Terças de aço formadas a frio são muito utilizadas em sistemas de cobertura e fechamento. Para conferir continuidade entre tramos adjacentes e possibilitar um melhor aproveitamento de material, são empregadas ligações parafusadas por transpasse e com luva. O comportamento estrutural dessas ligações é muito dependente da sua configuração geométrica e do nível de carregamento. Com base em uma série de nove experimentos e análises teóricas, o comportamento estrutural dessas ligações foi investigado no tocante aos esforços resistentes e à rigidez. Observou-se que o modo de falha tem sempre uma componente distorcional significativa e uma resistência menor que a prevista pela metodologia atual de projeto. No caso do momento fletor resistente, a distribuição de tensões de flexão oblíqua é a que melhor se aproxima do comportamento real das terças, sendo possível a partir de uma análise de estabilidade elástica considerando tal comportamento, e, baseado no método da resistência direta e na curva de dimensionamento do modo distorcional, obter uma previsão segura do momento fletor resistente. Além disso, a rigidez da ligação, com relação aos deslocamentos verticais é bastante dependente do tipo de ligação, sendo que as terças com ligações por luva são mais deformáveis que terças sem ligações. Por outro lado, terças com ligações por transpasse são menos deformáveis que terças fisicamente contínuas. As parcelas de rigidez da ligação são apresentadas, e a componente de deformação do furo é a mais significativa. Uma expressão para deduzir a rigidez rotacional da ligação é apresentada, juntamente com um modelo de barras para modelagem da ligação. Os resultados teóricos se ajustam muito bem aos experimentais. Conclui-se em linhas gerais, que as ligações por transpasse podem ser consideradas plenamente satisfatórias do ponto de vista de comportamento estrutural, sendo que terças com essas ligações são mais resistentes e rígidas que terças com continuidade física. O mesmo não ocorre nas terças com ligações por luva, porém, dada a limitação no número de ensaios, tais ligações carecem mais estudos. / Cold-formed steel purlins are widely used in roofs and wall systems. The continuity of long runs of cold-formed steel purlins is guaranteed by sleeve and overlap bolted connections, which allows a better load distribution and material savings. The structural behavior of these connections is highly dependent on their geometric configuration and load level. The strength and stiffness of these connections were determined through a series of nine experiments, numerical and analytical analysis. Results have shown that distortional buckling has a major contribution on the stability analysis of the cold-formed steel purlin. To safely determine the flexural strength of the purlin, one must consider unrestrained bending stress distribution and distortional buckling. The connection type influences the rigidity of the purlin thus the vertical displacement. Purlins with overlapped connections are stiffer than physically continuous ones, although purlins with sleeved connections are not. The bearing deformation at the connection region is responsible for a reduction in the system stiffness. To account for the change in stiffness and determine the vertical displacement, an expression for the bearing stiffness and a beam model are proposed. The results of this model show good agreement with experimental data. The general conclusion of this research is: overlapped bolted connections enhance the structural response of the purlins when compared to physically continuous ones. The same does not hold true for purlins with sleeved connections.

