118:2014 / Reliability analysis of the slab-column intersection under puching according to NBR 6118:2014

Silva, Gustavo Ribeiro da January 2017 (has links)
As demandas do mercado da construção civil têm exigido vãos cada vez maiores e ao mesmo tempo alturas cada vez menores das vigas. Isto tem levado muitos projetistas à adoção da solução do pavimento em laje lisa em concreto armado ou protendido. No entanto, a ausência das vigas torna possível a ruptura das lajes por puncionamento junto aos pilares. A norma NBR-6118:2014 prescreve as disposições para o projeto de lajes sob punção. O trabalho proposto teve como objetivo principal a análise da confiabilidade da ligação laje-pilar interno sob o efeito da punção em lajes que se apoiam diretamente sobre pilares de acordo com a NBR-6118:2014. Primeiramente, com o intuito de se entender melhor o fenômeno da punção, realizou-se uma breve revisão bibliográfica, identificando os principais parâmetros que influenciam na resistência da ligação, assim como os principais métodos de análise e trabalhos realizados na área. Em seguida, estudou-se o software de análise em elementos finitos ANSYS (Analysis Systems Incorporated), especificamente a ferramenta UPF (User Programmable Features), que foi utilizada para adoção de um modelo constitutivo para o concreto. Utilizando o software, foram modeladas lajes estudadas por outros autores, visando a validação do modelo numérico. Para o estudo da confiabilidade foi dimensionado um conjunto de lajes lisas seguindo as prescrições da NBR 6118:2014. A análise da confiabilidade foi realizada utilizando a ferramenta PDS (Probabilistic Design System), empregando o método de simulação numérica de Monte Carlo com amostragem por Latin Hypercube. Por fim, determinou-se o índice de confiabilidade em cada projeto e realizaram-se análises paramétricas com as variáveis adotadas no trabalho. Os resultados obtidos mostraram que as lajes lisas sem armadura de cisalhamento projetadas segundo a NBR 6118:2014 obtiveram, em sua maioria, índices de confiabilidade adequados. Porém, para as lajes lisas com armadura de cisalhamento, o índice de confiabilidade foi, em grande parte, menor que o índice de confiabilidade alvo adotado. / The demands of the construction market have required increasingly large spans while diminishing of the beam heights. This has led many designers to adopt the pavement solucion of reinforced or prestressed concrete flat slab. However, the absence of the beams makes it possible to slabs failure by punching shear. The Standard NBR-6118: 2014 prescribes the requirements for the design of slabs under punching. The aim of this work was to analyze the reliability of the internal slab-column intersection under punching in slabs supported directly on columns according to NBR-6118: 2014. Firstly, in order to better understand the punching phenomenon, a brief bibliographic review was carried out, identifying the main parameters that influence the connection strength, as well as the main methods of analysis and published in the area. Then, the finite element analysis software ANSYS (Analysis Systems Incorporated), specifically the UPF (User Programmable Features) tool, was used to adopt a concrete constitutive model. Using the software, slabs studied by other authors were modeled, aiming at the validation of the numerical model. For the reliability study, a set of flat slabs was designed following the requirements of NBR 6118: 2014. The reliability analysis was performed using the PDS (Probabilistic Design System) tool, using the Monte Carlo numerical simulation method with Latin Hypercube sampling. Finally, the reliability index was determined in each project and parametric analyzes were performed with the variables adopted in the study. The results from this study show that the flat slabs without shear reinforcement designed according to NBR Standarts obtained appropriate reliability index. However, for the flat slabs with shear reinforcement, the reliability index, in most cases, did not achieve the target reliability index.
4

Análise da confiabilidade da ligação laje-pilar interno sob punção de acordo com a NBR-6118:2014 / Reliability analysis of the slab-column intersection under puching according to NBR 6118:2014

