O comportamento mecânico de vigas em alvenaria estrutural submetidas ao cisalhamento é abordado de forma aprofundada neste trabalho. São apresentados neste estudo um extensivo levantamento bibliográfico, o qual estabelece um panorama sobre o tema, um programa experimental com ensaios de caracterização do material alvenaria e de vigas em escala natural e um estudo numérico das vigas ensaiadas em laboratório. Na etapa de caracterização dos materiais o comportamento compósito da alvenaria é analisado por meio de prismas submetidos à compressão em duas direções ortogonais, normal e paralela à junta. Para o estudo das vigas são realizados trinta e sete ensaios, nos quais são avaliadas as influências da geometria, das taxas de armaduras e da relação a/d (em que a é a distância da carga aplicada até o apoio e d é a altura útil) na capacidade resistente ao cisalhamento. Posteriormente, é realizada a modelagem numérica através do software DIANA® com o propósito de complementar as análises dos ensaios. A partir dos resultados experimentais e numéricos pôde-se concluir que, com exceção das vigas com armaduras longitudinais de 10 mm de diâmetro, os demais modelos atingiram a ruína por cisalhamento, devido à ausência de estribos ou pela sua insuficiência. O aumento da taxa de armadura longitudinal de 0,45 para 1,18% resultou em um incremento de 18,4% na resistência ao cisalhamento convencional. Para as duas geometrias (vigas com duas e três fiadas) e as duas relações a/d (0,77 e 1,72), constatou-se que não há uma melhora significativa na capacidade resistente quando a taxa de armadura transversal é aumentada de 0,05 para 0,07%. Os mecanismos resistentes, como o efeito de pino, foram efetivos na resistência dos modelos. Por fim, as análises numéricas reproduziram de forma satisfatória os experimentos, tanto no que diz respeito ao comportamento pré e pós-pico quanto na previsão da força última. / This work is an in depth study about the mechanical behaviour of masonry beams subjected to shear forces. An extensive literature review, which establishes a panorama on the subject, an experimental program considering material characterization and full scale beams tests and a numerical study for the tested beams are presented. For the beams, thirty seven tests are carried out in which the influence of geometry, reinforcements ratio and a/d ratio (where a is the distance from the load to adjacent support and d is the effective depth) on the shear strength are evaluated. Computational modelling is performed using the DIANA® software in order to complement the experimental results. From the experimental and numerical results it was possible to conclude that, except for beams with 10 mm diameter steel bar, the other models failed in shear, due to the absence of stirrups or their insufficiency. An increase in longitudinal reinforcement ratio from 0,45 to 1,18% improved the theoretical shear strength in 18,4%. For the beams with two and three courses and for a/d ratios 0,77 and 1,72 it was found that there is no significant improvement on the load capacity when the transverse reinforcement ratio is increased from 0,05 to 0,07%. Shear strength mechanisms, such as the dowel action, were effective in the models load capacity. Finally, the numerical analyzes satisfactorily reproduced the experiments, regarding to the pre and post-peak behaviour and in the prediction of the ultimate load.

To ensure stability of a construction the physical properties of its components have tobe well known. In a landfill, waste presents the largest structural element and controlsboth the stability and integrity of the lining system. In spite of this critical role there is adearth of knowledge on behaviour of waste as an engineering material. Wastevariability and changes in waste stream aggravate the assessment of wastemechanical properties.In a literature review the main influences on shear behaviour of municipal solid waste(MSW) were identified. Design values and recommendation for shear parameter weresummarised. To assess mechanical behaviour in a systematic way the use of aclassification system was deemed crucial for a comparison of different findings fromliterature and a categorisation of waste in regard to its composition. A framework for aclassification system was introduced. Main elements of a comprehensive classificationsystem were identified in a literature review and discussed, and data from literaturewas applied to the classification framework. For the validation of a classificationsystem, municipal solid waste was examined in an in-situ waste sorting analysis andalso applied to the framework.The findings from the waste sorting and the classification system were also used todevelop a family of synthetic waste to gradually examine the influencing factors onwaste mechanical behaviour. For this, the materials, size ranges and shapes of wastecomponents identified in the waste sorting analysis were reduced to a minimum butstill representative amount. A range of synthetic waste compositions was engineeredand tested in a large-scale shear device. Compression tests were also conducted in alarge compression cell. The results from the laboratory testing were compared tovalues from the literature and MSW mechanical behaviour was subsequentlydiscussed in view to potential changes from changing waste streams.The results from shear and compression tests (constrained and shear modulus) onsynthetic waste were linked to the classification system and trends of the mechanicalbehaviour in relation to the tested synthetic waste compositions were identified.A framework for classifying MSW and comparing waste mechanical behaviour waspresented and demonstrated. A family of synthetic wastes was engineered and testedin shear and compression tests. The results were comparable to values from theliterature. Further research is recommended to refine the synthetic waste and theclassification.

