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Yes / CDW-based concrete requires alkali-activators to generate geopolymerization process. These alkali-activators are difficult to be handled at the construction site and one of the rational ways to built reinforced geopolymer structures is the prefabricated construction. The connection of the precast structures is the most vulnerable component under the effect of seismic actions. Proper detailing and design of connections are crucial for sufficiently-ductile performance under seismic loading. Additionally, to achieve the disassembling and reusing of structural members, a demountable connection, i.e., dry connection, should be used instead of a wet connection. In this study, four novel fully-demountable connections for reinforced construction and demolition waste-based (CDW) geopolymer concrete members are developed. Seismic performances of these different demountable connections and one reference monolithic connections are experimentally investigated. The connections are subjected to reversed cyclic lateral displacements under constant axial loading. Comparisons are made referring to observed damage patterns, connection strengths, moment–curvature relations, initial stiffnesses, plastic hinge lengths, and energy dissipation characteristics of the proposed demountable connections and the monolithic connection. The results of the experimental study indicate that one proposed demountable connection exhibited larger lateral capacity and better seismic performance than its monolithic counterpart, whereas the other three proposals showed less performance than the monolithic counterpart. / The authors gratefully acknowledge the financial assistance of the European Union’s Horizon 2020 research and innovation programme under grant agreement No: 869336, ICEBERG

Uma ligação em estruturas de aço é denominada mista quando considera-se a contribuição da laje no seu comportamento. Assim, além do detalhe da ligação em aço, outros parâmetros interferem no comportamento da ligação mista, como a taxa de armadura e o nível de interação entre a laje e a viga de aço. Os métodos de cálculo de ligações mistas derivam do Método dos Componentes proposto pelo Eurocode 3 para cálculo de ligações em aço. Apresenta-se uma adaptação de um destes métodos para cálculo de ligações mistas que representam a realidade brasileira em termos de perfis e detalhes de ligação. Foi elaborado um programa experimental de caráter exploratório envolvendo ligações mistas com chapa de topo estendida. Foram ensaiados modelos simulando pilares internos e pilares de canto. Um modelo numérico foi desenvolvido utilizando o programa Ansys, que permite a análise destas ligações de maneira simples e satisfatória. Os resultados experimentais foram confrontados com os resultados da análise numérica e com os valores obtidos a partir do modelo analítico. / A composite joint is a joint between a composite beam and a steel or composite column in which reinforced concrete slab is take into account. The moment-rotation relationship of composite joints depends on a significant number of parameters besides the type and configuration of the steel connection, as for example: the amount of steel reinforcement of the slab and the degree of interaction between the slab and the steel beam section. Based on the Eurocode 3 method for bare steel connection (Components Method), some methods have been developed for prediction the moment capacities of composite connections. I this work, an adaptation of one of these methods has been developed in which steel sections and connections details common in Brazil are considered. A short experimental program was planed in order to understand the composite behaviour of extended end-plate composite beam-column connection. The test specimens were configured as cruciform type and cantilever type. Finally, a Finite Element model was built in Ansys software. The numerical modeling was found to have good approach with experimental results. Some analyses are done involving experimental, numerical and analytical results.

Nesta pesquisa estudou-se o comportamento de uma ligação viga-pilar em concreto pré-moldado utilizando perfis metálicos embutidos nos elementos estruturais. O modelo da ligação estudada permite a transmissão de momentos fletores positivo e negativo. Para a continuidade de momento fletor negativo, utilizam-se um consolo metálico com seção \"U\" embutido no pilar e dentes metálicos com seção tubular retangular embutidos nas vigas, soldados. Para a continuidade de momento positivo, utilizam-se cantoneiras metálicas embutidas no pilar que são soldadas à armadura positiva da viga. O estudo consistiu em análise experimental de um modelo cruciforme em duas etapas. Na primeira etapa o modelo foi solicitado a carregamentos cíclicos reversíveis por meio de um atuador servo hidráulico acoplado sobre o topo do pilar. Na segunda etapa, o modelo foi solicitado a carregamento estático monotônico por meio de macacos hidráulicos dispostos sob o pilar para causar a ruptura com momento negativo. O modelo apresentou uma considerável facilidade de montagem, já que na fase transitória a ligação é articulada e o consolo do pilar em perfil \"U\" permite a estabilidade lateral da viga. O consolo metálico embutido no pilar escoou muito antes de atingir a capacidade resistente dos outros componentes da ligação, pois na seção da ligação junto à face do pilar, apenas o consolo resiste à flexão. / In this research the behavior of a beam-column connection in precast concrete system using welded steel shapes built-in structural elements was studied. The model of the studied connection allows transmission of positive and negative moments. For the continuity of negative moment, is used a steel \"U\" shaped corbel inserted in the column welded with tubular section steel hangers inserted in each beam. For the continuity of positive moment, use is made of metal embedded in abutment ledges that are welded to the positive reinforcement of the beam. The study consisted on experimental analysis of a cross-shaped specimen in two steps. In the first step was applied to the specimen a cyclic load using hydraulic actuator coupled to the column head. In the second step was applied in the specimen a static load using hydraulic jack positioned under the column to cause rupture with negative moment. The connection model showed a considerably easy assembly, as in the transitional phase the connection is articulated and the steel \"U\" shaped corbel of the column allows the lateral stability of the beam. The rupture occurred by yielding of the steel U shaped corbel in the section near the column. The steel corbel inserted in the column yielded before reaches the resistant capacity of other components of the connection, because of the section in the connection close of the column, only steel corbel resists the negative moment.