Silva, Gustavo Ribeiro da January 2017 (has links)
As demandas do mercado da construção civil têm exigido vãos cada vez maiores e ao mesmo tempo alturas cada vez menores das vigas. Isto tem levado muitos projetistas à adoção da solução do pavimento em laje lisa em concreto armado ou protendido. No entanto, a ausência das vigas torna possível a ruptura das lajes por puncionamento junto aos pilares. A norma NBR-6118:2014 prescreve as disposições para o projeto de lajes sob punção. O trabalho proposto teve como objetivo principal a análise da confiabilidade da ligação laje-pilar interno sob o efeito da punção em lajes que se apoiam diretamente sobre pilares de acordo com a NBR-6118:2014. Primeiramente, com o intuito de se entender melhor o fenômeno da punção, realizou-se uma breve revisão bibliográfica, identificando os principais parâmetros que influenciam na resistência da ligação, assim como os principais métodos de análise e trabalhos realizados na área. Em seguida, estudou-se o software de análise em elementos finitos ANSYS (Analysis Systems Incorporated), especificamente a ferramenta UPF (User Programmable Features), que foi utilizada para adoção de um modelo constitutivo para o concreto. Utilizando o software, foram modeladas lajes estudadas por outros autores, visando a validação do modelo numérico. Para o estudo da confiabilidade foi dimensionado um conjunto de lajes lisas seguindo as prescrições da NBR 6118:2014. A análise da confiabilidade foi realizada utilizando a ferramenta PDS (Probabilistic Design System), empregando o método de simulação numérica de Monte Carlo com amostragem por Latin Hypercube. Por fim, determinou-se o índice de confiabilidade em cada projeto e realizaram-se análises paramétricas com as variáveis adotadas no trabalho. Os resultados obtidos mostraram que as lajes lisas sem armadura de cisalhamento projetadas segundo a NBR 6118:2014 obtiveram, em sua maioria, índices de confiabilidade adequados. Porém, para as lajes lisas com armadura de cisalhamento, o índice de confiabilidade foi, em grande parte, menor que o índice de confiabilidade alvo adotado. / The demands of the construction market have required increasingly large spans while diminishing of the beam heights. This has led many designers to adopt the pavement solucion of reinforced or prestressed concrete flat slab. However, the absence of the beams makes it possible to slabs failure by punching shear. The Standard NBR-6118: 2014 prescribes the requirements for the design of slabs under punching. The aim of this work was to analyze the reliability of the internal slab-column intersection under punching in slabs supported directly on columns according to NBR-6118: 2014. Firstly, in order to better understand the punching phenomenon, a brief bibliographic review was carried out, identifying the main parameters that influence the connection strength, as well as the main methods of analysis and published in the area. Then, the finite element analysis software ANSYS (Analysis Systems Incorporated), specifically the UPF (User Programmable Features) tool, was used to adopt a concrete constitutive model. Using the software, slabs studied by other authors were modeled, aiming at the validation of the numerical model. For the reliability study, a set of flat slabs was designed following the requirements of NBR 6118: 2014. The reliability analysis was performed using the PDS (Probabilistic Design System) tool, using the Monte Carlo numerical simulation method with Latin Hypercube sampling. Finally, the reliability index was determined in each project and parametric analyzes were performed with the variables adopted in the study. The results from this study show that the flat slabs without shear reinforcement designed according to NBR Standarts obtained appropriate reliability index. However, for the flat slabs with shear reinforcement, the reliability index, in most cases, did not achieve the target reliability index.
5

Análise da confiabilidade da ligação laje-pilar interno sob punção de acordo com a NBR-6118:2014 / Reliability analysis of the slab-column intersection under puching according to NBR 6118:2014

