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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

[en] COMPOSITE SLAB SYSTEM FOR RESIDENTIAL CONSTRUCTIONS USING COLD FORMED STEEL PLATES WITH EMBOSSMENTS / [pt] SISTEMA DE LAJE-MISTA PARA EDIFICAÇÕES RESIDENCIAIS COM O USO DE PERFIS EMBOSSADOS DE CHAPA DOBRADA

JULIANA DA CRUZ VIANNA 29 August 2005 (has links)
[pt] Nos trabalhos já concluídos nesta linha de pesquisa foram desenvolvidos protótipos de deck-metálico (steel-deck), empregando-se diversas formas de ligação entre a chapa de aço e o concreto armado, tais como: corrugações de alma (Andrade, 1986), parafusos auto-brocantes (Takey, 2001), septos em perfís tipo bandeja (Vieira, 2003) e corrugações circulares profundas (Beltrão,2003). Com a intenção de se desenvolver um novo perfil metálico que apresentasse uma boa aderência mecânica entre o concreto e o aço e com características de comportamento dúctil, estudou-se várias formas da seção transversal ideal. Variáveis como peso, altura, espessura, tensão de escoamento, vão máximo, e capacidade de suporte de carga foram consideradas. Após definição e otimização da seção do perfil metálico, foi efetuado um estudo experimental composto de uma série de ensaios. Foram executados dois ensaios de arrancamento (pull-out), nove ensaios de flexão do perfil metálico e um ensaio em escala real da laje mista. Os ensaios tipo pull-out foram executados para estabelecer a carga última de deslizamento na interface aço/concreto. Os ensaios dos perfis metálicos serviram para verificar a rigidez dos mesmos durante a fase de concretagem. Procurou-se com o ensaio em escala real determinar a resistência última da estrutura, o modo de ruína, as deflexões e as deformações. A fase final compreendeu a comparação dos resultados experimentais com os dos trabalhos desenvolvidos por Takey e Beltrão, bem como com resultados teóricos para validação de resultados do sistema proposto de laje mista. / [en] The research work in composite slabs so far conducted has investigated various alternatives for the development of an economic and efficient composite slab system. These alternatives evaluated the effectiveness of the concrete to steel plate bonding by means of: web corrugations (Andrade, 1986), self-drilling bolts (Takey, 2001), cold formed channel sections with diaphragms (Vieira, 2003), and the used of deep circular corrugations, (Beltrão, 2003). The present investigation main objective was to develop a cold formed profile presenting an efficient connection between the concrete and the steel profile that yields a ductile behaviour for such system. The first step of the investigation was devoted to the assessment of an optimum cold-formed profile geometry. This task was made taking into account parameters like: profile weight, plate thickness, yield stress, maximum span and load carrying capacity among others. Following the definition of the optimum cold formed steel profile an experimental program was conceived and executed. The first part of the experiments consisted on pull-outs tests made to access the concrete to steel bond resistance. This was followed by simple supported tests on the cold formed steel profile to evaluate their stiffness during concrete casting operation. Finally a full-scale composite slab system was performed. The main aim of this test was to determine the composite system load carrying capacity, typical failure modes, associated stresses and displacements. The final phase of this dissertation depicts comparisons of the already mentioned experiments to other tests made by Takey (Takey, 2001), and Beltrão (Beltrão, 2003), as well as comparison of theoretical results, to validate the proposed composite slab system results.
22

Leveraging Lessons from Earth to Space: Failure Analysis Framework Based on the Notion of "Embedded Pathogens” for Designing and Building Safe Extraterrestrial Systems

