Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. / Doubly symmetric I-section columns are often utilised in portal frame construction. The sheeting (or cladding) is carried by sheeting rails connected to the outer flange of these columns. Although it is common practice to include the sheeting rails in the longitudinal bracing system, by connecting the sheeting rail to the cross-bracing, designers must be wary because the connection between column and sheeting rail will not prevent twisting of the columns cross-section. It has been shown ([11], [12], [17]), that by including this eccentric restraint into the bracing of the column, that a torsional-flexural buckling mode of failure can occur when the column is subjected to axial load only. It was seen that this phenomenon is provided for in BS 5950 [18], but is not present in many other design codes of practice, in spite of this phenomenon being relatively well known. In some cases the compression resistance of a column can be significantly reduced when compared to that of a flexural buckled configuration. Previous work performed by Helwig and Yura [15] proposed specific column to sheeting rail connections which would allow for the sheeting rails to be used as elastic torsional braces and effectively rigid lateral braces. However, it is the objective of this investigation to determine if it is possible to include the eccentric sheeting rails into the bracing system, even when using a relatively simple cleat connection with only two bolts onto the sheeting rail. The objective of the research was investigated by conducting experimental tests coupled with a series of detailed finite element analyses. The purpose of the experimental set-up was to investigate the behaviour of a column laterally supported on one flange by a continuous sheeting rail and to compare it to the behaviour of a column laterally supported on both flanges by means of fly-braces (“kneebraces”). The behaviour of the columns, as determined by the experimental tests, was validated by the finite element analyses. The evident conclusion that can be drawn is that, for the case of a continuous sheeting rail, connected to column simply by two bolts and a cleat, that sufficient torsional restraint is provided to the column to prevent torsional-flexural buckling from being critical. This result is helpful, as it means that the buckling capacity of a column can be increased four-fold by enforcing the second flexural buckling mode instead of the first mode through utilising a continuous sheeting rail connected to a cross-bracing system as longitudinal bracing on the columns. This can be achieved without the need to provide any specific detailing to the column to sheeting rail connection. It is however, recommended that further experimental work be conducted on varying lengths of column in order to further validate the results of this work.

Made available in DSpace on 2014-06-11T19:25:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-19Bitstream added on 2014-06-13T19:32:22Z : No. of bitstreams: 1 pinto_el_me_ilha.pdf: 1624906 bytes, checksum: 5bc2d5cfa5a9fecd4b7df0008cf99be3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Fundação de Ensino Pesquisa e Extensão de Ilha Solteira (FEPISA) / O desenvolvimento da presente pesquisa tem a finalidade de estudar um dos efeitos principais de restrição de telhas conectadas nas terças, que é a rigidez ao cisalhamento. O valor da rigidez ao cisalhamento é determinado pela influência da restrição da telha no deslocamento lateral da terça sobre o seu eixo longitudinal, em função do espaçamento dos parafusos de conexão. Para a determinação da rigidez ao cisalhamento foi utilizado um procedimento experimental, semelhante ao modelo numérico, referido como DOUBLE BEAM SHEAR TEST - DBST, que permite avaliar a restrição dada pela telha à terça ao cisalhamento. Para os testes do modelo DBST foi utilizado o Laboratório de Engenharia Civil, onde foram ensaiadas séries desse conjunto para a determinação da rigidez ao cisalhamento. As terças são constituídas de perfil formado a frio. As distâncias entre as terças são compreendidas entre os valores de 1000 a 2300 mm. As telhas são do tipo ondulada com altura de 17 mm e trapezoidal com altura compreendida entre 25 mm e 100 mm. As espessuras das telhas estão entre os valores de 0,43 mm e 0,80 mm. / The development of the present research has the purpose to study one of the main effect of restriction of the sheeting connected in purlin, that it is the rigidity to the shear. The value of the rigidity to the shear is determined by the influence of the restriction of the sheeting in the lateral displacement of purlin on its longitudinal axis, in function of the spacing of the connection screws. For the determination of the rigidity to the shear an experimental procedure was used, similar to the numerical model, related as DOUBLE BEAM SHEAR TEST - DBST, that allows to evaluate the restriction given for the sheeting to purlin to the shear. For the tests of model DBST the Laboratory of Civil Engineering was used, where had been assayed series of this set for the determination of the rigidity to the shear. Purlins are constituted of the cold formed profile. The distances between purlins are understood between the values of 1000 the 2300 mm. The sheeting are of the type wavy with height of 17 mm and trapezoidal with height understood between 25 mm and 100 mm. The thicknesses of the sheeting are between the values of 0,43 mm and 0,80 mm.