O comportamento mecânico de vigas em alvenaria estrutural submetidas ao cisalhamento é abordado de forma aprofundada neste trabalho. São apresentados neste estudo um extensivo levantamento bibliográfico, o qual estabelece um panorama sobre o tema, um programa experimental com ensaios de caracterização do material alvenaria e de vigas em escala natural e um estudo numérico das vigas ensaiadas em laboratório. Na etapa de caracterização dos materiais o comportamento compósito da alvenaria é analisado por meio de prismas submetidos à compressão em duas direções ortogonais, normal e paralela à junta. Para o estudo das vigas são realizados trinta e sete ensaios, nos quais são avaliadas as influências da geometria, das taxas de armaduras e da relação a/d (em que a é a distância da carga aplicada até o apoio e d é a altura útil) na capacidade resistente ao cisalhamento. Posteriormente, é realizada a modelagem numérica através do software DIANA® com o propósito de complementar as análises dos ensaios. A partir dos resultados experimentais e numéricos pôde-se concluir que, com exceção das vigas com armaduras longitudinais de 10 mm de diâmetro, os demais modelos atingiram a ruína por cisalhamento, devido à ausência de estribos ou pela sua insuficiência. O aumento da taxa de armadura longitudinal de 0,45 para 1,18% resultou em um incremento de 18,4% na resistência ao cisalhamento convencional. Para as duas geometrias (vigas com duas e três fiadas) e as duas relações a/d (0,77 e 1,72), constatou-se que não há uma melhora significativa na capacidade resistente quando a taxa de armadura transversal é aumentada de 0,05 para 0,07%. Os mecanismos resistentes, como o efeito de pino, foram efetivos na resistência dos modelos. Por fim, as análises numéricas reproduziram de forma satisfatória os experimentos, tanto no que diz respeito ao comportamento pré e pós-pico quanto na previsão da força última. / This work is an in depth study about the mechanical behaviour of masonry beams subjected to shear forces. An extensive literature review, which establishes a panorama on the subject, an experimental program considering material characterization and full scale beams tests and a numerical study for the tested beams are presented. For the beams, thirty seven tests are carried out in which the influence of geometry, reinforcements ratio and a/d ratio (where a is the distance from the load to adjacent support and d is the effective depth) on the shear strength are evaluated. Computational modelling is performed using the DIANA® software in order to complement the experimental results. From the experimental and numerical results it was possible to conclude that, except for beams with 10 mm diameter steel bar, the other models failed in shear, due to the absence of stirrups or their insufficiency. An increase in longitudinal reinforcement ratio from 0,45 to 1,18% improved the theoretical shear strength in 18,4%. For the beams with two and three courses and for a/d ratios 0,77 and 1,72 it was found that there is no significant improvement on the load capacity when the transverse reinforcement ratio is increased from 0,05 to 0,07%. Shear strength mechanisms, such as the dowel action, were effective in the models load capacity. Finally, the numerical analyzes satisfactorily reproduced the experiments, regarding to the pre and post-peak behaviour and in the prediction of the ultimate load.

