Este trabalho aborda ligações semi-rígidas com o objetivo de verificar a influência da flexibilidade na análise de estruturas metálicas, com o propósito de apresentar um modelo que represente o real comportamento das conexões assumindo uma situação intermediária entre totalmente rígida e totalmente flexível. Os procedimentos empregados para determinar as propriedades destas conexões estão embasados nos métodos descritos pelo anexo J do Eurocode 3 e recomendações do BCSA/SCI. Com intuito de automatizar o cálculo das conexões semi-rígidas foi implementado um programa computacional que fornece as propriedades necessárias das ligações entre vigas e pilares através da entrada de dados geométricos e especificações do material empregado. São abordadas ligações soldadas e ligações parafusadas com chapa de extremidade.O trabalho apresenta, ainda, uma avaliação da redistribuição de solicitações nas estruturas de aço. Fazendo a análise de um pórtico plano empregando molas rotacionais nos nós de encontro entre vigas e pilares inserindo a rigidez rotacional obtida através dos procedimentos numéricos apresentados neste trabalho. Esta mesma estrutura foi analisada da maneira tradicional, ou seja, considerando nós rígidos no encontro entre vigas e pilares. Através da analogia entre os resultados obtidos pelas duas análises é possível visualizar a diferença entre a distribuição nas solicitações. Dessa forma, é possível verificar a influência da rigidez das ligações na análise das estruturas metálicas. / This work approaches semi-rigid connections with the purpose to verify the influence of connections in the analysis of steel structures, with the intention to present a model that represents the real behavior of the connections assuming an intermediate situation between totally rigid and totally pinned. The used procedures to determine the properties of these connections are based in the described methods for the Annex J of the Eurocode 3 and BCSA/SCI. With intention to speed the calculations of the semi-rigid connections a computational program was implemented that supplies to the necessary properties of the connections between beams and columns through the geometric data entry and specifications of the employed material. They are boarded welded connections and connections bolted with extend end plate. The work presents, still, an evaluation of the new distribution of loads in the steel structures. Making the analysis of a plain frame using rotational springs between beams and columns inserting the gotten rotational rigidity through the presented numerical procedures in this work. This same structure was analyzed in the traditional way, that is, considering rigid we in the meeting between beams and columns. Through the analogy it enters the results gotten for the two analyses is possible to visualize the difference enters the distribution in the requests. Of this form, it is possible to verify the influence of flexibility in the analysis of the metallic structures.

Master of Science / Department of Architectural Engineering / Kimberly W. Kramer / In structural steel connection design, simple shear connections are one of the most common connection types utilized. The industry, especially from the side of the engineer, tends to lean toward using Double Clip Angle Connections as the default standard for simple shear connections. A double clip angle connection is a connection consisting of two angles transferring the shear forces from one member to the next either through bolts or welds. The design of Double Clip Angle Connections is efficient and the connections themselves are easy to fabricate. However, benefits to utilizing other types of shear connections exist. Many of these benefits are seen in the fabrication shop or during erection and construction. This is especially true of single shear plate or shear tab connections when applied to open structure design. Shear tab connections consist of a single plate that transfers the shear forces from one member to the next with bolts or with welds. The design of shear tab connections can be a more involved process than the design of double clip angles. Sometimes the shear plate or shear tab has to be longer than is typical. This is called an extended shear plate connection. These extended shear plates can bring other variables into the design that typically don’t occur with Double Clip Angle Connections such as bending of the plate or the need for multiple bolt columns. However, with proper planning and detailing, the benefits and savings experienced in the fabrication or construction phase may outweigh what can be seen as a more laborious design task. The purpose of this report is to identify the possible benefits achieved in using each of these connections, highlight the differences in the design approach for each, and use a study model to compare the outcome of using one connection over another in the design of a typical open structure. Double clip angles are typically the most efficient approach when speed of design and simplicity of fabrication are the desired outcomes. However, shear plate or shear tab connections have the potential to provide safer erection alternatives and materials savings if used in appropriate ways and with the right applications.