Le travail de thèse présenté dans ce manuscrit est consacré au développement d’une nouvelle méthode de contrôle de la qualité d’un assemblage boulonné. Cette méthode utilise les courbes couple de serrage/angle de rotation de l’écrou obtenues lors d’un serrage et, plus précisément, les différents changements de pentes qui l’affectent. L’idée principale est d’utiliser ces changements de pentes pour découper la courbe en différents segments, correspondant chacun à un événement qu’il est alors possible d’identifier. Ces événements sont tout d’abord constitués d’une phase de freinage de l’écrou, suivie d’un « plateau », d’une éventuelle phase de réduction des jeux et enfin, d’un dernier segment linéaire traduisant le serrage. Afin de valider cette méthode, deux modèles, l’un analytique et l’autre de calcul par la méthode des éléments finis, ont été développés afin de créer une base de référence. Le modèle analytique est issu de la littérature tandis que le modèle éléments finis apporte une originalité car il simule la rotation de l’écrou mais également son freinage à travers une déformation préliminaire. Ces modèles sont ensuite validés lors d’une première campagne d’essais qui débute par le serrage d’échantillons de référence sans défaut. Puis des défauts sont introduits (jeux, bavures, copeaux…) afin d’évaluer les capacités de détection de la méthode. Des limitations sont alors découvertes, entraînant une modification des moyens de mesure. Un premier prototype est donc réalisé en instrumentant une visseuse pour pouvoir mesurer le couple de réaction (celui qui maintient la vis) en plus du couple de serrage. Cet ajout permet alors d’identifier des défauts qui restaient masqués. Finalement, un second prototype est conçu et réalisé, permettant de contrôler directement le serrage et ainsi de mettre en place de nouvelles stratégies pour le serrage prenant en compte les résultats obtenus lors des différentes campagnes d’essais. / The subject of the thesis presented in this manuscript is the development of a new method to control the quality of a bolted assembly. This method uses the tightening torque-turn angle of the nut curves, gathered during the tightening and, more precisely, the changes of slope that affects it. The main idea is to use these changes to divide the curve into segments, each corresponding to an event that it is then possible to identify. These events are: a nut locking phase, followed by a constant torque area, a possible gap reduction phase and finally, a last linear part corresponding to the actual tightening. To validate this method two models, one analytical and the other using the finite element method, have been developed to create a baseline. The analytical model is derived from the literature as the finite element model provides originality because it simulates the rotation of the nut but also the locking through a preliminary deformation. These models are then validated in a first test campaign, which begins with the tightening of reference sample without defects. Then, defects are introduced (gaps, burrs, chips...) in order to evaluate the method detection capabilities. Limitations are discovered leading to a modification of the measures means. A first prototype is designed by instrumenting a screwdriver to be able to measure the reaction torque (the one that holds the screw) in addition to the tightening torque. This addition improves the method by detecting hidden defects. Finally a second prototype was designed and built, with full control of the tightening and thus develop new strategies for tightening, taking into account the results obtained during the various test campaigns.

Este trabalho abordou o estudo de ligação viga de aço e pilar misto preenchido com concreto a partir da aplicação de modelos numérico para representar o comportamento de duas tipologias de ligação: uma ligação parafusada com aderência entre os parafusos passantes e o núcleo de concreto e uma ligação soldada, validadas com base em resultados experimentais existentes. Os resultados obtidos nessa etapa foram considerados satisfatórios, dentro da proposta de modelagem, apesar das simplificações adotadas. Após a validação do modelo numérico foi desenvolvido um estudo paramétrico dos modelos de ligação para entender a influência de alguns parâmetros no comportamento global da estrutura, que foram: resistência à compressão do concreto e espessura do perfil tubular e perfil da viga, com posterior discussão da relação momento-rotação das duas tipologias de ligação estudadas. A mudança do perfil da viga foi o parâmetro que mais influenciou no comportamento global da ligação parafusada; enquanto que, para a ligação soldada, as variações de todos os parâmetros influenciaram no comportamento da ligação, com destaque para a variação do perfil da viga. / This research studied connections typology between steel beams to column filled with concrete from the application of numerical models that reproduce the behavior of two connections: bolted beam-column connection and welded beam-column connection, which were calibrated using existing experimental results. At this stage, the results were considered satisfactory, within the proposed model, despite the adopted simplifications. After the calibration, a parametric study was developed with the aim of verifying the influence of some parameters on the overall behavior of the structure, such as the concrete compression strength, the thickness of the tube wall and the beam properties, with discussions of bending moment-rotation of the studied connections. The beam properties were the parameters that most influenced on the overall behavior of the bolted beam-column connection, while, for the welded connection, all parameters influenced on the overall behavior of the connection, specially the beam properties.