Aerospace structural components made from polymer matrix composites (PMCs) offer numerous advantages. Their high stiffness and high strength combined with low densities enable lower fuel consumption coupled with higher payloads. As a result, PMCs provide an important economic advantage over typical metallic airframes. Textile reinforcements for PMCs are made by assembling reinforcement fibres, typically carbon. Then, the textile reinforcements are typically cut into smaller pieces, stacked, draped and assembled into a dry assembly called a preform, the shape of which generally approaches that of the PMC part to be made. This manufacturing process is labour intensive and expensive. Novel thick, net-shape, drapable, high vf textile reinforcements used toward manufacturing aerospace PMCs are being developed at the University of Ottawa. The technology enables the manufacturing of flat, drapable multilayered near net-shape preforms. The bending and in-plane shear behaviours of such novel thick reinforcement textiles was investigated to understand and define the behaviour of such thick fabric reinforcements when formed into required shapes. A bending apparatus was developed for investigating the bending behaviour of these novel thick reinforcement fabrics and an articulated frame shear rig was used for investigating the in-plane shear behaviour. A non-destructive inspection method using infrared imaging was used for investigating and identifying flaws and defects in these thick, dry textile reinforcements, aiming at increasing the quality and reproducibility of the final PMC parts made from these reinforcements.

When subjected to a combination of moment and shear force, a reinforced concrete (RC) beam with either little or no transverse reinforcement can fail in shear before reaching its full flexural strength. This type of failure is sudden in nature and usually disastrous because it does not give sufficient warning prior to collapse. To prevent this type of shear failure, reinforced concrete beams are traditionally reinforced with stirrups. However, the use of stirrups is not always cost effective since it increases labor costs, and can make casting concrete difficult in situations where closely-spaced stirrups are required. The use of steel fiber reinforced concrete (SFRC) could be considered as a potential alternative to the use of traditional shear reinforcement. Concrete is very weak and brittle in tension, SFRC transforms this behaviour and improves the diagonal tension capacity of concrete and thus can result in significant enhancements in shear capacity. However, one of the drawbacks associated with SFRC is that the addition of fibers to a regular concrete mix can cause problems in workability. The use of self-consolidating concrete (SCC) is an innovative solution to this problem and can result in improved workability when fibers are added to the mix. The thesis presents the experimental results from tests on twelve slender self-consolidating fiber reinforced concrete (SCFRC) beams tested under four-point loading. The results demonstrate the combined use of SCC and steel fibers can improve the shear resistance of reinforced concrete beams, enhance crack control and can promote flexural ductility. Despite extensive research, there is a lack of accurate and reliable design guidelines for the use of SFRC in beams. This study presents a rational model which can accurately predict the shear resistance of steel fiber reinforced concrete beams. The thesis also proposes a safe and reliable equation which can be used for the shear design of SFRC beams.

When subjected to a combination of moment and shear force, a reinforced concrete (RC) beam with either little or no transverse reinforcement can fail in shear before reaching its full flexural strength. This type of failure is sudden in nature and usually disastrous because it does not give sufficient warning prior to collapse. To prevent this type of shear failure, reinforced concrete beams are traditionally reinforced with stirrups. However, the use of stirrups is not always cost effective since it increases labor costs, and can make casting concrete difficult in situations where closely-spaced stirrups are required. The use of steel fiber reinforced concrete (SFRC) could be considered as a potential alternative to the use of traditional shear reinforcement. Concrete is very weak and brittle in tension, SFRC transforms this behaviour and improves the diagonal tension capacity of concrete and thus can result in significant enhancements in shear capacity. However, one of the drawbacks associated with SFRC is that the addition of fibers to a regular concrete mix can cause problems in workability. The use of self-consolidating concrete (SCC) is an innovative solution to this problem and can result in improved workability when fibers are added to the mix. The thesis presents the experimental results from tests on twelve slender self-consolidating fiber reinforced concrete (SCFRC) beams tested under four-point loading. The results demonstrate the combined use of SCC and steel fibers can improve the shear resistance of reinforced concrete beams, enhance crack control and can promote flexural ductility. Despite extensive research, there is a lack of accurate and reliable design guidelines for the use of SFRC in beams. This study presents a rational model which can accurately predict the shear resistance of steel fiber reinforced concrete beams. The thesis also proposes a safe and reliable equation which can be used for the shear design of SFRC beams.

