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Analytical Model for Lateral Deflection in Cold-formed Steel Framed Shear Walls with Steel SheathingYousof, Mohamad 12 1900 (has links)
An analytical model for lateral deflection in cold-formed steel shear walls sheathed with steel is developed in this research. The model is based on the four factors: fastener displacement, steel sheet deformation, and hold-down deformation, which are from the effective strip concept and a complexity factor, which accounts for the additional influential factors not considered in the previous three terms. The model uses design equations based on the actual material and mechanical properties of the shear wall. Furthermore, the model accounts for aggressive and conservative designers by predicting deflection at different shear strength degrees.
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Shear and Bending Strength of Cold-Formed Steel Solid Wall Panels Using Corrugated Steel Sheets for Mobile SheltersDerrick, Nathan Lynn 12 1900 (has links)
The objective of this thesis is to determine if the single sided resistance spot weld (RSW) can be used as a feasible connection method for cold formed steel (CFS) shear walls subject to lateral force of either seismic or wind loads on mobile shelters. The research consisted of three phases which include: a design as a 3D BIM model, connection tests of the resistance spot weld, and full-scale testing of the designed solid wall panels. The shear wall testing was conducted on specimens with both resistance spot weld and self-drilling screws and the results from tests gave a direct comparison of these connections when the solid wall panel was subjected to in-plane shear forces. The full-scale tests also included 4-point bending tests which was designed to investigate the wall panel's resistance to the lateral loads applied perpendicularly to the surface. The research discovered that the singled sided resistance spot weld achieved similar performance as the self-drilling screws in the applications of CFS wall panels for mobile shelters. The proposed single sided resistance spot weld has advantages of low cost, no added weight, fast fabrication, and it is a feasible connection method for CFS wall panels.
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A Comprehensive Embodied Energy Analysis FrameworkTreloar, Graham John, kimg@deakin.edu.au,jillj@deakin.edu.au,mikewood@deakin.edu.au,wildol@deakin.edu.au January 1998 (has links)
The assessment of the direct and indirect requirements for energy is known as embodied energy analysis. For buildings, the direct energy includes that used primarily on site, while the indirect energy includes primarily the energy required for the manufacture of building materials. This thesis is concerned with the completeness and reliability of embodied energy analysis methods. Previous methods tend to address either one of these issues, but not both at the same time. Industry-based methods are incomplete. National statistical methods, while comprehensive, are a black box and are subject to errors. A new hybrid embodied energy analysis method is derived to optimise the benefits of previous methods while minimising their flaws.
In industry-based studies, known as process analyses, the energy embodied in a product is traced laboriously upstream by examining the inputs to each preceding process towards raw materials. Process analyses can be significantly incomplete, due to increasing complexity. The other major embodied energy analysis method, input-output analysis, comprises the use of national statistics. While the input-output framework is comprehensive, many inherent assumptions make the results unreliable.
Hybrid analysis methods involve the combination of the two major embodied energy analysis methods discussed above, either based on process analysis or input-output analysis. The intention in both hybrid analysis methods is to reduce errors associated with the two major methods on which they are based. However, the problems inherent to each of the original methods tend to remain, to some degree, in the associated hybrid versions.
Process-based hybrid analyses tend to be incomplete, due to the exclusions associated with the process analysis framework. However, input-output-based hybrid analyses tend to be unreliable because the substitution of process analysis data into the input-output framework causes unwanted indirect effects.
A key deficiency in previous input-output-based hybrid analysis methods is that the input-output model is a black box, since important flows of goods and services with respect to the embodied energy of a sector cannot be readily identified. A new input-output-based hybrid analysis method was therefore developed, requiring the decomposition of the input-output model into mutually exclusive components (ie, direct energy paths).
A direct energy path represents a discrete energy requirement, possibly occurring one or more transactions upstream from the process under consideration. For example, the energy required directly to manufacture the steel used in the construction of a building would represent a direct energy path of one non-energy transaction in length. A direct energy path comprises a product quantity (for example, the total tonnes of cement used) and a direct energy intensity (for example, the energy required directly for cement manufacture, per tonne).
