In single storey industrial buildings, the most common material used for the load-bearingsystem is steel. The load bearing system can be designed in different ways. The two mostcommon load-bearing systems of steel industrial buildings are portal frame and thetruss/pillar-system. The benefit of using these systems is the possibility of having largespan structures. These systems have also a high load capacity in function of its weight.Geometrical parameters like width, height, length, and roof slope of the building effectsthe design and the selection of which load-bearing system will be more suitable.The purpose of this thesis is to compare the two systems in terms of weight of steel, priceand global warming potential (GWP) and to see how the load-bearing systems differ. Tofulfil the purpose, it is necessary to find the geometrical parameters to design an optimalportal frame system and use the same parameters in order to design the truss/pillarsystem. By using the same geometrical parameters, the two systems can be comparable.The results of this thesis show that the truss/pillar system has less weight, lower price andlower global warming potential than the portal frame.As conclusions of this parametrical study, it was seen that the truss/pillar system isperforming better than the portal frame system. In general, it is not possible to say that thetruss/pillar-system is better. This is because this thesis work did not consider amongstithers the bracing system, foundation, connections, mounting or fabrication. But it ispossible to say that the differences between the two systems are not major.

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.

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

Submitted by Rodrigo Tumolin Rocha null (digao.rocha@feb.unesp.br) on 2016-09-09T20:48:05Z No. of bitstreams: 1 Tese_FInal.pdf: 13569204 bytes, checksum: 57c9cb53f7d15296a337d3d7544e5191 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-13T13:55:19Z (GMT) No. of bitstreams: 1 tumolinrocha_r_dr_bauru.pdf: 13569204 bytes, checksum: 57c9cb53f7d15296a337d3d7544e5191 (MD5) / Made available in DSpace on 2016-09-13T13:55:19Z (GMT). No. of bitstreams: 1 tumolinrocha_r_dr_bauru.pdf: 13569204 bytes, checksum: 57c9cb53f7d15296a337d3d7544e5191 (MD5) Previous issue date: 2016-08-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Recentemente, o interesse e a pesquisa de coleta de energia têm aumentado substancialmente no meio técnico-científico. Com a grande demanda mundial por energia elétrica, muitos pesquisadores, no Brasil e no Mundo, têm concentrado seus esforços na busca de novas fontes de energia. Além disso, com os avanços da tecnologia, é possível utilizar dispositivos de baixo consumo de energia, que são, na maioria das vezes, alimentados por uma bateria, que são fontes de energia finita havendo a necessidade da recarga ou troca periodicamente, das mesmas. No processo de coleta de energia, a energia elétrica é obtida através da conversão de energia mecânica criada por uma fonte de vibração do meio ambiente através de um transdutor. Entre os mais comuns meios de transdução de energia, o uso de materiais piezoelétricos vêm sendo de grande interesse em meio a coleta de energia devido sua facilidade de aplicação e seu uso para coleta de energia em um amplo intervalo de frequências. Fontes de vibração do meio ambiente podem ser causadas em estruturas através do movimento de veículos, um trêm, ondas do mar e até o deslocamento de pessoas. Com isso, este trabalho tem como objetivo estudar a coleta de energia utilizando uma plataforma aporticada não-linear de dois graus de liberdade contendo um material piezoelétrico não-linear acoplado a uma de suas colunas e excitado externamente em sua base. A plataforma não-linear possui ressonância interna 2:1 entre seus modos de vibrar. A não-linearidade do material é considerada através de uma relação matemática não-linear. Além disso, este trabalho será separado em duas partes para a análise das excitações externas. Em sua primeira parte, considera-se uma força harmonica excitando sua base. Na segunda parte, será considerando um vibrador eletrodinâmico com saída harmônica. A metologia empregada para a realização das análises deste trabalho foram: utilizar o método de múltiplas escalas para buscar as melhores configurações dos parâmetros e encontrar fenômenos devido à ressonancia interna 2:1; em seguida foram realizadas excessivas simulações numéricas utilizando o método de Runge-Kutta de quarta e quinta ordem com passo variável buscando otimizar a coleta de energia através da variação de parâmetros, diagramas de bifurcação, expoente de lyapunov, FFTs e históricos no tempo e outros tipos de simulações. Em geral serão feitas duas comparações muito importantes. A influência da não-linearidade do material piezoelétrico e do uso da força harmonica e do vibrador eletrodinâmico na coleta de energia. Os resultados mostraram grande influência da não-linearidade do material piezoelétrico, e utilizando o vibrador foi possível ter um ganho considerável na estabilidade do sistema. / Recently, the interest and research about energy harvesting has been increasing substantially in the technical-scientific community. With the great world demand for electrical energy, many researchers, in Brazil and in the World, have concentrated their efforts to seek new energy sources. In addition, with the technological advances is possible to use low-power consumption devices, that are, most of time, powered by a battery, which are limited energy sources having the necessity of recharging or substituting them periodically. In the energy harvesting process, the electrical energy is obtained through the conversion of mechanical energy created by a vibrating source in the environment using a transducer. Among the most common energy transduction mean, the use of piezoelectric materials has been of great interest in the energy harvesting matter due to its ease of application and its use to harvest energy in a wide range of frequencies. Vibration sources in the environment may occur in structures by vehicle traffics, a train movement, sea waves and even people. With that, the objective of this work is to study the energy harvesting using a nonlinear two-degrees-of-freedom portal frame platform with a nonlinear piezoelectric material coupled to one of its columns and externally base-excited. The nonlinear platform possesses two-to-one internal resonance between its two vibration modes. The nonlinearities of the piezoelectric material is considered as a nonlinear mathematical relation. Moreover, this work is separated in two parts to the analysis of the external excitations. In the first part, a harmonic force base-exciting the system is considered. In the second part is considered an electro-dynamical shaker with harmonic output. The employed methodology to carry out the analysis of this work was: the application of the method of multiple scales to find the best configuration of the parameters, and to find some kind of phenomena due to the two-to-one internal resonance; in the following were carried out several numerical simulations using the method of Runge-Kutta of 4th and 5th order with variable step seeking to optimize the energy harvesting through parametrical variations, bifurcation diagrams, FFTs, time histories and other typos of simulations. In general, it will be done two much important comparisons: the influence of the nonlinearity of the piezoelectric material and the use of the harmonic force and the shaker to the energy harvesting. The results showed great influence of the nonlinearity of the material, and using the electro-dynamical device it was possible to have a considerably gain in the system stability.