Este trabalho abordou o estudo de ligação viga de aço e pilar misto preenchido com concreto a partir da aplicação de modelos numérico para representar o comportamento de duas tipologias de ligação: uma ligação parafusada com aderência entre os parafusos passantes e o núcleo de concreto e uma ligação soldada, validadas com base em resultados experimentais existentes. Os resultados obtidos nessa etapa foram considerados satisfatórios, dentro da proposta de modelagem, apesar das simplificações adotadas. Após a validação do modelo numérico foi desenvolvido um estudo paramétrico dos modelos de ligação para entender a influência de alguns parâmetros no comportamento global da estrutura, que foram: resistência à compressão do concreto e espessura do perfil tubular e perfil da viga, com posterior discussão da relação momento-rotação das duas tipologias de ligação estudadas. A mudança do perfil da viga foi o parâmetro que mais influenciou no comportamento global da ligação parafusada; enquanto que, para a ligação soldada, as variações de todos os parâmetros influenciaram no comportamento da ligação, com destaque para a variação do perfil da viga. / This research studied connections typology between steel beams to column filled with concrete from the application of numerical models that reproduce the behavior of two connections: bolted beam-column connection and welded beam-column connection, which were calibrated using existing experimental results. At this stage, the results were considered satisfactory, within the proposed model, despite the adopted simplifications. After the calibration, a parametric study was developed with the aim of verifying the influence of some parameters on the overall behavior of the structure, such as the concrete compression strength, the thickness of the tube wall and the beam properties, with discussions of bending moment-rotation of the studied connections. The beam properties were the parameters that most influenced on the overall behavior of the bolted beam-column connection, while, for the welded connection, all parameters influenced on the overall behavior of the connection, specially the beam properties.

Este trabalho realiza estudo teórico e experimental de ligações parafusadas em chapas finas onduladas, com aço de alta resistência, submetidas a esforços de tração em situação de cisalhamento simples. A aplicação deste tipo de ligação ocorre em paredes de silos cilíndricos metálicos. Também foi avaliada a utilização de montagem com chapas duplas, utilizadas na prática para aumentar a espessura total da parede, devido a demanda por silos cada vez maiores. O programa experimental compreendeu 137 ensaios, nos quais foram variados parâmetros de interesse com aplicações práticas, resultando em dois modos de falha distintos, ruptura da chapa na seção líquida e esmagamento do aço na parede do furo. Foram propostas novas equações para o cálculo da resistência deste tipo de ligação. Os resultados experimentais obtidos mostraram que em ligações com falha por ruptura na seção líquida, reduzir a área líquida à uma área efetiva por meio de um coeficiente redutor resulta em valores conservadores para a resistência deste tipo de ligação. As ligações com chapas duplas apresentaram resistência elevada, superior à condição de chapa simples. / This work presents a theoretical and experimental study of bolted connections with thin, corrugated, high strength steel sheets, subjected to tension in simple shear condition. This type of connection is applicable in walls of cylindrical steel silos. It also was evaluated the case of double sheet assemblage, that is used in practice to increase the total wall thickness, due to the demand for bigger silos. The experimental program comprised 137 tests, in which it were varied chosen parameters of practical interest, providing failure by net section tension rupture and bearing of the sheet. New equations were proposed for the strength calculation of this type of connection. The experimental results indicated that in connections subject net section rupture, to reduce the net section area to an effective area through a reduction coefficient returns conservative values of resistance for this type of connection. The connections with double sheet exhibited high values of resistance, which resulted bigger than for simple sheet cases.