Silva, Gustavo Ribeiro da January 2017 (has links)
As demandas do mercado da construção civil têm exigido vãos cada vez maiores e ao mesmo tempo alturas cada vez menores das vigas. Isto tem levado muitos projetistas à adoção da solução do pavimento em laje lisa em concreto armado ou protendido. No entanto, a ausência das vigas torna possível a ruptura das lajes por puncionamento junto aos pilares. A norma NBR-6118:2014 prescreve as disposições para o projeto de lajes sob punção. O trabalho proposto teve como objetivo principal a análise da confiabilidade da ligação laje-pilar interno sob o efeito da punção em lajes que se apoiam diretamente sobre pilares de acordo com a NBR-6118:2014. Primeiramente, com o intuito de se entender melhor o fenômeno da punção, realizou-se uma breve revisão bibliográfica, identificando os principais parâmetros que influenciam na resistência da ligação, assim como os principais métodos de análise e trabalhos realizados na área. Em seguida, estudou-se o software de análise em elementos finitos ANSYS (Analysis Systems Incorporated), especificamente a ferramenta UPF (User Programmable Features), que foi utilizada para adoção de um modelo constitutivo para o concreto. Utilizando o software, foram modeladas lajes estudadas por outros autores, visando a validação do modelo numérico. Para o estudo da confiabilidade foi dimensionado um conjunto de lajes lisas seguindo as prescrições da NBR 6118:2014. A análise da confiabilidade foi realizada utilizando a ferramenta PDS (Probabilistic Design System), empregando o método de simulação numérica de Monte Carlo com amostragem por Latin Hypercube. Por fim, determinou-se o índice de confiabilidade em cada projeto e realizaram-se análises paramétricas com as variáveis adotadas no trabalho. Os resultados obtidos mostraram que as lajes lisas sem armadura de cisalhamento projetadas segundo a NBR 6118:2014 obtiveram, em sua maioria, índices de confiabilidade adequados. Porém, para as lajes lisas com armadura de cisalhamento, o índice de confiabilidade foi, em grande parte, menor que o índice de confiabilidade alvo adotado. / The demands of the construction market have required increasingly large spans while diminishing of the beam heights. This has led many designers to adopt the pavement solucion of reinforced or prestressed concrete flat slab. However, the absence of the beams makes it possible to slabs failure by punching shear. The Standard NBR-6118: 2014 prescribes the requirements for the design of slabs under punching. The aim of this work was to analyze the reliability of the internal slab-column intersection under punching in slabs supported directly on columns according to NBR-6118: 2014. Firstly, in order to better understand the punching phenomenon, a brief bibliographic review was carried out, identifying the main parameters that influence the connection strength, as well as the main methods of analysis and published in the area. Then, the finite element analysis software ANSYS (Analysis Systems Incorporated), specifically the UPF (User Programmable Features) tool, was used to adopt a concrete constitutive model. Using the software, slabs studied by other authors were modeled, aiming at the validation of the numerical model. For the reliability study, a set of flat slabs was designed following the requirements of NBR 6118: 2014. The reliability analysis was performed using the PDS (Probabilistic Design System) tool, using the Monte Carlo numerical simulation method with Latin Hypercube sampling. Finally, the reliability index was determined in each project and parametric analyzes were performed with the variables adopted in the study. The results from this study show that the flat slabs without shear reinforcement designed according to NBR Standarts obtained appropriate reliability index. However, for the flat slabs with shear reinforcement, the reliability index, in most cases, did not achieve the target reliability index.
6

Punção em lajes de concreto armado com furo e transferência de momento: comparação de normas. / Punching shear in reinforced concrete stabs with hole and moment transfer: comparison of standards.