Este trabalho apresenta resultados teóricos e experimentais sobre o comportamento estrutural de ligações parafusadas viga-coluna com chapa de topo. São estudados dois tradicionais métodos de dimensionamento e as ligações são analisadas numericamente, via método dos estados limites. Os resultados são comparados com os obtidos através de ensaios de 35 protótipos, nos quais variou-se, alternadamente, a espessura da chapa de topo e o diâmetro dos parafusos. Discute-se, em particular, a influência destes parâmetros no comportamento momento-rotação das ligações com chapa de topo e, ao final, apresentam-se as conclusões pertinentes e recomendações para o prosseguimento dos estudos. / This work presents the theoretical and experimental results on the structural behavior of bolted end plate connections. They are designed by two traditional methods and analyzed by the finite element method. Comparisons are made between the FEM results and those obtained by an experimental analysis on 35 cruciform welded profile models, in which end plate thickness and bolt diameter was alternately varied. Special attention is paid for evaluating the influence of these parameters in the moment rotation behavior of the connections. Finally, the remarks and conclusions are presented and some topics for posterior researches are suggested.

Este trabalho apresenta resultados teóricos e experimentais sobre o comportamento estrutural de ligações parafusadas viga-coluna com chapa de topo. São estudados dois tradicionais métodos de dimensionamento e as ligações são analisadas numericamente, via método dos estados limites. Os resultados são comparados com os obtidos através de ensaios de 35 protótipos, nos quais variou-se, alternadamente, a espessura da chapa de topo e o diâmetro dos parafusos. Discute-se, em particular, a influência destes parâmetros no comportamento momento-rotação das ligações com chapa de topo e, ao final, apresentam-se as conclusões pertinentes e recomendações para o prosseguimento dos estudos. / This work presents the theoretical and experimental results on the structural behavior of bolted end plate connections. They are designed by two traditional methods and analyzed by the finite element method. Comparisons are made between the FEM results and those obtained by an experimental analysis on 35 cruciform welded profile models, in which end plate thickness and bolt diameter was alternately varied. Special attention is paid for evaluating the influence of these parameters in the moment rotation behavior of the connections. Finally, the remarks and conclusions are presented and some topics for posterior researches are suggested.

There is a dearth of research on migrant entrepreneurship in the context of contemporary UK policy. At the same time, there is evidence of burgeoning transnational socio cultural connectivity. This thesis evaluates the impact of these conditions on migrant entrepreneurship in a rapidly changing policy environment. Migrant entrepreneurship is viewed differently in academia, policy and public perception. This causes significant policy tensions and disjunctions that are manifest a migration policy system which fails to take into account the agency of migrant entrepreneurs. In a break from previous studies, the migrant entrepreneur s negotiations of power and agency that stem from transnational connections in a contemporary UK context will be addressed. It is important to acknowledge structures of migration policy and economic landscape at national, regional and local scales. Three areas of the UK are addressed; London, focusing on Inner London East, Birmingham and the West Midlands and Cambridgeshire.