With the development of high-speed railroads the dynamic behaviour of railroad bridges is increasingly important to explore. Deeper knowledge about the influence of different factors and what should be included in a model is essential if the designer shall be able to make reliable estimates of responses in existing and new structures. One factor is the soil-structure interaction (SSI), describing how the foundation of the bridge and the soil properties affect the behavior of the bridge under dynamic loading. In this thesis, the influence of including SSI in a model of a portal frame railway bridge is studied, and an analysis procedure in the frequency domain for models with frequency-dependent boundary conditions is described. A 3D finite element model of an e isting bridge has been built up, based on the theory of linear elasticity. The model has been given three different types of boundary conditions: clamped, static stiffness and frequency-dependent stiffness from SSI. Results from simulated train passages, with a train set consisting of two wagons, were compared for the different boundary conditions. The models have also been compared with measurement data from the bridge, which has given indications about which model describes reality in the best way. The results show that the model in which SSI is included by frequency dependent boundary conditions is in slightly better agreement with measurement data than the clamped model and the model with static stiffness. The model gives a slightly better damping of the free vibrations and the natural frequencies correspond better with experimental data. The difference in maximum acceleration from a train passage is very small between the different models, even if it is found that the clamped model generally has lower accelerations and hence is non-conservative. It appears that the train speed affects the maximum acceleration, the size of the free vibrations and the natural frequencies that are present in the free vibrations in the models. Further studies are suggested where it is emphasized that an analysis with longer trains, which give resonance phenomena, should be made to see how the different eigenfrequencies in the models affect the accelerations at different speeds. It is also noted that more measurements would be needed in order to draw more general conclusions about the degree of correspondence between the measurements and the models, and to calibrate the parameters of the model against measurement data.

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

Nesta tese, apresenta-se a análise numérica e experimental do comportamento dinâmico não linear de um pórtico excitado por uma fonte não ideal - um motor elétrico de corrente contínua desbalanceado - como exemplo dessa classe de problemas. Elabora-se um modelo matemático com quatro graus de liberdade: dois relacionados com o deslocamento horizontal e vertical do ponto de apoio da máquina e dois com os parâmetros de funcionamento do motor elétrico. Adota-se a formulação Lagrangeana para gerar as equações de movimento contendo termos não lineares até ordem cúbica. A solução numérica é obtida através do método de Runge-Kutta com passo adaptativo. Ensaios dinâmicos e estáticos foram realizados com o motor e com o sistema completo, com vistas a validar o modelo matemático. Um sistema de medição digital armazenou todos os dados obtidos em arquivos de fácil leitura pelos programas atualmente disponíveis. Filmagens de alta velocidade e fotografia estroboscópica registraram movimentos típicos relacionados com comportamentos não lineares. Os resultados numéricos e experimentais mostram boa correlação entre si, além de apresentarem alguns dos fenômenos associados ao se forçar uma estrutura a passar por uma de suas ressonâncias excitando-a com um dispositivo com potência limitada, como o efeito Sommerfeld. Outros fenômenos, devido ao comportamento geometricamente não linear da estrutura, são também detectados, tais como saturação modal e transferência de energia. / Numerical and experimental analysis of the nonlinear dynamics of a portal frame excited by a non-ideal source - an unbalanced direct current motor - is presented in this thesis as an example of this class of problems. A four degree of freedom model is elaborated: two of them related to the horizontal and vertical structural displacements and two others to the functioning parameters of the motor. A Lagrangian approach for deducing the equations of motion, up to cubic non-linear terms is followed. The numerical solution is obtained through Runge-Kutta algorithm with adaptive step. Static and dynamic tests were performed with the motor and with the complete system, in order to validate the mathematical model. A digital acquisition system recorded all data in computer files, ready to be read by available commercial programs. High speed filming and stroboscopic photography were used to register typical movements related to nonlinear behavior. Numerical and mathematical results show good correlation, as well as present some phenomena related to passage through resonance with limited power excitation such as the Sommerfeld effect. Some other phenomena, related to the nonlinear behavior of the structure are also detected, as modal saturation and energy transference.