Terças de aço formadas a frio são muito utilizadas em sistemas de cobertura e fechamento. Para conferir continuidade entre tramos adjacentes e possibilitar um melhor aproveitamento de material, são empregadas ligações parafusadas por transpasse e com luva. O comportamento estrutural dessas ligações é muito dependente da sua configuração geométrica e do nível de carregamento. Com base em uma série de nove experimentos e análises teóricas, o comportamento estrutural dessas ligações foi investigado no tocante aos esforços resistentes e à rigidez. Observou-se que o modo de falha tem sempre uma componente distorcional significativa e uma resistência menor que a prevista pela metodologia atual de projeto. No caso do momento fletor resistente, a distribuição de tensões de flexão oblíqua é a que melhor se aproxima do comportamento real das terças, sendo possível a partir de uma análise de estabilidade elástica considerando tal comportamento, e, baseado no método da resistência direta e na curva de dimensionamento do modo distorcional, obter uma previsão segura do momento fletor resistente. Além disso, a rigidez da ligação, com relação aos deslocamentos verticais é bastante dependente do tipo de ligação, sendo que as terças com ligações por luva são mais deformáveis que terças sem ligações. Por outro lado, terças com ligações por transpasse são menos deformáveis que terças fisicamente contínuas. As parcelas de rigidez da ligação são apresentadas, e a componente de deformação do furo é a mais significativa. Uma expressão para deduzir a rigidez rotacional da ligação é apresentada, juntamente com um modelo de barras para modelagem da ligação. Os resultados teóricos se ajustam muito bem aos experimentais. Conclui-se em linhas gerais, que as ligações por transpasse podem ser consideradas plenamente satisfatórias do ponto de vista de comportamento estrutural, sendo que terças com essas ligações são mais resistentes e rígidas que terças com continuidade física. O mesmo não ocorre nas terças com ligações por luva, porém, dada a limitação no número de ensaios, tais ligações carecem mais estudos. / Cold-formed steel purlins are widely used in roofs and wall systems. The continuity of long runs of cold-formed steel purlins is guaranteed by sleeve and overlap bolted connections, which allows a better load distribution and material savings. The structural behavior of these connections is highly dependent on their geometric configuration and load level. The strength and stiffness of these connections were determined through a series of nine experiments, numerical and analytical analysis. Results have shown that distortional buckling has a major contribution on the stability analysis of the cold-formed steel purlin. To safely determine the flexural strength of the purlin, one must consider unrestrained bending stress distribution and distortional buckling. The connection type influences the rigidity of the purlin thus the vertical displacement. Purlins with overlapped connections are stiffer than physically continuous ones, although purlins with sleeved connections are not. The bearing deformation at the connection region is responsible for a reduction in the system stiffness. To account for the change in stiffness and determine the vertical displacement, an expression for the bearing stiffness and a beam model are proposed. The results of this model show good agreement with experimental data. The general conclusion of this research is: overlapped bolted connections enhance the structural response of the purlins when compared to physically continuous ones. The same does not hold true for purlins with sleeved connections.

La dissipation dans les systèmes mécaniques joue un rôle important dans la limitation des niveaux de vibrations qui peuvent causer des difficultés allant de l'inconfort jusqu'à la ruine des structures. L'amortissement intrinsèque des matériaux utilisés pour la fabrication de structures aéronautiques étant très faible, les jonctions représentent une des sources principales de dissipation. Dans le cadre du projet FUI MAIAS (Maitrise des Amortissements Induits dans les ASsemblages), les travaux présentés ici portent sur la maximisation de l'amortissement induit. Une grande partie des travaux de littérature s'intéressent à l'étude de jonctions élémentaires. On cherche donc ici à étudier la conception de jonctions dissipatives intégrées dans une structure globale. Pour limiter les applications, on se restreint plus particulièrement aux jonctions boulonnées rencontrées en construction aéronautique et à l'utilisation de matériaux viscoélastiques pour générer la dissipation.Une notion de couplage pour la mesure de la capacité des liaisons à dissiper est introduite pour s'assurer de leurs contributions au comportement vibratoire. En utilisant le couplage en tant que mesure de sensibilité des jonctions aux propriétés des matériaux viscoélastiques, en plus de l'étude de la tenue fonctionnelle d'une liaison boulonnée, une approche de conception de jonction boulonnée dissipative est