Uma ligação em estruturas de aço é denominada mista quando considera-se a contribuição da laje no seu comportamento. Assim, além do detalhe da ligação em aço, outros parâmetros interferem no comportamento da ligação mista, como a taxa de armadura e o nível de interação entre a laje e a viga de aço. Os métodos de cálculo de ligações mistas derivam do Método dos Componentes proposto pelo Eurocode 3 para cálculo de ligações em aço. Apresenta-se uma adaptação de um destes métodos para cálculo de ligações mistas que representam a realidade brasileira em termos de perfis e detalhes de ligação. Foi elaborado um programa experimental de caráter exploratório envolvendo ligações mistas com chapa de topo estendida. Foram ensaiados modelos simulando pilares internos e pilares de canto. Um modelo numérico foi desenvolvido utilizando o programa Ansys, que permite a análise destas ligações de maneira simples e satisfatória. Os resultados experimentais foram confrontados com os resultados da análise numérica e com os valores obtidos a partir do modelo analítico. / A composite joint is a joint between a composite beam and a steel or composite column in which reinforced concrete slab is take into account. The moment-rotation relationship of composite joints depends on a significant number of parameters besides the type and configuration of the steel connection, as for example: the amount of steel reinforcement of the slab and the degree of interaction between the slab and the steel beam section. Based on the Eurocode 3 method for bare steel connection (Components Method), some methods have been developed for prediction the moment capacities of composite connections. I this work, an adaptation of one of these methods has been developed in which steel sections and connections details common in Brazil are considered. A short experimental program was planed in order to understand the composite behaviour of extended end-plate composite beam-column connection. The test specimens were configured as cruciform type and cantilever type. Finally, a Finite Element model was built in Ansys software. The numerical modeling was found to have good approach with experimental results. Some analyses are done involving experimental, numerical and analytical results.

Nesta pesquisa estudou-se o comportamento de uma ligação viga-pilar em concreto pré-moldado utilizando perfis metálicos embutidos nos elementos estruturais. O modelo da ligação estudada permite a transmissão de momentos fletores positivo e negativo. Para a continuidade de momento fletor negativo, utilizam-se um consolo metálico com seção \"U\" embutido no pilar e dentes metálicos com seção tubular retangular embutidos nas vigas, soldados. Para a continuidade de momento positivo, utilizam-se cantoneiras metálicas embutidas no pilar que são soldadas à armadura positiva da viga. O estudo consistiu em análise experimental de um modelo cruciforme em duas etapas. Na primeira etapa o modelo foi solicitado a carregamentos cíclicos reversíveis por meio de um atuador servo hidráulico acoplado sobre o topo do pilar. Na segunda etapa, o modelo foi solicitado a carregamento estático monotônico por meio de macacos hidráulicos dispostos sob o pilar para causar a ruptura com momento negativo. O modelo apresentou uma considerável facilidade de montagem, já que na fase transitória a ligação é articulada e o consolo do pilar em perfil \"U\" permite a estabilidade lateral da viga. O consolo metálico embutido no pilar escoou muito antes de atingir a capacidade resistente dos outros componentes da ligação, pois na seção da ligação junto à face do pilar, apenas o consolo resiste à flexão. / In this research the behavior of a beam-column connection in precast concrete system using welded steel shapes built-in structural elements was studied. The model of the studied connection allows transmission of positive and negative moments. For the continuity of negative moment, is used a steel \"U\" shaped corbel inserted in the column welded with tubular section steel hangers inserted in each beam. For the continuity of positive moment, use is made of metal embedded in abutment ledges that are welded to the positive reinforcement of the beam. The study consisted on experimental analysis of a cross-shaped specimen in two steps. In the first step was applied to the specimen a cyclic load using hydraulic actuator coupled to the column head. In the second step was applied in the specimen a static load using hydraulic jack positioned under the column to cause rupture with negative moment. The connection model showed a considerably easy assembly, as in the transitional phase the connection is articulated and the steel \"U\" shaped corbel of the column allows the lateral stability of the beam. The rupture occurred by yielding of the steel U shaped corbel in the section near the column. The steel corbel inserted in the column yielded before reaches the resistant capacity of other components of the connection, because of the section in the connection close of the column, only steel corbel resists the negative moment.

