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The study of the response of tall buildings to wind has become more critical with the increase of super tall buildings in major cities around the world. Outrigger-braced tall building is considered as one of the most popular and efficient tall building design because they are easier to build, save on costs and provide massive lateral stiffness. Most importantly, outrigger-braced structures can strengthen a building without disturbing its aesthetic appearance and this is a significant advantage over other lateral load resisting systems. Therefore this thesis focuses on the optimum design of multi-outriggers in tall buildings, based on the standards set out in the Australian wind code AS/NZS 1170.2. / As taller buildings are built, more outriggers are required. Most of the research to date has included a limited number of outriggers in a building. Some tall buildings require more outriggers especially for those more than 500m building height. Therefore there is a need to develop a design that includes many outriggers (e.g. more than 5). In addition, wind-induced acceleration is not covered in most of the research on outrigger-braced buildings. The adoption of outrigger-braced systems in tall buildings is very common and therefore a discussion of wind-induced acceleration will be included in this thesis. / Most of the current standards allow for the adoption of a triangular load distribution in estimating the wind response of a structure. However, there are only few publications on the utilization of a triangular load distribution to determine the optimum location of a limited number of outriggers. This issue will be addressed in this thesis and will be compared with a uniformly distributed wind load. Further to this, an investigation will be carried out on the factors affecting the efficiency of an outrigger-braced system in terms of the core base bending moment and the total drift reduction. / This thesis principally provides a preliminary guide to assess the performance of outrigger-braced system by estimating the restraining moments at the outrigger locations, core base bending moment, the total building deflection, along-wind and crosswind acceleration of a tall building. While many computer programs can provide accurate results for the above, they are time-consuming to run. For designers working on the preliminary design in the conceptual phase, a quick estimation drawn from a simpler analysis is preferable. Therefore, as an alternative to computer-generated estimations, a methodology for an approximate hand calculation of the wind-induced acceleration in an outrigger-braced structure will be developed.

No description available.

Historicamente os engenheiros desenvolveram técnicas alternativas de análise de estruturas visando facilitar essa parte do processo de projeto que sempre é enjoada. Médio Contínuo (MC) é uma delas cujo emprego é factível em estágios iniciais do projeto. Etapas nas quais é preciso contar com uma ideia mesmo que bastante aproximada das dimensões dos diversos elementos da estrutura. No MC a abordagem da estrutura tridimensional é feita através da consideração das rigidezes planas dos diferentes elementos constituintes. É dizer, aquela rigidez que opõe-se ao carregamento contido no próprio plano do elemento. Os deslocamentos originários de carregamento lateral são obtidos como uma razão força/rigidez. Neste trabalho é abordada a Técnica do Médio Contínuo com carregamento dinâmico originário do sismo, com aplicação específica para os edifícios de certa envergadura, no entanto deixando em aberto uma futura pesquisa para atingir alturas maiores com outros sistemas estruturais além de se abrir um panorama de possibilidades com escopo de refinar este trabalho como a adopção de outro método mais requintado de análise sísmica, tal como a metodologia modal que sem dúvida é mais geral e está sujeita a menores restrições. / Historically, engineers have been developed alternative structural analysis techniques in order of facilitate this part of the design of process which is always difficult. Continuum medious (MC) it´s one theses whose use is feasible in the early stages of the project. Steps in which is necessary have an ideia that even very approximate dimensions of the various elements of the structure. In MC approach , the three dimensional structure is made considering the flat stiffness. That is, a stiffness oppose the load contained in the plane of element itself. The displacements are obtained as a ratio force/stiffness. The work is interesting com dynamical loading originating from the earthquake with specific application to the buildings medium tallest. Howewer futures research to achieve greater heights with other structural systems as well open up a panorama de possibilities with scope to improve this work as the adoption of a more refined method of seismic analysis, such as modal methodology that certainly is more general and is subject to fewer restrictions.