alors développée. Une étude expérimentale est ensuite effectuée pour la valider. Lors de la compagne d‘essais, des défauts de forme ont été détectés dans la structure. L'influence de ces défauts, susceptibles d'exister dans les structures réelles, sur l'amortissement est alors décrite. L'intégration pour un grand nombre de modèles physiques, détaillés au voisinage des jonctions, dans un modèle d'ensemble est généralement une problématique. Une représentation simplifiée s'avère être alors nécessaire. Une réduction de modèle peut être alors appliquée sur la partie linéaire du système. Cependant, pour les non-linéarités localisées au niveau des jonctions, une construction de méta-modèle caractérisant les efforts transmis dans les liaisons est alors proposée. Différentes stratégies de construction de méta-modèle, reproduisant les déformations et les efforts principaux de liaisons, sont proposées et étudiées en supposant des liaisons à comportement viscoélastique. Un modèle cylindrique à dix jonctions boulonnées, plus représentatif de l'architecture réelle des structures aéronautiques est étudié pour illustrer le cas des liaisons répétées dont le chargement réel de chacune est beaucoup plus complexe que les structures simples couramment étudiées. / Dissipation in mechanical systems plays an important role in limiting vibrationlevels. The present work deals with maximizing damping induced by junctions and treatsjunctions integrated into an overall structure. After introducing the physical models used inrepresenting viscoelastic behavior, a first example introduces the concept of coupling. Coupling,estimated by preliminary calculations of elastic natural frequencies sensitivity, ensures thatjunctions sufficiently contribute to the global behavior to induce damping. To study this couplingas well as obtain accurate damping predictions by complex modes calculation, model reductionmethods, adapted to parameterized problems, are needed and different strategies are detailedand validated. A structure representing aeronautic construction is then used to illustrate theproposed damping design process. The study highlights the functional importance of thecohesive zone under the bolt and the possibility of using the residual flexibility of the joint tointroduce a viscoelastic layer enabling high damping. Experimental modal tests confirm thevalidity of the design and the predicted trends, but also show the influence of manufacturingdefects which limit the induced damping. The manuscript finally addresses the need forrepresentative models of detailed joints in overall models. Although model reduction is possibleand desirable, the construction of meta-models representing the main forces transmitted by thejoints is useful in modeling and necessary for the operation of elementary tests. Generalstrategies for defining principal deformations and loads are introduced and their validity isillustrated.

Master of Science / Department of Architectural Engineering and Construction Science / Kimberly W. Kramer / Of seismic steel lateral force resisting systems in practice today, the Moment Frame has most diverse connection types. Special Moment frames resist lateral loads through energy dissipation of the inelastic deformation of the beam members. The 1994 Northridge earthquake proved that the standard for welded beam-column connections were not sufficient to prevent damage to the connection or failure of the connection. Through numerous studies, new methods and standards for Special Moment Frame connections are presented in the Seismic Design Manual 2nd Edition to promote energy dissipation away from the beam-column connection. A common type of SMF is the Reduce Beams Section (RBS). To encourage inelastic deformation away from the beam-column connection, the beam flange’s dimensions are reduced a distance away from the beam-column connection; making the member “weaker” at that specific location dictating where the plastic hinging will occur during a seismic event. The reduction is usually taken in a semi-circular pattern. Another type of SMF connection is the Kaiser Bolted Bracket® (KBB) which consists of brackets that stiffen the beam-column connection. KBB connections are similar to RBS connections as the stiffness is higher near the connection and lower away from the connection. Instead of reducing the beam’s sectional properties, KBB uses a bracket to stiffen the connection. The building used in this parametric study is a 4-story office building. This thesis reports the results of the parametric study by comparing two SMF connections: Reduced Beam Section and Kaiser Bolted Brackets. This parametric study includes results from three Seismic Design Categories; B, C, and D, and the use of two different foundation connections; fixed and pinned. The purpose of this parametric study is to compare member sizes, member forces, and story drift. The results of Seismic Design Category D are discussed in depth in this thesis, while the results of Seismic Design Category B and C are provided in the Appendices.