Master of Science / Architectural Engineering and Construction Science / Donald J. Phillippi / Special steel moment frames are one of the most common systems used to resist high seismic forces. Well-proportioned moment resisting connections are essential. Special steel moment frame connections must be capable of transferring moment and shear forces that are developed in the beams to the column. These connections must be designed as a highly ductile element in order to dissipate extensive energy thus undergo inelastic deformations. Doubler plates and continuity plates have been recommended by several design codes and standards in order to strengthen the column web and prevent the inelastic deformation of the panel zone due to high shear stress concentrations. However, doubler plates and continuity plates are very expensive due to the large amount of detailing and welding requirements. Furthermore, the extensive welding may affect the properties of the steel in which it may cause shrinkage, lower potential notch toughness and cracking. In any of these cases, there is high potential of losing the desirable inelastic performance required for these SMF. This report investigates the design of the special steel moment frame connections thus eliminating the use of doubler and continuity plates in these connections. Tables are provided that show all steel W-Shape beam sizes with all the adequate steel W-Shape column sizes used in special steel moment frames without the use of doubler and continuity plates in frame connections.

Modern Western Culture (MWC) is based in a materialist and mechanistic ontology that has marginalized spiritual relationality with the natural world. Awe of the Earth once maintained respectful relations between humans and Nature, where shared community existence was a primary concern. Through the rise of the MWC, reverence for the spirit of the Earth has gradually been lost and has altered the way humans situate themselves in the world. Many claim that as the divide between humans and Nature grows, significant barriers to thoughtful and sustainable ways of living have emerged, and reconnecting, or healing this divide is essential in the movement toward environmental sustainability. To address this divide, this research uses the reflective and iterative processes of action research together with feminist post-structural analysis to examine barriers to human-Nature relations at a spiritual level. It explores dominant discourses that act on middle years students and determine what is possible for student-Nature relations in a public school setting. The dominant discourses are embedded in three main themes: role of the city, social acceptance, and technology. Discourses within each theme have been deconstructed, identifying how they are reproduced or disrupted, the implications of adopting the discourses, and how alternatives may be encouraged in school to support spiritual relations with Nature. This research takes a small step toward broadening the possibilities of how people relate with Nature by including spiritual relations with Nature, and begins to erode a clearly identified barrier to achieving sustainability.

Cross frames are critical for the stability of straight and curved steel bridges. Conventional cross frames are often fabricated from steel angles which are welded to gusset plates through one leg only. Due to this eccentric connection, these angles have substantial bending at the connection that can reduce the member stiffness and can potentially decrease fatigue performance. Because of the low buckling strength, cross frames with angle diagonals are often designed as tension-only systems, therefore increasing the necessary steel to be an effective brace. Improved behavior may result if concentric members are utilized. The increased buckling strength of tubes and double angles results in effective members in both compression and tension, and a single diagonal cross frame can provide effective bracing; however, a suitable connection must be developed. Tubes are often connected by slotting the tube in the center and welding to a gusset plate, which requires precise fabrication. Two proposed solutions that would connect easily to the ends of the member and seal the end of the tube include a steel casting and a T-stem connection. The dissertation studies the development of a steel casting for use in cross frame design and evaluates the performance of the various details described herein in regards to stiffness, strength, and fatigue. Additionally, the dissertation covers the behavior of single angle X and K frame configurations. To date, the determination of the single angle fatigue detail has been largely based on component tests only. The project incorporated full-scale cross frame fatigue tests to fully examine the interaction of the cross frame members with the overall structure. Results from currently used details and proposed connections provide insight to the live load behavior of these braces and multiple recommendations are made to improve the fatigue life. The project examined the stiffness behavior of current and proposed cross frame layouts with large-scale laboratory tests and computational modeling. From these results, a case study compares the fatigue analysis of a commercial structural software package to the stress ranges obtained in a three-dimensional finite element model. Suggestions on how to properly model the cross frames are given. / text

My mission is to bring attention to the unusual, undefined, and fluid connections we have to objects through various avenues of experience. Things, objects, and devices have shaped our culture, environment, and personal philosophies. We live, grow, learn, and mourn with objects. We worship, sympathize, and relate to objects. But what I am most interested in is a human tendency to retreat to objects, allowing them to mediate experiences of friendship and intimacy between people. During my graduate studies, I have been evaluating my personal and professional connections with others in order to understand how technology such as smart phones and computers have become so intertwined in these relationships.