Carolina Ribeiro da Silva 06 December 2017 (has links)
O crescente uso de lajes sem vigas (lisa com ou sem capitel) como solução estrutural de edificações, justificado por questões econômicas e construtivas, têm destacado a importância do estudo desses elementos estruturais. Já as desvantagens desse sistema estrutural estão associadas às altas tensões geradas na região próxima dos pilares, originando o fenômeno de punção. As normas atuais especificam uma seção íntegra resistente para dimensionamento à punção, entretanto, devido principalmente à passagem de instalações hidráulicas e elétricas através dos pavimentos, é necessária a execução de furações, em alguns casos muito próximas ao contorno dos pilares, o que implica diretamente na redução dessa seção e da resistência das lajes. Portanto, são necessários modelos de cálculo específicos para isso. A NBR 6118 tem critérios para esse problema, mas são antigos e precisam ser modernizados. Assim, comparando os dados experimentais de algumas pesquisas com as cargas últimas estimadas para normas vigentes (fib MC2010:2013, EC2:2004, ACI-318:2014 e NBR 6118:2014), este trabalho teve como objetivo identificar limitações das normas estudadas e verificar a eventual possibilidade de melhorias. Com base nos resultados observados foi proposta uma alteração para a NBR 6118: 2014 no cálculo da punção para lajes lisas com furo(s) na região do pilar, de modo que seja considerado no dimensionamento o momento gerado pela excentricidade do perímetro crítico devido à presença de furo(s) na laje. / The increasing use of flat slabs (slabs without beams with or without drop panel) as a structural solution of buildings, justified by economic and constructive issues, has highlighted the importance of the study of these structural elements. The disadvantages of this structural system are associated with high stresses generated in the region near of the columns, causing the punching shear phenomenon. The current standards specify a resistant section for punching shear design, however, due mainly to the passage of hydraulic and electric installations through the floors, it is necessary to execute holes, in some cases very close to the boundaries of the columns, which reduces this section and the slab strength. Therefore, it is necessary to specify calculation models for that. The NBR 6118 has criteria for this problem, nonetheless it is old and needs to be modernized. Comparing experimental data from some researches, with the estimated ultimate loads for current standards (fib MC2010: 2013, EC2: 2004, ACI-318: 2014 and NBR 6118: 2014), this work had as objective to identify limitations of the standards studied and verify possible improvements. Based on the observed results, it was proposed a modification for NBR 6118: 2014 in the design of the punching shear of flat slabs with hole(s) near of the column, considering the moment caused by the eccentricity of the critical perimeter due to the presence of hole(s) in the slab.
7

Design adjustment factors and the economical application of concrete flat-slabs with internal spherical voids in South Africa

Marais, Corneille Charles 23 August 2010 (has links)
Long span flat slab systems with internal spherical void formers have been used in Europe for a decade now. Cobiax® is the brand name of a successful system, recently introduced in South Africa. It is a bi-axial reinforced concrete flat slab system, with a grid of internal spherical void formers. The main advantage is the possibility of long spans due to the significant reduction in own weight, as well as the fast construction sequence with the use of flat slab formwork systems. Design requirements of SANS 10100:2000 are affected. Vertical shear capacity is a concern due to loss of aggregate interlock. Research in Germany proved a factor of 0.55 to be a conservative shear resistance reduction factor for Cobiax slabs. Theoretical and preliminary laboratory South African research suggests that a greater factor of 0.85 might be used when considering the shear capacity of the steel cages. These cages’ vertical legs also cross the cold joint caused by the two concrete pours required for Cobiax slabs, and proved to provide sufficient horisontal shear resistance if the correct cage diameters are used. Laboratory tests in Germany supported by theoretical calculations further showed reduced deflections for Cobiax slabs. Although stiffness and own weight are reduced due to the voids, Cobiax slabs had smaller absolute deflections than solid slabs with the same thickness. Cobiax research factors are safe to apply to SANS 10100-01:2000. The economy of Cobiax slabs was tested against that of coffer and post-tensioned slabs. Different span lengths and loads were considered. Based on 2007 material costs in South Africa, Cobiax slabs subject to the same loads and span lengths will be slightly more expensive than that of coffer slabs and post-tensioned slabs when considering only direct slab construction costs. Cobiax will be most appropriate where a flat soffit is required for high multi-storey buildings, requiring large spans with a light load application. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Civil Engineering / unrestricted
8

Punching Shear of Flat Slabs

Lyčka, Lukáš January 2019 (has links)
The use of flat slabs in constructions due to its many functional and economic advantages is wide-spread. Behavior of flat slabs in shear and flexure is a fairly complex problem. Therefore, the punching shear failure belongs to one of the most critical aspects in the design of concrete buildings. Over the last decades several buildings have collapsed due to the failure of the punching shear strength, resulting in loss of lives and financial damages. These disasters revealed gaps in the current (or former) design codes and recommendations. As a part of theoretical framework of the dissertation a method for predicting the punching shear strength of flat slabs was developed. Several experiments on scaled down slabs were conducted in order to verify the proposed method and for optimization of its parameters. Proposed method in development predicts the punching shear for slabs without shear reinforcement according to the EC2 and replaces the area of the shear crack with a system of struts and ties.
9

Punching shear of concrete flat slabs reinforced with fibre reinforced polymer bars