The skyline of many 'world cities' are defined and punctuated by tall buildings. The drivers for such dominant skylines range from land scarcity and social needs; high real estate values; commercial opportunity and corporate demand, through to metropolitan signposting. This fascination with tall buildings started with the patrician families who created the 11th Century skyline of San Gimignano by building seventy tower-houses (some up to 50m tall) as symbols of their wealth and power. This was most famously followed in the late 19th Century with the Manhattan skyline, then Dubai building the world's highest building, then China building some eighty tall buildings completed in the last 5 years, then UK building Europe's highest tower, the Shard and finally back to Dubai, planning a kilometre tall tower, potentially realising Ludwig Mies van der Rohe's 'Impossible Dream' of the 1920's and Frank Lloyd Wright's 1956 'Mile High Illinois'. This ambition to build higher and higher continues to challenge the Architects, Engineers and Builders of tall buildings and is expected to continue into the future. The tall building format is clearly here to stay.

The purpose of this thesis is to create basic design guidance for tall buildings and their aerodynamic modifications as a resource for architects, engineers, developers, and students. It aims to make a contribution to and strengthen particularly the architect&amp / #8217 / s understanding of tall building design, that requires a high level of interdisciplinary approach, by providing a broad overview of the tall building with its general concepts / to demonstrate the importance of human element as a critical component in the design of tall building by clarifying the wind forces and resulting movements which cause discomfort to building occupants and create serious serviceability issues / and to show the significance of aerodynamic modifications as an effective design approach in terms of mitigating wind excitation. In order to achieve these purposes, firstly, a comprehensive literature survey, which includes the definition, emergence and historical background, basic planning and design parameters, and lateral load considerations of tall buildings is presented. Following a structural classification of the tall buildings, wind excitation, its negative effects on occupant comfort and serviceabilty issues, and the methods to control wind excitation are studied. Finally, the significance of aerodynamic modifications against wind excitation, which include modifications of building&amp / #8217 / s cross-sectional shape and its corner geometry, sculptured building tops, horizontal and vertical openings through-building, are presented from the scholarship on this topic.

Historicamente os engenheiros desenvolveram técnicas alternativas de análise de estruturas visando facilitar essa parte do processo de projeto que sempre é enjoada. Médio Contínuo (MC) é uma delas cujo emprego é factível em estágios iniciais do projeto. Etapas nas quais é preciso contar com uma ideia mesmo que bastante aproximada das dimensões dos diversos elementos da estrutura. No MC a abordagem da estrutura tridimensional é feita através da consideração das rigidezes planas dos diferentes elementos constituintes. É dizer, aquela rigidez que opõe-se ao carregamento contido no próprio plano do elemento. Os deslocamentos originários de carregamento lateral são obtidos como uma razão força/rigidez. Neste trabalho é abordada a Técnica do Médio Contínuo com carregamento dinâmico originário do sismo, com aplicação específica para os edifícios de certa envergadura, no entanto deixando em aberto uma futura pesquisa para atingir alturas maiores com outros sistemas estruturais além de se abrir um panorama de possibilidades com escopo de refinar este trabalho como a adopção de outro método mais requintado de análise sísmica, tal como a metodologia modal que sem dúvida é mais geral e está sujeita a menores restrições. / Historically, engineers have been developed alternative structural analysis techniques in order of facilitate this part of the design of process which is always difficult. Continuum medious (MC) it´s one theses whose use is feasible in the early stages of the project. Steps in which is necessary have an ideia that even very approximate dimensions of the various elements of the structure. In MC approach , the three dimensional structure is made considering the flat stiffness. That is, a stiffness oppose the load contained in the plane of element itself. The displacements are obtained as a ratio force/stiffness. The work is interesting com dynamical loading originating from the earthquake with specific application to the buildings medium tallest. Howewer futures research to achieve greater heights with other structural systems as well open up a panorama de possibilities with scope to improve this work as the adoption of a more refined method of seismic analysis, such as modal methodology that certainly is more general and is subject to fewer restrictions.

No description available.