Elektrische Verbindungen in der Elektroenergietechnik sind aus technologischen und konstruktiven Gründen beim Zusammenschalten von Betriebsmitteln in Schaltanlagen und auf den Übertragungswegen bei Kabeln und Freileitungen notwendig. Als elektrischer Kontakt wird die Berührung zweier stromführender Leiter verstanden. Eine Verbindungsart, die häufig bei Stromschienen eingesetzt wird, ist die Schraubenverbindung. Um eine Lebensdauer dieser Verbindung von üblicherweise 50 Jahren und mehr zu gewährleisten, ist es notwendig, die Alterung abhängig von der Zeit und der Temperatur zu kennen. Neben dem Kraftabbau und den chemischen Reaktionen / Fremdschichtbildung bei Verbindungen mit Kupfer- oder Aluminiumleitern ist die Interdiffusion bei Bimetallverbindungen und bei Verbindungen mit beschichteten Kontaktpartnern von Bedeutung. In dieser Arbeit wurde der Kraftabbau bei Schraubenverbindungen mit Stromschienen aus Cu-ETP (Werkstoff-Nr. CW004A) und CuAg0,1P (Werkstoff-Nr. CW016A) im Temperaturbereich zwischen 105 °C und 160 °C untersucht. Es wurde die Kraft und der Widerstand an stromdurchflossenen Verbindungen abhängig von der Zeit bis zu 2,4 Jahren gemessen. Des Weiteren wurde der Einfluss von verschiedenen federnden und nicht federnden Elementen im Verbindungssystem auf den Kraftabbau untersucht. Es wurde eine statische Mindestverbindungskraft bestimmt, der Kraftabbau bis zu einer Lebensdauer von 50 Jahren berechnet und daraus eine Grenztemperatur für diese Verbindungsart bestimmt. Neben dem Kraftabbau wurde die Alterung durch Interdiffusion an Schraubenverbindungen mit verzinnten und versilberten Cu-ETP Stromschienen im Temperaturbereich zwischen 115 °C und 140 °C untersucht. Es wurde an stromdurchflossenen und im Wärmeschrank gelagerten Verbindungen der Verbindungswiderstand abhängig von der Zeit bis zu 2 Jahren gemessen. Die Langzeitversuche wurden durch mikroskopische Untersuchungen ergänzt, in denen die Dicke der sich gebildeten intermetallischen Phasen gemessen und bewertet wurde. Ergänzend zu den Langzeituntersuchungen wurden aktuelle Erkenntnisse zu den chemischen Reaktionen / Fremdschichtbildung auf Kupfer-, Silber- und Zinnoberflächen zusammengestellt und bewertet. / Electrical joints are necessary for technological and design reasons to connect electric equipment and to realize the transmission of electrical energy by cables and overhead lines. The contact between two current-flown electrical conductors is called electrical joint. One joint type often used is the bolted joint. To allow a lifetime of this joint of 50 years and longer it is necessary to know the ageing depend on time and temperature. In addition to ageing by force reduction and the chemical reactions / impurity layers at joints with copper und aluminium conductors, the interdiffusion has a great influence at bi-metal joints and joints with plated conductors. In this work the force reduction was analysed at bolted joints with bus bars made of Cu-ETP (material number CW004A) and CuAg0.1P (material number CW016A) in a temperature range between 105 °C and 160 °C. The joint force and the joint resistance were measured time-depended at current-flown joints up to 2.4 years. Furthermore the influence on the force reduction by different resilient und non-resilient elements in the joint system was tested. There was a minimum static joint force appointed and the force reduction calculated to a lifetime of 50 years. Out of these results a category temperature for these joints was defined. Additionally the ageing due to interdiffusion at bolted joints with tin and silver plated Cu-ETP bus bars was analysed at the temperatures 115 °C and 140 °C. At joints aged by current-flown and in the heating cabinet the joint resistance was measured time-dependent up to 2 years. These long-term tests were supplemented by microscopic examinations. The thickness of the grown intermetallic compounds was measured and stated. Additional to the long-term tests the topical knowledge to chemical reactions / impurity layers at copper, silver and tin surfaces was composed and stated.

The Master’s thesis concerns a design of load bearing multi-storey steel construction of scientific institution in Brno. This thesis contains three different solutions of a draft proposal and for the elected solution is processed technical report, structural analysis, material list and drawings.