Avanços nas pesquisas em Veículos Agrícolas Autônomos (VAA\'s) e de Robôs Agrícolas Móveis (RAM\'s) têm sido conquistados nos últimos anos. Entretanto, um número limitado de trabalhos foca o desenvolvimento das estruturas destes veículos. O presente trabalho apresenta uma revisão de materiais encontrados na literatura e no mercado. Estudou-se modelagem cinemática de veículos autônomos que possuem configurações de suas estruturas projetadas para ter mobilidade melhorada. Estudaram-se estruturas mecânicas de máquinas que atuam em vários estádios de desenvolvimento de lavouras típicas brasileiras. Baseado no levantamento e esse estudo, foi projetado e construído um veículo com conceito modular e de pórtico para ser uma plataforma robótica no qual é utilizado para o sensoriamento em área agrícola. Uma modelagem cinemática simplificada do veículo foi realizada, fundamentada nos conceitos básicos de cinemáticas em robôs móveis. Por fim é apresentado o desenvolvimento da estrutura em pórtico do veículo. Pretende-se que o resultado auxilie no desenvolvimento de projeto de VAA\'s. / Advance on AAV (Autonomous Agriculture Vehicle) and MAR (Mobile Agriculture Robots) research are noticed in the recent years. However, a limited number of works focus in the structure development of such vehicles. This work introduces a review of the materials found in literature and market. Kinematics models of Autonomous Vehicles that have its structures designed to have mobility improved have been studied. It was studied mechanical structures of machines that act in various stages of typical brazilians crops. Based on this study and survey, a vehicle has been built with a modular concept and portal frame structure format to be used as a robotic platform in which it performs remote sensing in agricultural areas. A simplified Kinematic model have been done using basics concepts of mobile robots kinematics. At the end of this work is presented the portal frame structure development. The results obtained may assist in the design development of AAV\'s.

Avanços nas pesquisas em Veículos Agrícolas Autônomos (VAA\'s) e de Robôs Agrícolas Móveis (RAM\'s) têm sido conquistados nos últimos anos. Entretanto, um número limitado de trabalhos foca o desenvolvimento das estruturas destes veículos. O presente trabalho apresenta uma revisão de materiais encontrados na literatura e no mercado. Estudou-se modelagem cinemática de veículos autônomos que possuem configurações de suas estruturas projetadas para ter mobilidade melhorada. Estudaram-se estruturas mecânicas de máquinas que atuam em vários estádios de desenvolvimento de lavouras típicas brasileiras. Baseado no levantamento e esse estudo, foi projetado e construído um veículo com conceito modular e de pórtico para ser uma plataforma robótica no qual é utilizado para o sensoriamento em área agrícola. Uma modelagem cinemática simplificada do veículo foi realizada, fundamentada nos conceitos básicos de cinemáticas em robôs móveis. Por fim é apresentado o desenvolvimento da estrutura em pórtico do veículo. Pretende-se que o resultado auxilie no desenvolvimento de projeto de VAA\'s. / Advance on AAV (Autonomous Agriculture Vehicle) and MAR (Mobile Agriculture Robots) research are noticed in the recent years. However, a limited number of works focus in the structure development of such vehicles. This work introduces a review of the materials found in literature and market. Kinematics models of Autonomous Vehicles that have its structures designed to have mobility improved have been studied. It was studied mechanical structures of machines that act in various stages of typical brazilians crops. Based on this study and survey, a vehicle has been built with a modular concept and portal frame structure format to be used as a robotic platform in which it performs remote sensing in agricultural areas. A simplified Kinematic model have been done using basics concepts of mobile robots kinematics. At the end of this work is presented the portal frame structure development. The results obtained may assist in the design development of AAV\'s.