Building engineering is called upon to keep up with the pace and challenges of modern design, which aims not only to build higher and greener, but also to fulfill the demands of the growing population and simple human curiosity. The main purpose of this study was to examine the global behavior of a slender and inclined (V-shaped) 300 m high rise building with different structural systems applied. In order to properly evaluate them, four different parametric studies were conducted. These included determining the appropriate inclination angle and the geometry of a simple beam system and later comparing fourteen different structural systems, namely trusses, diagrids, Tubed Mega Frames and moment frames. Parallel to this, a further investigation was made on a shell and beam element model, in order to assess the simplifications made and to control the obtained results. This study was based on various simulations in Finite Element Analysis programs, primarily ETABS, but also SAP2000 and Autodesk Robot Structural Analysis. The modelling included the definition of geometry and applied loads and results in extracting the desirable forces and deformations. Additionally, the automatic design for structural members was used for the purpose of a comprehensive study of the chosen structural systems. The designed structures were subjected to static analysis (dead, live, wind, seismic load), dynamic analysis (response spectrum and time history function) and nonlinear P-delta effect. A buckling analysis was also performed to determine the modes and associated load factors for buckling. In the end, the structural response in terms of displacement and acceleration was compared. The inclination angle study set the defining angle at 10° from vertical, with respect to the serviceability limit deflection. Comparing alternative truss geometries in a 2D parametric study resulted in the choice of four different systems (X, N, K and W trusses). In the 3D analysis, the chosen truss systems, together with three variations of diagrid systems, and seven Tubed Mega Frames with two moment frame structures were further analyzed. In both groups, the mass and the material of the systems were kept similar and the comparison was basically based on the obtained maximum displacement and natural periods of the buildings. The shell and frame model comparison gave a difference in displacements between 0 and 12%. Finally, the comprehensive study of the Tubed Mega Frame, X truss and diagrid structures showed that these buildings were performing similarly to vertical buildings with a top story displacement within the suggested limits (less than 673 mm). Further investigation should be made concerning the acceleration under synthetic earthquake, which exceeded the suggested norms, as well as the connecting nodes between the trusses and the inclined columns. The outcome of this study implied the possibility of construction and usability of inclined, slender, tall buildings with respect to the Ultimate Limit State and the Service Limit State, as specified in the American standard, ASCE 7-10, and opened new possible issues for further research.

O núcleo resistente, considerado um dos principais elementos componentes dos sistemas estruturais de edifícios de andares múltiplos, quando associado ao sistema de contraventamento, consegue conferir à estrutura um razoável acréscimo de rigidez. O núcleo é ainda o único elemento estrutural capaz de resistir isoladamente a todos os esforços atuantes na estrutura de um edifício, contribuindo na determinação mais precisa dos seus deslocamentos. Baseado nestes fatores, acredita-se que as diferentes modelagens, adotadas para o núcleo, proporcionarão diferentes resultados para a mesma estrutura de contraventamento. Este trabalho tem como principal objetivo analisar a influência que estas modelagens exercem na estrutura de contraventamento. Inicialmente, são apresentadas algumas das modelagens mais utilizadas para o núcleo. Com estas modelagens foram processadas algumas estruturas, e os diversos resultados obtidos utilizados no processo comparativo. Para o processamento foram consideradas análises em teoria de primeira e segunda ordem e, para as fundações, vinculação rígida. Não serão consideradas as deformações por esforço cortante nos elementos. / Resistant cores, are considered one of the principal elements of the structural systems of multistory buildings. When associated to the bracing structure, it gives to the structure a reasonable stiffness increment. The core is still the only structural element capable to resist separately all the efforts in the structure of a building, contributing to a more accurate determination of its displacements. Based on these factors, it is believed that different modeling adopted for the cores will provide different results for the same bracing structure. The main aim of this work is to analyze the influence that these modeling exerts on the bracing structure. First, some of the most used core modeling were presented. Then some structures were processed, using these modeling. The several obtained results were compared. For all the analysis it was considered the first and second order theory and rigid connections for the foundations. Shear deformation were not considered in the elements.