Orientador: Renato Bertolino Junior / Banca: José Antonio Matthiesen / Banca: Francisco Carlos Rodrigues / Resumo: O desenvolvimento da presente pesquisa tem a finalidade de estudar um dos efeitos principais de restrição de telhas conectadas nas terças, que é a rigidez ao cisalhamento. O valor da rigidez ao cisalhamento é determinado pela influência da restrição da telha no deslocamento lateral da terça sobre o seu eixo longitudinal, em função do espaçamento dos parafusos de conexão. Para a determinação da rigidez ao cisalhamento foi utilizado um procedimento experimental, semelhante ao modelo numérico, referido como DOUBLE BEAM SHEAR TEST - DBST, que permite avaliar a restrição dada pela telha à terça ao cisalhamento. Para os testes do modelo DBST foi utilizado o Laboratório de Engenharia Civil, onde foram ensaiadas séries desse conjunto para a determinação da rigidez ao cisalhamento. As terças são constituídas de perfil formado a frio. As distâncias entre as terças são compreendidas entre os valores de 1000 a 2300 mm. As telhas são do tipo ondulada com altura de 17 mm e trapezoidal com altura compreendida entre 25 mm e 100 mm. As espessuras das telhas estão entre os valores de 0,43 mm e 0,80 mm. / Abstract: The development of the present research has the purpose to study one of the main effect of restriction of the sheeting connected in purlin, that it is the rigidity to the shear. The value of the rigidity to the shear is determined by the influence of the restriction of the sheeting in the lateral displacement of purlin on its longitudinal axis, in function of the spacing of the connection screws. For the determination of the rigidity to the shear an experimental procedure was used, similar to the numerical model, related as DOUBLE BEAM SHEAR TEST - DBST, that allows to evaluate the restriction given for the sheeting to purlin to the shear. For the tests of model DBST the Laboratory of Civil Engineering was used, where had been assayed series of this set for the determination of the rigidity to the shear. Purlins are constituted of the cold formed profile. The distances between purlins are understood between the values of 1000 the 2300 mm. The sheeting are of the type wavy with height of 17 mm and trapezoidal with height understood between 25 mm and 100 mm. The thicknesses of the sheeting are between the values of 0,43 mm and 0,80 mm. / Mestre

A three-dimensional finite element model is developed, validated and used in the parametric study to investigate the influence of shear stud's position and profiled sheeting thickness on the strength, ductility and failure modes of the headed shear stud welded to the modern profiled sheeting. A total of 240 push tests were analysed with different sheeting thicknesses, positions of the shear stud in the trough, concrete strengths and transverse spacings. The results showed that the sheeting thickness influenced the shear connector resistance of studs placed in the unfavourable position more than studs placed in favourable and central positions. The strength of the shear connector placed in the unfavourable position increased by as much as 30% when the sheeting thickness was increased. The shear connector resistance of the unfavourable stud was found to be primarily a function of the strength and the thickness of the profiled sheeting rather than the concrete strength. The strength prediction equations for unfavourable and central studs were also proposed. The results suggested that the strength of the shear connector increased as the distance of the shear stud increased from the mid-height of the deck rib in the load bearing direction of the stud. The load¿slip behaviour of the studs in the unfavourable position was more ductile than the studs in the favourable position, with slip of 2-4 times higher. It was found that the increase in sheeting thickness and transverse spacing improved the ductility of the stud in unfavourable position, but had no effect on the stud in the favourable position. The failure modes suggested that the favourable and central studs failed by concrete cone failure and unfavourable studs failed by rib punching together with crushing of the narrow strip of the concrete in front of the stud.