The input-output model was decomposed into direct energy paths for the residential building construction sector. It was shown that 592 direct energy paths were required to describe 90% of the overall total energy intensity for residential building construction. By extracting direct energy paths using yet smaller threshold values, they were shown to be mutually exclusive. Consequently, the modification of direct energy paths using process analysis data does not cause unwanted indirect effects.
A non-standard individual residential building was then selected to demonstrate the benefits of the new input-output-based hybrid analysis method in cases where the products of a sector may not be similar. Particular direct energy paths were modified with case specific process analysis data. Product quantities and direct energy intensities were derived and used to modify some of the direct energy paths. The intention of this demonstration was to determine whether 90% of the total embodied energy calculated for the building could comprise the process analysis data normally collected for the building. However, it was found that only 51% of the total comprised normally collected process analysis. The integration of process analysis data with 90% of the direct energy paths by value was unsuccessful because:
typically only one of the direct energy path components was modified using process analysis data (ie, either the product quantity or the direct energy intensity);
of the complexity of the paths derived for residential building construction; and
of the lack of reliable and consistent process analysis data from industry, for both product quantities and direct energy intensities.
While the input-output model used was the best available for Australia, many errors were likely to be carried through to the direct energy paths for residential building construction. Consequently, both the value and relative importance of the direct energy paths for residential building construction were generally found to be a poor model for the demonstration building. This was expected. Nevertheless, in the absence of better data from industry, the input-output data is likely to remain the most appropriate for completing the framework of embodied energy analyses of many types of productseven in non-standard cases.
Residential building construction was one of the 22 most complex Australian economic sectors (ie, comprising those requiring between 592 and 3215 direct energy paths to describe 90% of their total energy intensities). Consequently, for the other 87 non-energy sectors of the Australian economy, the input-output-based hybrid analysis method is likely to produce more reliable results than those calculated for the demonstration building using the direct energy paths for residential building construction.
For more complex sectors than residential building construction, the new input-output-based hybrid analysis method derived here allows available process analysis data to be integrated with the input-output data in a comprehensive framework. The proportion of the result comprising the more reliable process analysis data can be calculated and used as a measure of the reliability of the result for that product or part of the product being analysed (for example, a building material or component).
To ensure that future applications of the new input-output-based hybrid analysis method produce reliable results, new sources of process analysis data are required, including for such processes as services (for example, banking) and processes involving the transformation of basic materials into complex products (for example, steel and copper into an electric motor).
However, even considering the limitations of the demonstration described above, the new input-output-based hybrid analysis method developed achieved the aim of the thesis: to develop a new embodied energy analysis method that allows reliable process analysis data to be integrated into the comprehensive, yet unreliable, input-output framework.
Plain language summary
Embodied energy analysis comprises the assessment of the direct and indirect energy requirements associated with a process. For example, the construction of a building requires the manufacture of steel structural members, and thus indirectly requires the energy used directly and indirectly in their manufacture. Embodied energy is an important measure of ecological sustainability because energy is used in virtually every human activity and many of these activities are interrelated.
This thesis is concerned with the relationship between the completeness of embodied energy analysis methods and their reliability. However, previous industry-based methods, while reliable, are incomplete. Previous national statistical methods, while comprehensive, are a black box subject to errors.
A new method is derived, involving the decomposition of the comprehensive national statistical model into components that can be modified discretely using the more reliable industry data, and is demonstrated for an individual building. The demonstration failed to integrate enough industry data into the national statistical model, due to the unexpected complexity of the national statistical data and the lack of available industry data regarding energy and non-energy product requirements.
These unique findings highlight the flaws in previous methods. Reliable process analysis and input-output data are required, particularly for those processes that were unable to be examined in the demonstration of the new embodied energy analysis method. This includes the energy requirements of services sectors, such as banking, and processes involving the transformation of basic materials into complex products, such as refrigerators. The application of the new method to less complex products, such as individual building materials or components, is likely to be more successful than to the residential building demonstration.