Al Ajami, Abdulhamid January 2018 (has links)
Fibre reinforcement polymers (FRP) are non-corrodible materials used instead of conventional steel and have been approved to be an effective way to overcome corrosion problems. FRP, in most cases, can have a higher tensile strength, but a lower tensile modulus of elasticity compared to that of conventional steel bars. This study aimed to examine flat slab specimens reinforced with glass fibre reinforced polymer (GFRP) and steel bar materials for punching shear behaviour. Six full-scale two-way slab specimens were constructed and tested under concentric load up to failure. One of the main objectives is to study the effect of reinforcement spacing with the same reinforcement ratio on the punching shear strength. In addition, two other parameters were considered, namely, slab depth, and compressive strength of concrete. The punching shear provisions of two code of practises CSA S806 (Canadian Standards 2012) and JSCE (JSCE et al. 1997) reasonably predicted the load capacity of GFRP reinforced concrete flat slab, whereas, ACI 440 (ACI Committee 440 2015) showed very conservative load capacity prediction. On the other hand, a dynamic explicit solver in nonlinear finite element (FE) modelling is used to analyse a connection of column to concrete flat slabs reinforced with GFRP bars in terms of ultimate punching load. All FE modelling was performed in 3D with the appropriate adoption of element size and mesh. The numerical and experimental results were compared in order to evaluate the developed FE, aiming to predict the behaviour of punching shear in the concrete flat slab. In addition, a parametric study was created to explore the behaviour of GFRP reinforced concrete flat slab with three parameters, namely, concrete strength, shear load perimeter to effective depth ratio, and, flexural reinforcement ratio. It was concluded that the developed models could accurately capture the behaviour of GFRP reinforced concrete flat slabs subjected to a concentrated load. Artificial Neural Networks (ANN) is used in this research to predict punching shear strength, and the results were shown to match more closely with the experimental results. A parametric study was performed to investigate the effects of five parameters on punching shear capacity of GFRP reinforced concrete flat slab. The parametric investigation revealed that the effective depth has the most substantial impact on the load carrying capacity of the punching shear followed by reinforcement ratio, column perimeter, the compressive strength of the concrete, and, the elastic modulus of the reinforcement.
10