Takaharu Igarashi (19734085) 25 September 2024 (has links)
<p dir="ltr">The deep human drive to explore and inhabit new frontiers underpins the emerging field of space architecture, as evidenced by the proliferation of diverse design concepts and growing momentum in extraterrestrial construction. However, the endeavor of building off-world environments remains in its infancy, facing numerous challenges due to remoteness, novelty, complexity, and other inherent characteristics. Significant technical and methodological gaps exist between visionary designs and the practical engineering and management intricacies of complex projects. These gaps must be addressed to overcome the challenges in extraterrestrial construction.</p><p dir="ltr">The field is limited by the scarcity of both failures and successes in extraterrestrial construction from which to draw lessons. Furthermore, the understanding of construction system failures is constrained by the limited application of systems perspectives in construction safety literature. Existing accident causation models in system safety literature are ill-suited for describing construction system failures.</p><p dir="ltr">The overall objective of this research is to inform the planning and design of extraterrestrial construction to mitigate the risk of building and installing defective systems in space. To achieve this goal, the research process followed iterative cycles of failure case studies, extracting insights through the lens of a new accident causation model. The cycles of model application evolved through three major stages: (1) developing a model specifically tailored to construction system failures, (2) deriving concepts and principles for interpreting the model depictions, and (3) compiling lessons from a systematically selected set of failure cases for planners, designers, and key stakeholders of future extraterrestrial construction projects.</p><p dir="ltr">Following a comprehensive literature review, this study developed an accident model termed the framed-and-layered accident pathogen propagation (FLAPP) model. The basic concept of the model consists of frames representing the temporal dimension, layers depicting the hierarchical aspects of the sociotechnical framework of construction projects, and graphical notation illustrating the sequence of defective processes and pathogens embedded in the constructed artifact.</p><p dir="ltr">To interpret the graphical illustrations of failure cases, the study introduced the concept of pathogen threads to describe multiple sequences of defective processes ultimately interacting with the physical artifact. To further explain the underlying mechanisms of how design decisions incubate into system failures, the concept of design-induced strains was proposed. This concept represents the lingering effects that design solutions can have on physical artifacts and downstream organizational processes. Additionally, categories of inadequate organizational factors from the Human Factors Analysis and Classification System (HFACS) were incorporated to explain the underlying causes within project organizations that allowed the mishandling of physical and organizational strains.</p><p dir="ltr">To evaluate the applicability of the FLAPP model and observe general trends in system failures across various contexts, the study selected failure cases attributable to embedded pathogens with sufficient available information. Ensuring that the case set included diverse cases and covered all specific technical challenges of extraterrestrial construction, the selection resulted in a set of 40 cases comprising 10 space systems, 13 buildings, 10 bridges and tunnels, and 7 systems in specialized environments. Results highlighted typical and exceptional cases among different systems and the general trends of occurrence prevalence of concept instances among different system contexts (space, building, bridge/tunnel, specialized environment) and duration ranges (short, medium, long). The comparison of Earth-based and space-based systems revealed several critical questions for the space domain: how to ensure, maintain, and improve the reliability and quality of unique and site-specific systems; how to establish and enforce minimum quality standards to reduce unintended physical strains; and how to prepare for extended project timelines with dynamic and transient organizational networks.</p><p dir="ltr">Future research should address the theoretical and methodological limitations of the FLAPP model by extending it to investigation methods and risk assessment techniques. Additionally, the failure case study approach should be enhanced by expanding the case set, exploring source documents, and applying additional analysis approaches. This dissertation concludes by demonstrating that guidance and principles with discipline-specific vocabulary can be derived by referencing documented best practices in systems engineering and project management.</p><p><br></p>
23

Implementering av transportkoordinationssystem i byggsektorn: utmaningar och strategier