Nos últimos anos tem sido observada uma significativa redução do uso das telhas pesadas nas edificações industriais, como as telhas de fibrocimento, por exemplo, e a preferência por telhas mais leves e que permitem maior racionalização da construção, como as telhas metálicas (aço zincado e alumínio). Assim, a fixação por meio de ganchos foi naturalmente sendo substituída por parafusos auto-atarraxantes, permitindo uma elevada eficiência estrutural da interação terça-telha, portanto, as terças que eram tratadas como elementos estruturais independentes passaram a ser projetadas com base no comportamento conjunto com as telhas. Diante disso, este trabalho apresenta um estudo sobre o comportamento estrutural de terças de aço considerando a interação terça-telha, com ênfase na distorção lateral. Para tanto, são analisados os modelos teóricos encontrados na literatura e os procedimentos normativos, bem como são desenvolvidas análises numéricas de sistemas representativos de coberturas, via método dos elementos finitos (MEF), que incluem os efeitos da não-linearidade física e geométrica. Através destes modelos numéricos, validados por resultados experimentais de ensaios realizados na EESC-USP, é realizada uma avaliação da influência da rigidez à flexão da terça, da conexão telha-terça, do tipo de seção da terça e da presença e posicionamento de tirantes de travamento lateral das terças. Neste contexto, concluiu-se que as telhas, desde que fixadas adequadamente as terças, contribuem para a estabilidade lateral, impondo mecanismos de falha que diferem substancialmente dos mecanismos clássicos da teoria da estabilidade elástica. / Recent years have seen a significant reduction in the use of heavy sheeting such as fiber cement roof sheets in industrial buildings, and an increasing preference for lighter sheeting that allows for greater rationalization of the construction, such as metallic sheeting (zinc-coated and aluminum). Thus, fixing by means of hooks was naturally replaced by screws, allowing for high structural efficiency of the purlin-sheeting combination, and purlins, which heretofore had been treated as independent structural elements, began to be designed based on their combined behavior with sheeting. This paper discusses the findings of a comprehensive on the structural behaviour of steel purlins under wind uplift considering the purlin-sheeting combination, with emphasis on lateral distortional. To this end, an analysis is made of the theoretical models available in the literature and in standard procedures, and systems representative of roofs are analyzed numerically via the finite elements method (FEM), including the effects of physical and geometrical nonlinearity. Based on these numerical models, which are validated by the experimental results of tests conducted at School of Engineering of São Carlos - University of São Paulo, an evaluation is made of the influence of the purlin\'s flexural stiffness, the sheeting-purlin connection, the type of purlin section (channel and Z-sections), and the number of rows of bridging (bracing). In this context, it was concluded that sheeting, provided it is properly fixed to the purlins, contributes toward lateral stability, imposing failure modes that differ considerably from the classic mechanisms of the theory of elastic stability.