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Modelagem numérica de ligações viga-coluna em aço sob momento fletor e força normal. / Numerical modeling of steel beam-to-column joints subjected to bending and normal force.Monique Cordeiro Rodrigues 14 August 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As ligações desempenham um papel fundamental no comportamento global das estruturas de aço. Inúmeros trabalhos de pesquisa têm sido desenvolvidos para entender o comportamento real de uma ligação e sua influência na resistência global dos pórticos. Atualmente, a Norma Brasileira de estruturas de aço de edificações, NBR 8800, considera o comportamento das ligações entre duas situações extremas: rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferindo momento fletor, força cortante e força normal; ou flexíveis, caracterizadas pela liberdade de rotação entre os membros conectados, impedindo a transmissão de momento fletor. Outras normas de projeto de estruturas de aço, consideram que as ligações apresentam um comportamento intermediário, ou seja, semi-rigídas, que podem estar submetidas a uma combinação de momento fletor e esforço normal. Porém, mesmo com a combinação, estas normas não consideram a presença de esforço normal (tração e/ou compressão). Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. Para o estudo da ligação semi-rigída será utilizada a filosofia do Método das Componentes, que verifica a resistência da ligação e sua classificação quanto à rigidez rotacional, desenvolvida através de modelos mecânicos (modelos de molas). O objetivo deste trabalho é descrever alguns resultados de caracterização de ligações viga-coluna com placa de extremidade ajustada à altura da viga obtidos através de um modelo de elementos finitos. Para tal, será realizada uma análise não-linear geométrica e de material. Esta análise possibilitará avaliar os principais parâmetros que influenciam no comportamento deste componente no que diz respeito a sua avaliação em termos de distribuição de tensões e deformações no modelo de forma global. / The joints develop a fundamental role in the global behaviour of steel structures. Several researches are being developed to understand the real behaviour of a joint and its influence in the global frame capacity and beam-to-column joints of the steels buildings. Nowadays, the Brazilian Code of the Steel Portal Frame Design, NBR 8800, considers the joint behaviour between two extreme situations: rigid, where any rotations dont occur between the connected members, transfering substantial bending moments, and also shear and axial forces; or pinned, its characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. However, some actual codes of the steel structures project, consider that the joints present an intermediate behaviour, in other words, semi-rigid, that may be subjected to a combination of bending moment and axial force. But, these codes dont consider the presence of axial force (tension and/ or compression). A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. This filosofy design is based on components method, for joint capacity evaluation and its classification concerning the joint rotation stiffness. This component method is based on mechanical models (spring model) created by an association of rigids and flexible joints components represented by a translacional spring. The objective of this present work is describing some results of flush endplate semi-rigids beam-to-column joints obtained across finite elements method and geometric and material non-linear analises. These consider the main parameters that influence the components behaviour about the stress and deformation distribution.
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Modelagem numérica de ligações viga-coluna em aço sob momento fletor e força normal. / Numerical modeling of steel beam-to-column joints subjected to bending and normal force.Monique Cordeiro Rodrigues 14 August 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As ligações desempenham um papel fundamental no comportamento global das estruturas de aço. Inúmeros trabalhos de pesquisa têm sido desenvolvidos para entender o comportamento real de uma ligação e sua influência na resistência global dos pórticos. Atualmente, a Norma Brasileira de estruturas de aço de edificações, NBR 8800, considera o comportamento das ligações entre duas situações extremas: rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferindo momento fletor, força cortante e força normal; ou flexíveis, caracterizadas pela liberdade de rotação entre os membros conectados, impedindo a transmissão de momento fletor. Outras normas de projeto de estruturas de aço, consideram que as ligações apresentam um comportamento intermediário, ou seja, semi-rigídas, que podem estar submetidas a uma combinação de momento fletor e esforço normal. Porém, mesmo com a combinação, estas normas não consideram a presença de esforço normal (tração e/ou compressão). Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. Para o estudo da ligação semi-rigída será utilizada a filosofia do Método das Componentes, que verifica a resistência da ligação e sua classificação quanto à rigidez rotacional, desenvolvida através de modelos mecânicos (modelos de molas). O objetivo deste trabalho é descrever alguns resultados de caracterização de ligações viga-coluna com placa de extremidade ajustada à altura da viga obtidos através de um modelo de elementos finitos. Para tal, será realizada uma análise não-linear geométrica e de material. Esta análise possibilitará avaliar os principais parâmetros que influenciam no comportamento deste componente no que diz respeito a sua avaliação em termos de distribuição de tensões e deformações no modelo de forma global. / The joints develop a fundamental role in the global behaviour of steel structures. Several researches are being developed to understand the real behaviour of a joint and its influence in the global frame capacity and beam-to-column joints of the steels buildings. Nowadays, the Brazilian Code of the Steel Portal Frame Design, NBR 8800, considers the joint behaviour between two extreme situations: rigid, where any rotations dont occur between the connected members, transfering substantial bending moments, and also shear and axial forces; or pinned, its characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. However, some actual codes of the steel structures project, consider that the joints present an intermediate behaviour, in other words, semi-rigid, that may be subjected to a combination of bending moment and axial force. But, these codes dont consider the presence of axial force (tension and/ or compression). A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. This filosofy design is based on components method, for joint capacity evaluation and its classification concerning the joint rotation stiffness. This component method is based on mechanical models (spring model) created by an association of rigids and flexible joints components represented by a translacional spring. The objective of this present work is describing some results of flush endplate semi-rigids beam-to-column joints obtained across finite elements method and geometric and material non-linear analises. These consider the main parameters that influence the components behaviour about the stress and deformation distribution.