The behaviour of connections in fire has become of particular interest to the structural engineering community following the possible link of connection failure to the collapse of the World Trade Centre building 7 and the failures and huge distortion of some connections after the Cardington full scale tests. In order to widen the understanding of the complex behaviour of connections in fire this thesis discusses a number of specific issues relating to connections in fire and their influence on structural response. The first part of this work presents a finite element model for predicting connection temperature profiles. A parametric study is then carried out to investigate which factors have the greatest influence on temperature prediction. This method is compared to the currently available methods for connection temperature prediction presented in the Eurocodes: using a percentage of the beam mid-span lower flange temperature to estimate the temperature across the connection and a lumped capacitance method to calculate average joint temperature based on the mass of material and surface area. In each case, along with the predicted temperatures, the influence on connection material strength is also presented. The three methods have varying levels of accuracy. The finite element model provides detailed and accurate results due to the thorough consideration given to the input parameters. The percentages method gives reasonable estimates in the heating phase but is less accurate in cooling and the lumped capacitance method is only suitable for crude estimations. The remainder of the thesis is concerned with how a number of phenomena affect the overall structural behaviour of buildings: the inclusion of detailed connection models within larger, less complex, finite element models; the effects of connection rotational capacity and the composite beam-slab shear connection. A finite element model for isolated joints is presented in detail for a number of heating regimes and connection types. The influence of the bolt shear and tensile properties is considered in detail and the need for further testing on bolts at high temperatures is discussed. The model has the capacity to predict a number of failure modes and also shows a good comparison between experimental and theoretical deflected shapes. This connection model is then inserted into a large model. It is shown that whilst the inclusion of the shell connection has a small influence on the residual deflections of a structure after cooling when compare to a model where connections are simple and fixed, the difference between heating and not heating the connection does effect structural deflections. Following on from the previous full scale model, simple connections are then exclusively included where the connection rotational capacity is varied. Results show that there is not a large effect on the structural deflections or beam axial and shear forces when rotational behaviour is changed. However column bending moments are hugely increased during heating both in the fire compartment and away from it and fixed connections result in larger bending moment that pinned ones. Finally, the shear interaction between the slab and beams is investigated. The detailed development of both an ambient temperature and then an elevated temperature model of a beam-slab system including explicit shear studs are presented. A study is then carried out looking at the effects on deflections and beam forces when the strength and ductility of the studs are altered. It is found that more ductile studs with a high shear capacity are beneficial for reducing forces in beams and limiting their deflections. Finally the shear studs are included in the larger model used in previous chapters where results are similar to those seen in the beam-slab model, but are less pronounced.

There has been undoubtedly a rapid economic growth in China over the last few decades and globalization has affected many business practices in China. Therefore this study addressed the interesting question of how the traditional concept of ‘guanxi’ works in modern day China. This was investigated through the lived experiences and perceptions of how Hong Kong executives establish business relationships in China. This research is important because ‘guanxi’ has often been associated with the success factor of business practices in China. Through a qualitative research methodology this research found that the practices of ‘guanxi’ take a changing and integrated approach. While some elements including favours and benefits have changed to become more indirect, less materialistic and depend on trust, other elements like socializing, hierarchy and the long term orientation in a business context have decreased in importance. Further the different experiences in the government sector, different company size, geographic locations in China, as well as the emergence of a new generation, have shown that the formation of networks cannot be generalized, but take different approaches depending on the situation. The significance of this is that ‘guanxi’ is less important for large organizations and the new generation of Western influenced managers in China. Finally while experiences of ‘guanxi’ change, they take a more international perspective while maintaining some traditional elements such as face. This suggests that Chinese business practices combine and accept apparent opposite values of international and traditional practices.

No description available.

Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer / This report discusses the two main types of structural connections used for fiber reinforced polymer (FRP) pultruded shapes, which are mechanical and bonded connections. The most common types of mechanical and bonded connections for FRP pultruded shapes are bolted and adhesively bonded joints respectively, and the advantages and disadvantages of each are discussed. Bolted connections are the most common type of connection used for FRP pultruded shapes and are therefore the focus of this report. Limit states and critical stresses for FRP bolted connections are explained along with the appropriate material properties that are needed to determine them. A simplified mechanics approach to determining the stresses in the FRP material and connection is presented along with a design procedure for FRP connections. A design example is given for a simple beam-to-column shear connection using three materials: FRP pultruded shapes, W-flange steel shapes, and wood sawn lumber in which the beam-to-column shear connection is compared. It is found that the FRP connection is comparable to the steel and wood connections, and all three are able to meet the requirements for the loading conditions given with reasonable results. Possible uses for FRP that would be more ideal than using steel or wood members are presented and areas that still need to be developed or require further research are discussed.

Numerous structural end connections are utilized everyday in the marine industry for ship design and/or maintenance. End connection design has been developed in earlier vessel designs and adapted as a general standard for all vessels being designed / built at a facility. Usually the supporting calculations developed to analyze the structural end connection are not available for engineers to re-examine. Furthermore, young engineers employ un-proven end connections in their designs, using the justification “It has been done like this in the past, it should work.” In this thesis, the author concentrates on finite element analysis for thirteen typical end connections used in the marine industry and correlated the shear and moment transfer to an AISC developed empirical beam equation for comparison. The author will rely on first principle equations and finite element analysis to prove the efficiency of various end connections, and draw comparative conclusions per each end connection analyzed.