Persson, Jacob January 2024 (has links)
Ett effektivt informationsflöde är väsentligt för att skapa möjligheter till väl fungerande transportkoordination. Utmaningen i byggbranschen är att det finns flera aktörer som behöver ta del av informationen. Systemen som används i dagsläget har sällan möjlighet att dela information med varandra. Den bristande informationsdelningen har lett till en fragmenterad försörjningskedja vilket påverkar projektens produktion negativt.   Tidigare studier har tydliggjort behovet av digitala verktyg för styrning av försörjningskedjan inom byggprojekt. Andra studier har identifierat problem vid implementation av nya rutiner och digitala verktyg i byggbranschen. Därmed finns det ett behov av att undersöka hur företag framgångsrikt kan implementera digitala verktyg för att underlätta informationsdelning och transportkoordination.  Målet med studien har varit att definiera transportkoordinationssystem, samt analysera och undersöka vilka strategier byggherrar kan tillämpa för en effektiv implementering i byggsektorn. Syftet är att identifiera de bakomliggande hinder som begränsar företagen att använda systemen. Utifrån begränsningar och lösningar görs rekommendation för vilka strategier som bör användas.   Studien har utförts som en flerfallsstudie på större husbyggnationsprojekt i Sverige och Norge. I fallstudien ingick sju projekt, där samtliga använt sig av ett transportkoordinationssystem under produktion. Transportkoordinationssystemet har använts i olika utsträckning i varje projekt, beroende på hur logistiklösningen var utformad. Datainsamling genomfördes med semi-strukturerad intervjustudie där minst en representant från vart projekt medverkade. Utöver respondenterna från byggprojekten inkluderades även intervjuer med två konkurrerande mjukvaruutvecklare.   En analys av effekten av logistiklösningen i de olika projekten, och framför allt transportkoordinationssystemets påverkan har genomförts. Det har varit av stor vikt att särskilja det digitala verktygets påverkan från den generella logistiklösningens påverkan. Från respondenterna har det framkommit tydligt att olika strategier vid implementation har haft varierande mottagande i produktionen.   Studien har identifierat tre nyckelfaktorer som ligger till grund för strategier vid implementationen av digitala verktyg:  <li data-leveltext="" data-font="Symbol" data-listid="5" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="1" data-aria-level="1">Kravställning - Förutsättningarna för projektet måste framgå tydligt i ett tidigt skede. Om beställaren sätter krav på huvudentreprenören blir implementationen smidigare, då under-leverantörer och -entreprenörer måste anpassa sig för att vinna kontrakten.  <li data-leveltext="" data-font="Symbol" data-listid="5" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="2" data-aria-level="1">Integration - Då det förekommer många aktörer på projekten behöver man ha möjlighet att integrera systemet med redan befintliga.   <li data-leveltext="" data-font="Symbol" data-listid="5" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="3" data-aria-level="1">Incitament - För att främja användningen kan man med fördel använda bonussystem, som gynnar aktörerna som använder systemet. Allt fler aktörer kommer därmed få positiva erfarenheter av systemet vilket kan underlätta en bredare implementation.   Tidigare studier har beskrivit att byggherrarna inte tidigare fokuserat på bygglogistik. Studien har bekräftat att det i viss mån fortfarande är så, då logistiklösningar främst utformas vid större projekt. Från respondenterna har det framkommit att mindre projekt inom samma byggkoncern inte har samma resurser eller fokus på bygglogistik. Samtidigt kan de större projekten fungera som pilotprojekt, och ligga till grund för en bredare implementation. / An effective flow of information is essential to create opportunities for well-functioning construction logistics. One of the challenges in the construction industry is the number of stakeholders who need access to the information. The systems currently in use often lack the ability to share information with each other. This lack of information sharing has led to a fragmented supply chain, which negatively impacts projects performance.   Previous studies have highlighted the need for digital tools to coordinate the construction logistics in projects. Other studies have identified problems with implementing new procedures and digital tools in the construction sector. Therefore, there is a need to investigate how companies can successfully implement digital tools to facilitate information sharing and transport coordination.   The aim of the study has been to define transport coordination systems. Furthermore, analyze and investigate the strategies that can be applied for effective implementation in the construction sector. The purpose is to identify the underlying obstacles that limit companies from using these systems and provide recommendations for strategies to overcome these limitations.   The study was conducted as a multiple case study on large construction projects in Sweden and Norway. Seven projects were included in the case study, all of which utilized a transport coordination system during production. The extent of use of the system varied in each project depending on the logistics solution. The data collection was done through semi-structured interviews with at least one representative from each project participating. In addition to the respondents from the construction projects, interviews were also conducted with two competing software developers.   An analysis of the impact of the logistics solution in different projects was conducted, which focused on the impact the transport coordination system had. It has been crucial to distinguish the impact of the digital system from the general logistics solution. Respondents have clearly indicated that different strategies have had varied acceptance in production.   The study has identified three key factors underlying strategies for implementing digital tools:  <li data-leveltext="" data-font="Symbol" data-listid="4" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="4" data-aria-level="1">Requirement specification – The project’s requirements must be clearly stated at an early stage. If the client sets requirements for the main contractor, the implementation becomes smoother as subcontractors and suppliers must adapt to win the contracts.   <li data-leveltext="" data-font="Symbol" data-listid="4" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="5" data-aria-level="1">Integration – Since there are many stakeholders involved in projects, there is a need to be able to integrate the system with existing ones.   <li data-leveltext="" data-font="Symbol" data-listid="4" data-list-defn-props="{&quot;335552541&quot;:1,&quot;335559685&quot;:720,&quot;335559991&quot;:360,&quot;469769226&quot;:&quot;Symbol&quot;,&quot;469769242&quot;:[8226],&quot;469777803&quot;:&quot;left&quot;,&quot;469777804&quot;:&quot;&quot;,&quot;469777815&quot;:&quot;hybridMultilevel&quot;}" aria-setsize="-1" data-aria-posinset="6" data-aria-level="1">Incentives – To promote usage, a bonus system can be beneficial, favoring actors who use the system correctly. As more actors have a positive experience with the system, it can facilitate broader implementation.   Previous studies have described how developers have not previously focused on construction logistics. The study confirmed that to some extent this is still the case, as logistics solutions are primarily designed for larger projects. Respondents have indicated that smaller projects within the same company do not have the same resources or focus on construction logistics. Hopefully larger projects can serve as pilot projects and form the basis for broader implementation.
24

Simulace revitalizace panelového domu se záměrem dosažení mezinárodního certifikátu pro výstavbu budov / Simulation of renovation of block-of-flats building with a focus on gaining an international certificate for building construction

Balúch, Tomáš January 2019 (has links)
The aim of this diploma thesis is to revitalize the selected type of panel house in the selected locality in order to meet the standards of international certification for the design and sustainable construction of buildings. First, the thesis analyzes the chronological development of the panel housing estates in Brno and compares the individual structural systems that were historically used for panel construction in Brno. Furthermore, the most used certification methodologies are compared and a specific certification is selected for next simulation. The chapter called solution is focused on performing a simulated certification process for design and sustainable construction of selected panel building, in three phases of its revitalization. The hypotheses describing the individual phases of revitalization are intended to confirm or disprove the achievement of this objective, moreover to say the extent of revitalization that has to be done in order to achieve our goals.

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