Construction in in-situ cast flat slabs using steel fibre reinforced concrete

Jarrat, Robert 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Fibre reinforced concrete (FRC) transforms concrete from a characteristically brittle material to one with a post-crack tensile residual capacity. Its application in industry has varied over the past of which the tensile properties have generally been used in the form of crack mitigation. More recently, the introduction of steel fibres has broadened this scope to structural applications in which the resisting tensile stresses that develop within a steel FRC (SFRC) element can be rather significant. This thesis reviews the existing practices and design models associated with SFRC and the suitability of its implementation as the sole form of reinforcement in in-situ cast flat slab systems. As a material SFRC is dependent on a number of factors which include the fibre type and volume, fibre distributions, element size, as well as the support and applied load conditions. Thus, its performance can be considered rather variable in comparison to conventional concrete should the incorrect practices be implemented. In order to adequately define the material characteristics, it is necessary to use test procedures that accurately reflect on the intended structural application. As a result a number of test procedures have been developed. In addition to this, the post-crack material performance is associated with a non-linear behaviour. This attribute makes the design of structural SFRC elements rather difficult. In an attempt to simplify this, existing design models define stress-strain or stress-crack width relations in which assumptions are made regarding the cross-sectional stress distribution at specified load states. This thesis takes on two parts in defining the suitability of SFRC as the sole form of reinforcement in flat slab systems. The first is a theoretical investigation regarding the micro and macro scale material performance of SFRC, the practices that exist in defining the material properties and its application in structural systems (particularly suspended slab systems), and a breakdown of the existing design models applicable to strain softening deflection hardening SFRC materials. The second part is an experimental program in which the fresh state and hardened state material properties of specified SFRC mix designs defined through flow and beam testing respectively. These properties are then implemented in the design and construction of full scale flexural and punching shear test slabs in an attempt to verify the theory applied. The investigation reveals that the use of SFRC significantly improves the ductility of concrete systems in the post-crack state through fibre crack bridging. This ductility can result in deflection hardening of flat slab systems in which the redistribution of stresses increases the load carrying capacity once cracking has taken place. However, the performance of large scale test specimens is significantly influenced by the construction practices implemented in which the material variability increases as a result of non-uniform fibre distributions. The results indicate that the load prediction models applied have potential to adequately predict the ultimate failure loads of SFRC flat slab systems but however cannot account for possible non-uniform fibre distributions which could result in premature failure of the system. / AFRIKAANSE OPSOMMING: Vesel versterkte beton (VVB) verander beton van die kenmerkende uiters bros material na ‘n material met ‘n residuele post-kraak trekkapasiteit. Die toepassing daarvan in die bedryf het in die verlede gewissel en die trek eienskappe is oor die algemeen gebruik vir kraak vermindering. Meer onlangs het die bekenstelling van staal vesel hierdie omvang verbreed na die strukturele toepassings waar trekspannings wat ‘n VVB element kan weerstaan noemenswaardig kan wees. Hierdie tesis ondersoek bestaande praktyke en ontwerpmodelle met die oog op staalvesel versterkte beton (SVVB) en die geskiktheid van die implementering daarvan as die enigste vorm van bekisting in in-situ gegiete plat blad stelsels. As ‘n materiaal, is SVVB afhanklik van ‘n aantal faktore wat die tipe vesel en volume, vesel verspreiding, element grootte, sowel as die randvoorwaardes tipe aangewende las insluit. As gevolg hiervan, kan die gedrag van SVVB, wat korrek geïmplimenteer word, as redelik varieerbaar beskou word wanneer dit met konvensionele beton vergelyk word. Ten einde die materiaaleienskappe voldoende te definieer, is dit noodsaaklik dat prosedures wat die strukturele toepassing akuraat voorstel, getoets word en daarom is ‘n aantal toets prosedures ontwikkel. Verder het die post-kraak materiaalgedrag ‘n nie-lineêre verband wat struktuurontwerp met SVVB redelik moeilik maak. Om dit te vereenvoudig, definieer bestaande ontwerpmodelle spanning-vervorming of spanning-kraakwydte verhoudings waarin aannames gemaak word ten opsigte van die spanningsverdeling oor ‘n snit, gegewe sekere lastoestande. Hierdie studie bestaan uit twee dele wat die geskiktheid van SVVB as die enigste vorm van bikisting in plat blad stelsels definieer. Die eerste deel bestaan uit ‘n teoretiese ondersoek wat handel oor die mikro- en makro-skaal materiaalgedrag van SVVB, die praktyke wat bestaan om die materiaaleienskappe en toepassing in strukturele sisteme (spesifiek opgelegde blad stelsels) te definieer, en ‘n uiteensetting van die bestaande ontwerpmodelle wat van toepassing is vir defleksie as gevolg van vervormingsversagting wat SVVB material verhard. Die tweede deel bestaan uit ‘n eksperimentele program waarin die materiaaleienskappe van gespesifiseerde SVVB meng-ontwerpe in die vars toestand en in die verharde toestand gedefinieer word deur middel van vloei- en balktoetse onderskeidelik. Hierdie eienskappe word dan toegepas vir die ontwerp en konstruksie van volskaalse buig- en ponsskuif toetsblaaie ten einde die modelle en teorie wat toegepas is, te bevestig. Die ondersoek toon dat die gebruik van SVVB die duktiliteit van beton sisteme noemenswaardig verbeter in die post-kraak toestand deur kraak oorbrugging. Hierdie duktiliteit kan defleksie verharding van plat blad stelsels veroorsaak waarin die herverdeling van spannings, nadat kraking plaasgevind het, die lasdraende kapasiteit verhoog. Die gedrag van die grootskaalse toetsmonsters word egter noemenswaardig beïnvloed deur die konstruksiemetodes wat geïmplementeer word waarin die materialveranderlikheid toeneem as ‘n gevolg van nie-uniforme vesel verdelings. Die resultate dui daarop dat die modelle wat toegepas is om die laste te voorspel, die potensiaal het om die grens falingslas van SVVB plat blad stelsel voldoende te voorspel, maar neem nie moontlike nie-uniforme veselverdelings wat kan lei tot vroeë faling van die stelsel in ag nie.

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