Terças e longarinas metálicas são geralmente projetadas no Brasil desconsiderando a interação com as telhas, ou seja, como barras isoladas, apesar da norma brasileira NBR 14762:2001 apresentar um procedimento de cálculo que leva em consideração tal interação (método do fator R). O comportamento estrutural do sistema terça-telha é complexo e a análise completa deve considerar a não-linearidade geométrica e física, bem como a influência do contato e da conexão terça-telha. Foram analisados modelos numéricos propostos na literatura e desenvolvido um modelo via método dos elementos finitos (MEF) que incorpora as não-linearidades e o contato terça-telha. O modelo foi calibrado com resultados experimentais e posteriormente foi realizada uma análise paramétrica, a qual permitiu gerar expressões que relacionam a força (vento de sucção) com os deslocamentos. Foi também analisada a viabilidade da aplicação do método da resistência direta (MRD) ao dimensionamento de terças restringidas pela telha, empregando o método das faixas finitas (MFF) para a análise de estabilidade elástica, em que a restrição promovida pela telha foi modelada por meio de vínculos elásticos na mesa conectada com a telha. Foram considerados dois casos de distribuição de tensões normais: (i) tensões oriundas somente da flexão e (ii) tensões oriundas da flexão e torção. Em ambos os casos o momento resistente apresentou diferenças relativamente elevadas em relação ao obtido pelo método do fator R, refletindo a necessidade de uma abordagem específica do método para o sistema terça-telha. / The structural behavior of purlin-sheeting system is complex and the complete analysis should consider the physical and geometrical nonlinearity, as well as the influence of the purlin-sheeting contact and connection. The brazilian code NBR 14762:2001 provides a design procedure to consider the interaction between a purlin or girt connected to the sheeting (factor R method). In Brazil purlins and girts are typically designed as isolated beams, without consideration for this purlin-sheeting combination. Numerical models proposed in the literature were analyzed and a finite element model (FEM) was developed considering nonlinearities and the contact between purlin and sheeting. The model was validated through experimental results and then implemented in a parametrical analysis. Expressions were generated using the parametrical results to relate the loading (wind uplift) to the displacements. The direct strength method (DSM) was analyzed to the designed of purlins restrained by sheeting. The finite strip method (FSM) was used for elastic buckling determination. The restraint applied to the sheeting was modeled using an elastic foundation on the flange connected to the sheeting. Two stress distributions were considered: (i) bending stresses and (ii) bending and warping stresses. In both cases the nominal flexural strength presented considerable differences compared to the factor R design method, reflecting the necessity of a specific study to evaluate the viability of the DSM approach for purlin design.

Terças e longarinas metálicas são geralmente projetadas no Brasil desconsiderando a interação com as telhas, ou seja, como barras isoladas, apesar da norma brasileira NBR 14762:2001 apresentar um procedimento de cálculo que leva em consideração tal interação (método do fator R). O comportamento estrutural do sistema terça-telha é complexo e a análise completa deve considerar a não-linearidade geométrica e física, bem como a influência do contato e da conexão terça-telha. Foram analisados modelos numéricos propostos na literatura e desenvolvido um modelo via método dos elementos finitos (MEF) que incorpora as não-linearidades e o contato terça-telha. O modelo foi calibrado com resultados experimentais e posteriormente foi realizada uma análise paramétrica, a qual permitiu gerar expressões que relacionam a força (vento de sucção) com os deslocamentos. Foi também analisada a viabilidade da aplicação do método da resistência direta (MRD) ao dimensionamento de terças restringidas pela telha, empregando o método das faixas finitas (MFF) para a análise de estabilidade elástica, em que a restrição promovida pela telha foi modelada por meio de vínculos elásticos na mesa conectada com a telha. Foram considerados dois casos de distribuição de tensões normais: (i) tensões oriundas somente da flexão e (ii) tensões oriundas da flexão e torção. Em ambos os casos o momento resistente apresentou diferenças relativamente elevadas em relação ao obtido pelo método do fator R, refletindo a necessidade de uma abordagem específica do método para o sistema terça-telha. / The structural behavior of purlin-sheeting system is complex and the complete analysis should consider the physical and geometrical nonlinearity, as well as the influence of the purlin-sheeting contact and connection. The brazilian code NBR 14762:2001 provides a design procedure to consider the interaction between a purlin or girt connected to the sheeting (factor R method). In Brazil purlins and girts are typically designed as isolated beams, without consideration for this purlin-sheeting combination. Numerical models proposed in the literature were analyzed and a finite element model (FEM) was developed considering nonlinearities and the contact between purlin and sheeting. The model was validated through experimental results and then implemented in a parametrical analysis. Expressions were generated using the parametrical results to relate the loading (wind uplift) to the displacements. The direct strength method (DSM) was analyzed to the designed of purlins restrained by sheeting. The finite strip method (FSM) was used for elastic buckling determination. The restraint applied to the sheeting was modeled using an elastic foundation on the flange connected to the sheeting. Two stress distributions were considered: (i) bending stresses and (ii) bending and warping stresses. In both cases the nominal flexural strength presented considerable differences compared to the factor R design method, reflecting the necessity of a specific study to evaluate the viability of the DSM approach for purlin design.