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Análise térmica de estruturas de aço utilizadas no sistema light steel framing / Thermal analysis of light steel framing structuresTorres Filho, Rodrigo José de Almeida 18 April 2017 (has links)
O presente trabalho apresenta uma análise numérica do desempenho térmico de painéis construídos utilizando o sistema light steel framing (LSF) submetido a ação térmica decorrente de um incêndio. O objeto de estudo foram painéis utilizados na construção de duas casas modelo localizadas na Universidade Tecnológica Federal do Paraná campus Curitiba, construídas com materiais disponíveis comercialmente no Brasil e as análises utilizaram propriedades disponibilizadas pelos fabricantes e pela norma brasileira. A análise numérica foi realizada no software ANSYS, com base no método dos elementos finitos em análise térmica transiente. O modelo foi validado com base em comparação com análises experimentais pesquisadas na literatura. Quatro painéis obtidos das casas modelo foram analisados. Os painéis que utilizaram lã de PET para preenchimento da cavidade foram também analisados com preenchimento de lã de vidro. Um painel simples, com a cavidade preenchida por ar foi analisado para ser usado como referência. Por fim, com a utilização de coeficientes de redução da resistência ao escoamento propostos pela ABNT NBR 14323:2001, determinou-se a redução da resistência do aço do perfil de acordo com o tempo de exposição ao incendio e o tempo de resistência ao fogo dos perfis. Com base nos resultados obtidos é possível afirmar que mesmo para os paneis com pior desempenho, a proteção obtida pode ser suficiente, a depender do carregamento aplicado ao montante e do Tempo requerido de resistência ao fogo necessário. O presente trabalho apresenta informação relevante sobre o desempenho térmico em situação de incêndio do sistema LSF constituído com materiais brasileiros. / The thermal performance of light steel framing (LSF) panels was the objective of this study. The study subject was panels used in the construction of two model houses located at Federal Technology University – Parana, built with materials commercially available in Brazil. The analysis was set with material properties from the manufacturer and in compliance with the Brazilian regulation, using the finite element method for a transient thermal analysis. The model validation was based on experimental tests available in the literature. Based on the validated model, the four panels have been analyzed. Two of the panels used PET wool in the cavity for insulation and the analysis was repeated with them replacing it for glass wool. A panel with no insulation was also analyzed to be used as reference. Based on the analysis results and the resistance reduction coefficients proposed by ABNT NBR 14323:2001, the resistance decrease of the studs due to the fire exposure and the panels resistance to fire were determined. Based on the obtained results, it can be affirmed that, depending on the applied load and the required Equivalent time of fire exposure, even the less protective configuration of the panels presented can be viable. The current study presented relevant information about the performance of LSF manufactured in Brazil when exposed to fire.
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Vyhlídková věž v Beskydech / Viewing tower in BeskydyPojezný, Tomáš January 2014 (has links)
This work contains structural design and static assessment of the viewing tower in Beskydy. Construction is shaped like fir cone and it is made from glued laminated profiles and steel square tubes. Joints are realized from steel structural elements. Ground plan is regular octagon with external diameter changeable from 7,3 m to 9,3 m. Tower has five viewing platforms. Total height of construction is 27,5 m. For designed structure is made detailed static assessment and drawing documentation.
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