When subjected to a combination of moment and shear force, a reinforced concrete (RC) beam with either little or no transverse reinforcement can fail in shear before reaching its full flexural strength. This type of failure is sudden in nature and usually disastrous because it does not give sufficient warning prior to collapse. To prevent this type of shear failure, reinforced concrete beams are traditionally reinforced with stirrups. However, the use of stirrups is not always cost effective since it increases labor costs, and can make casting concrete difficult in situations where closely-spaced stirrups are required. The use of steel fiber reinforced concrete (SFRC) could be considered as a potential alternative to the use of traditional shear reinforcement. Concrete is very weak and brittle in tension, SFRC transforms this behaviour and improves the diagonal tension capacity of concrete and thus can result in significant enhancements in shear capacity. However, one of the drawbacks associated with SFRC is that the addition of fibers to a regular concrete mix can cause problems in workability. The use of self-consolidating concrete (SCC) is an innovative solution to this problem and can result in improved workability when fibers are added to the mix. The thesis presents the experimental results from tests on twelve slender self-consolidating fiber reinforced concrete (SCFRC) beams tested under four-point loading. The results demonstrate the combined use of SCC and steel fibers can improve the shear resistance of reinforced concrete beams, enhance crack control and can promote flexural ductility. Despite extensive research, there is a lack of accurate and reliable design guidelines for the use of SFRC in beams. This study presents a rational model which can accurately predict the shear resistance of steel fiber reinforced concrete beams. The thesis also proposes a safe and reliable equation which can be used for the shear design of SFRC beams.

Design of landfills must consider both stability and integrity of the lining system. Therefore, stresses and strains in both mineral and geosynthetic lining materials must be controlled. Interaction between waste and barrier system is of particular importance for assessing the stability and structural integrity of steep non-self supporting barrier systems. The most appropriate approach to assess the interaction is the use of numerical modelling techniques, and therefore an appropriate constitutive model for waste material is required to represent its mechanical behaviour. In a literature review the key aspects of mechanical behaviour of municipal solid waste (MSW) were investigated, including the influence of compressible and reinforcing particles on compression and shear behaviour of MSW were identified. Constitutive modelling of both MSW and soil material were reviewed, based on which the methodology for this study have been developed. In addition, requirements of an appropriate constitutive model for MSW have been suggested from the numerical modelling experience, and a framework to develop a constitutive model for MSW was produced. A one-dimensional compression model was developed by including the influence of compressible particles on MSW compression behaviour. One-dimensional compression tests on both real and synthetic waste samples were modelled and the results have shown that the compression model can reproduce the measured behaviour. A fibre reinforcing model was developed by including the influence of reinforcing particles on MSW shear behaviour. A triaxial compression test on fibre reinforced sand was modelled and the results have shown that the reinforcing model can predict its shear strength. A constitutive model for MSW has been developed by combining the Modified Cam-Clay with the one-dimensional compression and the fibre reinforcing models. Typical MSW triaxial compression tests have been modelled and the results have shown that the MSW model can reproduce the stress-strain behaviour in specific strain ranges. The constitutive model for MSW has been coded into a non-linear elasto-plastic finite element method program. Comparisons between the finite element analysis results and the analytical solutions have been performed and good agreements have been obtained.

Experiments were conducted to investigate the shear behaviour of large deep beams subjected to uniform load. Six tests were performed on specimens with identical cross sections and reinforcing, but under different loading configurations. Variables included: span, degree of cracking prior to loading, proximity to a disturbed region near a reaction, and type of flexural stress on the loaded face. The findings indicate a specific set of variables resulting in unconservative predictions made using a strut-and-tie model for simply-supported beams subjected to uniform load, confirming and validating recent results by other researchers. A fanning strut model is proposed and is shown to provide more conservative results. The emerging trend of high capacity in continuous uniformly-loaded specimens is supported by the experimental results, as is the high capacity of specimens uniformly-loaded on their flexural tension face. Further, the high strength of specimens with suboptimal crack orientations supports recent experimental work.

Experiments were conducted to investigate the shear behaviour of large deep beams subjected to uniform load. Six tests were performed on specimens with identical cross sections and reinforcing, but under different loading configurations. Variables included: span, degree of cracking prior to loading, proximity to a disturbed region near a reaction, and type of flexural stress on the loaded face. The findings indicate a specific set of variables resulting in unconservative predictions made using a strut-and-tie model for simply-supported beams subjected to uniform load, confirming and validating recent results by other researchers. A fanning strut model is proposed and is shown to provide more conservative results. The emerging trend of high capacity in continuous uniformly-loaded specimens is supported by the experimental results, as is the high capacity of specimens uniformly-loaded on their flexural tension face. Further, the high strength of specimens with suboptimal crack orientations supports recent experimental work.