Nos últimos anos tem sido observada uma significativa redução do uso das telhas pesadas nas edificações industriais, como as telhas de fibrocimento, por exemplo, e a preferência por telhas mais leves e que permitem maior racionalização da construção, como as telhas metálicas (aço zincado e alumínio). Assim, a fixação por meio de ganchos foi naturalmente sendo substituída por parafusos auto-atarraxantes, permitindo uma elevada eficiência estrutural da interação terça-telha, portanto, as terças que eram tratadas como elementos estruturais independentes passaram a ser projetadas com base no comportamento conjunto com as telhas. Diante disso, este trabalho apresenta um estudo sobre o comportamento estrutural de terças de aço considerando a interação terça-telha, com ênfase na distorção lateral. Para tanto, são analisados os modelos teóricos encontrados na literatura e os procedimentos normativos, bem como são desenvolvidas análises numéricas de sistemas representativos de coberturas, via método dos elementos finitos (MEF), que incluem os efeitos da não-linearidade física e geométrica. Através destes modelos numéricos, validados por resultados experimentais de ensaios realizados na EESC-USP, é realizada uma avaliação da influência da rigidez à flexão da terça, da conexão telha-terça, do tipo de seção da terça e da presença e posicionamento de tirantes de travamento lateral das terças. Neste contexto, concluiu-se que as telhas, desde que fixadas adequadamente as terças, contribuem para a estabilidade lateral, impondo mecanismos de falha que diferem substancialmente dos mecanismos clássicos da teoria da estabilidade elástica. / Recent years have seen a significant reduction in the use of heavy sheeting such as fiber cement roof sheets in industrial buildings, and an increasing preference for lighter sheeting that allows for greater rationalization of the construction, such as metallic sheeting (zinc-coated and aluminum). Thus, fixing by means of hooks was naturally replaced by screws, allowing for high structural efficiency of the purlin-sheeting combination, and purlins, which heretofore had been treated as independent structural elements, began to be designed based on their combined behavior with sheeting. This paper discusses the findings of a comprehensive on the structural behaviour of steel purlins under wind uplift considering the purlin-sheeting combination, with emphasis on lateral distortional. To this end, an analysis is made of the theoretical models available in the literature and in standard procedures, and systems representative of roofs are analyzed numerically via the finite elements method (FEM), including the effects of physical and geometrical nonlinearity. Based on these numerical models, which are validated by the experimental results of tests conducted at School of Engineering of São Carlos - University of São Paulo, an evaluation is made of the influence of the purlin\'s flexural stiffness, the sheeting-purlin connection, the type of purlin section (channel and Z-sections), and the number of rows of bridging (bracing). In this context, it was concluded that sheeting, provided it is properly fixed to the purlins, contributes toward lateral stability, imposing failure modes that differ considerably from the classic mechanisms of the theory of elastic stability.

This thesis deals with the foundation of multifunctional building in Karlovy Vary. The aim of this thesis is to design a safe, economical and functional solutions for sheeting underground floors of the building and design of foundation structures.

The diploma thesis deals with foundations of a new learning and research center of the Charles University. Goal is economical and secure design of geotechnical structures. In this thesis, has been used less known technology of deep foundations. The author points to the diversity of utilization, such as sealing wall, anchored and unanchored sheeting, columns designed to influence tension and pressure. For the static calculation have been used programs Scia Engineer and Geo5 v19. Part of this thesis the technological process of technology of the soil improvement by DSM.